Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management [1 ed.] 9781617619106, 9781608762699

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Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael Rios,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

AGRICULTURE ISSUES AND POLICIES SERIES

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

SUSTAINABLE AGRICULTURE: TECHNOLOGY, PLANNING AND MANAGEMENT

No part of this digital document may be reproduced, stored in a retrieval system or transmitted in any form or by any means. The publisher has taken reasonable care in the preparation of this digital document, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained herein. This digital document is sold with the clear understanding that the publisher is not engaged in rendering legal, medical or any other professional services.

Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

AGRICULTURE ISSUES AND POLICIES SERIES Agriculture Issues & Policies, Volume I Alexander Berk (Editor) 2001. ISBN 1-56072-947-3

Hired Farmworkers: Profile and Labor Issues Rea S. Berube (Editor) 2009. ISBN 978-1-60741-232-8

Agricultural Conservation Anthony G. Hargis (Editor) 2009. ISBN 978-1-60692-273-6

Agricultural Wastes Geoffrey S. Ashworth and Pablo Azevedo (Editors) 2009. ISBN: 978-1-60741-305-9

Agricultural Conservation Anthony G. Hargis (Editor) 2009. ISBN 978-1-60876-813-4 (Online Book)

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Environmental Services and Agriculture Karl T. Poston (Editor) 2009. ISBN: 978-1-60741-053-9 Weeds: Management, Economic Impacts and Biology Rudolph V. Kingely (Editor) 2009. ISBN 978-1-60741-010-2 Soybean and Wheat Crops: Growth, Fertilization and Yield Samuel Davies and George Evans 2009. ISBN: 978-1-60741-173-4 Effects of Liberalizing World Agricultural Trade Henrik J. Ehrstrom (Editor) 2009. ISBN: 978-1-60741-198-7 Effects of Liberalizing World Agricultural Trade Henrik J. Ehrstrom (Editor) 2009. ISBN: 978-1-60876-601-7 (Online Book)

Sugar Beet Crops: Growth, Fertilization & Yield Claus T. Hertsburg 2009. ISBN: 978-1-60741-491-9 Economic Impacts of Foreign-Source Animal Disease Jace R. Corder (Editor) 2009. ISBN: 978-1-60741-601-2 Economic Impacts of Foreign-Source Animal Disease Jace R. Corder (Editor) 2009. ISBN: 978-1-60876-602-4 (Online Book) Essential Oils: Art, Agriculture, Science, Industry and Entrepreneurship (A Focus on the Asia-Pacific Region) Murray Hunter 2009. ISBN: 978-1-60741-865-8 Corn Crop Production: Growth, Fertilization and Yield Arn T. Danforth 2009. ISBN: 978-1-60741-955-6

Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

Corn Crop Production: Growth, Fertilization and Yield Arn T. Danforth 2009. ISBN: 978-1-60876-860-8 (Online Book)

Drivers and Restraints for Economically Efficient Farm Production Helena Hansson Karin Larsén Bo Öhlmér 2010. ISBN: 978-1-60876-171-5

Phosphate Solubilizing Microbes for Crop Improvement Mohammad Saghir Khan and Almas Zaidi (Editors) 2009. ISBN: 978-1-60876-112-8

Agriculture and Food Claus Schäfer 2010. ISBN: 978-1-60692-038-1

Organic Food - Economics and Issues Earl D. Straub (Editor) 2009. ISBN: 978-1-60741-130-7 Global Beef Trade Alessandro Ferrara (Editor) 2009. ISBN: 978-1-60741-121-5

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Ecophysiology of Tropical Tree Crops Fabio DeMatta (Editor) 2010. ISBN 978-1-60876-392-4 Assessing Disease Potential in U.S. Aquaculture Industry Emilija Kalnins (Editor) 2010. ISBN: 978-1-60741-543-5 Inspection and Protection of U.S. Meat and Poultry Finn J. Amundson (Editor) 2010. ISBN: 978-1-60741-120-8

Agriculture Research and Technology Kristian Bundgaard and Luke Isaksen (Editors) 2010 ISBN: 978-1-60741-850-4 Agricultural Economics: New Research Tomas H. Lee (Editor) 2010. ISBN: 978-1-61668-077-0 U.S. Biobased Products Market Potential and Projections through 2025 Meredith A. Williamson 2010 ISBN: 978-1-60741-033-1 The Sugar Industry and Cotton Crops Peter T. Jenkins (Editor) 2010. ISBN: 978-1-61668-320-7

Soil Phenols A. Muscolo and M. Sidari (Editors) 2010. ISBN: 978-1-60876-264-4

Tomatoes: Agricultural Procedures, Pathogen Interactions and Health Effects Eric D. Aubé and Frederick H. Poole (Editors) 2010. ISBN: 978-1-60876-869-1

No-Till Farming: Effects on Soil, Pros and Cons and Potential Earl T. Nardali (Editor) 2010. ISBN: 978-1-60741-402-5

Organic Farming and Peanut Crops Darren C. Grossman and Terrance L. Barrios (Editors) 2010. ISBN: 978-1-60876-187-6

Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

Farm Bill of 2008: Major Provisions and Legislative Action Mary T. Conner (Editor) 2010. ISBN: 978-1-60741-750-7

Governance of Agrarian Sustainability Hrabrin Bachev (Author) 2010. ISBN: 978-1-60876-888-2

America's Family Farms Efren J. Tamayo (Editor) 2010. ISBN: 978-1-60741-751-4

Transformation of U.S. Animal Agriculture Justin M. Daigle (Editor) 2010. ISBN: 978-1-60876-938-4

Pesticide Resistance, Population Dynamics and Invasive Species Management Gregory J. McKee, Colln A. Carter, James A. Chalfant, Rachael E. Goodhue, and Frank G. Zalom 2010. ISBN: 978-1-60741-758-3

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Rethinking Structural Reform in Turkish Agriculture: Beyond the World Bank's Strategy Baris Karapinar, Fikret Adaman and Gokhan Ozertan (Editors) 2010. ISBN: 978-1-60876-718-2 Manure Use for Fertilizer and Energy Connor D. Macias (Editor) 2010. ISBN: 978-1-60876-847-9

The Peanut Plant and Light: Spermidines from Peanut Flowers Victor S. Sobolev, James B. Gloer and Arlene A. Sy 2010. ISBN: 978-1-61668-028-2 Agriculture and Environmental Security in Southern Ontario's Watersheds Glen Filson, Bamidele Adekunle, and Katia Marzall 2010. ISBN: 978-1-61668-156-2 Sustainable Agriculture: Technology, Planning and Management Augusto Salazar and Ismael Rios (Editors) 2010. ISBN: 978-1-60876-269-9

Price Dynamics behind Consumer Food Purchases Morgan D. Fitzpatrick (Editor) 2010. ISBN: 978-1-60876-892-9

Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

AGRICULTURE ISSUES AND POLICIES SERIES

SUSTAINABLE AGRICULTURE: TECHNOLOGY, PLANNING AND MANAGEMENT

AUGUSTO SALAZAR Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

AND

ISMAEL RIOS EDITORS

Nova Science Publishers, Inc. New York

Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

Copyright © 2010 by Nova Science Publishers, Inc.

All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic, tape, mechanical photocopying, recording or otherwise without the written permission of the Publisher. For permission to use material from this book please contact us: Telephone 631-231-7269; Fax 631-231-8175 Web Site: http://www.novapublishers.com NOTICE TO THE READER The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers‘ use of, or reliance upon, this material.

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Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA Sustainable agriculture : technology, planning and management / editors: Augusto Salazar and Ismael Rios. p. cm. Includes bibliographical references and index. ISBN:  (eBook) 1. Sustainable agriculture. I. Salazar, Augusto. II. Rios, Ismael. S494.5.S86S877 2010 630--dc22 2009042170

Published by Nova Science Publishers, Inc.  New York Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

CONTENTS Preface Chapter 1

Sustainable Greenhouse Systems Giuliano Vox, Meir Teitel, Alberto Pardossi, Andrea Minuto, Federico Tinivella and Evelia Schettini

1

Chapter 2

Mechanisms of Governance of Agrarian Sustainability Hrabrin Bachev

81

Chapter 3

The Role of Plant Genetic Resources in the Sustainable Agriculture J.B. Alvarez, M.A. Martín, L. Caballero and L.M. Martín

Chapter 4 Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

ix

Phytotoxins Produced by Fungi Responsible for Forestall Plant Diseases Antonio Evidente, Anna Andolfi, Alessio Cimmino and Mohamed A. Abouzeid

145

177

Chapter 5

Rethinking the Notion of ‗Multifunctional Agriculture Geoff A. Wilson

Chapter 6

The Sustainability of Cotton Production in China and in Australia: Comparative Economic and Environmental Issues 265 Xufu Zhao and Clem Tisdell

Chapter 7

Role of Plant Rhizosphere-Associated Fluorescent Pseudomonads in Sustainable Agriculture P. Ravindra Naik, G. Raman and N. Sakthivel

Chapter 8

The Survival of Small-Scale Agricultural Producers in Asia, Particularly Vietnam: General Issues Illustrated by Vietnam‘s Agricultural Sector, Especially Its Pig Production Clem Tisdell

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291

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viii Chapter 9

Chapter 10

Chapter 11

Chapter 12

Chapter 13

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Chapter 14

Contents The Biochar Approach: A Complementary Use of Waste Biomass for Renewable Energy Production, Carbon Sequestration and Soil Fertility Enhancement Christoph Steiner Control Methods for Reducing Nitrate Accumulation in Vegetables Cultivated Soilless under Protected Conditions: A Review Wenke Liu and Qichang Yang Sustainable Use of Waste Chicken Feather for Durable and Low Cost Building Materials For Tropical Climates Menandro N. Acda Role of Plant Growth-Promoting Bacteria in Sustainable Agriculture Fábio Fernando de Araújo, Ademir Sérgio Ferreira de Araújo and Márcia do Vale Barreto Figueiredo Chromosomal Integration and Heterologous Expression of the Morganella Morganii phoC Gene in Pseudomonas Putida N-14 Reinaldo H. Fraga Vidal, Hilda Rodríguez Mesa, Tania González Díaz de Villegas Talking to Each Other through Volatile Organic Compounds and Living Together: A Natural Engagement that Helps Sustainable Agriculture Daniela Minerdi and Marino Moretti

Index

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PREFACE Sustainability is defined as the use of natural resources without risking their exploitation by future generations. Agriculture can only be considered as sustainable if it includes a suitable system of plant genetic resources conservation. In this book, the modern concepts of agricultural sustainability and the economics of agricultural sustainability are discussed. A new framework for analysis and improvement of the governance of agrarian sustainability is presented. In addition, specific modes for environmental governance in Bulgarian agriculture are identified and the efficiency of market, private and public modes are assessed. Furthermore, the regulation measures through nutrient solution regulation and environmental control on nitrate accumulation in vegetables are summarized, highlighting the control strategy. Arguments for and against government strategies to promote large-scale agricultural units in emerging economies are also analyzed and an economic theory that models agricultural supply in emerging economies is presented. Other chapters in this book describe the role of fluorescent pseudomonads in soil fertility, biodegradation of agricultural pollutants, plant growth-promotion, biocontrol of weeds, phytopathogens and nematodes. Information about the global relevance of China's and Australia's cotton industries are also given, and the structure and other significant features of their cotton industries are compared. The main characteristics and importance of plant growth-promoting bacteria in sustainable agriculture in tropical agriculture are looked at as well. Developing alternative ways to control plant disease, with good agronomic and horticultural practices is becoming the focus of many researchers. This book also includes information on ways to control plant diseases in order to maintain the quality and abundance of food produced by growers around the world. Chapter 1 - Greenhouse systems improve growing conditions of vegetable, fruit and ornamental crops. Greenhouse coverage protects plants from adverse atmospheric agents and, together with suitable equipment, influences and ultimately modifies the crop microclimate, thus lengthening the market availability of the products, improving their quality and allowing higher yields. Greenhouse production has a higher return per unit area than crops grown in the open field, but it requires the use of large amounts of energy to operate the equipment on one hand and generates huge quantities of wastes to be disposed of on the other hand. Protected cultivation can be environmentally unfriendly, especially in areas with a large concentration of greenhouses. Therefore, the steady worldwide increase in the area covered by greenhouses has generated the need for developing sustainable protected horticulture. Sustainable greenhouse horticulture can be achieved by means of different cultivation techniques, adequate equipment management and innovative materials aimed to reduce agro-chemicals

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and energy use, water consumption and waste generation. The achievement of optimal greenhouse microclimate conditions, the application of integrated pest management strategies and the use of innovative closed-loop fertigation systems with water recycling result in a significant reduction of plant diseases—and, consequently, of agro-chemicals use—and in a decrease in the consumption of both water and fertilisers as well as in the contamination of water bodies associated with nutrient leaching. Optimal climate control and reduction of energy consumption can be obtained by using suitable active and passive systems including proper control strategies for equipment and the use of innovative covering materials. Renewable energy sources and technologies, such as solar thermal and photovoltaic systems, can be used to reduce fossil fuel consumption for climate control. Waste generation mainly concerns the use of materials such as covering and mulching plastic films that must be disposed of at the end of their life; the introduction of innovative biodegradable materials can reduce this kind of waste, improving crop sustainability. The chapter presents the design concepts of greenhouse sustainable systems based on the application of innovative covering materials, microclimate control strategies, renewable energy sources and the use of leading technologies. In addition, it considers fertigation and integrated pest management strategies that may contribute to sustainable operations. Chapter 2 - In this paper the authors incorporate the interdisciplinary New Institutional and Transaction Cost Economics (combining Economics, Organization, Law, Sociology, Behavioral and Political Sciences), and suggest a framework for analyzing the mechanisms of governance of agrarian sustainability. Firstly, the authors discuss the modern concepts of agricultural sustainability and the economics of agricultural sustainability. Secondly, the authors present a new framework for analysis and improvement of the governance of agrarian sustainability. This new approach takes into account the role of a specific institutional environment; and the behavioral characteristics of individual agents; and the transaction costs associated with the various forms of governance; and the critical factors of agrarian activity and exchanges; and the comparative efficiency of market, private, public and hybrid modes; and the potential of farming structures for adaptation; and the comparative efficiency of alternative modes for public intervention. Finally, the authors identify specific modes for environmental governance in Bulgarian agriculture; and access the efficiency of market, private and public modes; and estimate the prospects for evolution of environmental governance in the conditions of EU CAP implementation. Agrarian development is associated with specific (different from other European states) environmental challenges such as degradation and contamination of farmland, pollution of surface and ground waters, loss of biodiversity, significant greenhouse gas emissions etc. That is a result of the specific institutional and governing structure evolving in the sector during the past 20 years. Implementation of the common EU policies will have unlike results in ―Bulgarian‖ conditions enlarging income, technological, social and environmental discrepancy between different farms, sub-sectors and regions. Dominating subsistence farming, production cooperatives, small-scale commercial farms, and large business firms will be highly sustainable in years to come. Chapter 3 - The sustainability is defined as the use of natural resources without risking their exploitation by future generations. Agriculture can only be considered as sustainable if it includes a suitable system of plant genetic resources conservation. Modern agriculture has caused a drastic reduction of fields‘ biodiversity. Over the last four decades, considerable

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Preface

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efforts in collecting, characterizing and conserving crops genetic diversity have been carried out, although for minor crops this conservation has been sensitively lower. The genetic resources of the crops include both the old and neglected varieties and the relative species. The conservation of plant genetic resources can be achieved by different ways: ex-situ conservation, in-situ conservation and on-farm conservation. This last type of conservation has increasing attention, since conserves the dynamic process of crop evolution and includes the traditional knowledge associated with its use. Our group is working in the evaluation and characterization of on-farm conservation systems in Spain, both on neglected crops and agroforestry crops. Among the neglected crops, the hulled wheats (einkorn, emmer and spelt) present a new revival in diverse regions of the World. In Spain, spelt continues being cultivated in Asturias (Northern of Spain) where it is associated to traditional and sustainable agricultural systems. Other crop with traditional management and use in Spain is the chestnut, which is associated to regions with special environmental interest (Natural Parks). Our studies have indicated that both cases are valued systems of on-farm conservation. The recognition of this fact could allow increasing the economic and social sustainability of these traditional agricultural systems. Chapter 4 - Toxins produced by phytopathogenic fungi have assumed great importance because of their involvement in several plant diseases. These pathogens have seriously damaged plants of agrarian, forestall and environmental interest. Several studies have been carried out to understand the role of bioactive microbial metabolites in pathogenesis and therefore to use them against specific diseases. This manuscript will describe the chemical and biological characterization of the phytotoxins produced by fungus Sphaeropsis sapinea f.sp. cupressi, the causal agent of canker disease of cypress in the Mediterranean basin, and by fungal species belonging to Diplodia, Biscognauxia and Sphaeropsis genera, which are widely spread in the Sardinian oak forests, and are considered one of the main causes of cork oak (Quercus suber L.) and pine (Pinus radiata) decline with important social and economical implications. Chapter 5 - The debate surrounding the notion of ‗multifunctional agriculture‘ is gathering speed. This has assumed greater importance as global agriculture is facing renewed pressures for intensification based on rising demand for agricultural commodities and biofuel production. European and American debates on agricultural change intertwine, especially with regard to calls for a more environmentally sustainable agriculture, highlighting similarities in changing nature-society interactions across cultural and geographical divides. This article addresses the issue of agricultural change from a conceptual perspective. It suggests that agricultural change can be understood as occurring along a spectrum of decision-making bounded by the ‗extreme‘ spaces of ‗productivism‘ and ‗non-productivism‘, and anchors the notion of ‗multifunctional agriculture‘ within this spectrum of decisionmaking. The article suggests that this enables a normative view of multifunctionality based on strong, moderate and weak multifunctional agricultural pathways. Building on work by human geographers and other social scientists, this normative view challenges often simplistic policy-based and economistic conceptualisations of multifunctionality. The article argues that the multifunctionality spectrum provides a robust framework with which to understand agricultural change in any location, and suggests that ‗strong‘ multifunctionality should be the type of multifunctionality that agricultural stakeholders and policy-makers should be striving for. The article concludes by cautioning that many research challenges lie ahead, in particular as future methodologies for assessing multifunctional quality need to move away from

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absolute and ‗measurable‘ indicators and, instead, adopt more qualitative approaches to assess subtle attitudinal and identity-related shifts that form crucial components of the multifunctionality spectrum. Chapter 6 - After providing some background about the importance of cotton as a fibre, this article provides information about the global relevance of China‘s and Australia‘s cotton industries and compares the structure and other significant features of their cotton industries. Attention is given to trends in overall cotton yields and the volume of production of cotton globally, in Australia, and in China as indicators of the sustainability of cotton supplies. Some simple economic theory is applied to indicate the relationship between market conditions and the sustainability of global cotton supplies. Then the environmental and economic factors that challenge the sustainability of Australian cotton production are outlined and analysed and this is done subsequently for China‘s cotton production. Geographical and regional features that affect the sustainability of cotton supplies in Australia and China are given particular attention. Some new economic theory is proposed to model hysteresis in Australia‘s supplies of cotton. Ways of coping with the sustainability difficulties that are being encountered by both these nations are compared. Many of the sustainability challenges facing these two countries are found to differ but some of their environmental obstacles to sustainable cotton production are similar. Chapter 7 - Fluorescent pseudomonad group of bacteria are often predominant among bacterial species associated with the plant rhizosphere. This group of bacteria has innate traits of bacterial fitness in soil such as the ability to adhere to soil particles and to the rhizoplane, motility and prototrophy, synthesis of antibiotics, production of hydrolytic enzymes, and synthesis of hormones. Fluorescent pseudomonad bacteria have the capability to suppress disease severities and enhance growth of crop plants. In addition, fluorescent pseudomonads play a vital role in inducing systemic resistance in crop plants against pathogens and also known for their participation in bioremediation of soil pollutants. This chapter describes the role of fluorescent pseudomonads in soil fertility, biodegradation of agricultural pollutants, plant growth-promotion, biocontrol of weeds, phytopathogens and nematodes. Chapter 8 - Economic growth in more developed countries has resulted in farms increasing their scale of production and becoming more specialized in their production. The sizes of farms have tended to increase, agricultural production has become more capitalintensive, and the percentage of the workforce employed in agriculture has shown a falling trend. This process has been brought about by the operation of market systems and has reduced the number of small-scale agricultural producers. Asia still has a huge number of small-scale agricultural producers. As Asian countries experience economic growth and as market systems become more established in Asia, the survival of Asia‘s small-scale agricultural producers is likely to be threatened. Since these producers are poor, this is of concern to several international aid agencies. On the other hand, some Asian governments (such as Vietnam‘s) want to encourage larger scale agricultural production units. This article presents arguments for and against government strategies to promote large-scale agricultural units in emerging economies and presents an economic theory that models agricultural supply in emerging economics as being dualistic in nature. It provides information about the predominance of small-scale units in agricultural production in Vietnam, particularly in pig production, and assesses policies proposed for by Vietnam‘s Government for increasing the size of units producing pigs.

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Chapter 9 - Extraordinary demands are being placed on agricultural systems to produce food, fiber and energy. Biomass burning and the removal of crop residues reduce carbon in soil and vegetation, which has implications for soil fertility and the global carbon cycle. Pyrolysis of waste biomass generates fuels and biochar (charcoal) recalcitrant against decomposition. The process of pyrolysis or carbonization is known globally. It can be implemented on a small scale (e.g., cooking stove) as well as a large scale (e.g., biorefinery) and in most agricultural systems. Biochar offers unique options to address issues emerging from the conflicts and complementarities between cultivating crops for different purposes, such as for energy or for CO2 sequestration or for food and the impacts on food security, soil degradation, water, and biodiversity. Biochar is proposed as a soil amendment in environments with low carbon sequestration capacity and previously carbon-depleted soils (especially in the Tropics). From recent studies it is known that biochar amendments to soil increase and maintain fertility and the humanmade Terra Preta soils in the Amazon prove that infertile soils can be transformed into fertile soils and long-term SOC enrichment is feasible even in environments with low carbon sequestration capacity. The prospects are to increase the sustainability of land use, establish a large carbon sink, reducing the rate of deforestation and competition between different land use purposes through waste biomass utilization. This chapter reviews the potential of waste biomass utilizations, the importance of the soil organic carbon pool for climate and explains our options to manage this carbon pool by biochar carbon sequestration. Chapter 10 - Vegetables, particularly leafy vegetables, are dominant sources of nitrate intake through dietary pathway for human due to high level nitrate accumulation and large consumption. Today, off-season vegetable production in winter and spring, are usually cultivated under protected conditions worldwide. As a result, more nitrate would be accumulated in vegetables when they were cultured under protected conditions for the weaker inner light intensity. Excessive intake of nitrate will pose potential hazards on human health. Therefore, to develop efficient measures to decrease nitrate content in vegetables before harvest is a hot research issue worldwide in the past more than thirty years. Nowadays, based on our knowledge, it has been realized that nitrate content in vegetables cultivated soilless can be successfully controlled through nutrient solution regulation and environmental factor control. In this paper, the regulation measures through nutrient solution regulation and environmental control on nitrate accumulation in vegetables were summarized, highlighting the control strategy. Chapter 11 - Chicken feathers are waste products of the poultry industry. Billions of kilograms of waste feathers are generated each year by commercial poultry processing plants creating a serious solid waste problem in many countries. Traditional disposal strategies of chicken feathers are expensive and difficult. They are often burned in incineration plants, buried in landfills or recycled into low quality animal feed. These disposal methods are restricted, generate green house gases or pose danger to the environment. Several commercial applications have been explored to utilize fibers from chicken feathers. However, due to the low volume requirements of these products they had not significantly reduced the volume of feathers generated each year. An innovative way to utilize poultry feathers into a novel composite material is to bind them with Portland cement. Recent studies showed that cement

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bonded chicken feather composites (called featherboards) are suitable for non structural applications in low cost housing projects in developing countries. Tests showed that stiffness (MOE), flexural strength (MOR) and dimensional stability of featherboards were slightly lower or comparable to that of commercially available wood-fiber cement board in the market (HardieLite®, HardieFlex Philippines) of similar thickness and density. Cement bonded featherboards had excellent decay (Basidiomycetes) and termite (Coptotermes, Macrotermes, Microcerotermes, Nasutitermes spp) resistance which made them very attractive as construction materials in tropical climates. Despite the need for more research on the use of waste chicken feather as reinforcement in cement bonded composite, it offers an environmentally friendly method of disposing a serious waste product and promotes competitiveness of both the poultry and construction industries. Chapter 12 - Soil is a dynamic, living, no-renewable resource vital to the production of food and fiber and important to global balance and ecosystem function. In the last decades, it has been given importance to biological processes involving soil microorganisms, contributing to maintenance of soil fertility in relation to N and P and reducing the losses of nutrients, by lixiviation or volatilization. The number of soil microorganisms in a fertile soil can exceed nine billion. Thus, soil microbial has an important role in agriculture, mainly plant growth-promoting bacteria. The most studied genera are still those belonging to the aerobic endospore-forming bacteria, including Bacillus spp. and Paenibacillus spp., to Pseudomonas spp. and to the Rhizobiales order, including Rhizobium spp., Bradyrhizobium spp., Mesorhizobium spp. Ensifer spp. and others. In this way, there are several roles of these bacteria on plant growth and yield, mainly in tropical regions. In this chapter, the authors will show the main characteristics and importance of these bacteria in tropical agriculture. Chapter 13 - This work reports the chromosomal insertion of a heterologous gene, encoding an acid phosphatase enzyme, in a putative plant growth-promoting bacterium. The phoC gene from Morganella morganii was subcloned in the suicide delivery vector pJMT6 (a pUT/mini-Tn5 derivative vector). The recombinant construction pLF17, containing the nonantibiotic resistance selection marker potassium tellurite, was transformed in Escherichia coli CCpir, and further transferred to Pseudomonas putida N-14 for chromosomal integration of the phoC gene. P. putida N-14::Tn5-phoC produces high levels of the enzyme, which is not synthesized in the wild type strain, and provides the recombinant bacterium with the additional capacity to mineralize phosphorus from organic compounds. The original plant growth-promoting traits of Pseudomonas putida N-14 strain are not affected by the heterologous expression of phoC. Chapter 14 - The control of plant diseases is of high priority to maintain the quality and abundance of food produced by growers around the world. Different approaches may be used to prevent, mitigate or control plant diseases. The exceptional improvements in crop productivity and quality over the past 100 years were significantly due to growers‘ heavy use of chemical fertilizers and pesticides. The environmental pollution caused by excessive use of agrochemicals, as well as the increasing public concern for human health, has led to considerable changes in people's attitudes towards the use of pesticides in agriculture. Today, there are strict regulations regarding chemical pesticide use and there is political pressure to remove the most hazardous chemicals from the market. Thus, developing alternative ways to control plant disease, with good agronomic and horticultural practices, is becoming the focus of many researchers. Among these alternatives are those referred to as biological control that involve disease-suppressive microorganisms or biocontrol agents (BCAs) to improve plant

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health. Broadly, disease suppression by BCAs is the sustained manifestation of interactions among plant, pathogen, BCA, the microbial community around the plant, and the physical environment. Microbial interactions via infochemicals are fundamental to the development of spatial distribution and activity variations in ecosystems. Microorganisms produce a wide range of infochemicals, frequently secondary metabolites, many of which are volatile. Volatile organic compounds (VOCs)-mediated interactions can results in functional responses by the organisms involved that result in selective advantage to some community members. Positive, negative or neutral interactions can occur between a wide range of soil bacteria and fungi. In the present commentary the production of bioactive VOCs by two antagonistic fungi, F. oxyporum strain MSA 35 and Muscodor albus, and their potential applications as mycofumigants in sustainable agriculture will be presented and discussed.

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ISBN: 978-1-60876-269-9 ©2010 Nova Science Publishers, Inc.

Chapter 1

SUSTAINABLE GREENHOUSE SYSTEMS Giuliano Vox*1, Meir Teitel2, Alberto Pardossi3, Andrea Minuto4, Federico Tinivella4 and Evelia Schettini1 1

University of Bari, Bari, Italy Agricultural Research Organization, Bet Dagan, Israel 3 University of Pisa, Pisa, Italy 4 Regional Research and Extension Centre for Agriculture (CE.R.S.A.A.) – Special Agency of Chamber of Commerce, Industry, Handicraft and Agriculture of Savona, Albenga (SV), Italy 2

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ABSTRACT Greenhouse systems improve growing conditions of vegetable, fruit and ornamental crops. Greenhouse coverage protects plants from adverse atmospheric agents and, together with suitable equipment, influences and ultimately modifies the crop microclimate, thus lengthening the market availability of the products, improving their quality and allowing higher yields. Greenhouse production has a higher return per unit area than crops grown in the open field, but it requires the use of large amounts of energy to operate the equipment on one hand and generates huge quantities of wastes to be disposed of on the other hand. Protected cultivation can be environmentally unfriendly, especially in areas with a large concentration of greenhouses. Therefore, the steady worldwide increase in the area covered by greenhouses has generated the need for developing sustainable protected horticulture. Sustainable greenhouse horticulture can be achieved by means of different cultivation techniques, adequate equipment management and innovative materials aimed to reduce agro-chemicals and energy use, water consumption and waste generation. The achievement of optimal greenhouse microclimate conditions, the application of integrated pest management strategies and the use of innovative closed-loop fertigation systems with water recycling result in a significant reduction of plant diseases—and, consequently, of agro-chemicals use—and in a decrease in the consumption of both water and fertilisers as well as in the contamination of water bodies associated with nutrient leaching. Optimal climate control and reduction of energy * Department of Engineering and Management of the Agricultural, Livestock and Forest Systems (PROGESA), University of Bari, Via Amendola 165/a, 70126, Bari, Italy. E-mail: [email protected] Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Giuliano Vox, Meir Teitel, Alberto Pardossi et al. consumption can be obtained by using suitable active and passive systems including proper control strategies for equipment and the use of innovative covering materials. Renewable energy sources and technologies, such as solar thermal and photovoltaic systems, can be used to reduce fossil fuel consumption for climate control. Waste generation mainly concerns the use of materials such as covering and mulching plastic films that must be disposed of at the end of their life; the introduction of innovative biodegradable materials can reduce this kind of waste, improving crop sustainability. The chapter presents the design concepts of greenhouse sustainable systems based on the application of innovative covering materials, microclimate control strategies, renewable energy sources and the use of leading technologies. In addition, it considers fertigation and integrated pest management strategies that may contribute to sustainable operations.

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1. INTRODUCTION Greenhouse cultivation is the most intensive form of crop production with a yield per cultivated unit area up to 10 times superior to that of a field crop. Vegetable, ornamental and fruits crops are cultivated worldwide under greenhouse conditions. Greenhouse equipment and covering material provide a controlled microclimate that may be adapted to the needs of the crops, resulting in higher yield, quality and in the lengthening of the market availability of the products. Greenhouse production requires the use of large amounts of energy, water and agro-chemicals, and it usually generates huge quantities of wastes to be disposed of. Investment, labour and energy costs per unit area are much larger in the greenhouse industry than in any other agricultural sector. Gafsi et al. (2006) have defined sustainable agriculture as ―the ability of farming systems to continue into the future‖; i.e., sustainable agriculture means a ―maintenance of the adaptive capacity of farming systems‖, which allows preserving the natural resources and the ability to farm and produce food into the future without reducing the options available for following generations. Many advocates of sustainable agriculture claim that modern intensive agriculture, which includes greenhouse horticulture, has undermined values such as the conservation of the natural resources and the safety of food products that are associated with sustainable agriculture (Aerni, 2009). Such growing environmental interest has prompted several authors to study and propose solutions to improve sustainability with regard to particular aspects of greenhouse systems. Van Os (1999) studied the sustainability of Dutch greenhouse horticulture with emphasis on the systems aimed to reduce the leaching of water and fertilizers into the ground and surface water. Bot (2001) focused attention on energy saving in climate control of greenhouses located in North European maritime climate areas. De Pascale and Maggio (2005) analyzed some aspects concerning the sustainability of Mediterranean greenhouse systems, focusing on the use and management of water, which is a scarce resource in Mediterranean areas. Plant response-based sensing for microclimate control strategies was indicated by Kacira et al. (2005) as a tool to improve greenhouse sustainability. The effectiveness of innovative technologies aimed to improve protected horticulture sustainability can be evaluated by means of Life Cycle Assessment (LCA), by analyzing the input and output of energy and resources needed per unit of product (Munoz et al., 2008a; Russo and De Lucia Zeller, 2008).

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Sustainable greenhouse systems, which must be resource-conserving, socially supportive, commercially competitive and environmentally sound, rely on cultivation techniques, equipment management and constructive materials aimed to reduce agro-chemicals, energy and water consumption as well as waste generation. The objectives can be obtained by means of the following: i)

ii) iii) iv) v)

the efficient management of climatic parameters, i.e., solar radiation, air temperature, relative humidity and carbon dioxide (CO2) concentration in order to guarantee suitable growing condition for the crop and energy savings; the use of renewable energy sources in place of fossil fuels; the use of innovative greenhouse covering materials with suitable physical properties and low generation of after-use waste; the optimisation of water and nutrient delivery to the plants in order to reduce water and nutrient consumption and drainage with ground water and soil preservation; the integrated management of pests and diseases with a significant reduction of agrochemical use.

The chapter presents the recent trends of the research aimed to increase the sustainability of the greenhouse industry, investigating aspects concerning the microclimate control and energy sources, covering materials, plant nutrient and water delivery and management of pests and diseases.

2. MICROCLIMATE AND ENERGY

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M. Teitel and G. Vox 2.1. Introduction The level of microclimate control varies greatly, from the basic shelter type greenhouse to the fully computerized actively conditioned greenhouse. The aim of full climate control of greenhouses is summarized by Albright (2002) as follows: ―Plant production within closed environments strives to bring each plant to its genetic potential‖. In principle, in sustainable production the efforts taken to control the microclimate should take into account that the rate of renewable resource consumption should not exceed the regeneration rate. In addition, the rate of non-renewable resource consumption should not exceed the rate of renewable replacement resource development and, finally, the pollutant emission rates should not exceed the environment capacity to absorb and regenerate them (De Pascale and Maggio, 2005). In the last decade, there have been considerable efforts to manipulate greenhouse microclimate by using sustainable approaches. The focus was mainly on parameters that affect crop microclimate such as temperature, humidity and CO2 concentration. The following concentrates on the effect of these parameters in greenhouse cultivation and reports on the upto-date techniques to manage them with emphasis on the use of sustainable approaches.

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2.1.1. Temperature The management of the greenhouse environment is strongly reliant on temperature manipulation. Temperature manipulation is critical to influencing plant growth and morphology and so is a major strategy in environmental modification of crops. The response of plants to increasing temperature is reasonably predictable. There is a temperature range, for most plants, from 10°C to 24°C, over which there is a near linear positive response in terms of increased growth (Nelson, 2002). There are optimum temperatures for each crop and for each stage of development. At the high end of the temperature range, above the optimum, losses in quality can be experienced such as longer stems, thinner stems, fewer flowers, bleaching of flowers and slower flower bud development. At excessively high temperatures plant damage will occur. The base temperature, below which there is no growth, is also important as it provides a minimum set point for heating. Maintaining the optimum temperature for each stage of growth is the ideal in greenhouse environmental control however many greenhouses have limited capacity to modulate temperature precisely. The optimum temperature of a crop may not be the temperature that produces the highest yield. The temperature setting for heating controls (set point temperature) is usually a compromise point between the cost of the heat energy and the diminishing crop returns from the elevated temperatures. The natural diurnal cycle of low night temperature and higher day time temperature can be used by growers to manipulate plant development. As a general rule, under sunny conditions, crops are grown at a day time temperatures of 8°C to 10°C higher than night time temperature (Nelson, 2002). The use of environmental modification techniques to control the plant form, rather than a chemical (growth retardant) is a positive step towards sustainability. This, for instance, can be done by changing DIF (day time temperature minus night time temperature) values. The normal temperature regime of warm days and cold nights represents a positive DIF. Manipulation of the greenhouse environment using DIF requires precise monitoring and control of the greenhouse environment. The latest increases in price of fossil fuels created increased interest in improving energy use efficiency and energy savings in production greenhouses. The temperature management of crops is one strategy that is being adopted. The response of the crop to changed temperature regimes is a critical aspect that needs to be understood. The simple approach of reducing set point temperatures reduces energy consumption but may also result in a greater reduction in income. The manipulation of greenhouse air temperatures to achieve energy savings is a common practice. Higher average temperatures can be achieved using higher day time temperatures. This allows lower night time temperatures which results in lower heating fuel costs. Temperature integration aims to maintain the same average temperature while minimizing heating demand (Adams, 2006). Pressman et al. (2006) reported that exposing pepper plants to extremely high day temperatures (day/night temperatures of 36 ± 2/10 ± 2°C), obtained by keeping the greenhouse closed during the day to exploit solar heating, prevented the development of low night temperature symptoms. They indicated that their results could support the development of a novel procedure for producing greenhouse crops with minimum or even with no fuel consumption for heating during the winter nights in regions with bright and sunny days. Anyway, high temperatures in the daytime, which may be stressful for the crops, must be carefully controlled.

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2.1.2. Humidity Humidity in greenhouses is controlled for various reasons. The two main reasons are: avoiding too high humidity to avoid fungal infection and regulating transpiration. As a general guide it is often recommended that greenhouse relative humidity be maintained in the range of 60% to 80% for healthy growth. At high levels of relative humidity the risk for condensation on leaves is high (especially at night) and thus the risk of Botrytis and other fungal diseases to develop increases. In contrast to Botrytis and most other diseases, there are few fungi that thrive under low relative humidity. Renown is powdery mildew caused by different fungi in different crops. The evaporation rate is driven by the difference in energy levels or pressure of water vapour between the leaf (saturated) and the surrounding atmosphere. This is the vapour pressure deficit (VPD). The temperature of the air, the relative humidity of the air and the temperature of the leaf are required to determine the VPD. The greenhouse environment should be managed to maintain an acceptable VPD. High values of relative humidity can be reduced by ventilation and/or heating. Minimising the areas of wet surfaces, including plants, soils and floors, is another strategy to minimize elevated relative humidity. According to Campen et al. (2003) the methods used for dehumidification are: natural ventilation, condensation on a cold surface, forced ventilation in conjunction with a heat exchanger and hygroscopic dehumidification. During periods of heat demand, the most economic method of dehumidification is ventilation combined with heating because it has relatively low operating costs (Campen et al., 2003). Energy could be saved by applying heat recovery, and with rising energy prices this will soon be economically viable. Air circulation within the total greenhouse space is important, as it encourages a more even environment and prevents the localised build up of water vapour. A recent trend to the installation of air circulation fans has proved beneficial in greenhouses where natural air movement is poor. The exact number and arrangement of fans are determined by the greenhouse type and size (Mastalerz, 1977; Hanan, 1998). The use of covering films, which incorporate anti droplet formulations, is another effective way of treating the symptoms of high humidity. Due to the way in which these chemicals are released from the film, this property only has a limited life of one to two seasons. It is difficult to accurately predict its effectiveness, as it is dependent on several factors, including the rate of formation of condensation on the covering surface, the general greenhouse climatic conditions and the effect of pesticides and fungicides sprayed to protect the crop on the plastic film. 2.1.3. Carbon Dioxide The production of healthy, high-yielding greenhouse crops can require the uptake of CO2 at rates higher than the ones allowed by the typical atmospheric concentration (350–370 ppm). The enrichment of the greenhouse atmosphere with CO2 concentrations in excess of 1,000 ppm has been found to be beneficial, with increases in growth rates and in some cases increases in product quality. On the other hand, in well sealed greenhouses and in particular in plastic shelters, due to the photosynthesis and to the uptake of CO2 by plants, internal CO2 concentration may be much lower than outside ambient levels, thus resulting in dramatic reduction of crop growth and yield. For instance, Baille (2001) has reported CO2 concentration down to 200 ppm in plastic greenhouses. Mixing of the greenhouse air is required to ensure healthy plant

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microclimates and prevent localized CO2 deficiencies. This is achieved by horizontal air flow fans and vertical mixing fans. Most greenhouse crops show a positive response to increased CO2 levels up to 1,000 1,500 ppm (Nelson, 2002). There is an upper limit for enrichment beyond which there is no additional benefit. There is the risk of plant toxicity and potentially harmful effects for people if the levels are above 5,000 ppm. The response of crops to elevated CO2 is greatest in the lower concentrations. According to Nederhoff (1995) increasing the concentration from 350 ppm to 400 ppm is the most effective. Plant response to CO2 enrichment is dependent on the light intensity. Lower light intensities are associated with lower threshold enrichment levels. Moreover, it is documented in the literature that optimum temperature for crops is higher with raised CO2 levels. Therefore, another benefit of CO2 enrichment is the possibility to keep the greenhouse air temperature during the day slightly higher than without enrichment and thus reducing ventilation. This may save energy when forced ventilation is applied. There are a variety of systems available to CO2 enrich the greenhouse atmosphere. CO2 burners using propane gas are commonly used. Pure CO2 is available as an industrial gas and can be supplied to the greenhouse in a regulated way from an onsite storage tank (Figure 1). This tends to be a relatively expensive enrichment technique and uneconomic if significant ventilation is required to maintain acceptable greenhouse air temperatures.

Figure 1. Pure CO2 supplied to the greenhouse in a regulated way from an onsite storage tank.

CO2 can also be extracted from the flue gases of fossil fuel furnaces. Hot water boilers are operated during the day, when the gas can be utilized by the crop, and the generated hot Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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water stored in insulated tanks for night time distribution. Suitable fuels include natural gas, LPG and propane. CO2 can also be obtained by burning biogas that is generated in municipal solid waste landfills and supplying the purified exhaust gases to the greenhouse (Jaffrin et al., 2003). The cost of enrichment should be taken into account. The benefits of enrichment depend on increase in yield and quality due to CO2 enrichment as well as on the price of the produce. Excessive enrichment is sometimes waste of money while moderate enrichment to prevent depletion and keep the concentration at about ambient levels may be more economic and reduce contamination of the atmosphere. Stanghellini et al. (2009) indicated that allowing for higher than external concentration obviously reduces the efficiency of the supply, but it does not necessarily reduces profit. By applying some economics to a simple assimilation model they showed that in many conditions, particularly with relatively high radiation, maintaining higher than external concentrations does make economic sense, certainly up to ventilation rates of 10 h-1. They concluded that the optimal management of carbon fertilisation should aim at concentrations well above 1,000 vpm in the absence of ventilation, and gradually decrease to maintaining the external value at ventilation rates well in excess of 10 per hour. Market conditions (value of produce vs price of CO2) should determine the trend between these two extremes. In another paper Stanghellini et al. (2008) analysed costs, potential benefits and consequences of bringing in more CO2 either through ventilation or artificial supply. They showed that whereas the reduction in production caused by depletion is comparable to the reduction resulting from the lower temperature caused by ventilation (in chilly days) to avoid depletion, compensating the effect of depletion is much cheaper than making up the losses by heating. Ohyama et al. (2005) indicated that the control strategy that keeps the CO2 concentration in the greenhouse at about the same level as outside is widely used in European countries with cool climates but is not popular in Asian countries that have a warm climate and require high ventilation rates. Therefore, they have extended the CO2 concentration control method, which is used in Europe, for greenhouses with higher ventilation rates in moderate and hot climate regions. Reduction of CO2 exhaust from greenhouses is important in light of the Kyoto treaty for CO2 emission levels. The target is that emissions should be reduced by 6% in the period 2006-2010 compared with emission levels in 1990.

2.1.4. Dynamic Climate Control Sustainability in greenhouse production can be achieved by dynamic control of the microclimate. It is now well established that many greenhouse plants have the ability to tolerate variations in temperature and provided that the average temperature remains approximately constant, production is unaffected. This has resulted in the development of control strategies that are based on temperature integration as a method for reducing energy consumption. Currently this approach is applied to raising the temperature set point for ventilation to increase the average day temperature and lowering night time set point to reduce heating (Dieleman et al., 2005). The average temperature is unaffected. Limits are placed on the permitted temperature deviations and on the duration of the integration period. Trials in greenhouses on commercial nurseries have given energy savings of 5% to 15%. Temperature integration can be extended by relating the heating temperature to external conditions, particularly wind speed, which affect the rate of heat loss from heated

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greenhouses (Bailey, 1986). Hence, heating in periods of the night when wind velocity is low will allow energy saving. An approach that dynamically controls the climate in a greenhouse that is based on the resources available for photosynthesis (e.g. light) was reported by Ottosen and Rosenqvist (2006). They indicated that experiments in Denmark showed that it is possible to save between 25% and 48% of energy consumption without affecting plant quality and production time by using a control system that regulates temperature and CO2 concentration according to outdoor Photosynthetic Photon Flux Density and photosynthesis models.

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2.2. Heating To time production for a specific market and to have some control over crop quality and yield, growers need to heat their greenhouse whenever its temperature drops below the recommended temperature for their specific crop. Except of raising the air and crop temperatures to the desired level, heating is also applied in cases where there is a need to reduce air humidity (e.g. to reduce the probability of condensation on plant organs and thus reduce development of fungal diseases). In cold countries greenhouses are heated during most of the year, while in mild climates the heating period is shorter and heating is usually applied during the winter. In countries with a warm climate such as in Israel, heating is mainly applied during winter nights. Greenhouses in the Mediterranean region have much lower energy needs than those in north European countries. According to De Pascale and Maggio (2005) in Southern Italy, one hectare of cut roses requires between 5,200 and 6,800 GJ yr-1 vs. 16,000 GJ yr-1 required in the Netherlands for cut flower production. However, despite these lower heating requirements, it should be pointed out that the majority of Mediterranean greenhouse systems depend on non-renewable energy sources (fossil fuels) with a high impact on the environment. Sustainability in cold and warm climates can be improved by using alternative energy sources such as organic waste, geothermal water or renewable energy sources (solar, wind) and through the reuse of energy (Bot, 2004; Short, 2004) and better insulating the greenhouse. The amount of heat, qh, required to balance the heat loss from a greenhouse can be estimated by (Bakker et al., 1995):

qh  U Ac T  (1   ) solar S0 Af

(1)

where U is a total heat transfer coefficient which takes into account heat transfer through cladding material by conduction, convection, radiation and also air infiltration, Ac is the cover area of the greenhouse, T is the temperature difference between the greenhouse air and the ambient,  is an evaporation coefficient, solar is the transmissivity of the cover, S0 is the solar radiation outside the greenhouse and Af is the greenhouse floor area. For a given greenhouse, the maximum required heating capacity is determined according to Eq. (1) by the cover area, the thermal properties and thickness of the cover material, and the difference between the desired greenhouse air temperature and the design outside air temperature, which generally occurs at night.

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A heating system is generally made up of a fuel-supply system, fuel burner, heat exchanger, heat distribution system and a control unit. Heating systems are usually classified as central or local. In a central system (Figure 2) the boiler is located in a separate house outside the greenhouse and the heat is distributed to the greenhouses by a distribution system. In a local system the heat is released directly to the greenhouse space since the furnace and thus combustion are within the greenhouse space.

Figure 2. Central heating system with boilers located outside the greenhouse.

The central hot water boiler is the standard for greenhouse heating in the Netherlands (Bakker et al., 1995) and is also very common in other European countries. On the other hand, in warmer countries (e.g. Israel), the hot air furnace is the most common because of its initial lower price in comparison to the hot water heating system. The hot water systems become more economic, in Israel, only in very large structures. There are a number of advantages to the central heating system: 1) a central plant offers greater flexibility to use alternative energy sources; 2) it uses less greenhouse space since the central plant is located in a separate building; 3) partial load performance might be much more efficient; 4) maintenance and control is easier and cheaper and 5) since combustion is done outside the greenhouse, improper combustion does not increase the probability of damaging the crop due to toxic flue gases (e.g. ethylene). Nevertheless, if a grower has a few small greenhouses, a central heating system may be more expensive than placing local systems in each greenhouse because of the need for a distribution system with the central unit. There are four primary systems for greenhouse heating: 1) steam, 2) hot water, 3) hot air and 4) infrared.

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Steam and hot water are usually delivered to the greenhouse by main supply and return system of pipes that are insulated from the surrounding to minimize heat loss. These pipes are connected to a secondary net of pipes (Figure 3) which is installed inside the greenhouse. The water circulates through the secondary net of pipes and heat is delivered to the crop by convection and radiation.

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Figure 3. Hot water distribution system.

Air circulation by fans can reduce temperature stratification in the greenhouse during heating and reduce energy loss. Installing horizontal air flow fans that move the air at 0.3 to 0.6 m s-1 can limit temperature differences in the growing area. Floor heating is considered good practice where plant containers can be set directly on the floor (ASABE EP406.4 standard, 2007). Loose gravel, porous concrete, solid concrete or sand can be used for the floor material. Floor heating systems can be either by buried pipes or flooded floor (Aldrich and Bartok, 1992). For floor heating the pipes are usually buried 10 cm in a porous concrete or 30 cm in ground. Floor heating is generally not sufficient for keeping the plants at the desired temperature and additional heat distribution equipment is needed to heat the space. Floor heating was also described by Kozai (1989) who reported on a system of pipes buried in the greenhouse soil that was used for nocturnal heating. The excess solar heat during the day was stored in the soil by circulating the warm air in the greenhouse through the buried pipes in the greenhouse soil. The stored heat was then released from the soil to air by recirculating the air through the pipes during the night when heating was required.

2.2.1. Combined Heat and Power Small scale combined heat and power (CHP) systems, also known as co-generation systems, are now quite common in modern large greenhouse structures. They use an internal Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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combustion engine or a gas turbine to drive an electric generator and generate electricity in addition to heat. Such systems have been installed in the last decade in many greenhouses in the Netherlands and the UK (Critten and Bailey, 2002). In most cases the systems were operated to have geographically dispersed electricity generation. The heat produced is supplied to the greenhouse by heating pipes and the engine exhaust gases are distributed in the greenhouse through perforated tubes to provide CO2 enrichment. Because CO2 enrichment is beneficial during the day, the CHP systems operate during the day and the heat produced that is in excess of the greenhouse demands is stored in large water tanks and used during night. The electricity produced by the generators is usually used in the greenhouse (e.g. for supplementary lighting) and sold to electricity companies by connecting to the national electric grid. The performance of such a system was studied by Giniger and Mears (1984) who concluded that the optimum matching of the unit‘s capacity and operating time to the heat and electricity demands of a greenhouse facility are necessary if the most economical possible use is to be made of the unit. To improve the performance of CHP systems, de Zwart (1997) used a simulation model to determine the energy saving obtained by heat storage facilities with different dimensions and demonstrated that the amount of CO2 supplied to the greenhouse during the day has a significant effect on the optimum storage capacity. Hamer and Langton (2005) carried out simulations to study the efficiency and effect on cost of using micro-turbine CHP units in ornamental production. Their simulations were carried out using an energy balance model for a typical ornamentals lighting installation based on a CHP system comprising a micro-turbine CHP unit, a heat store and a back-up boiler. Energy profiles were compared with those given by a conventional system comprising a boiler to provide the heat, and taking electricity for the lamps from the National Grid. Separate simulations were conducted for four different lighting regimes, each with and without ―temperature integration‖ (an energy-saving protocol). The simulations indicated that CHP can give running cost savings of 30% to 42%, with the higher savings achieved at long operating times. Furthermore, micro-turbine CHP reduced CO2 emissions by between 25% and 35%. They showed that temperature integration can save energy, particularly for the shorter lighting period. However, they indicated that for the grower the micro-turbine is not a cost-effective means of providing energy unless the existing mains supply is not large enough to meet the power demand. This is because the repayment of the capital investment is large and similar to the running costs. Furthermore the potential benefit of increased availability of CO2 is not realised because the CHP is frequently not running at times when CO2 would have benefited production.

2.2.2. Other Concepts of Greenhouse Heating Bot et al. (2005) developed a ―solar greenhouse‖ for high value crop production without the use of fossil fuels. The main approach was to first design a greenhouse system requiring much less energy, next to balance the availability of natural energy with the system‘s energy demand, and finally to design control algorithms for dynamic system control. Increasing the insulation value of the greenhouse cover was the first step towards a reduction in energy demand. The challenge was in maintaining a high light transmission at the same time. A first generation of suitable materials was developed. The realizable energy saving was almost 40%. The next reduction in fossil fuel requirement was accomplished by capturing solar energy from the greenhouse air during the summer months with heat exchangers (Figure 4), storing it in an underground aquifer at modest temperatures, and finally using the stored

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energy during the winter months by using heat pumps. The total realizable energy saving was reported to be more than 60%.

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Figure 4. Efficient heat exchangers to collect heat from the greenhouse air during summer. The heat is stored in the aquifer.

A novel model of Latent Heat Convertor (LHC) capable to reduce the air relative humidity in the greenhouse as well as supply energy required for greenhouse heating was developed and presented by Assaf and Zieslin (2003). The principle of LHC is based upon direct contact of air with flowing hygroscopic solution known as brine. Following contact of the humid greenhouse air with the brine the vapour is condensed on the brine. The sensible heat of the condensation heats the brine and the warm brine heats the air which is introduced back with a lower relative humidity into the greenhouse. Such a system was tested in a 3,600 m2 (120m x 30 m) greenhouse at ambient temperature of 11°C and 90% relative humidity. A continuous maintenance of the greenhouse air at 18°C during 12h night required 963 kWh, and resulted in a relative humidity of 87–88% in comparison to 1,545 kWh and relative humidity of 90–95% in the neighbouring greenhouse with a conventional heating system. Phase change materials (PCMs) were used by several authors in an attempt to save energy in greenhouse heating. Nishina and Takakura (1984) used a PCM with a melting point around 20°C and a heat of fusion of 56 cal cm-3 to store heat from day to night. The greenhouse air was sucked by a fan into the PCM unit, exchanged heat with it and returned into the greenhouse through a polyethylene film duct. Two identical heat storage units were installed in a greenhouse with a total amount of 2.5 tonnes PCM and a potential value of latent heat conversion of 1 x 105 kCal. In the daytime, the two fans of the heat storage units

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were operated to store heat when the inside air temperature was above 22°C. The roof ventilators were opened when the inside air temperature was above 28°C. In the night-time, the fans were operated to deliver heat when the inside air temperature was below the set point. No auxiliary heating system was needed during the experimental period, and tomatoes grew well. The PCM heating method was also investigated by Nishina et al. (1988) who used solar heating during day to store heat and release it during night. They indicated that seventy percent of oil consumption was saved. The PCM method was also applied by Basçetinçelik et al. (1997) for seasonal heat storage. Geothermal energy has been used most extensively in agriculture for greenhouse heating. According to Popovski (1993) many European countries are experimenting but also regularly using geothermal energy for commercial out of season production of flowers, vegetables and fruits. Worldwide use of geothermal energy in greenhouse heating increased by only 15.7% (or 3.0% annually) during 2000–2005 (Lund et al., 2005), which is slightly higher than during the 1995–2000 period. The installed capacity in 2005 was 1,404 MWt and the annual energy use was 20,661 TJ yr-1. A total of 30 countries report geothermal greenhouse heating, the leading countries being Georgia, Russia, Turkey, Hungary, China and Italy. Most countries did not distinguish between covered (greenhouses) versus uncovered ground heating, and also did not report the area heated. Several countries, such as Macedonia, reported a decrease in geothermal greenhouse use, due to economic problems. Using an average energy requirement, determined for the World Geothermal Congress 2000 data, of 20 TJ yr-1 ha-1 for greenhouse heating, the 20,661 TJ yr-1 corresponds to about 1,000 ha of greenhouse heated worldwide. There are a few problems with geothermal heating as was pointed out by Hanan (1998) and Popovski (1993). The water supply may be highly corrosive, for deep sources there is a cost of drilling a well and attendant piping, pumping may be required which increases cost and the location of the wells may be remote.

2.2.3. Solar Thermal Systems Solar thermal systems can be used to produce low enthalpy thermal energy for sustainable greenhouse heating systems. Solar thermal systems, based on solar collectors, have higher energy exchange ratio and a better cost-effectiveness with relatively low installation price, in comparison with photovoltaic systems. Common solar collectors consist of a series of copper pipes, which are painted black, sitting inside a thermal insulated box fronted with a glass panel. The fluid to be heated passes through the collector and into a tank for storage, the fluid can be cycled through the tank several times to raise the fluid temperature to the required value. Due to the intermittent nature of the solar radiation and in relation with the size of the storage tank an auxiliary power supply is often necessary; a burner fed by biomass or fossil fuel can be used as auxiliary power supply; electrical heat pumps fed by wind turbines and/or photovoltaic systems can be used for co-heating as well. Voulgaraki and Papadakis (2008) simulated a solar heating system with seasonal storage for a 1,000 m2 greenhouse located in Thessaloniki, Greece, latitude 40° N; the simulation showed that with 900 m2 of solar collectors and a storage volume of 552 m3, about 40 % of the total heating load can be provided from the solar energy, while the rest of the energy need must be provided by an auxiliary power supply. The self sufficiency, i.e., when the total heating load is provided by the solar energy, can be obtained with several combinations of collectors area and heat storage volume; the self sufficiency can be reached, for example, with

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3,000 m2 of solar collectors area and 1,200 m3 of storage volume or with 2,000 m2 of solar collectors area and 1,840 m3 of storage volume. Over the last years experimental tests have been carried out at the University of Bari on the application of solar thermal collectors for greenhouse heating; the tests were performed on a greenhouse located in Southern Italy, latitude 41° N (Vox et al., 2008a). The solar thermal systems consisted of: a boiler for the hot water storage, with a capacity of 1 m3, and 12 m2 of solar collectors, positioned on the south-facing greenhouse surface (Figure 5), with an elevation angle of 90° in order to capture more solar radiation in cold than in warm periods. The water heated by the sun in the solar collectors flowed into the hot water tank where it was mixed (direct system) with the water circulating in the plastic pipes used to heat the plants; an electrical heat source was used as auxiliary power supply. Warm water was circulated inside the pipes heating the plants at a temperature of about 40°C. The low enthalpy heating system required a high level of thermal insulation; low tunnels covered with plastic films were mounted over the cultivation area inside the greenhouse and an aluminised thermal screen was used during the night in order to reduce the long wave infrared losses from the greenhouse. The air temperature heating set point inside the heated low tunnels was 14°C. The results of the experimental tests showed that about 34% of the solar energy incident on the thermal collectors was converted into usable thermal energy that was stored and then used for plant heating; about 64% of the total thermal energy heating the plants was provided from the solar energy, while the rest of the required energy was provided by the auxiliary power supply. The tests showed that, in these conditions, 0.15 m2 of solar thermal collectors and storage of 0.012 m3 can meet the energy needs of 1 m2 of greenhouse floor area for a greenhouse located in Southern Italy.

Figure 5. Solar thermal flat collectors mounted on the south-facing greenhouse surface at the experimental farm of the University of Bari, Italy. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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2.2.4. Concepts of Energy Savings Thermal radiation can become the dominant mechanism of night-time heat loss from a greenhouse, particularly when there is a clear sky (Silva and Rosa, 1987). To reduce this heat loss, thermal screens are commonly drawn over the crop at sunset and removed at sunrise; they can reduce the overnight heat loss by 35–60% (Bailey, 1981). In addition to reducing thermal radiation, screens that are impermeable to air decrease the volume of the greenhouse air that needs to be heated and form an extra air gap between the crop and the greenhouse roof (Öztürk and Basçetinçelik, 1997), thereby reducing the heat transfer to the surroundings. Thus, they keep the internal air temperature higher than it would be without a screen (Montero et al., 2005). Furthermore, because screens reduce thermal radiation, heat loss by radiation from the crop is reduced and crop temperature is expected to be raised (Teitel et al., 2009). Kittas et al. (2003) considered the influence of an aluminised thermal screen on greenhouse microclimate and canopy energy balance, and they reported that with a thermal screen the microclimate at crop level was more homogeneous and the average air and canopy temperatures were higher than without a screen. Another approach for energy saving involves double covers; either double glass with a layer of air between the sheets of glass or a double plastic cover that is inflated with air by a blower. The idea is to increase the heat conduction resistance of the greenhouse cover. Although experiments have shown that it can save as much as 40%, this method was not widely accepted as it resulted in reduction in light level during the days and unacceptable yield loss and crop delay. Other miscellaneous energy conservation methods are given by Hanan (1998).

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2.3. Ventilation The primary purpose of ventilation is to prevent excessive rise of temperature and humidity. This is achieved by replacing the hot and humid air of the greenhouse with ambient cooler and dryer air. In some cases, it is applied to prevent CO2 depletion in greenhouse air caused by photosynthesis. At the same time, ventilation can reduce the concentration of pollutant gases and during winter, in cases where the heating unit is installed in the greenhouse, keep the combustion of the fuel at high efficiency since the lack of adequate oxygen results in incomplete combustion and carbon monoxide buildup. In the extreme case, a complete lack of ventilation on a summer day could result total loss of the crop due to excessively high temperatures causing wilting followed by damage to plant tissue. Inadequate ventilation can have an effect on the crop which may not be apparent immediately. For example, the timing of flowering of a carnation crop can be influenced by excessively high temperatures with severe restricted growth delaying the next flush of flowers. Two types of ventilation can be distinguished: natural and forced. Natural ventilation is driven by two mechanisms, namely the pressure field induced by the wind around the greenhouse and the buoyancy force induced by the warmer and more humid air in the greenhouse. Forced ventilation is accomplished by fans that are capable to move large quantities of air at relatively low pressure drop. A sustainable greenhouse will heavily rely on natural ventilation as it is driven by renewable energy. Ventilation rate is specified in the literature as air changes per hour (units of h-1), or flow rate per unit floor area (units of m3 s-1 m-2). The former is not an appropriate measure since

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solar radiation which is causing the heat load on the greenhouse is the same per unit of floor area whether the structure is high or low. For example, if sixty air changes per hour are required for ventilation (one air change per minute) then in a greenhouse with an average height of 3 m, every square meter of floor area which has a column of air of 3 m3 above it will be ventilated by a flow rate of 3/60 = 0.05 m3 s-1 m-2 (floor area). If, however, the average height of the structure is 5 m, then the same flow rate per unit floor area results in only 0.05x3,600/5 = 36 air changes per hour. By using an energy balance on a greenhouse the flow rate Q required to keep the greenhouse air at a temperature Ti can be calculated, which according to the ASABE EP406.4 standard (2007) is:

 QAf c pex   (Tex  Tinl ) (1   )  S0 Af  UAc (Ti  T0 )     ex 

(2)

Seginer (1997) proposed alternative design formulae for estimating the required ventilation rate of a greenhouse. These formulae refer to canopy rather than to air temperature and can be extended to situations where the Bowen ratio (the ratio of sensible to latent energy fluxes) is negative. One of the formulas proposed by him is:

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Q

  S0  c p    (Tcr  T0 )  1

(3)

By solving an example with  = 0.25 K-1,  = 0.4, requiring Tcr – T0 = 5 K and assuming a positive Bowen ratio he showed that 50% more ventilation is needed than for attaining Ti – T0 = 5 K. On the other hand for a negative Bowen ratio, the opposite is true, namely less ventilation is required to maintain a certain temperature difference relative to Tcr than to Ti. He concluded that the larger the humidity gradient between the greenhouse interior and exterior, the less ventilation is required.

2.3.1. Forced Ventilation The basic requirements of a fan for greenhouse ventilation are that it should be capable of moving large quantities of air at relatively low pressure drops. Of the different types of fan available the most suitable is the axial fan which consists of direct-driven or belt-driven impellers with a varying number of blades. The fans are usually mounted on the sidewalls because of structure limitation and to minimize shading. Teitel et al. (2004) proposed to use variable speed fans to control the speed of rotation of the fans. They showed that with such control it is possible to save about 25–30% of energy and keep the same microclimate as with ON_OFF control. Similar results were reported by Davies et al. (2008) who reported that reducing the speed can cut the energy usage per volume of air moved by more than 70%. They also indicated that powering a greenhouse fan from a photovoltaic generator is an interesting option. The capital cost of a system that utilizes a photovoltaic generator is high however there are advantage in terms of independence and reliability especially in places such as developing countries where the grid

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supply may be intermittent. Davies et al. (2008) indicted that currently the availability of energy saving fans using low-speed, sunlight-controlled variable speed or solar-power (e.g., using brushless DC motors) is rather poor.

2.3.2. Natural Ventilation Natural ventilation can be achieved by opening windows at the top of the greenhouse and/or at the sidewalls. The number and size of the windows and mechanisms for window opening vary. Many different arrangements of opening ventilators have been used in glass and plastic covered houses. Ridge openings can be classified under the type headings of continuous or non-continuous and they are usually on both sides of the ridge though hoses with openings on one side only are also constructed. Roof vents are either fixed or fully automatic (movable roof vents). A fixed overlapping vent on gable ridge provides ventilation while preventing penetration of rain and hail. Movable roof vents are formed by, e.g., film roll-up from gutter to ridge, ridge hinged arched vents, vertical opening at the center of the arc which run the entire length of the roof, vertical roof opening that starts at the gutters and extends to a height of about 1 m, vertical opening at the center of the arched roof which run the entire length of the roof. The position and hinging of the vent at the ridge are the basis of a better evacuation of the hot and humid air which builds up at the top of the greenhouse. In Venlo greenhouses the ventilators in most of the houses are hinged from the ridge and extend half way to the gutter or as far as the gutter. The idea is to provide a large opening area especially in warm and humid areas. Recent greenhouse designs provide retractable roofs. The new designs are traditional A-frame greenhouses with articulating roofs that either hinge at the gutters and open at the peak or hinge at one gutter and the peak while opening at the opposite gutter and moving across the greenhouse bay. Side ventilation is usually achieved by rolling up curtains with central mechanism operated manually or by an electric motor. Mechanisms that open the side vents from bottom to top or vice versa are available, where the most common operate from bottom to top. Side openings with flaps that are hinged from the top are also used however they are more common in glasshouses than in plastic covered greenhouses. Buoyancy Driven Ventilation Temperature and humidity differences between the inside and outside of a greenhouse produce forces that drive flow. The natural tendency for hot and humid air to rise and accumulate towards the upper part of a space leads to stable stratification, and this has a significant influence on the flow patterns within the greenhouse. The determining factor in the form of the vertical stratification is the location of the openings. A vertical opening at the top of a single span greenhouse will allow exchange of warm and humid air outwards and cool dryer air inwards. The warm and humid air will flow out through the upper area of the opening and the cool air will enter through the lower area of the opening. The incoming air will descend as a turbulent plume that will tend to mix the air within the space. This type of ventilation is known as mixing ventilation. If two vents are open, one at the top of the greenhouse and the second near the bottom, warm humid air flows out through the upper opening and cool dry air enters through the lower opening. This form of ventilation is known as displacement ventilation. It is characterized by larger temperature gradients with respect to height than those observed with mixing ventilation (Zhao et al., 2001).

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Wind Driven Ventilation Wind effect on greenhouse ventilation is influenced by the shape of the greenhouse and its openings and by the proximity to other structures. Generally speaking, pressures are higher on the windward side of the greenhouse and lower on the leeward side and on the roof. Wind creates a pressure distribution over a greenhouse which is influenced both by the mean wind speed and turbulence. Combining Wind and Buoyancy Effects Greenhouses are most of the time subject to both buoyancy and wind-induced pressure forces. The processes are nonlinear and so the combined effects cannot be obtained simply by adding the results of the two different processes acting in isolation. The nonlinearity arises because the flows through openings are a nonlinear function of the pressure drop across them (Hunt and Linden, 1999). The extent to which the wind hinders or enhances the ventilation of the greenhouse depends upon its strength and direction as well as upon the structure of the greenhouse and its openings and the temperature and humidity differences between the internal and external environments. Most authors assume the pressure field on the greenhouse is a sum of the pressure fields due to both wind and buoyancy, i.e., P = Pw + Pbu and this leads to the following relation:

Q  (Qw2  Qbu2 )0.5

(4)

Boulard and Baille (1995) proposed the following relation for a greenhouse equipped with only roof openings:

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Q

AV T HV Cd (2 g  Cw w2 )0.5 2 T0 4

(5)

For a greenhouse with roof and side openings with areas At and Ab, Kittas et al. (1997) suggested the following relation:

 T ( At Ab ) 2 At  Ab 2 2   Q  Cd  2 g Z  ( ) C w w T0 ( At2  Ab2 ) 2  

0.5

(6)

Buoyancy driven ventilation is significant only at low wind speeds. The literature indicates that for a wind speed higher than 2 m s-1 the buoyancy effect is small and may thus be neglected. Kittas et al. (1997) suggested that for a greenhouse with roof and side vents the 0.5 buoyancy driven ventilation dominates when w / T  1.

2.4. Cooling Systems The large quantity of heat that has to be removed from greenhouses, especially in warm regions, preclude the possibility of using mechanical refrigeration for greenhouse cooling since mechanical refrigeration will require huge capital investment in equipments, operating costs and maintenance. Therefore, all commercial greenhouses that utilize a cooling system

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use evaporative cooling which is much cheaper. Evaporative cooling is based on the conversion of sensible heat into latent heat. When non-saturated air comes in contact with free moisture and the two are thermally isolated from outside heat source, there is transfer of mass and heat. Because the vapour pressure of the free water is higher than that of the unsaturated air, water transfers in response to the difference in vapour pressure. The transfer involves a change of state from liquid to vapour, requiring heat for vaporization. This heat comes from the sensible heat of the air and the water resulting in a drop of temperature in both of them. Since no outside heat is added during this process, it can be assumed that the total heat (enthalpy) of the air does not change. The process the air undergoes can be described on a psychrometric chart. The lowest temperature the air can get is the wet bulb temperature. Under practical greenhouse conditions, however, the air does not become completely saturated. In this process the wet bulb of the temperature is remained constant, the dry bulb temperature is lowered and the relative humidity is increased. The efficiency of the cooling unit is the ratio between the change in saturation actually achieved to the potential change in saturation. It can be calculated from:



T0  Tp T0  TWB

(7)

The amount of water evaporated in this process can be calculated from:

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m   Q( p  0 )

(8)

Evaporative cooling techniques have recently become more popular in areas like the Mediterranean basin. This new interest is associated with the incorporation of insect proof screens that impede ventilation and increase air temperature (Montero, 2006; Teitel, 2007; Teitel et al., 2005). Evaporative cooling demands high quality water, but water is often a scarce natural resource in horticultural areas. For this reason, it is necessary to know the water consumption of evaporative cooling systems and, more importantly, to understand how evaporative cooling affects plant transpiration in different crops. Montero (2006) indicated that fogging can reduce transpiration by between 12% and 51% depending on the crop leaf area index (LAI). As LAI increased, the fog contribution to transpiration reduction decreased, since the humidity level in a greenhouse with a fully developed crop is higher and also because of the reduced need to artificially add water vapour to the air. The following lists several systems, which can satisfactorily provide cooling by evaporating water: sprinkling, fan and pad and fogging.

2.4.1. Sprinkling Spraying water onto a surface of the roof and/or the canopy using sprinklers enlarges the free surface of the water and hence increases the evaporation rate. The evaporation process causes cooling of the canopy and of the air in the immediate vicinity, in accordance with the local microclimate. The advantage lies in the low cost. The main disadvantage of this method is the creation of conditions favourable to the development of fungal diseases. Also, sprinkling usually results in scalding and deposition of precipitates on the surfaces of the

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leaves and the fruits, especially when water quality is poor. Therefore, sprinkling is inferior in this respect to the fan and pad and fog systems.

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2.4.2. Fan and Pad The currently accepted method is based on placing fans in one wall and the wet pad (Figure 6) in the opposite one. Outside air is sucked into the greenhouse through the wet pad, and is thus humidified and cooled. From the wet pad, this air flows through the greenhouse, absorbing heat and water vapour, and is removed by the fans at the opposite end. Generally the efficiency of a pad is about 80–90 %. The advantages of this method lie in its simplicity of operation and control and also in that it does not entail any risk of wetting the foliage. The main disadvantages are: relatively high cost; lack of uniformity of the climatic conditions, which are characterized by rising temperature and water vapour (due to solar heating and transpiration of the plants) along the length of the structure and in the flow direction; electric power failure transforms the greenhouse into a heat trap; low cooling effect compared with a fogging system; and waste of water—to prevent blockage of the wet pad, water-bleed is necessary. Nearly all fan and pad systems use fresh water which is a drawback in regions with water scarcity. Davies et al. (2006) have shown that effective evaporative cooling can be achieved using seawater in place of fresh water. They claimed that some simple calculations suffice to show that there is in fact little difference in efficacy between using seawater and fresh water. Another system that uses cold seawater to both cool the greenhouse air and provide fresh water was described by Bent (2005).

Figure 6. Vertical pad in a greenhouse cooling system.

Two types of pads are acceptable, the vertical and the horizontal pads. Dripping water onto the upper edge can wet the porous vertically mounted pads. A drip collector and return Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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gutter are mounted at the bottom of the pad and are used to re-circulate the water. In the horizontal pad, loose straw or small pieces of wood are distributed over horizontally supported wire mesh netting. The water is sprayed on the entire surface of the pad. Horizontal pads are more effective than vertical pads regarding pad plugging in dusty areas. The outside air is generally cooled by evaporation to within about 1.5°C of the wet bulb temperature. In regions with very low humidity the outside air temperature can be reduced by as much as 10– 25°C cooler than ambient temperature. Temperature differences ranging from 3–7°C between fan and pad are quite common. When the system is operating, overhead ventilators and other openings must be closed. Pads must be continuous to avoid warm areas in the greenhouse. The most common pads are made of aspen wood excelsior, corrugated cellulose, honeycomb paper and polyvinyl chloride (PVC).

2.4.3. Fogging The fogging method is based on supplying water in the form of the smallest possible drops (in the fog range, diameter 2–60 m) so as to enhance the heat and mass exchange between the water and the air (Figure 7). This is because (for a given quantity of water) the surface area of the water in contact with the air increases in a direct relationship to the diminution in the diameter of the drops. Also characteristic of drops in this size range is that the frictional forces arising from movement of the drops through the air are relatively large, so that the terminal velocity of the falling drops is low, which results in a long residence time, allowing complete evaporation of the drops. Furthermore, because of their small size these drops are properly carried by the airflow. These combined characteristics ensure highly efficient evaporation of the water, while keeping the foliage dry. The high efficiency is because, in addition to the evaporation of water to cool the air that enters the greenhouse (similarly to the wet pad), it is possible to evaporate water in quantities sufficient to match the energy absorbed in the greenhouse. Most fogging systems are based on high-pressure nozzles, characterized by low cost and high cooling effect relative to other systems, as discussed by Arbel et al. (1999). In the light of these considerations, the following scheme is recommended, comprising uniform roof openings, fans in all walls and nozzles uniformly distributed at the height of the structure. The air that enters the greenhouse through the roof openings carries the water drops with it, and the water evaporates within the flow. As a result, the air is cooled (by water evaporation), both on its entry into the greenhouse and in the course of its passage among the canopy, and absorbs excess heat. Arbel et al. (2003) focused on the operational characterization of a fogging system in combination with forced ventilation following the above scheme. The results obtained revealed inside greenhouse air temperature and relative humidity of 28ºC and 80% respectively during the summer at midday when ambient conditions were 36ºC and about 25 % relative humidity. Furthermore, the results obtained revealed generally high uniformity of the climatic conditions, within the greenhouse. Such an arrangement may lead to: uniform climatic conditions within the desired range, even in the summer months; good control over the climatic conditions through reduction of the influence of the wind; operation of the greenhouse by means of a relatively simple control system; the establishment of greenhouses in large units and, consequently, better exploitation of the land area and significant reduction in the cost per unit area of the structure. The main drawback of this method is still the technical problems in preventing nozzle partial or complete clogging and thus formation of

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large droplets which do not evaporate completely and fall on the foliage and proper control of water spaying and fan operation.

Figure 7. Fogging system for greenhouse cooling. At the top right corner is a close-up of the nozzle.

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2.4.4. Other Concepts of Greenhouse Cooling Heat Exchange with an Underground Aquifer Bakker et al. (2006) described a greenhouse cooling system with heat storage in an underground water aquifer for a completely closed greenhouse. The cooling system has been designed, based on the use of a fine wire heat exchanger (Figure 4). The performance of the fine wire heat exchangers was tested under laboratory conditions and in a small greenhouse compartment. The effects of the system on the environmental conditions (temperature and humidity distribution) in the greenhouse were simulated to decide on the final lay out of the system. A sprinkling system that is used to collect energy from the greenhouse cover during periods with a heat surplus was presented by de Zwart (2005) and it showed promising results. He showed that such a system potentially collects more than 500 MJ per m2 per year, which gives the opportunity to save this amount of fossil fuel (about 16 m3 of natural gas per m2 per year). Shading The shading (Figure 8) of the crop is also an effective method of high temperature control, as it directly reduces the greenhouse heat load and also reduces the intensity of the solar radiation incident on the crop foliage. Moveable shading screens have the significant advantage of allowing shading to be in place only at the times of high solar intensity. Knowledge of the light requirements of the crop is essential, if shading is to be employed.

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Shading in combination with medium to high air exchange rates is often an effective approach for many greenhouse situations.

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Figure 8. Black shading screens on top of the greenhouse cover.

Whitewashing Photoselective paints are already common in many countries. The paints are sprayed on the greenhouse roof to reduce the heat load. Compared with 20 years ago whitewash as a shading paint has undergone a technological revolution. Today‘s shading paints allow a higher percentage of photosynthetically active radiation (PAR) to penetrate the greenhouse and block out the infrared range which cause warming. Whitewash reduces light also in hours when light is not in excess, which reduces growth and production. Therefore it should be used sparsely and mainly on regions of the greenhouse cover that are subject to direct solar radiation. The advantage of the new shading paints is that they can be washed off at the end of the warm season. Furthermore, shading paints that dissolve naturally at the end of the season have been developed, which reduce labour work.

2.5. Energy Sources 2.5.1. Photovoltaics for Greenhouse Systems Electricity to feed greenhouse equipments such as fans, fertigation and lighting systems can be generated in a sustainable way by means of photovoltaic (PV) systems. The electricity is generated in presence of solar radiation however the greenhouse equipments, for example lighting systems, require the energy also when solar radiation is low, in winter, or absent, during the night. As a consequence PV systems require electricity storage that can be realised

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by means of batteries in stand alone systems or by means of the public power distribution grid in grid-connected systems. Stand alone PV systems are suitable in places where electric grid is unavailable and for low power requirements since a high battery capacity needs high investment and maintenance costs, which are not present in grid-connected systems. Energy generated by photovoltaic modules in greenhouse farms that exceeds the equipment energy needs can be inserted into the grid and sold to other utilities. The economic viability of photovoltaic systems, which are grid connected, depends on the produced energy; utilities in Italy and Israel pay approximately 0.40 and 0.35 €, respectively, per kWh produced by the PV generator. Grid connected PV systems in Southern Italy have a financial pay back time between 9 and 10 years with public incentives; in fact the investment cost of a PV system is approximately 5,000-6,000 € per kWp (peak power), the yearly production of electricity in Southern Italy at a latitude of 41° N is 1,300–1,400 kWh kWp-1, the cumulative yearly solar radiation on horizontal surface being more than 5 GJ m-2. The use of PV systems in Northern European countries is less profitable, the yearly production of electricity in the Netherlands at a latitude of 52° N can be estimated in 860 kWh kWp-1 (JRC European Commission, 2009). Tests have been conducted at the experimental farm of the University of Bari, latitude of 41° N, on stand-alone and grid connected PV systems (Figure 9); the electrical energy produced was used for powering 4 fans of the ventilation system of an arched roof greenhouse covered with a plastic film. The electricity obtained during the tests ranged from 2.2 kWh d-1 kWp-1 in December to 4.9 kWh d-1 kWp-1 in July.

Figure 9. Photovoltaic modules supplying greenhouse equipment at the experimental farm of the University of Bari, Italy.

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The control system was designed to maximise the consumption of the energy at the time of its production, reducing the stored energy. It is a design requirement both for stand alone and for grid connected systems, reducing the battery bank size in stand-alone systems and the losses for electric power transmission for grid connected systems. For this purpose the number of the working fans was correlated both to the greenhouse air temperature and to the level of solar radiation in order to generate and use electricity at the same time; Figure 10 shows the external and greenhouse air temperature, the solar radiation and the power delivered to the fans by the PV system. 1000

40 Ext. Solar Radiation, Wm-2 Fans Power, W Ext. Air T, °C Greenhouse Air T, °C

900

35

30 700 25

600 500

20

400

15

temperature, °C

radiation, Wm-2 / fans power, W

800

300 10 200 5

100

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2300

2200

2100

2000

1900

1800

1700

1600

1500

1400

1300

1200

1100

900

1000

800

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0

0

0

hour

Figure 10. External and greenhouse air temperature (°C), solar radiation (Wm-2) and power delivered to the fans (W) by the photovoltaic system at the experimental farm of the University of Bari, Italy.

Electricity available during the warm season can be used to feed greenhouse cooling systems such as fans, fog and pad evaporative systems, while during cold periods greenhouse heating systems use generally fuels, such as diesel fuel or gas, but rarely electricity. Electrical energy generated by means of renewable sources could be applied to heating systems based on ground-source heat pumps and pond water heat pumps. The main drawback of photovoltaic systems concerns the high costs related to the poor efficiency of the solar cells. The performance of PV systems can be improved by means of the introduction of photovoltaic concentrators (CPV), which use less expensive lenses or mirrors as receiving surfaces in place of solar cells. With such systems the sun radiation is concentrated on high efficient solar cells of reduced surface (Whitfield et al., 1999). Such systems have high technological complexity requiring accurate tracking to follow the sun in order to maintain the focus of the concentrated incoming radiation on the solar cell. Concentration photovoltaic systems have been developed by utilities for power plants but no application at greenhouse farm level has been tested so far. Greenhouses are suitable for the

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Giuliano Vox, Meir Teitel, Alberto Pardossi et al.

application of CPV systems because they are characterized by the production of electrical energy combined with heat which should be removed. The produced waste heat could be used as integration of the greenhouse heating system in cold periods and in systems based on absorption chillers for greenhouse cooling in warm periods. Photovoltaic modules as well as concentrating systems can be installed on the ground of the farm outside the greenhouse area, facing south without shading obstacles. Integration of such systems in greenhouse structure is possible however; shadows on the cultivated area inside the greenhouse should be avoided. Concerning integrated systems in greenhouse structures, Souliotis et al. (2006) proposed the use of transparent glass type Fresnel lenses as greenhouse covering material in order to concentrate the direct fraction of solar radiation on photovoltaic receivers positioned inside the greenhouse and lowering the greenhouse air temperature when necessary. It is an application that requires the study of suitable greenhouse structures and that meets the microclimate requirements of Mediterranean greenhouses.

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2.5.2. Wind Turbines for Greenhouse Systems Wind turbines, which generate electrical energy, can be integrated in a stand-alone system or can be connected to the grid. Today, large wind turbines with a power of 2-3 MW can generate electricity for less than 0.05 € per kWh, a price that is competitive with power plants using fossil fuels, but investment cost and maintenance make large wind turbines suitable more for utilities than for greenhouse farmers.

Figure 11. 1 kW wind turbine at the experimental farm of the University of Bari, Italy.

Small wind turbines with a power of 1–20 kW are less competitive; annual mean wind speed of the site, installation and maintenance costs must be carefully evaluated to assess the economic viability of the installation. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Many small wind turbines start generating energy at wind velocity of 3–4 ms-1, while the maximum energy is obtained with wind velocity of 10–15 ms-1. Tests carried out at the experimental farm of the University of Bari (Figure 11) showed that 1 kW wind turbine produced an average daily value of 0.53 kWh of electrical energy. The site was characterized by an average yearly wind velocity of 2.6 ms-1 and a percentage of wind, occurring over the threshold of 4 ms-1, equal to 17.3 %.

3. COVERING MATERIALS E. Schettini and G. Vox

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3.1. Introduction Covering materials, which protect crop from adverse weather conditions, influence the greenhouse microclimate modifying the growing conditions of the crop in comparison with the external climatic conditions. Glass, semi-rigid plastics, plastic films and plastic nets are the most widely used greenhouse covering materials. The capacity of the covering materials to modify the greenhouse microclimate depends strongly on their radiometric properties, mainly the transmissivity, which is expressed by means of transmissivity coefficients. They are calculated as average values of the spectral transmissivity, (), over different wavelength intervals, i.e., the solar range, the PAR range and the long wave infrared radiation (LWIR) range, whereas () represents the fraction of the incident energy radiant flux that is transmitted at a specific wavelength  (Papadakis et al., 2000). For purposes of calculating radiometric coefficients of materials in the solar range, the spectral distribution of solar radiation at the earth‘s surface must be taken into account as a weighting function. Solar radiation received at the surface of the earth has a spectral distribution so that about 50% of the total energy is emitted in the near infrared radiation (NIR) range (700–2,500 nm) and about 40% in the PAR range (400–700 nm), where the solar radiation has a maximum at a wavelength of about 500 nm (Duffie and Beckman, 1991). The transmissivity coefficient in the solar wavelength range, solar, from 300 nm to 2,500 nm, represents the fraction of the overall solar radiation passing through the material. The higher the value of the solar transmissivity coefficient, the higher is the rise of the air temperature inside the greenhouse. Solar radiation in the PAR wavelength range is necessary for photosynthesis which is the basic process for crop production (Monteith and Unsworth, 1990). The transmissivity coefficient in the PAR range, PAR, which expresses the quantity of solar PAR radiation transmitted by the covering material, strongly influences crop growth and yield. Generally, greenhouse covering materials must have high values of the PAR coefficient. Another radiometric property is the reflectivity that also affects the greenhouse microclimate: the higher the reflectivity coefficient of the covering material, the lower is the increase of the temperature inside the greenhouse. Long wave infrared radiation energy losses from a protected volume depend on the transmissivity of the covering material in the LWIR range, which extends for wavelength values higher than 3,000 nm. However, the LWIR

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transmissivity coefficient, LWIR, is defined as the average value of the spectral transmissivity in the range 7,500–12,500 nm, where the bodies at ambient temperature have the maximum energy emission as expressed by Planck‘s spectral distribution of emissive power (Siegel and Howell, 1972). The indoor greenhouse air temperature rises with the decrease of the LWIR transmissivity coefficient of the greenhouse covering material. Greenhouse air temperature is also affected by the emissivity of the material which is a measure of the thermal radiative energy emitted in the LWIR range by the covering material: the higher the emissivity coefficient of the external surface, the higher are the energy losses from the material and from the whole protected volume. Since energy losses through the covering material are high, the radiometric properties of the greenhouse cover play an important role in reducing energy consumption. Sustainability of greenhouse industry can be increased with innovative covering materials aimed to obtain energy savings in greenhouse heating and cooling together with profitable yield. Besides, covering materials able to modify the spectral distribution of the solar radiation can be used to influence plant growth in place of agro-chemicals. In recent decades research has been addressed to improve the radiometric properties of glasses and more recently of plastic films that are the most widespread greenhouse covering materials. In protected cultivation, the yearly consumption of plastic films as greenhouse coverings and for soil mulching is about 1.3 million tonnes (Jouët, 2001) with the generation of huge quantities of after-use plastic. Such wastes are often heavily contaminated with soil and agro-chemicals making the recycling process time-consuming and expensive so that plastic waste is often burned in uncontrolled conditions or left on the side of the field (Kapanen et al., 2008); the use of biodegradable films that can be disposed of in the field is a sustainable solution to the problem. Biodegradable film can be used in a profitable way also to mulch the growing substrate, which is a practice often applied in greenhouse industry. The main advantages of the mulches are the decrease of the use of chemicals in weed control, the reduction of water consumption, the faster crop development, the improvement of the plants health and of the product quality. Transparent mulching films can be used for soil sterilization by means of solarization practice, heating up the higher layers of the soil in greenhouse to temperatures lethal for a wide range of soil-borne pathogens thus reducing the use of agro-chemicals. The following paragraphs describe how research has been recently addressed towards sustainable materials aimed to obtain energy savings, plant growth control and to reduce after-use wastes.

3.2. Covering Materials and Energy Saving Among the greenhouse covering materials glass is characterized by a very low LWIR transmissivity coefficient (Table 1) that strongly reduces the energy radiative transfer from inside to outside the greenhouse. Low transmissivity values imply for glasses high values of emissivity, which causes energy losses due to the high infrared emission from the outside glass surface and partially reduces the advantage related to the low LWIR transmissivity. The use of low-emission glass, which has a coating of low-emissive metal oxide on the external surface, reduces the LWIR radiative thermal losses; it allows higher greenhouse temperatures thus obtaining energy savings in greenhouse heating. Another sustainable solution to reduce energy consumption for heating is the use of double-wall glass, which allows a decrease of

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the convective energy losses; the drawback of the double-wall glass is the reduction of the transmissivity in the solar range up to 8%–10%; such reduction can be attenuated with the application of anti-reflection coatings, which increase solar transmissivity by 6.8%–7.4% (Hemming et al., 2009). For purpose of reducing greenhouse temperature during the warm periods, glasses filtering out NIR solar radiation can be used in warm areas, where energy consumption for greenhouse cooling is high. Shading, which is another method to reduce high air temperatures, is obtained by means of plastic nets that are mounted generally above the greenhouse covering materials or on screen-house structures. Nets, which are permeable to air flow, are generally made with polypropylene (PP) or high density polyethylene (HDPE). Nets are characterized by the shading factor that represents the capacity of the net to reduce the incoming solar radiation and that can range from 10% to 90%. Net mesh size, which is the distance between two threads in warp or weft direction, varies from 0.2 mm to 3.1 mm for insect nets, from 1.7 mm to 7.0 mm for shade nets, from 2.5 mm to 4.0 mm for anti-hail nets, from 1.8 mm to 7.0 mm for windbreak nets, while higher values, 3–4 cm, characterize the anti-birds nets (Briassoulis et al., 2007; Castellano et al., 2008). Table 1. Transmissivity coefficients of different greenhouse covering materials; PAR, photosynthetically active radiation; LWIR, long wave infrared Transmissivity coefficients, % Thickness, mm

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solar PAR LWIR

Glass 4 80.4 87.5 0.0

LDPE 0.180 88.6 91.0 53.7

EVA 0.180 89.1 89.7 25.9

ETFE 0.100 93.1 92.4 10.9

Unlike glass, plastic films are characterized by low cost and require a lighter and cheaper support frame. They are characterized by good mechanical and thermo-optical properties, chemical resistance, opposition to microbial degradation, as well as by easy processability. Over the last decades several kinds of plastic films for greenhouse covering have been developed using different raw materials and additives. Low density polyethylene (LDPE) based plastic films, which are the most widespread greenhouse covering materials, are characterized by good mechanical and radiometric properties. Figure 12 shows the transmissivity in the solar range of a glass and of a LDPE film, the latter being characterized by higher transmisivity; unfortunately LDPE films have generally high values of the LWIR coefficient as well (Table 1). Due to their lower LWIR transmissivity polyethylene-co-vinyl acetate (EVA) films have been introduced as alternative to LDPE films (Figure 13), allowing reductions of the thermal infrared losses with consequent energy savings in greenhouse heating. More recently ethylene–tetrafluoroethylene copolymer (ETFE) films have been developed; such innovative materials are characterized by very good radiometric properties, i.e., high transmissivity in the solar range and low transmissivity in the LWIR range (Figure 13; Table 1). ETFE films have costs higher than LDPE and EVA films and a useful life of 10–15 years longer than the life of LDPE and EVA films, which ranges from some months to 3–4 years.

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glass EVA LDPE 80

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Figure 13. Long wave infrared (LWIR) transmissivity of a glass (thickness: 4 mm), of a low density polyethylene (LDPE) film (180 m), of a polyethylene-co-vinyl acetate (EVA) film (180 m) and of an ethylene–tetrafluoroethylene copolymer (ETFE) film (180 m), in the wavelength range 3,000– 25,000 nm.

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3.3. Covering Materials as Growth Regulators

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Plastic films and nets can be designed with the aim of modifying the spectral distribution of the solar radiation passing through the cover in order to influence plant vegetative and productive activity (Clifford et al., 2004; Rajapakse et al., 1999; Shahak et al., 2004), which is often controlled by means of agro-chemicals (Wilson and Rajapakse, 2001). Greenhouse industry sustainability can be increased using covering materials as plant growth regulators in place of agro-chemicals. Variations of red (R, 650–670 nm), far-red (FR, 720–740 nm) and blue (B, 400-500 nm) radiation in the growing environment affect plant photomorphogenesis involving the activation of photoreceptors, such as the phytochrome and the cryptochrome. The phytochrome response is characterized in terms of the R/FR ratio of the photon fluence rate in the red to that in the far-red (Kittas and Baille, 1998; Kittas et al., 1999; Murakami et al., 1996; Oren-Shamir et al., 2001; Smith, 1982; Takaichi et al., 2000). Significant increases of the growth and of the elongation of shoots were pointed out in peach and cherry trees grown under a photoselective film that reduced the R/FR ratio to 0.93, from the value 1.15, which was recorded in open-field at the University of Bari (Italy). Tests carried out on ornamental plants showed that the increase of the R/FR ratio has a dwarfing effect on the plant growth (Smith, 1982). Figure 14 shows the transmissivity of a photoselective film that reduces the R/FR ratio of the photon fluence rate in the red to that in the far-red by means of different values of transmissivity in the red and in the far red wavelength range.

Figure 14. Total transmissivity of a photoselective film that reduces the R/FR ratio of the photon fluence rate in the red (R, 650–670 nm) to that in the far-red (FR, 720–740 nm), in the wavelength range 200–800 nm.

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Experimental tests carried out using photoluminescent films at the University of Bari (Italy) and tests performed using coloured nets by Ovadia et al. (2009) showed that an increase of the vegetative activity can be induced under covering materials that increase red radiation in comparison with the other radiation of the solar spectrum, while a dwarfing effect can be obtained under covering materials producing a higher level of blue radiation. Figure 15 shows the transmissivity of a red and of a blue net, filtering out part of the solar spectrum in order to raise the relative level of red (600–700 nm) and blue radiation (400–500 nm), respectively.

Figure 15. Total transmissivity of a red and of a blue net in the wavelength range 300–800 nm; the nets filter out part of the solar spectrum to raise the relative level of the red (600–700 nm) and blue radiation (400–500 nm), respectively.

3.4. Plastic Films Lifetime LDPE and EVA film lifetime ranges from some months to 3–4 years as a function of the plastic film thickness and of the additives; the useful life is reduced by the degradation of the polymer induced by the prolonged exposure to solar radiation, wind, high air temperature and relative humidity, and to agro-chemicals used during cultivation (Briassoulis, 2005; Desriac, 1991; Lemaire, 1993; Vox and Schettini, 2007). The plastic film degradation is characterised by discoloration, cracking of surface, stiffening, and a decrease in the physical and mechanical properties up to rupture (Figure 16). The ageing degradation process is caused mainly by the ultra violet (UV) radiation in the solar spectrum, especially by UV-B and UVA radiation, that occur in the wavelength range from 280 nm to 400 nm (Nijskens et al.,

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1990). Degradation of the physical and mechanical properties of greenhouse films results in the generation of huge quantities of plastic wastes (Figure 17) that must be removed needing a correct collection, disposal of and recycling process, thus reducing the sustainability of the greenhouse industry.

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Figure 16. Rupture of a greenhouse covering film due to the ageing degradation in field.

Figure 17. Post-using plastic waste of greenhouse covering films nearby a greenhouse area in Italy. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Research has been addressed in order to extend the life of the LDPE and EVA films, thus reducing the amount of post-use plastic wastes. In order to extend film lifetime, UV stabilizers, such as UV absorbers, hindered amine light stabilisers (HALS) and nickel quenchers, can be added to mitigate degradation through the prevention of solar radiation absorption as well as minimizing any subsequent radical oxidation reactions (Sanchez-Lopez et al., 1991; Vox et al., 2008b).

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3.5. Biodegradable Materials Petroleum based plastic films are widespreadly used in greenhouse industry as covering materials and for soil mulching. In recent decades, a growing environmental awareness has been prompting research to develop biodegradable materials for agricultural purposes formed with raw materials from renewable origin to be used as environmentally friendly alternatives to synthetic petro-chemical polymers (Avella et al., 2001; Avella et al., 2007; BIO.CO.AGRI., 2005; BIOPLASTICS, 2005; De Prisco et al., 2002; Gáspár et al., 2005; Imam et al., 2005; Immirzi et al., 2003; Kapanen et al., 2008; Kaplan et al., 1993; Kyrikou and Briassoulis, 2007; Lawton, 1996; Malinconico et al., 2008; Russo et al., 2004; Russo et al., 2005; Tzankova Dintcheva and La Mantia, 2007). These materials have to retain their physical and mechanical properties while in use, and at the end of their life they are integrated directly in the soil where bacteria flora transforms them in carbon dioxide or methane, water and biomass; alternatively they can be blended with other organic material, to generate carbon rich composts (Chandra and Rustgi, 1998; Doran, 2002; Kaplan et al., 1994; Malinconico et al., 2002; Narayan, 2001). Thermo-plasticizing, casting and spraying processes have been employed to perform biodegradable materials for agricultural scope. Natural polymers such as starch (Bastioli, 1998; Lawton, 1996; Gáspár et al., 2005; Marques et al., 2006), cellulose (Immirzi et al., 2003), chitosan (Mormile et al., 2007), alginate (Mormile et al., 2007; Russo et al., 2005; Immirzi et al., 2009) and glucomannan (Schettini et al., 2007) have been experimented and tested in the frame of the employment of new eco-sustainable materials for agricultural applications. Thermoplasticised extruded starch-based films (Mater-Bi, Novamont Co., Novara, Italy) (Bastioli, 1998), tested as low tunnel and soil mulching films within the project ―BIOPLASTICS‖ (BIOPLASTICS, 2005; Briassoulis, 2004a, 2004b and 2006a; Malinconico et al., 2008; Scarascia-Mugnozza et al., 2004; Scarascia-Mugnozza et al., 2006; Vox and Schettini, 2007), were obtained with the same film extrusion line used to extrude and blow commercial LDPE films, with minor modifications (Briassoulis, 2006b and 2007), in this way ensuring economic viability. These biodegradable extruded starch-based films can be installed by means of the same machine used for laying LDPE films, with the same work speed and gear. An innovative approach, developed within the project ―BIO.CO.AGRI.‖ (BIO.CO.AGRI., 2005), consisted of forming mulch coating directly in field by covering the soil with a thin protective geo-membrane obtained by spraying water-based solutions of natural polysaccharides, such as sodium alginate, glucomannan, chitosan and cellulose (Avella et al., 2007; Immirzi et al., 2009; Malinconico et al., 2008; Mormile et al., 2007; Schettini et al., 2007). In the polymeric water solutions natural plasticizers, fillers and coloured pigments can be dispersed to assure the mechanical resistance and suitable

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radiometric properties of the coating during cultivation (Immirzi et al., 2009; Kamel et al., 2004; Urreaga and de la Orden, 2006). The coatings, able to follow the unevenness of the soil surface, were obtained when the water content of polymeric network was removed through evaporation. The spray technique, used by the farmers to spread agro-chemicals during the cultivation, could be a suitable alternative to the mechanical setting up and removal of plastic pre-formed films, in this way contributing to a reduction of the labour cost. The biodegradable starch-based films and water-born coatings described in this chapter are materials at an experimental stage so their functionality was investigated by means of several cultivation field tests and laboratory tests. The requirements concerning their mechanical and physical properties have not been defined by international standards so far. The LDPE films currently used for low tunnel covering and soil mulching must satisfy standards such as EN 13206 (EN 13206, 2001) and EN 13655 (EN 13655, 2002).

3.5.1. Thermoplasticised Extruded Starch-Based Films The research carried out within the project ―BIOPLASTICS‖ (BIOPLASTICS, 2005) showed that the thermoplasticised extruded starch-based biodegradable films had mechanical and radiometric properties and performance in field (Figures 18 and 19) suitable for them to replace LDPE films both as low tunnel and as soil mulching films (Briassoulis, 2004a, 2004b and 2006a; Malinconico et al., 2008; Scarascia-Mugnozza et al., 2004; Scarascia-Mugnozza et al., 2006; Vox and Schettini, 2007). The mechanical and the radiometric behaviour of the biodegradable films were influenced by the film thickness, by the different kind and quantity of biodegradable master batches and of stabilizers used, and, furthermore, by the manufacturing processes (Vox and Schettini, 2007; Briassoulis, 2006a). As happens to LDPE films, the ageing process due to their exposure to atmospheric agents and to agro-chemicals used during cultivation affected the physical and mechanical properties of the biodegradable materials. It has been proven that the mechanical and radiometric properties of the biodegradable films continued to be in the range necessary for agricultural applications during their useful life (Briassoulis 2006a, 2006b and 2007; Malinconico et al., 2008; ScarasciaMugnozza et al., 2004; Scarascia-Mugnozza et al., 2006; Vox and Schettini, 2007).

Figure 18. Biodegradable melt-extruded mulching film inside the greenhouse at the experimental farm of the University of Bari, Italy. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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% on initail weight

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Figure 19. Biodegradable melt-extruded low tunnel and mulching films at the experimental farm of the University of Bari, Italy. 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0

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Figure 20. Variation of the residues in the soil of a 50 m and a 25 m biodegradable melt-extruded mulching films, as a function of the burying time, recorded at the experimental farm of the University of Bari, Italy.

The biodegradable nature of the raw material indicates that starch-based films can be fully considered for eco-sustainable use in agriculture: these materials degrade to harmless end products in the soil within a reasonable time frame (Kapanen et al., 2007). Figure 20 shows the degradation of the residues of two biodegradable mulching films, characterised by

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different thickness, buried in the field soil after the tillage performed at the end of the cultivation period: after 12 months the residues were less than 4% of the initial weight of the installed film. The results obtained by Kapanen et al. (2007) showed that the thermoplasticised extruded starch-based biodegradable films did not cause any environmental risk to the agricultural soil. Low Tunnel Films The EN 13206 Standard (EN 13206, 2001) establishes for LDPE and EVA films used as greenhouse covering the minimum values of tensile stress and tensile strain at break. The mechanical tests carried out on the biodegradable low tunnel films before the installation in the field showed a comparable or, in some cases, inferior mechanical behaviour to that of the corresponding commercial LDPE low tunnel films in terms of tensile strength in both the directions (Briassoulis, 2006b, 2007). Variability in the thickness was significant so it influenced the mechanical laboratory tests (Briassoulis, 2006a). During the field experiments the biodegradable low tunnel films retained a satisfactory mechanical performance over their useful lifetime (Briassoulis, 2006a, 2006b, 2007; Scarascia-Mugnozza et al., 2004; Vox and Schettini, 2007). The lifetime of the biodegradable low tunnel films ranged from 3 to 9 months as a function of the UV stabilizers and of the thickness (Briassoulis, 2006a); thinner low tunnel films were used for shorter cultivation covering period. Future developments of the research will be addressed on UV stabilizers suitable to extend the film lifetime and to increase the mechanical resistance in order to obtain biodegradable covering films having a roll width up to 8–10 m, useful for covering larger tunnel or greenhouse structures. 100

total - LDPE film 90

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Figure 21. Total and diffuse spectral transmissivity of a low density polyethylene (LDPE) low tunnel film (40 m) and of a biodegradable melt-extruded low tunnel film (30 m), in the wavelength range 200–2,500 nm.

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Giuliano Vox, Meir Teitel, Alberto Pardossi et al. Concerning the radiometric properties, the

total coefficient varied from 80.81% to  solar

88.13% (Vox and Schettini, 2007). The biodegradable low tunnel films can be compared to thermic diffusing covering films in accordance with the EN 13206 Standard (EN 13206; 2001) for LDPE and EVA films; moreover these values are comparable with the coefficient of anti-fogging (82.8%) and diffuse (79.8%) LDPE films for greenhouse covering as reported by Pearson et al. (1995). These films are characterised by high radiation scattering capacity like the biodegradable films. Figure 21 shows the total and diffuse transmissivity in the solar range of a LDPE film and of a biodegradable low tunnel film, the latter was characterised by a high capacity to diffuse solar radiation, mainly in the PAR wavelength range. Because of the high

diffuse coefficients, ranging from 45.13% to 75.51% (Vox and Schettini, 2007),  solar

solar radiation was uniformly scattered under the low tunnels covered with the biodegradable films, having a positive effect on plant growth and reducing the incidence of scorch (Pearson et al., 1995). 100

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Figure 22. Long wave infrared (LWIR) spectral transmissivity of a low density polyethylene (LDPE) low tunnel film (40 m) and of a biodegradable melt-extruded low tunnel film (40 m), in the wavelength range 2,500–25,000 nm.

The biodegradable low tunnel films reduced the radiative energy losses from the enclosed volume in the LWIR range much better than the LDPE films due to their low  LWIR coefficients (2.98%–31.27%) (Vox and Schettini, 2007). Figure 22 shows the huge differences of the spectral trasmissivity in the LWIR range of a biodegradable low tunnel film compared to a commercial LDPE low tunnel film. The lowest value of the  LWIR coefficient

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among the biodegradable low tunnel films (2.98%) was lower than the coefficients of the best thermic LDPE and EVA films (>12%) used for greenhouse covering (Papadakis et al., 2000; von Zabeltitz, 1999). The microclimate under the biodegradable films was positively influenced by the capacity of the biodegradable films to reduce the LWIR energy losses from the low tunnel. During the night when the LWIR radiation energy exchange plays an important role, the air temperature inside the protected volumes with biodegradable materials was always warmer than the air temperature under the low tunnels covered with LDPE films. Soil Mulching Films Although the starch-based mulching films tested were characterised by values of tensile stress and strain at break lower than the values required for LDPE films (EN 13655, 2002), their mechanical properties were sufficiently in the range necessary to be used in the period from planting to harvesting, applying the same cultivation techniques currently used for LDPE mulching films (Vox et al., 2005; Briassoulis, 2006a; Malinconico et al., 2008; Scarascia-Mugnozza et al., 2006). In fact, during the crop cycles the edges of the biodegradable mulching films buried continued to satisfy their function to hug the soil bed by stretching the film. The starch-based mulches lasted in the field for a period from 5 to 9 months (Scarascia-Mugnozza et al., 2006; Vox et al., 2005), a lifetime longer than the one of other biodegradable films of similar thickness reported in literature (Halley et al., 2001; Martin-Closas et al., 2002; Novamont, 2009; Shogren, 2000; Tocchetto et al., 2002). The EN 13655 standard (EN 13655, 2002) states that, independently of their thickness, black LDPE plastic mulching films must have a

total coefficient less than 0.01 %. The  PAR

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biodegradable black mulching films with a thickness higher than 25 m met the standard total while, for thinner black films,  PAR ranged from 0.00% to 0.45% (Vox and Schettini, 2007). All the biodegradable black mulching films, however, inhibited weed growth in the period from planting to harvesting like the black LDPE films did, satisfying in the field one of the main task of mulch.

3.5.2. Water-Born Sprayable Coatings Innovative sprayable biodegradable water-born solutions were tested as growing media mulching coatings in greenhouse cultivation. Such coatings, developed within the project ―BIO.CO.AGRI.‖ (BIO.CO.AGRI., 2005), were obtained using natural polymers coming both from terrestrial origin, such as cellulose and glucomannan, and from marine origin, such as chitosan and alginate (Avella et al., 2007; Immirzi et al., 2003; Immirzi et al., 2009; Mormile et al., 2007; Malinconico et al., 2008; Russo et al., 2005; Schettini et al., 2007; Schettini et al., 2008). Plasticizing polymers, such as hydroxyethylcellulose, and natural plasticizers, such as glycerol and polyglycerol, were included in the aqueous polymeric blends to improve the mechanical response of the mulching coatings. Carbon black and fillers, such as cellulose fibres, fine bran of wheat and powdered seaweeds, can be used together with the polymeric matrices in order both to improve the mulching function and to increase the tensile strength of the coating formed upon drying. One polymeric blend consisted of a water mixture of glucomannan (PSS20 Protective Surface System, PSI Polysaccharide Industries AB, Stockholm, Sweden) with the addition of a non-gelling concentration of agarose and of glycerol (Malinconico et al., 2008). This blend was used both as it was (Figure 23) and with carbon black (Figure 24). To the blend used as it

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was cellulose fibres were added as reinforcing fillers, so the coating was waterproof due the employment of cellulose, a polysaccharide with an enhanced resistance to wet environment (Schettini et al., 2007). As alternative the carbon black was dispersed into the blend in order to make the coating opaque to the PAR solar radiation to prevent the spontaneous weeds growth (Schettini et al., 2008).

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Figure 23. Spray biodegradable coating realised on growing media in greenhouse using a transparent polymeric blend at the University of Bari, Italy.

Figure 24. Spray soil mulching performed with a black biodegradable water-born coating inside the greenhouse at the experimental farm of the University of Bari, Italy.

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Another polymer selected as the matrix to be sprayed was sodium alginate, a polysaccharide obtained from seaweeds; hydroxyethylcellulose and polyglycerol were added to improve the mechanical behaviour of the coating (Immirzi et al., 2009). This blend was sprayed on the soil previously covered with a pulverized mixture of seaweeds flour and fine bran of wheat to provide a fibrous bed of natural materials (Figure 25).

Figure 25. Spray soil mulching realised with a biodegradable water-born coating inside the greenhouse at the experimental farm of the University of Bari, Italy; the spray was performed on a raised bed covered by fillers.

Quantity of the water-born solution determines coating‘s thickness and lifespan from few weeks to few months, as a function of the crop cycle. The solutions can be applied on the soil by means of an airbrush using a spray machine, which is commonly used in agriculture. Soil preparation, such as ploughing and tilling, does not differ from those performed for the installation of extruded films. The soil should be loose and refined and the surface should be as flat as possible in order to prevent holes and cracks of the coatings that can facilitate weed development. The side slope of raised beds should be limited in order to avoid a possible sliding of the water-born coating at the liquid state during the spraying before the dry process. In case of seeds or bulbs sowed before the spraying, buds hole the coatings without any problem (Figure 26) while seedlings transplanting can be performed holing the coating when the drying process of the coating is completed (Figure 27).

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Figure 26. Spray mulching coating holed by the bud at the experimental farm of the University of Bari, Italy.

Figure 27. Holing of the coating before seedling transplanting inside the greenhouse at the experimental farm of the University of Bari, Italy.

The biodegradable water-born coatings described in this chapter blocked weeds growth during the crop cycle satisfying the mulching task of weed control such as LDPE and starch-

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total coefficient of the sprayed  PAR

coatings varied from 0.10% to 7.89% while the EN 13655 standard (EN 13655, 2003) states

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that black LDPE mulching films must have a

total coefficient less than 0.01% (Schettini et  PAR

al., 2008; Malinconico et al., 2008). The water-born coatings, characterised by transmissivity coefficients in the LWIR range lower than 1%, can increase the temperature regime of the mulched soil thanks to their high capacity to reduce the radiative LWIR losses (Schettini et al., 2007; Schettini et al., 2008; Malinconico et al., 2008). Because of their composite nature the water-born coatings were characterised by inhomogeneous surfaces and irregular thickness, which varied from 1.5 to 5 mm. Differently to LDPE and biodegradable extruded films, laboratory mechanical testing methods cannot be applied for the water-born coatings. It was not possible to evaluate the mechanical properties of the water-born coatings by testing the composites obtained spraying the solution onto a model support, since it could not reproduce the interaction between the coating and the soil found in the field. Also, the particular physical structure of the water-born coating did not allow the application of tensile and/or shear tests because these methods are not indicators of the real behaviour of the coating itself. To simulate the mechanical performance in terms of resistance to hail or rain, Malinconico et al. (2008) proposed a new test, called ―puncture test‖. Due to the innovativity of the test, it was not possible to compare the values obtained with the puncture test with the mechanical requirements established by the EN 13655 standard (EN 13655, 2003) and also with the values measured for the biodegradable starchbased extruded mulching films described in this chapter. The mechanical performance and the radiometric properties of the biodegradable waterborn coatings were adequate for their durability and functionality from planting to harvesting and their lifetime was from 3 to 6 months (Immirzi et al., 2009; Malinconico et al., 2008; Schettini et al., 2007; Schettini et al., 2008). The coatings created a physical barrier to prevent airborne weed seeds. The lifetime of the biodegradable mulching coatings decreases if they are used in the open field rather than inside a greenhouse since the life depends on several climatic factors, particularly rainfall, hail and wind. In greenhouse industry, sprayable mulching coatings are particularly suitable for plants grown in pots or trays where the application of extruded films require time and labour cost. At the end of the crop cycle the biodegradable water-born coatings were fragmented and mixed with plant residue and the soil. Experimental data showed that the time frame necessary for the degradation of the residues disposed of in the soil was at most 1 month (Malinconico et al., 2008; Schettini et al., 2007).

4. HYDROPONIC TECHNOLOGY A. Pardossi Soilless (hydroponic) culture, which was initially developed for studying plant mineral nutrition (Savvas and Passam, 2002), is thought to be one of the main elements of sustainable cropping systems under greenhouse conditions (Pardossi et al., 2006; Savvas and Passam,

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2002). In fact, the implementation of closed hydroponics may reduce drastically the use of water and fertilizers and the environmental pollution associated to over-irrigation, which is quite common in protected horticulture (Pardossi et al., 2006; Thompson et al., 2007). However, the application of closed-loop hydroponic technology is scarce on a commercial scale (Jouet, 2001; Pardossi et al., 2006) and, with the exception of The Netherlands where closed systems are obligatory, open (free-drain) culture is commonly used in protected horticulture, since its management is much simpler. Herein the main technical features of hydroponic technology are illustrated and the possible environmental implications associated to its application in commercial greenhouses are discussed.

4.1. Techniques

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Hydroponics is a broad term that includes all techniques for growing plants in media other than soil (substrate culture) or in aerated nutrient solution (water culture). The classification of soilless culture considers the type of substrate and container, how the nutrient solution is delivered to the plant (drip irrigation; subirrigation; flowing, stagnant or mist nutrient solution culture) and the fate of the drainage nutrient solution: open (free-drain) or closed (recirculating water) systems. The most widely used soilless techniques are drain-to-waste substrate cultivation, while water culture systems such nutrient film technique (NFT), floating culture and aeroponics are widely used for research work, but much less on commercial scale. Table 2 summarizes the main characteristics of different hydroponic techniques, including the growing risk associated to the technical failure of the equipments and to the occurrence of root diseases. Table 2. Foremost characteristics of various hydroponic techniques Substrate and drip Substrate and NFT irrigation subirrigation Large Large Scarce

Application for commercial production Type of crops Fruit vegetables Strawberry Cut flowers Growing media Yes (organic and/or inert) Recirculating solution Yes/no Investment costs Running costs System‘s buffer Growing risks

Moderate/high Moderate/high High Moderate

Floating system Increasing

Aeroponics Rare

Pot plants

Leafy Leafy vegetables vegetables Bulb flowers

Vegetables

Yes (organic) Yes

No

No

No

Yes

Stagnant or fairly static High High Low Moderate/high Moderate Low High Low High Moderate High Moderate

Yes Very high Fair/high Very low Very high

4.1.1. Substrate Culture Substrate culture is generally used for row crops, such as fruit vegetables (Solanancea, Cucurbits), strawberry and cut flowers (rose, gerbera, anthurium, etc.) (Figure 28). Different

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containers (banquette, pots, bags, slabs) are used filled with inorganic or organic substrate, or a combination of two or three different materials, such as the peat-perlite or peat-pumice mixture. An excess of nutrient solution (with respect to crop water requirement) is typically supplied to the crop by drip irrigation up. In the cultivation of pot ornamentals, subirrigation is increasingly adopted; the pots are cultivated in gullies with an intermittent flow of nutrient solution or in ebb-and-flow benches. Both open and closed system may be set-up for dripirrigated substrate culture. In closed systems, the drainage water is captured and reused following the adjustment of pH and nutrient concentration (namely, the electrical conductivity (EC)) and, eventually, disinfection to minimize the risks of root-borne diseases (Figure 29).

Figure 28. Long-cycle tomato culture in perlite bags in a greenhouse in Turkey.

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Figure 29. Layout of a closed-loop substrate culture. The nutrient solution is supplied by drip irrigation and the drainage water is recollected and reused after disinfection and the adjustment of pH and electrical conductivity (EC).

Many types of growing media are used. They are generally selected by the growers on the basis of their availability and cost (including shipping), as well as the local experience; however, any media should have the following characteristics: (i) low bulk density to facilitate the installation of otherwise weighty growing systems; high porosity (not less than 75–80%); (ii) a satisfactory distribution of air (oxygen) and water; sub-acid pH or easily adjustable, like sphagnum peat, which is quite acid and is neutralised with calcium carbonate; (iii) low salinity; (iv) chemical inertia, that is the material must not interfere with the nutrient solution by releasing inorganic ions and phytotoxic compounds, or by immobilising nutrients, as it may occur for phosphorus and nitrogen in some substrates (Lemaire, 1995); (v) the ability to maintain the original characteristics during the cultivation, which may be quite long (for instance, in rose culture); and (vi) the absence of pathogens and pests. Hydraulic properties are of particular relevance, in particular the water retention at container capacity, which is the amount of water and, for difference, of air retained by the container after complete water saturation and free drainage. While peat is largely used for pot ornamentals, the most popular growing media for growing row crops are perlite and rockwool, which are easy to handle, sterilise and re-use for a few years. In Europe, where soilless culture is more spread compared to other continents, the estimated yearly consumption of rockwool in professional horticulture is about 900,000 m3 against 140,000 m3 for perlite and 11.9 millions m3 for peat (European Commission, 2005). Mineral wool provides a sort of benchmark for growing media in consideration of their physical and chemical properties (high porosity, for instance) and the standardization of the products on the market. However, this substrate is generally produced (very) far from where greenhouses are concentrated; therefore, market price is high and, moreover, there is the problem originated by the disposal of exhausted material after a reasonable number of

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growing cycles, since it is not degradable. In some regions recycling or recovery options are not available to the growers, and exhausted slabs must be disposed to landfills. In Mediterranean countries, perlite, pumice and other volcanic material are widely used in soilless cultivations. Transportation generally represents the most important cost components for the growers; their main disadvantages are the low water holding capacity and the poor stability. The disposal of exhausted perlite seems easier compared to rockwool, since it could be used as soil conditioner. Alternative reuse is the production (close to greenhouse clusters) of blocks for construction industry. A study in this direction is currently carried out in Italy in the framework of a FP7 research project ―EUPHOROS‖ funded by the European Commission (EUPHOROS, 2008). Peat is appropriate for almost all horticultural crops, but it is used mostly for pot ornamentals and propagation materials (seedlings, cuttings and micro-propagated plantlets). In mixture with perlite, it is largely used also for bag culture of strawberry (Figure 30). Peat is produced primarily in Northern Europe and America. Nevertheless, the price of peat is increasing and in the last ten years an ―anti-peat‖ campaign have been originated in many European countries (Holmes, 2007), which has stimulated the search for alternative substrates. In most cases, these materials are based on industrial or municipal waste byproducts. At the moment the most important alternatives to peat are timber industry byproducts, coconut coir and high-quality green compost. Coir products are particularly promising.

Figure 30. Suspended bag culture of strawberry. This growing method culture reduces the requirements of hand-labour and make the fruits cleaner and less affected by Botrytis cinerea compared to soil culture.

4.1.2. Water Culture The most used water culture methods are NFT, floating raft systems and aeroponics, which are closed systems.

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Figure 31. Floating raft system for producing basil shoots in a plastic tunnel in Italy.

In NFT, a film of nutrient solution is recirculated (in general, intermittently) in lightinsulated plastic gullies where bare-rooted plants are planted. The high installation costs, the small buffering capacity and some still unresolved problems, like those related to both nonparasitic (root death; Cooper, 1979; Pardossi et al., 2000) and parasitic diseases of root system, have hampered the commercial application of NFT, which are generally used for short-season crops. In floating system the plants are grown in styrofoam trays (―rafts‖) placed on stagnant or fairly static nutrient solution. The system is mostly used for leafy vegetables, herbs, bulb flowers (especially tulips; James, 2002) (Figure 31). Aeroponics is another type of water culture technique where the plants are cultivated in holed plastic panels with the roots suspended in the air beneath the panel in the darkness in order to avoid the formation of algae. The roots are misted with nutrient solution very frequently, normally for a few seconds every 5–10 minutes. Aeroponics is an excellent tool for plant scientists; however, its application for commercial production is rare, since it is quite expensive and difficult to manage.

4.2. Water and Nutrient Supply With the exception of some cultivations of pot ornamentals where the fertilisation is provided by controlled release fertilisers incorporated in the substrate prior to planting, the water and mineral requirements of soilless-grown plant are fulfilled by means of soluble salts dissolved in the irrigation water (fertigation). The nutrient solution used for hydroponic crops

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contains all macronutrients (nitrogen, phosphorus, potassium, calcium, magnesium and sulphur) and micronutrients (iron, boron copper, manganese, zinc and molybdenum) at concentration of the order of milli-moles (mM) and micro-moles (M) per liter, respectively. Optimal pH values for the solubility and root uptake of nutrients are between 5.5 and 6.5. Depending on crop characteristics (e.g., tolerance to salinity) and stage, environmental conditions and hydroponic system, total molar concentration ranges between 20 and 40 mM with nitrate as a dominant ion. Plenty of different nutrient solution formulas have been published, which can be distinguished in two main types (Table 3): the more concentrated nutrient solutions are used for fast-growing crops, such as vegetables, while for ornamental plants and strawberry lower nutrient concentrations are normally used. In general, the same nutrient solution can be used for different crops, and that the same crop can be cultivated successfully with different nutrient solutions. Table 3. Typical range of macronutrient concentrations (mM) in the hydroponic nutrient solution used for different crop species

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N-NO3- N-NH4+ P Vegetable crops 14.0–15.0 < 1.0 1.5–2.0 Ornamentals and strawberry 10.0–11.0 1.0–3.0 1.0–1.2

K 7.0–8.0 5.0–5.5

Ca Mg S 4.0–5.0 1.0–1.5 2.0–3.0 3.0–3.5 1.0–1.2 1.5–2.0

4.2.1. Open Systems In substrate culture systems an excess of fresh (newly prepared) nutrient solution is generally supplied to overcome the difficulties associated the unequal transpiration of individual plants and to prevent the salt accumulation and the imbalance in the nutrient solution in the root environment. Typically, a drain fraction of at least 25–30% is used in substrate cultivation to prevent root zone salinisation. For this reason, in open soilless systems there is a massive waste of water and nutrients (Table 4), which is responsible for an increase in running costs and in a contamination of deep and surface water bodies. Table 4. Water and nitrogen balance of open-loop substrate (rockwool) culture (nearly four months under the typical greenhouse growing conditions of Central Italy) of greenhouse tomato

Water (m3 ha-1) Nitrogen (kg ha-1) Phosphorus (kg ha-1)

Supply 2,450 510 130

Crop uptake 1,840 352 95

Loss 610 158 35

Accurate irrigation scheduling is a pre-requisite to minimise drainage and runoff. Crop water needs can be estimated on the basis of climatic conditions in the greenhouse. Low-cost devices are now commercially available for irrigation control on the basis of simple measurement of solar radiation, and eventually of air temperature and humidity. Other control systems are based on the measurement of the water content in the substrate by different type of sensors, such as hydraulic tensiometer or dielectric probes (Pardossi et al., 2009a). Irrigation is automatically initiated when the substrate moisture (or tension) content drops below a pre-set value (typically, between 5 and 15 kPa) as moisture tension, which can be

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modulated according to crop transpiration as assessed through meteorological measurement (Norrie et al., 1994); typically, the moisture content of the substrate is increased with increasing transpiration. Whatever the approach to estimate the time of irrigation, water supply is normally adjusted on the basis of regular or online measurements of both volume and EC of the drainage solution; more irregularly, the EC of the substrate is also determined.

4.2.2. Closed Systems In closed systems, the drainage water is collected and re-circulated after proper adjustment of pH and nutrient concentration (as a matter of fact, EC) and, eventually, disinfection in order to prevent the diffusion of root diseases from infected plants. Closed systems have been developed to avoid the environmental problems related to nutrient runoff of open systems. Unfortunately, the use of closed loop hydroponics is scarce and, with the exception of The Netherlands where closed systems are compulsory, open (free drain) substrate cultures are usually used for greenhouse crops in reason of relatively easy management (Pardossi et al., 2006). In addition to the possible diffusion of root pathogens, the salinity of irrigation water represents the main difficulty for the management of closed growing systems. When only saline water is available to the grower, there is a more or less rapid accumulation of ballast ions (e.g., sodium and chloride) that are dissolved at concentration higher that the uptake concentration (i.e., the ion to water uptake ratio). Salt accumulation may result in a concomitant increase in the EC of nutrient solution, if the control strategy aims to maintain constant nutrient concentration, or in a parallel depletion of nutrients, if the fertigation is based on a feed-back control of EC. Under these conditions, the nutrient solution is generally recirculated till EC and/or the concentration of some toxic ion remain below an acceptable threshold, afterwards it is replaced, at least partially (the term ‗semi closed‘ is used for such systems). In the Netherlands, growers are allowed to flush out the exhausted nutrient solution whenever a crop specific ceiling of Na concentration is reached: for example, 8 mM in tomato and 4 mM in cut roses (Baas and van der Berg, 1999). Based on a simulation, Stanghellini et al. (2005) concluded that closed systems are not financially viable under stringent environmental rules when the quality of irrigation water is poor and that, under these circumstances, the most valuable strategy is the improvement of water quality by means of desalinization or rainwater collection. Nevertheless, on species with some salt tolerance (e.g., tomato and melon), the application of particular fertigation procedures may improve both crop sustainability by allowing the growers prolong the recirculation of the same nutrient solution and/or minimize the content of polluting agents, like nitrates and phosphates, in the effluents, when the water is discharged in the end. Apart from the development of smart, low-cost chemo-sensors for continuous monitoring of the ion concentration, the innovation specific to closed hydroponics concerns the application of procedures for fertigation management that are alternative to the conventional feed-back control of EC and pH. Indeed, the enthusiasm originated about chemo-sensors has decreased very much and probably in the next future there will be not a real commercial exploitation of these devices, at least for hydroponic management. However, the actual concentration of nutritive and nonnutritive ions in the recycling water could be monitored on a wider time scale (e.g. weekly)

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by using quantitative or semi-quantitative quick tests, such those employed in environmental or industrial sector, which are easy-to-use and cheap (Thompson et al., 2009). Both review (Klaring, 2001; Savvas, 2002; Bugbee, 2004; Pardossi et al., 2006) and research papers (Brun et al., 2001; Pardossi et al., 2002) were published on the procedures to control fertigation in closed hydroponic systems. However, only a few works were carried out to develop an appropriate management of nutrient solution recyling in the presence of saline water (Raviv et al., 1998; Bar-Yosef et al., 2001; Pardossi et al., 2002) and, among these, only the papers published by Raviv et al. (1998) and by Pardossi et al. (2002) reported a detailed study on the effect of fertigation procedure on crop yield, water and nutrient use efficiency and the environmental impact associated to the periodical discharge of exhausted nutrient solution. Other measures to reduce the environmental pollution provoked by nitrogen leaching in open or semi-closed soilless cultures with no important effects on crop yield are the programmed nutrient addition or the use of reduced nutrient concentration in the fertigation water (Maruo et al., 2001; Zheng et al., 2005; Munoz et al., 2008b) or nutrient starvation (Siddiqi et al., 1998; Le Bot et al., 2001; Voogt and Sonneveld, 2004). Programmed nutrient addition, which has been proposed for both experimental and commercial hydroponics (Ingestad and Lund, 1992), may represent an alternative method to control mineral nutrition of hydroponically-plants. In this case a desired rate of nutrient uptake is maintained, rather than a concentration set-point. In an experiment with NFT-grown melons, Pardossi et al. (2002) compared a conventional control system based on EC adjustment nutrient solution to a nutrient addition based on pre-established weekly supply of macronutrients, without any attempt to maintain constant EC. Compared to the EC control, the second procedure did not affect fruit yield but reduced significantly the use of water and fertilisers, and eliminated nutrient runoff. In a research conducted in two consecutive years with tomato plants grown in closedloop rockwool culture and using irrigation water with a NaCl concentration of approx. 9.5 mmol L-1, Pardossi et al. (2009b) tested three different fertigation strategies: (A) crop water uptake was compensated with fresh nutrient solution (EC = 2.5 dS m-1) and recirculating nutrient solution (RNS) was flushed out whenever EC exceeded 4.5 dS m-1; (B) EC was maintained at about 3.0 dS m-1 and RNS was flushed out whenever sodium concentration exceeded 20.0 mM and the concentration of nitrate was lower than 1.0 mM, a concentration considered acceptable from the environmental viewpoint (for instance, the maximum acceptable N concentration established by Italian legislation for the disposal of wastewater to surface water is 1.4 mM); and (C) as strategy A, but when the EC of RNS reached 4.5 dS m-1, crop water consumption was compensated with fresh water only in order to take out the nitrates from RNS before discharge. It was found that neither crop water uptake nor fruit yield was affected by the method to manage fertigation. However, the discharges of nutrient solution were much less in strategies A than in strategies B and C and this resulted in increased water and nutrient use as well as a more severe environmental impact due to nitrate leaching.

4.3. Advantages and Disadvantages Soilless culture may provide conditions for fast plant growth and development and abundant yield irrespective of the type of soil. However, advantages and disadvantages over

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the conventional soil have to be critically assessed when soilless culture is as a possible option for commercial production. The first advantage of hydroponic technology is that it eliminates the needs of soil disinfection with steam or pesticides. In this regard, soilless culture is considered one of the most viable alternatives to methyl bromide soil fumigation for greenhouse cultures, which was banned by the end of 2005. Moreover, hydroponic can reduce the crop‘s susceptibility to diseases by reducing the humidity inside the greenhouse and increasing the vigour of the plants. For instance, in strawberry, the suspended bag culture reduces considerably the susceptibility to gray mold (Botrytis cinerea), in addition reducing hand-labour for planting and harvesting. It is also possible to improve crop‘s resistance to some pathogens by specific manipulation of the nutrient solution composition. For instance, Savvas et al. (2009) reported that the supply of at least 1 mM of potassium silicate via the nutrient solution enhanced both tolerance to salinity and powdery mildew (Sphaerotheca fuliginea) in zucchini squash (Cucurbita pepo). Generally, the increased production of hydroponics over traditional soil cultures is a consequence of better growing conditions in both the root zone and in the aerial environment. In Italy, where hydroponics is developing slowly, many hydroponic installations failed not due to the scantiness of the greenhouse structure and the poor climate control. As a matter of fact, the occurrence of stressful temperature conditions, reduced CO2 concentration due to poor ventilation and low light transmission of covering materials cancelled out the stimulating effects on crop yield of hydroponic technology. As far as produce quality is concerned, the difference between soil culture and hydroponics has been investigated almost exclusively in vegetables. Of course, the vegetables grown hydroponically do not contain the residues of chemicals used for soil disinfection and, usually, they are very clean. This is essential, for instance, in the case of strawberry and of minimally-processed (fresh-cut) leaf and shoots vegetables. Moreover, an appropriate adjustment of the nutrient solution may represent an effective mean to improve crop quality. The removal of nitrogen from the nutrient solution during the last days of culture or the use of appropriate ammonium/nitrate ratio can reduce significantly the nitrate concentration of leafy vegetable that tend to accumulate large amount of these compounds potentially dangerous to human health (Santamaria et al., 2001). In cherry tomato the reduction of nitrogen content along with the use of high EC is the most effective method to reduce vegetative growth and improve the fruit content of sugars and acids. Soilless culture has also several shortcomings resulting from the low volume of the root zone that increases the risks of management mistake and environmental stress. For instance, high root zone temperature may reduce plant growth during summer and increase crop susceptibility to some root pathogens like Pythium (Pardossi et al., 1992). Actually, the heat stress in the root zone during summer is one of the main constraints to the development of hydroponics in the Mediterranean countries. Moreover, in closed systems the recirculating nutrient solution may increase the risk of root-borne diseases. In addition, some pathogens, like Fusarium oxysporum f. sp. radicis-lycopersici and Pythium itself, seem more virulent in soilless culture than in soil (Van Assche and Vaugheel, 1997; Ozbay and Newman, 2004). To avoid the risks of root diseases the nutrient solution can be disinfected by means of pasteurisation, UV light or slow sand filtration (Runia, 1995). However, the primary obstacle to the implementation of hydroponics in greenhouse industry is the high capital investment costs (Uva et al., 2001). Moreover, the management of

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soilless culture needs a skilful and highly-trained staff with some basic knowledge of plant physiology and adequate know-how on fertigation and the use of electric devices and electronic instruments. Installation costs range from a few € m-2 (floating raft system) to 7–15 € m-2 (closed substrate culture, NFT) and up to 50–70 € m-2 (movable ebb-and-flow benches for pot ornamentals). If greenhouse and climatic unit are included, capital investment may exceed 700 k€ ha-1. Compared to soil culture, running costs may be lower on account of lower labour requirements, but in general the production costs are higher. Recently, Papadopoulos et al. (2008) evaluated in terms of investments different hydroponic systems for greenhouse production of both ornamentals and vegetables in Western Macedonia, Greece, and concluded that such an investment is advantageous only with subsidy. Higher yield and better quality (then higher market price) might compensate higher production costs; however, not necessarily the price for hydroponic products very seldom is higher compared to soil-grown products, also because they are not distinguished by the final consumers. Moreover, hydroponics and, more generally, high-tech cropping systems (as indeed greenhouse crops are) production are not well accepted by an increasing number of greenthinking people. Hydroponic is not compatible with the philosophy and, more practically, with the rules of organic agriculture in Europe (Commission Regulation, 2008) and it is not allowed also by some grower associations (e.g., the consortium for the protection of geographical indication of tomatoes and melons grown in Pachino area in Sicily, Italy). Therefore, effective marketing has to increase the consumer‘s acceptance of hydroponically-grown products, in particular of vegetables, which not few people still deem without taste and flavour or even dangerous.

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4.4. General Remarks An ideal soilless growing system must be economical, flexible and environmentally safe. Instead, soilless culture is still a capital-intensive technology and, in case of free-drain system, it may results in a huge waste of water and fertilisers. Moreover, it needs a skilful management of both fertigation and climate management to exploit the most of its numerous and undoubted advantages. Indisputably, the phase out of methyl bromide and other substances for soil disinfection has stimulated the application of soilless culture in greenhouse crops. However, it is difficult to predict to what extent this growing method will develop on a commercial scale, since in many countries protected horticulture is still based on small operations, which use simple, low-cost technologies and for which the investment in hydroponic culture is often risky.

5. INTEGRATED PEST AND DISEASE MANAGEMENT A. Minuto and F. Tinivella 5.1. Introduction Pest and disease management in intensive agricultural systems has often been based almost exclusively on the application of pesticides. Recent changes in consumers‘ needs, who are more keen towards a more sustainable production obtained with a very low use of

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chemical compounds, has favoured the application of alternative control strategies, and that is valid especially for vegetables grown in greenhouses (Albajes et al., 2000). Vegetable crops have to face many problems: in greenhouses they are characterized by short crop cycles, very narrow rotations and high pest and disease pressure. Damages posed by weeds are not less severe being able to host viruses, pests and diseases too. Their spread can be favoured by cultural practices themselves; moreover, their control throughout the use of herbicides may pose serious problems due to the phytotoxicity risks of a not proper herbicide application or due by residual effects on non target crops. Furthermore, under specific conditions, the application of integrated control strategies is necessary in order to allow the crop to be identified with the label of guaranteed protection (DOP) according to specific production protocols which foresee the use of different strategies and not only the chemical ones. Given these premises, the lack of registered pesticides and the low interest paid by agro-chemical companies towards many vegetables, among which the so called minor crops (Albajes et al., 2000), have made the use of integrated control strategies, which could rationally combine conventional and unconventional chemical (Dayan et al., 2009), genetic, agronomic and biological means (Pilkington et al., 2009), even more necessary. Techniques, which foresee the control and the modification of the environmental parameters within a greenhouse, can be successfully exploited for creating less conductive conditions for pests and diseases (Albajes et al., 2000). Modern control strategies for greenhouse climate control can be used in order to reduce disease infection and to influence plant development and, at this regard, computersupported anti-botrytis climate control management have been recently developed based on a plant canopy model (Juergen and Lange, 2003) and, in some cases, it is possible to reach an almost complete control effectively interfering with the life cycles of some pests and so avoiding the use of traditional control measures (Albajes et al., 2000).

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5.2. Pest and Disease Control Strategies Different methods are available to put into action an integrated pest management strategy. The use of genetic and agronomic methods is particularly efficient for several pathosystems. Nevertheless, in the vegetable sector the use of certain resistant or tolerant varieties can lapse due to the continuous and quick change in market needs and characteristics. We will try hereby to briefly describe means that can be used and integrated with traditional control strategies and tools.

5.2.1. Biological Control Agents for Pest and Disease Management Globally, the use of biopesticides is growing annually while the use of traditional pesticides is on the decline. North America uses the largest percentage of the biopesticide market share at 44%, followed by the EU and Oceania with 20% each, South and Latin American countries with 10%, and Asia and India with about 6%. Although biopesticide growth is projected at 10% annually, it is highly variable among the regions constrained by factors such as regulatory hurdles, public and political attitudes, and limitations for market expansion (Bailey et al., 2009). An outstanding example of adoption of non chemical control tools and strategies is represented by Almeria and Murcia greenhouse industry (SE of Spain). In Almeria, where there is the largest greenhouse concentration in the world (about 27,000 ha), protected crops using biocontrol agents have recently increased from 3% in 2006 to 28%

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in 2007 (Bielza et al., 2008). In order to set up effective disease control strategies with particular regards to minor crops, it is important to remind here that the speed up and the simplification of the registration process of agro-chemicals according with 91/414 CEE regulation would be highly needed in order to face emerging or manage already known pests or diseases. Unfortunately the difficulties related to the registration progress of both traditional and biological means and the low interest shown by agro-chemical companies towards minor crops make the process even more difficult needing the economical support of national and local Government and of grower associations. Several microorganisms are currently available on the EU market and are registered as biological control means according with EU and national regulations. Among them we remind an Ampelomyces quisqualis based formulate, an antagonist fungus specifically developed for the biological control of powdery mildew. It is a specific hyperparasite effective towards more than 60 fungal species causing powdery mildew (Punja and Utkhede, 2003). Other formulates nowadays commercialized were developed from Trichoderma asperellum (formerly T. harzianum) and T. viride (Punja and Utkhede, 2003). These are antagonistic fungi known and used since a long time for the control of different pathogens such as grey mould (Botrytis cinerea) (Figures 32 and 33). Some strains of T. asperellum proved to be effective for the control of pathogens which affect the aboveground part of the plant and the underground one (Fusarium oxysporum f.sp. radicis lycopersici; Rhizoctonia solani; Sclerotium rolfsii) (Howell, 2003).

Figure 32. Stem necrosis caused by Botrytis cinerea infection on greenhouse tomatoes.

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Figure 33. Botrytis cinerea infection on eggplant fruits.

A mixture of Trichoderma asperellum and Trichoderma viride has been recently introduced into the Italian market and registered for the treatment of growing media or soil in nurseries, greenhouses and open field on different vegetables (tomato, pepper, lettuce, radicchio, endive, rocket, melon, fennel, artichoke, basil, celery, bean, French bean, squash, eggplant, cucumber, fresh herbs). Streptomyces griseoviridis is a bacterium that have been studied and developed as biocontrol agent in Northern Europe for the control of some soilborne pathogens. It acts mainly through competition for nutrients and space and it is effective for the control of root and crown diseases on many vegetables (Minuto et al., 2006a). For instance in Italy the compound is registered on tomato, pepper, eggplant, cucumber, melon, pumpkin, watermelon and basil.

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Figure 34. Symptoms caused by infection of Sclerotinia sclerotiorum on protected lettuce crop.

Coniothyrium minitans is an antagonist fungus which can be used against root pathogens (Whipps and Gerlagh, 1992): it parasitizes sclerotia belonging to the genus Sclerotinia. It should be distributed on the soil preferably on crop debris: in this way mycelium generating from the spores can parasitize sclerotia, devitalizing them in 60–90 days. Temperature and soil moisture influenced both apothecial production of S. sclerotiorum and mycoparasitism of C. minitans and inoculum concentration of C. minitans and time of application appear to be important factors in reducting apothecial production by S. sclerotiorum (Jones et al., 2003). However a recent paper has demonstrated the sensitivity of such antagonist to different pesticides such as azoxystrobin, chlorotalonil, fluazinam, pyraclostrobin, tebuconazole and diclosulam, which negatively affected both its mycelial development and conidial germination. C. minitans anyway demonstrated to be able to survive and to parasitize sclerotia of S. minor even when combined with azoxystrobin, chlorotalonil, diclosulam, fluazinam, flumioxazin, S-metolachlor, pendimethalin, pyraclostrobin and tebuconazole, but only S-metolachlor, an erbicide registered on some open field crops, tomato and bean, had no influence on the ability to parasitize pathogen sclerotia (Partridge et al., 2006). In Italy, for instance, the microorganism is specifically registered on lettuce and on other greenhouse crops and on vegetables, flowers and fruit crops susceptible to Sclerotinia spp (Figure 34) for soil application in open field. Bacillus subtilis is a bacterium which acts preventively controlling or reducing parasitic fungi through competition for nutrients and space and inhibition of germination. It has been developed for disease control on pome fruit and grapevine (Sharma et al., 2009), but it could be useful for the control of grey mould on vegetables too. It proved to be effective for the control of seedborne agents of antrachnose of bean and pea when applied as seed treatment (Tinivella et al., 2008). Pseudomonas chlororaphis is a rhizobacterium (i.e., isolated from the rizosphere) that produces a fungi-toxic metabolite (2,3-deepoxy-2,3-didehydro-rhizoxin) able to effectively

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control fungi causing take-all on cereals thanks to antibiosis and competition mechanisms (production of siderophores which make iron unavailable for pathogens) and resistance induction (increased synthesis of phytoalexin, poliphenols and other compounds inside the plant) and it can produce substances similar to hormones. When applied to seeds the bacterium multiplies assuring a long lasting protection on cereals till 5 leaves stage (Johnsson et al., 1998). Experimental trials showed its effectiveness in some pathosystems when applied as seed dressing to control seedborne pathogens (Tinivella et al., 2008). Biological pest control applied in protected crops has spread as an alternative to chemical application because of the selection of resistant populations of arthropods derived from a too high use of pesticides with a consequent increase in the risk posed to workers (Albajes et al., 2000, Bielza et al., 2008). Success in measuring efficacy of potential biocontrol agents remains somewhat of an art due to the multitude of factors influencing their efficacy, but might be improved by attention to characterization of natural enemy candidates using morphological taxonomy or genetic markers at the onset of a program, climatic matching candidate agents when possible, and evaluations in semi-field or field cage conditions following quarantine evaluations whenever possible before proceeding with widespread releases (Hoelmer and Kirk, 2005). The good results obtained with natural impollination carried out by bumble bees instead of chemicals applied for setting (up to 80% of total surface of tomato cultivated in greenhouse in some Italian regions) has determined a reduction of treatments together with a more aware choice of selective and less harmful compounds. Moreover the possibility of using honey bees and bumble bees to vector a commercial formulation of Trichoderma asperellum for the control of Botrytis cinerea on strawberries was demonstated: T. asperellum delivered by bumble bees or honey bees provided better B. cinerea control than that applied as a spray. In addition, the bee-delivered T. asperellum provided the same or a better level of control of B. cinerea as commercial fungicides applied at bloom (Kovach et al., 2000). The environmental isolation of protected crops, the simplicity of such ecosystem, the longer lasting control carried out by beneficials if compared to pesticide treatments has favoured the application of biological control measures. Its spread in Europe is favoured by the commercial availability of beneficials, which can cover the entire spectrum of pests widespread in protected crops (Weintraub and Cheek, 2005) and by costs comparable to pesticides. Thrips control (i.e., Thrips tabaci and Frankliniella occidentalis) can be achieved through the introduction of different species of Orius (O. laevigatus and O. majusculus) and of some species of Phytoseid mites belonging to Amblyseius genus. Biological control of aphids on nightshades and cucurbits (mainly Myzus persicae, Aphis gossypii, Macrosyphum euphorbiae and Aulachortum solani) is based on parasitoids like Aphidius colemani and Lysiphlebus testaceipes or on predators such as Adalia bipunctata and Chrysoperla carnea (which is active against thrips and white flies to a lower extent). Against main white flies of vegetables (i.e., Trialeurodes vaporariorum and Bemisia tabaci) the Aphelinids Encarsia formosa, Eretmocerus mundus and E. eremicus and the predator Myrid Macrolophus caliginosus are available. Leafminers Liriomiza bryoniae, L. huidobrensis and L. trifolii can be controlled by Eulophid Diglyphus isaea. Against red spider mite Tetranychus urticae the Phytoseid Phytoseiulus persimilis is used since a long time and, more recently, Amblyseius californicus proved to be effective too. Relevant to other pests, such as moths and some spider mite species, biological control based on beneficials has not reached a significant level of

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application yet. Different effective control measures alternative to chemicals based on microorganisms and on other compounds registered for organic farming are known. Several species which infest greenhouses, such as Spodoptera littoralis, Chrysodeixes chalcites and Helicoverpa armigera (Nottuid moths) and Ostrinia nubilalis (Piralyd moth), can be controlled by different strains of Bacillus thuringiensis active against moth caterpillars. Sulphur (traditionally effective against powdery mildew) can be used for the control of spider mites, which infest greenhouses located in Southern Italy such as the tarsonemid Polyphagotarsonemus latus, harmful to pepper, and the eriophyid Aculops lycopersici, harmful to tomato (Figure 35).

Figure 35. Fruit crakings and bronzing caused by Aculops lycopersici on tomato fruits.

An important mechanism for insect pest control should be the use of fungal entomopathogens. Even though these organisms have been studied for more than 100 yr, their effective use in the field is not largely adopted. Some entomopathogenic fungi such as Beauveria bassiana and Paecilomyces fumoroseus, can be effectively used for the control of white flies, thrips and spider mites sometimes in combination with beneficials. Particularly B. bassiana have been commercially formulated, distributed and adopted particularly to control pest for minor crop. Recently, however, it has been discovered that many of these entomopathogenic fungi including Lecanicillium spp. and Metarhizium spp. play additional roles in nature. They are endophytes, antagonists of plant pathogens, associates with the rhizosphere, and possibly even plant growth promoting agents (Vega et al., 2009). These

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findings indicate that the ecological role of these fungi in the environment is not fully understood and limits our ability to employ them successfully for pest management. Biological control is a complex technique with application issues that depend on variables which are not always fully understood and which can be biased by operators (Albajes et al., 2000). Crucial factors related to effectiveness are: infestation level and prey/predator ratio; quality of beneficials (sometimes affected by breeding techniques and by storing and shipment conditions); climatic conditions of the greenhouse which often prevent beneficial from fully carrying on its biological activity; cultivation techniques adopted (species and cultivar, transplanting period, crop cycles duration, etc.) with particular regards to some agricultural practices such as leaf removal on tomato plants; control measures adopted (Hoelmer and Kirk, 2005; Pilkington et al., 2009). The cooling down during winter that can strongly limit the biological activity of entomophagous arthropods represents one of the main issues that affect the good outcome of biological control techniques applied in protected crops in the Mediterranean area. Some beneficials largely used in heated greenhouses in continental Europe showed to be ineffective when applied in the cold ones in Southern areas. For instance, Encarsia formosa, which is the most used parasitoid in Europe for the control of white flies, is mostly effective in non-heated greenhouses just since late spring, but often resulted to be ineffective (Albajes et al., 2000). Even the control of Frankliniella occidentalis by Orius laevigatus can be difficult since the thrips can mate many times even during the winter time, while the activity of the predator is negatively affected by winter diapause. However O. laevigatus can be profitably used only during spring-summer months. Nevertheless, during the last years the introduction of biological agents more active at low temperatures coming from the Mediterranean area increased the effectiveness of such control strategies (Nicoli and Burgio, 1997). Application of biological control techniques depends even on the other phytosanitary measures undertaken and, above all, on the active ingredients used, the number of treatments, the time of application, etc. in order not to compromise or even neutralise the activity of beneficials. Practical information about toxicity towards beneficials and persistence of main pesticides can be found in the documentation offered by some bio fabrics; this can help in a more proper combination of biological and chemical control means. In many cases the difficulties met in obtaining robust results using beneficials induced farmers to rely just on chemical control and that is in counter trend compared to what happens in other Mediterranean countries. A very significant example about the application of biological and integrated control strategies is represented by pepper produced in protected environment in Campo de Cartagena (Spain) where, despite the high risk of TSWV (Tomato spotted wilt virus) incidence transmitted by Frankliniella occidentalis, it was possible to nearly eliminate insecticide treatments applying beneficials (Sanchez and Lacasa, 2006).

5.2.2. Use of Suppressive Composts At the moment composts used as growing media for ornamental and vegetable crops is not as important as other substrates such as peat (Minuto et al., 2006b), but the use of such materials in the nursery sector could lead to the exploitation of interesting mechanisms of disease suppressiveness (Moral et al., 2009). A recent interdisciplinary study allowed researchers to describe, together with the characteristics of some composts deriving from agro-industrial waste materials, the possibility to use such composts for the control of some pathogens which cause crown, root and vascular diseases in different plant species (Minuto et

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al., 2006b). The greater interest posed at the moment in the exploitation of suppressiveness, a mechanism known since a long time and practically exploited since the sixties (Noble and Coventry, 2005), is mainly due to the possibility to control, although not completely, one or more pathogens even during the cultivation of susceptible hosts and with the presence of pedological and environmental conditions conductive for the disease. The development and use of suppressive substrates against harmful pathogens is an interesting opportunity especially for those crops for which only few pesticides are registered (Moral et al., 2009). Notwithstanding, at the moment, the low uniformity of materials used for compost production can negatively affect its broader use on vegetables (especially in nursery).

5.2.3. Resistance Inducers (SAR Mechanisms) The possibility to use resistance inducers (which act on SAR mechanisms) could represent an interesting perspective even for disease control on vegetables (Walters, 2009). A pesticide, which has been traditionally exploited for its capacity to induce resistance in the host was Fosetyl-Al. The methilic ester of benzo (1,2,3)-thiadiazole-7-carbothiolic (BTH, acibenzolar-S-methyl) acid is at present available in Italy. It is a particularly effective resistance inducer but application doses must be carefully chosen in order to avoid potential phytotoxic effects (Friedrich et al., 1996). Such compound, currently registered on tomato, has shown some effects against fungal and bacterial diseases. Many other compounds, which can switch SAR mechanisms could be used for the control of plant pathogens; unfortunately for many plant species there are no registered products available at the moment (Gozzo, 2003).

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5.3. Case Studies 5.3.1. Integrated Control of Pests and Limitation of Related Virus Damages Protected crops represent a dynamic system exposed to new and quickly changeable problems can occur. Particularly, the accidental introduction in Italy of F. occidentalis (TSWV vector) and of new Bemisia tabaci biotypes (vectors of TYLCSV and TYLCV— Tomato yellow leaf curl Sardinia virus and Tomato yellow leaf curl virus—and of ToCV— Tomato chlorosis virus) (Figure 36) has made the disease control based on biological methods much more difficult on some vegetables (especially tomato and pepper). In the Southern Mediterranean countries such as the Southern part of Italy, where climatic conditions enhance the development of such pests and where virus diseases have already been reported, it is necessary to turn to an integrated use of control methods, privileging the preventive ones. Effective management of insect and mite vectors of plant pathogens is of crucial importance to minimize vector-borne diseases in crops. Pesticides play an important role in managing vector populations by reducing the number of individuals that can acquire and transmit a virus, thereby potentially lowering disease incidence. Certain insecticides exhibit properties other than lethal toxicity that affect feeding behaviours or otherwise interfere with virus transmission. Sustainability of insecticides is an important goal of pest management and more specifically resistance management, especially for some of the most notorious vector species such as B. tabaci and Myzus persiscae that are likely to develop resistance (Castle et al., 2009).

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Figure 36. Leaf yellowing and plant stunting caused by infection of TYLCV (tomato yellow leaf curl virus) on protected tomatoes.

Chemical control of these pests is extremely difficult because of their very high reproducing rate and the capacity to quickly differentiate resistant strains (Bielza et al., 2008). Risk related to the transmission of virus diseases, which can be very high even at a very low level of vector population, forces to prefer preventive techniques, which aim at minimizing the contact between vector and host plant. Some agricultural practices proved to be very useful for this purpose: the complete removal of plant debris at the end of crop cycle; the removal of spontaneous plants near the greenhouses which can host vectors of virus diseases; the shift of transplanting time in order to avoid periods when the density of vectors is higher (e.g., July and August and sometimes September relevant to B. tabaci); timely uprooting of infected plants. A key control technique against virus vectors is based on the application of adequate screening nets to the lateral opening of greenhouses (Berlinger et al., 2002; Hilije et al., 2001) and on the protection of seedlings during first development stages through tissues realised with a continuous yarn. Protection of openings through insect-proof nets, although being effective from a phytosanitary point of view, it is not free from drawbacks, such as the change induced to

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greenhouse inner climate (limited ventilation, increased temperatures, difficult management of relative humidity, etc.). Covering greenhouse roof and lateral firm frames with photoselective UV-absorbing films can reduce infestations of B. tabaci and, therefore, the spread of TYLCV (Rapisarda et al., 2005). The reduction of the UV portion of light spectrum alters pest sight capacity and therefore limits crop infestation (Antignus, 2000). Population of white flies can be reduced adopting yellow traps to catch adults. Yellow coloured, 30 cm high sticky rolls, which can be placed few cm above plants are also available. F. occidentalis can be monitored through blue coloured sticky traps which can be triggered with an aggregating pheromone in order to increase their effectiveness (Gomez et al., 2006). Identification and synthesis of such pheromone, which attracts males and females (Hamilton et al., 2005), can lead to the application of control techniques based on mass trapping even for this species.

5.3.2. Tomato: Grey Mould and Climatic Management of Cultivation Environment The control of Botrytis cinerea has always been a key issue for many protected vegetables such as tomato, strawberry, basil and lettuce. On tomato grey mould infections are extremely harmful during autumn, winter and spring time and in all periods characterized by sudden temperature changes between night and day which favour condensation on leaf, flower and fruit surface (Shpialter et al., 2009) (Figure 37). The most effective control strategy should be based on a correct management of the growing site. It has been demonstrated that the adjustment of the relative humidity through dehumidification can effectively limit damages caused by pathogen infections (Albajes et al., 2000, 1993; Prichard et al., 1999; Sharabani et al., 1999). Particularly, the control technique is based on the possibility to interrupt the infective process. Unfortunately this remedy, relying on heating systems, is not always economically sustainable with the exception of some value crops such as basil and some cut flowers. Agronomical control techniques, as the one above mentioned, have been combined with pesticide application in order to be more effective (Prichard et al., 1999; Sharabani et al., 1999; Albajes et al., 2000). The combination between biological control and non chemical means was proved to be effective in non heated protected crops by other authors, e.g. a decisional support system suggests the correct application time of T. harzianum depending on the evaluation of climatic conditions and infection risk. In this way the rate of application of such compound was reduced by 50% (Shtienberg and Elad, 1997).

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Figure 37. Leaf guttation on tomato plants often causes the onset of leaf and fruit rot of protected tomatoes.

5.3.3. Control of Soilborne Pathogens: Solarization, Grafting on Resistant Rootstock, Biofumigation, Soilless Cultivation Soiborne pathogens can pose big constraints to protected vegetable production because of the recent phase out of methyl bromide, particularly in developed countries where only few critical uses are still allowed. The lack of fumigants characterized by a wide spectrum of activity and effectiveness comparable to methyl bromide imposes the adoption of alternative strategies not only based on chemicals. Relevant to protected crops, solarization and grafting on resistant rootstock represent two of the most important techniques for the control of soilborne pathogens. Solarization — Different fumigants alternative to methyl bromide and nowadays available can be applied through drip fumigation under plastic films laid down on the soil at least during the hottest months of the year. The same films can be kept for 2–3 weeks exploiting the heating effect due to the solar radiation and enhanced by the application carried out inside a greenhouse. Significant results were obtained for the control of gall nematodes (Meloidogyne spp.) (Figure 38) and of pathogens causing root, crown and vascular diseases (Martin, 2003). Grafting on resistant rootstock — Grafting commercial cultivars susceptible to Verticillium onto resistant rootstocks was developed as a replacement for fumigation. However, the practice of growing grafted vegetables started in Japan and Korea in the late 1920s (Lee, 1994). Grafting vegetables onto resistant rootstocks represents a technically and economically feasible alternative particularly in Japan and in Korea where 54% and 81%, respectively, of vegetables grown are grafted (Rivero et al., 2003). In the Mediterranean region, grafting represented an opportunity to maintain productivity of crops such as watermelon, cantaloupe, tomato, pepper, and eggplant (Bletsos et al., 2003; Diánez et al.,

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2007). It was rapidly adopted and for instance in Greece, 90–95% of watermelon, 40–50% of cantaloupe, 5–8% of tomato and 5–8% and 2–4% of cucumber and eggplant are now grafted (Traka-Mavrona et al., 2000); in Spain 98% of watermelon and 10% of tomato, in Morocco and Netherlands more than 25% and 50% of protected tomatoes and in Cyprus 80% of watermelon (Diánez et al., 2007). Over 5 million eggplants and 5.8 million tomato plants were produced from grafted seedlings in Italy in 2005 (Minuto et al., 2007b).

Figure 38. Galls caused by the heavy infestation of root knot nematodes (Meloidogyne sp.) on melon roots.

Formerly quite costly, it can be nowadays considered technically and economically effective as demonstrated by the increasing cultivation of grafted vegetables like melon, watermelon, tomato and eggplant. Grafting vegetables onto resistant rootstocks offers numerous advantages including: resistance to soil pathogens, specifically Verticillium and Fusarium (Lee, 1994; Bletsos et al., 2003), improved yield in infested soils (Bletsos et al., 2003), greater tolerance against low and high temperatures and salt stress (Rivero et al., 2003) and higher plant vigour that can support longer crop cycles. Bletsos et al. (2003) found that grafted eggplants had not only increased fruit yield of up to 79% over non-grafted plants in Verticillium-infested soil (Bletsos et al., 2003) but they also produced fruit a week earlier (Khahm, 2005). Fruits from grafted eggplants contain fewer seeds than from non-grafted plants (Khahm, 2005) and this is regarded as another qualitative benefit to the consumer. Several rootstocks are available for grafting of tomato and eggplant, the most common being tomato hybrids (―Energy‖, ―Kyndia‖) and interspecific hybrids of L. esculentum and L. hirsutum (―He Man‖, ―Beaufort‖, ―Maxifort‖, ―Trifort‖). For grafted eggplant Solanum torvum was introduced and now represents more than the 70% of the total market of eggplant rootstocks in the south Italy (Minuto et al., 2007b). Other Solanum species could be adopted

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for grafting eggplant including S. sisymbriifolium, but S. torvum guarantees the highest resistance against Verticillium wilt (Bletsos et al., 2003) and also carries traits of resistance to the most serious disease of eggplant namely bacterial wilt (Ralstonia solanacearum) and nematodes (Gousset et al., 2005). Among the major constraints and limitations of grafted rootstocks is that resistance may break down under high pathogen population pressure, that new races of the pathogen may evolve, and under some environmental stresses such as high temperature and salinity, the plants may prematurely collapse. Furthermore, pathogens generally considered minor can become major pathogens on the rootstocks in the absence of soil fumigation. As an example, novel root rots caused by Colletotrichum coccodes were repeatedly observed on rootstocks currently used for grafting tomatoes and eggplant (Garibaldi and Minuto, 2003). Although C. coccodes was previously reported to infect L. hirsutum rootstocks, it was never observed on L. lycopersicum x L. hirsutum hybrids, the most widely used rootstocks. Grafted hybrids of L. lycopersicum x L. hirsutum (―Beaufort‖, ―He Man‖) and of L. lycopersicum (―Energy‖) can be infected by Phytophthora nicotiane and Rhizoctonia solani accompanied by some plant stunting (Minuto et al., 2007b). Finally, eggplants (―Black Bell‖, ―Mirabell‖) grafted onto rootstock of S. torvum that confer a high degree of nematode tolerance can exhibit a partial tolerance against Verticllium wilt (Garibaldi et al., 2005).

Figure 39. Plant wilting caused by Verticillium dahliae on Solanum torvum.

The relatively low tolerance of S. torvum to V. dahliae was known (Ginoux and Laterrot, 1991; Gousset et al., 2005). Ginoux and Laterrot (1991) confirmed the resistance of S. torvum against V. dahliae particularly under mild climate conditions and in sandy soils and when 70– 80-day-old grafted plants were transplanted. In trials carried out with 15-day-old Solanum

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spp. seedlings belonging to 14 different species vertical resistance to V. dahliae was not found but there was only tolerance to wilt symptoms (Nothamann and Ben-Yephet, 1979). Experiments conducted in highly infested fields confirmed that S. torvum conferred only partial wilt resistance (30–50% infection plants compared with non grafted eggplant 80– 100% infection), while L. lycopersicum x L. hirsutum and L. lycopersicum hybrid rootstocks always showed low infection (7–10% infected plants) (Minuto et al., 2007b) (Figure 39). In Northern Italy since 1997, sudden collapse of grafted plants in protected and open field tomatoes (―Cuore di Bue‖, ―Marmande-Raf‖) grafted on ―He-Man‖ and on ―Energy‖ rootstocks were observed (Garibaldi and Minuto, 2003). The collapse before or after fruit setting during spring and summers was in the 15–70% range. Sudden collapses were also observed on ―Iride‖, ―Naomi‖, ―Cuore di Bue‖ and ―Marmande-Raf‖ grafted on ―He-Man‖, ―Energy‖ and sometimes on ―Beaufort‖, regardless of the season or phenological stage of plants in Southern Italy (Garibaldi and Minuto, 2003). This collapse appears to be a direct consequence of the incompatibility between scion and rootstock or the climatic conditions during fruit setting and ripening. Similar collapses were observed on eggplant grafted on tomato rootstocks (Ginoux and Laterrot, 1991) demonstrating the importance of rootstock selection. S. torvum performs best as an eggplant rootstock during warm seasons, but may reduce plant vigor during other seasons. Tomato rootstocks should be more vigorous and possess cold tolerance, but graft incompatibility may reduce cold tolerance (Minuto et al., 2007b). With tomato rootstocks grafted onto eggplant one often finds that the diameter of the rootstocks is double that of the scion but this is not the main reason for graft incompatibility. This is inferred from the fact that plants with tomato rootstocks transplanted in late spring to early summer do not show signs of damage although the size differences between rootstock and scion are present. Catara et al. (2001) found a widespread dieback of eggplant (―Mission Bell‖), grafted onto the interspecific hybrid (―Beaufort‖) and on tomato hybrid (―Energy‖) during winter cultivation. Bacteria isolated from symptomatic tissues were identified as Pectobacterium carotovorum subsp. carotovorum and P. carotovorum subsp. atrosepticum and confirmed to be pathogenic. Ginoux and Laterrot (1991) recognized these same symptoms as a graft incompatibility enhanced by low temperature and by heavy leaf guttation and water soaked leaf areas and lesions. Since the wide scale adoption of S. torvum for eggplant grafting, this type of plant dieback is no longer considered important. Biofumigation — Different species belonging to Brassicaceae family can produce metabolites deriving from an enzymatic (myrosinase) degradation of glucosinlates, which accumulate within plant tissues and have biocide properties. Such compounds belong mainly to isothiocyanates and they can act as soil fumigants for the control of different pests and pathogens on semi-intensive crops (Gamliel and Stepleton, 1993; Lazzeri and Manici, 2000). Cultivation and green manuring of brassicas selected for their high content of glucosinolates can bring to the soil compounds characterized by a high fungitoxic activity. For this purpose since 1997 the Istituto Sperimentale per le Colture Industriali in Bologna (Italy) has selected different species of brassicas (Brassica juncea, Eruca sativa, B. nigra, Rapistrum rugosum, Iberis amara). Later on the same Institute has set up a procedure for the production of oil-free flours and pellets deriving from different plant portions (Lazzeri et al., 2002). Soilless cultivation — This technique can be used for the control of soilborne pathogens affecting vegetables through e.g. the exploitation of the suppressiveness related to such

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cultivation methods without falling back upon expensive procedures such as disinfestation or renewal of growing media. The possibility to control infections of Fusarium oxysporum f.sp. radicis lycopersici (agent of crown and root rot of tomato) simply re-using not infected growing media (perlite and rock wool) already used as cultivation substrates has been demonstrated. Such substrates in fact did not induce the disease in the crop even in the presence of artificial infections of the pathogen (Minuto et al., 2007a). This finding is important since the same pathogen, that is often very harmful to crops grown in saline soils or when saline water is used (Triky-Dotan et al., 2005), can easily colonize environments with a poor microflora and therefore settle in soilless cultivation systems (Ozbay and Newman, 2004). The exploitation of suppressiveness, such as the one above mentioned, can be based on different mechanisms (microbiological, chemical) depending on the growing medium used (perlite, peat, rockwool, pomix, mixtures of different materials) which becomes a key element that must be taken into account (Minuto et al., 2007a; Clematis et al., 2009). In conclusion the emergence of new pathogens and pests or the fresh outbreak of already known parasites (even if not so harmful in a sector characterized by a high specialization as the intensive horticultural one) complicates the management of disease control strategies. Virus diseases transmitted by pest vectors represent a key issue in vegetable production. Among different control measures that could be easily adopted in this sector, the exploitation of genetic resistance represent the most sustainable choice from an economic and a technical point of view as recently demonstrated for the control of Fusarium wilt of lettuce (Matheron et al., 2005). Moreover the use of genetic means requires an on-going research activity in order to individuate the plant material characterized by a satisfactory level of resistance or tolerance as long as it enters the market. This can be hard especially towards some necrotrophic fungal pathogens. On the contrary, the integration of different control means, although complicating crop management, is the only strategy, which can guarantee the farmers a medium- or long-term application perspective.

6. SUMMARY AND FUTURE PERSPECTIVES In recent decades, a growing environmental awareness has prompted the public to ask for environmental protection and nature conservation. This awareness has led, in addition, to the developing of sustainable strategies to meet the needs of the present without compromising the ability of future generations to achieve their own needs. Protected crops are intensive agricultural systems that strongly influence air, soil and water of the agricultural settlement due to their environmental loads, i.e., water, energy and agro-chemical use as well as waste disposal. Thus, a sustainable greenhouse system must reduce environmental degradation, conserve natural resources, maintain a stable rural community, provide a productive agriculture in both the short and the long term, and must be commercially competitive and economically viable. The protection of the natural resources implies innovative solutions concerning greenhouse microclimate control, renewable energy use, covering materials, plant fertigation and pest and disease management. Greenhouse microclimate, in terms of air temperature and relative humidity, carbon dioxide concentration and solar radiation, has an effect on crop growth and on the severity and incidence of pests and diseases. Over the recent

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decades, several strategies have been developed to improve greenhouse microclimate control; a sustainable approach to microclimate management has the objective to guarantee optimal growing conditions for the plants as well as energy savings. Microclimate control performed by means of temperature integration could lead to a novel procedure that will allow growing greenhouse crops with minimum or even with no fuel consumption for heating. Dynamic control of greenhouse temperature and carbon dioxide concentration, according to photosynthesis models and outdoor available radiation for photosynthesis, permits up to 48% in energy saving for climate control. Co-generation systems, which generate electricity and heat, are suitable for both greenhouse climate control and geographically dispersed electricity generation, thus increasing the energy efficiency of the systems. An increasing use of renewable energy with a decreasing use of fossil fuel consumption must be achieved for sustainable greenhouse production as soon as possible, especially in light of the increases in fuel prices in recent years. Among renewable energy sources, geothermal energy, where available, is already used in greenhouse heating. Other renewable energy sources can be applied to the greenhouse industry, even if they require additional reduction in cost of application and further improvements in terms of energy efficiency. Solar thermal systems can be integrated in the existing greenhouse heating systems, which use warm water and are fed by fossil fuels such as diesel fuel or gas. In this case, solar thermal collectors produce a fraction of the thermal energy, allowing the reduction of fossil fuels consumption. Low enthalpy thermal energy produced by means of solar thermal collectors could be integrated with thermal energy produced by means of heat pumps fed by renewable sources such as photovoltaic modules or wind turbines. Photovoltaic systems are easy to install and need low maintenance, but they have a high installation cost. Public incentives have helped to improve the economic viability of photovoltaic systems. Furthermore, increases in cell efficiency and cost reduction are expected over the next years. New techniques could lead to a widespread use of solar photovoltaic systems — for example, concentrating technologies — which could lower installation costs and increase energy efficiency. Besides, concentrating systems could be used for co-generation of heat and power or for tri-generation, i.e., the simultaneous production of cooling, heating and power. The use of wind energy appears cost-effective with large-size high-performance wind turbines in power plants with a size of several MW, but presents high investment costs and maintenance, making large wind turbines more suitable at the moment for electric utilities than for greenhouse farms. Greenhouse microclimate can be also conditioned and managed by means of covering materials with different properties. Low-emission glass, double-wall glass, and ethylene– tetrafluoroethylene copolymer plastic films can be used to obtain energy savings in greenhouse heating. A sustainable control of plant vegetative activity of vegetable, fruit and ornamental species and a few pests in place of agro-chemicals can be achieved by designing innovative covering materials with specific radiometric properties that alter spectral wavelength distribution of the solar radiation passing through the cover. Plastic films produced with fossil raw materials are used worldwide in greenhouse industry as covering materials and for soil mulching, and thus huge quantities of plastic wastes that must be disposed of are generated in protected cultivation. Biodegradable materials for agricultural purposes, formed with raw materials from renewable origin, can be used as environmentally friendly alternatives to synthetic petro-chemical polymers. In fact, at

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the end of their life, biodegradable materials can be integrated directly into the soil where bacterial flora transform them into carbon dioxide or methane, water and biomass; alternatively, they can be blended with other organic material to generate carbon rich composts. Thermo-plasticizing, casting and spraying processes have been employed to perform biodegradable materials for greenhouse applications. Among possible strategies to achieve effective water and soil protection, soilless culture represents one of the main elements for a sustainable greenhouse cropping system. The implementation of closed hydroponics could drastically reduce the use of water and fertilizers and the environmental pollution associated with over-irrigation, which is quite common in protected horticulture. Hydroponic technology eliminates the need for soil disinfection with steam or pesticides. In this regard, soilless culture is considered one of the most viable alternatives to methyl bromide soil fumigation, particularly in high-tech protected crops. Moreover, hydroponics can reduce a crop‘s susceptibility to diseases by reducing the humidity inside the greenhouse, increasing the vigour of the plants and making the root environment more suppressive against soilborne fungi. Nevertheless, the emergence of new pathogens and pests or the fresh outbreak of alreadyknown parasites complicates the management of pest and disease control strategies. Moreover, the limitation of availability of chemical control strategies, together with the increased demand of fresh and/or processed vegetables with no pesticide residues, encourage the proper adoption of innovative pest and disease management strategies. Among different control measures that could be easily adopted in this sector, the exploitation of genetic resistance represents the most sustainable choice from an economic and a technical point of view. The use of genetic means requires on-going research activity in order to individuate the plant material characterized by a satisfactory level of resistance or tolerance as long as it enters the market. The integration of different control means, although complicating crop management, is the only strategy that can guarantee the farmers a medium- or long-term application perspective. The application of innovative microclimate control strategies, soilless cropping systems and integrated pest and disease control techniques increases productive costs for greenhouse farmers. Nevertheless, improved plant health and better yield and quality result in a higher value-added production and gross income meeting the end-consumers requirements. Nowadays, the application of the described sustainable solutions is not as widespread as it should be, because, the exploitation of renewable energy sources requires strong public financial support and the application of innovative biodegradable materials, which are at an experimental stage, needs more research before implementation on a commercial scale for market availability. It is noted that hydroponic systems are applied extensively only in Dutch greenhouse horticulture. Environmental laws and binding technical standards aimed to push towards environmentally friendly greenhouse systems could encourage a faster application of the described sustainable solutions. Nevertheless, increased operational costs due to the application of innovative and more complex growing methods and strategies have to be shared within all stakeholders and end-consumers, while taking into account the economical support of local and national governments aimed at maintaining, improving, encouraging and sponsoring environmental protection, preservation and renewal.

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ACKNOWLEDGMENTS

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Meir Teitel wishes to thank Geoffrey John Connellan for his contribution. The research described in ―Covering Materials as Growth Regulators‖ has been carried out under the project ―Research for the Improvements of the Fruit Trees Protected Cultivation in Southern Italy – FRU.MED.; subproject DAFME‖, funded by the Italian Ministry of Agriculture and Forestry Policy; publication n 74. The research described in ―Biodegradable Materials‖ was carried out within the project RTD QLRT ―Environmentally Friendly Mulching and Low Tunnel Cultivation – Bioplastics‖ (Contract n° QLK5-CT-2000-00044) and the project LIFE Environment ―Biodegradable Coverages for Sustainable Agriculture – BIO.CO.AGRI‖ (LIFE03 ENV/IT/000377), both funded by the European Commission. The research described in ―Hydroponc Technology‖ has been funded by the European Commission by an EU FP7 research project entitled ―Reducing the Need for External Inputs in High Value Protected Horticultural and Ornamental Crops (EUPHOROS)‖. The research and information reported in the paraghraph ―Integrated Pest and Disease Management‖ was been funded both by the Italian Ministry of Agriculture and Forestry Policy – MiPAAF (projects OIGA DM 2065 – Prot. 2502, 30/01/2009 ―Pesticide Registration for Minor Crops‖ and OIGA DM 2065 – Prot. 2479, 30/01/2009 ―Management of Soilless Cut flowers‖) and by Regione Liguria (Department for Agriculture, Civil Defence and Tourism) in the framework of the project ―Territory Monitoring and Agro Environmental Services‖. The section ―Microclimate and Energy‖ was written by Meir Teitel and Giuliano Vox, the section ―Greenhouse Covering Materials‖ by Evelia Schettini and Giuliano Vox, the section ―Hydroponic Technology‖ by Alberto Pardossi and the section ―Integrated Pest and Disease Management‖ by Andrea Minuto and Federico Tinivella.

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Sustainable Greenhouse Systems

LIST OF SYMBOLS

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A Cd cp Cw CHP CO2 CPV DIF EC ETFE EVA g H HALS HDPE LAI LCA LDPE LHC LWIR m NFT NIR PAR PCM PP PV Q q RNS S T ToCV TSWV TYLCSV TYLCV U UV VPD w Z

area discharge coefficient specific heat wind coefficient combined heat and power carbon dioxide concentrating photovoltaics day time temperature minus night time temperature electrical conductivity ethylene–tetrafluoroethylene copolymer polyethylene-co-vinyl acetate gravitational acceleration height hindered amine light stabilisers high density polyethylene leaf area index life cycle assessment low density polyethylene latent heat convertor long wave infrared mass flow rate nutrient film technique near infrared photosynthetically active radiation phase change material polypropylene photovoltaic flow rate heat recirculating nutrient solution solar radiation temperature tomato chlorosis virus tomato spotted wilt virus tomato yellow leaf curl Sardinia virus tomato yellow leaf curl virus heat transfer coefficient ultra violet vapour pressure deficit wind speed distance between centers of top and bottom openings

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80

Giuliano Vox, Meir Teitel, Alberto Pardossi et al. List of Symbols (Continued)

          

coefficient evaporation coefficient heating coefficient of solar radiation efficiency of a pad constant wavelength specific volume of air density transmissivity of the cover ventilation regime coefficient humidity ratio

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SUBSCRIPTS b bu c cr DB ex f h i inl p t v w WB 0

at the bottom of the greenhouse buoyancy greenhouse cover crop dry bulb at exit floor heating of air in the greenhouse at inlet at pad outlet at the top of the greenhouse opening due to wind effect wet bulb ambient

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Chapter 2

MECHANISMS OF GOVERNANCE OF AGRARIAN SUSTAINABILITY Hrabrin Bachev Institute of Agricultural Economics, Sofia, Bulgaria

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ABSTRACT In this paper we incorporate the interdisciplinary New Institutional and Transaction Cost Economics (combining Economics, Organization, Law, Sociology, Behavioral and Political Sciences), and suggest a framework for analyzing the mechanisms of governance of agrarian sustainability. Firstly, we discuss the modern concepts of agricultural sustainability and the economics of agricultural sustainability. Secondly, we present a new framework for analysis and improvement of the governance of agrarian sustainability. This new approach takes into account the role of a specific institutional environment; and the behavioral characteristics of individual agents; and the transaction costs associated with the various forms of governance; and the critical factors of agrarian activity and exchanges; and the comparative efficiency of market, private, public and hybrid modes; and the potential of farming structures for adaptation; and the comparative efficiency of alternative modes for public intervention. Finally, we identify specific modes for environmental governance in Bulgarian agriculture; and access the efficiency of market, private and public modes; and estimate the prospects for evolution of environmental governance in the conditions of EU CAP implementation. Agrarian development is associated with specific (different from other European states) environmental challenges such as degradation and contamination of farmland, pollution of surface and ground waters, loss of biodiversity, significant greenhouse gas emissions etc. That is a result of the specific institutional and governing structure evolving in the sector during the past 20 years. Implementation of the common EU policies will have unlike results in ―Bulgarian‖ conditions enlarging income, technological, social and environmental discrepancy between different farms, sub-sectors and regions. Dominating subsistence farming, production cooperatives, small-scale commercial farms, and large business firms will be highly sustainable in years to come.

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Hrabrin Bachev

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INTRODUCTION The governance of agrarian sustainability is among the most topical issues in academic, business, and policy debates in developed, transitional, and developing countries [Bachev, 2009; EC; OECD; Ostrom; Raman; UN; VanLoon et al.]. It is widely recognized that achievement of economic, social, environmental, intra- and inter-generational goals of sustainable development requires an effective social order (governance) and coordinated actions at various levels (individual, organizational, community, regional, national, transnational). The governing mechanisms that could be effectively used include a mixture of ―invisible hand of market‖ (market order), individual initiatives and contracts (private order), ―visible hand of the manager‖ (fiat), collective decision-making (collective order), government intervention (public order), multinational actions (international order), and hybrid modes. It is also known that the effective forms of governance of agrarian sustainability are rarely universal and there is a big variation among different countries, regions, subsectors, etc. Experience shows that different societies achieve to a different extent the economic, social, environmental, etc., goals of sustainable development. That is a result of the specific governing structures that affect in dissimilar ways an individual‘s behavior, give unlike benefits, command different costs, and lead to diverse actual performances. Despite that, institutional aspects are largely ignored and a ―normative‖ approach dominates while the costs of governance are not included in analyses. Consequently, the potential of market and private governing modes for the specific economic, institutional and natural environment in each country, region, and sub-sector can not be properly assessed. Nor the effective modes for public (government, UN, EU, international assistance, etc.) interventions in agrarian sphere designed. Research on mechanisms of governance of agrarian sustainability is at the beginning stage due to the ―newness‖ of the problem, and the emerging new challenges for the governance, and the fundamental modernization during the last two decades, and the ―lack‖ of long-term experiences and relevant data. Most studies are focused on the governance of an individual (economic or social or environmental) aspect of sustainability, or on formal modes and mechanisms. What is more, they are typically restricted to a certain form (contract, cooperative, an industry initiative, a public program), or a management level (farm, ecosystem), or a particular location (region). Besides, uni-sectoral analyses are broadly used separating the governance of farming from the governance of overall households and rural activities. Moreover, ―normative‖ (to some ideal or external model) rather than comparative institutional approach between feasible alternatives is employed. Likewise, the significant social costs associated with the governance (known as transaction costs) are not taken into consideration. Furthermore, uni-disciplinary approach dominates, and efforts of researchers in Economics, Organization, Law, Sociology, Ecology, Technology, Behavioral and Political Sciences are rarely united to deal with that complex matter. And lastly, there are few studies on specific institutional, economic, cultural, natural, etc., factors responsible for the big variation among countries, regions, industries, and organizations. Consequently, our understanding on the institutional, behavioral, technological, ecological, international, etc., factors of the governance of agrarian sustainability is impeded. Neither the spectrum of feasible formal, informal, market, private, public, integral,

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multilateral, transnational, etc., modes of governance can be properly identified. Nor their efficiency (potential, limits), complementarities, and prospects of development correctly assessed. All these restrict our capability to assist improvement of public policies and modes of intervention, and to support individual and collective actions for sustainable development. In this paper we incorporate the interdisciplinary New Institutional and Transaction Cost Economics (combining Economics, Organization, Law, Sociology, Behavioral and Political Sciences) [Coase; Furuboth and Richter; North; Williamson], and suggest a framework for analysis of mechanisms of governance of agrarian sustainability. Firstly, we discuss the modern concepts of agricultural sustainability and the economics of agricultural sustainability. Secondly, we present a new framework for analysis and improvement of the governance of agrarian sustainability. This new approach takes into account the role of specific institutional environment; and the behavioral characteristics of individual agents; and the transaction costs associated with the various forms of governance; and the critical factors of agrarian activity and exchanges; and the comparative efficiency of market, private, public and hybrid modes; and the potential of farming structures for adaptation; and the comparative efficiency of alternative modes for public intervention. Finally, we identify specific modes for environmental governance in Bulgarian agriculture; and access the efficiency of market, private and public modes; and estimate the prospects for evolution of environmental governance and farms sustainability in the conditions of EU CAP implementation.

CONCEPT OF AGRICULTURAL SUSTAINABILITY

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Ideology, Strategy, or System Characteristics Sustainability movements evolved in developed countries as a response to concerns about the impacts of agriculture on the depletion of non-renewable resources, soil degradation, health and environmental effects of chemicals, inequity, declining rural communities, loss of traditional values, food quality, workers safety, decline in self-sufficiency, decreasing number of farms, etc. [Edwards et al.]. Very often the ―sustainable‖ agriculture is used as an umbrella term of ―new‖ approaches to the ―conventional‖ (capital-intensive, large-scale, monoculture, etc.) agriculture, and includes the organic, biological, alternative, ecological, low-input, biodynamical, regenerative, etc., agriculture. More recently the ―social‖ issues such as modes of consumption and quality of life; decentralization; community and rural development; gender, intra (―North-South‖) and inter-generation equity; preservation of agrarian culture and heritage; improvement of nature; ethical issues (like animal welfare, use of GM crop) etc. all have been incorporated into the sustainability concept [VanLoon et al.]. The 1992 Rio Earth Summit addressed the global problem of sustainable development and adopted the Declaration of its ―universal principles‖ [UN]. They comprise: rights on healthy and productive life in harmony with nature for every individual; protecting the rights of future generations; integration of environmental, social and economic dimensions at all levels; international cooperation and partnerships; new international trade relations; application of precaution approach in respect to environment; polluter liability; environmental impact assessment; recognition of women, youth, and indigenous role and interests; peace

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protection, etc. The emergence of that ―new ideology‖ has been associated with a considerable shift of the ―traditional paradigm‖ of development. Apart from that general description, there have also appeared more ―operational‖ definitions for sustainability. For instance, sustainability is often defined as ―set of strategies‖. Management approaches that are commonly associated with the agrarian sustainability are: self-sufficiency through use of on-farm or locally available ―internal‖ resources and know how; reduced use or elimination of soluble or synthetic fertilizers; reduced use or elimination of chemical pesticides and substituting integrated pestmanagement practices; increased or improved use of crop rotation for diversification, soil fertility and pest control; increase or improved use of manures and other organic materials as soil amendments; increased diversity of crop and animal species, reliance of broader set of local crops and local technologies; maintenance of crop or residue cover on the soil; reduces stocking rates for animals; full pricing of agricultural inputs and charges for environmental damages etc. [Mirovitskaya and Ascher]. However, interpreting the sustainability as ―an approach‖ is not always useful for ―guiding change in agriculture‖. Firstly, the fact that some forms of agriculture are more enabling factor to ecological, social or economic sustainability (than others) does not mean that sustainability is inherent to any particular set of practices, technologies, farming systems or policies. Secondly, strategies, which emerge in response to the problems in developed countries, may be inappropriate in the regions where circumstances and problems are quite different (e.g. underdeveloped, developing or transitional countries). Third, it may lead to rejection of some approaches associated with the conventional agriculture but nevertheless enhancing sustainability. Next, it makes impossible to evaluate the contribution of a strategy to sustainability since that particular approach has already been used as a ―criterion‖ for defining the sustainability. Finally, because of the limited knowledge during implementation of a strategy it is likely to make errors ignoring some that enhance sustainability or promoting others that threaten (long-term) sustainability. Another concept characterizes sustainability of agricultural system as ―ability to satisfy a diverse set of goals through time‖ [Hansen; Raman]. The goals generally include provision of adequate food (food security), economic viability, maintenance or enhancement of natural environment, some level of social welfare etc. However, usually there is ―conflicts‖ between different qualitative goals and that creates problems of assessment (needs for integration, ranking, trade-offs). Besides, ―subjectivity‖ of the specification of goals links the criteria for sustainability with the value of pre-set goals (e.g. the interests of stakeholders, the priorities of development agencies, the standards of analysts etc.) rather than to the agricultural system itself. At last, at the low levels of analysis (parcel, farm, sector, region) most of the objectives are exogenous and belong to a larger system. A number of authors interprets sustainability as an ―ability (potential) of the system to maintain or improve its functions‖ [Hansen; Mirovitskaya and Ascher; VanLoon et al.]. Accordingly, the main system attributes that influence sustainability are specified as: resilience; survivability; profitability; productivity; quality of soil, water, and air; energy efficiency; wildlife habitat; quality of life; and social acceptance etc. Indicators for the measurement of all these attributes are identified and their time trends evaluated. Since trends represent an aggregate response to several determinant that eliminate the needs to devise aggregation schemes. Usefulness of that definition comes for suggesting operational criteria for sustainability, providing a basis for identifying constraints and evaluating various

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approaches to improvement of agrarian sustainability. The most common critics are that it is impossible to find a single measure for different attributes; the assumption that future state of the system can not be approximated by the past trends; and the ignorance of the needs and the goals of human actors within the system. Having in mind the constantly evolving feature of the sustainability concept and the dynamism of the agricultural system itself, the sustainability is increasingly perceived as a ―process of learning about changes and adapting to these changes‖ [Raman]. According to that new understanding the agricultural sustainability is always specific to a time, situation, and component, and refers to the capability of agricultural systems to evolve and endure by adapting to and accommodating changes over time and in space. Furthermore, that inbuilt dynamism of the systems also includes a feasible ―finite life‖ (no system is sustainable forever) as agricultural system is considered sustainable if it attains its expected life span. We believe that sustainability has to be a criterion for guiding changes in policies, farming and consumption practice, agents behavior, focusing of research and development priorities etc. Therefore, definition of sustainability has to be based on the ―literal‖ meaning of the sustainability – thus perceived as a system characteristics and ―ability to continue (maintain) over time‖. Besides, the characterization has to be ―system-oriented‖ while system is to be clearly specified, including its time and spatial boundaries, components, goals, and context in the hierarchy. What is more, it is to include taking into account the adaptation potential of the major system‘s elements to the evolving natural and social environment. Moreover, our approach has to allow a comparative analysis of the different agricultural systems1. The characterization of sustainability must be predictive since it deals with future changes rather than past and present. And finally, it should be diagnostic, and to focus intervention by identifying and prioritizing constraints, testing hypothesis, and permitting assessments in a comprehensive way.

Economics of Agricultural Sustainability The problem of sustainability has been always an important part of the economic theory. Most often it is discussed in relation to (in)efficiency of using common natural resources (―tragedy of commons‖) [Hardin], and to ―negative externalities‖ associated with some activities [Pigou]. In recent years, it is increasingly associated with the multi-functionality (joint production character) of agriculture [OECD, 2001]. When common ownership and ―open access‖ to natural resources exists, there is tendency for inefficient use (―overuse‖) of resources. For example, there are certain natural limits for ―sustainable‖ exploration of a meadow for livestock farming or a pond for fishing or irrigation. The long-term efficiency (output) would decrease if number of the grazing animals or caching fish increase beyond these norms of an effective natural reproduction. In a one-person farm or private ownership, there will be no conflict between the efficiency and sustainability (maximization of the output over time). However, in a situation of multiple users and open access, there are strong individual interests for overusing the common 1

Certain authors wrongly associate the comparability with a ―continues (quantitative) rather than discrete property‖ of a system [Hansen]. In fact, there is no reason to believe that sustainability of an agricultural system could only increase or decrease. Discrete features (―sustainable‖-‖non-sustainable‖) are possible, and of importance for the farm managers, interests groups, and policy makers [Bachev and Peeters].

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resources since the private costs are not proportionate to the private benefits. In that case, individuals get full output from increasing the number of animals (or fish catch) while bear a small portion of the overall decrease in the total yield as a result of over-exploitation. Consequently, a constant overuse (non-sustainability) and a low long-term efficiency come out as a result of this form of organization of natural resources. In the modern (globalize) world a great number of the natural and environmental resources have been increasingly affected by the ―tragedy of commons‖, and the water crisis, biodiversity crisis, global warning etc. are top on the agenda. Nonetheless, the ―tragedy of commons‖ could be avoided by an alternative institutional arrangement [Ostron]. For instance, an introduction of a collective or public regulation on the exploitation of natural resources, such as distribution (and enforcement) of quotas for farmers and fishermen, would keep sustainability. In other instances, the privatization of natural resources would be an effective solution since it would create strong private incentives for the long-term preservation of resources. In the later case, a private agent (the owner) will contract and control an effective and sustainable use of the limited natural resources. Another classical case of ―market failure‖ for the allocation and sustainable use of natural resource is caused by the negative externalities of certain activities. The free-market prices do not always reflect the effect on third party‘s welfare, and that is why they cannot govern effectively the resource allocation and uses. For instance, the price of livestock products does not comprise the costs of the pollution of underground water by the farm activity. Since private agents (farmers, consumers of farm products) do not pay the full price and the costs associated with their activity, they are not interested in the most effective (and sustainable) use of natural resources. Maximization of the social output and welfare cannot be achieved, and an inefficient allocation and overuse of resources, and unsustainable development come out as a result. Thus efficiency and sustainability of some elements of the system (e.g. farms) are in conflict with the efficiency and sustainability of the other elements of the system (e.g. consumers) or the system as a whole. Therefore, an elimination of the differences between the ―social‖ and ―private‖ prices (―internalization of externalities‖) through taxes, norms etc. is commonly suggested. Besides, various monetary and nonmonetary2 methods for the ―evaluation of environmental resources and costs‖ are developed and used in the analysis of overall efficiency. At the same time, the effectiveness of suggested methods is questioned because the role and services of the natural resources are not always known, and the entire ―social‖ (present and future) value could be rarely properly evaluated. Besides, monetary assessments and dollars calculations of the most part of negative externalities (the adverse ―impact‖ on human health; the ―value‖ of lost biodiversity; the ―exhausting‖ of non-renewable resources, etc.) do not often make sense since they are not socially acceptable (no ―trade-off‖ is possible). Coase has proved that the problem of ―social costs‖ does not exist in a world of zero transaction costs and well-defined private rights [Coase]. The situation of maximum efficiency is always achieved independent of the initial allocation of rights. If for instance, a farmer has the ―right to pollute‖, the affected agents would pay him an appropriate ―bribe‖ (equal to the lost income or welfare) to stop polluting activity. If the opposite is true and the farmer does not have the ―right to pollute‖, then farmer would pay the appropriate bribe to other agents to let him certain pollution. In either case, the welfare of all agents is maximized 2

E.g. eco, carbon, energy, water etc. footprints.

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and the maximum efficiency (known as Pareto optimum) reached without a need for any public intervention. However, when transaction costs are significant, then costless negotiation and exchange of rights is not possible. Therefore, the initial allocation of the property rights between individuals is critical for the overall efficiency and sustainability. Consequently, the institutional structures for carrying out the agrarian activities become an important factor, which eventually determine the outcome of the system (the efficiency) and the type of the development (sustainability) [Bachev, 2007]. ―Jointness of production‖ is a fundamental characteristic of the farming. The classical example is when a market-oriented farm produces ―multiple products‖ such corn and hogs, and feed corn to the hogs. That is caused by the opportunities for more productive use of resources (economy of scale and scope) or as a risk reduction strategy (diversification, integration of critical transactions) of the farm manager. In modern farming there are also outputs, which are less desired – e.g. wastes. And finally, the farming output consists of both ―private‖ and ―public goods‖ such as food, rural amenities (hunting, landscape etc), ecological and cultural services, habitat for wildlife, biodiversity etc. A great part of the farm‘s ―non-commodity‖ outputs is ―not-separable‖ from the major farming activities. Moreover, for these (public, quasi public) goods no markets exist or markets function very poorly. Since these outputs are not ―tradable‖ (profitable) the farmers have no incentives to produce them in a socially demanded scale. For the effective execution of such ―public‖ functions of farms and for the production of the appropriate amount of the positive and negative externalities by the agriculture it is necessary to develop and apply other (nonmarket) modes for governance [Bachev, 2007]. The principal role of the governance for the character and the pace of development is recognized and intensively studied [North; Furuboth and Richter; Williamson]. The specific institutional environment in which activity takes place eventually determines the level of economic performance and the sustainability in different industries, regions, countries or periods of history. The factors for the emergence and evolution of various types of institutions are quite specific for each society, and require a multidisciplinary analysis and explanation [Norht]. In the long-run, the institutions are endogenous parameters of the system and the institutional ―development‖ is to be included in the model along with the economic, social and environmental components. On the other hand, in the specific institutional environment the ―sustainability‖ of various market, private, collective etc. modes of governance will depend on the comparative efficiency of the alternative governing arrangements [Bachev, 2007]. However, a high efficiency and sustainability of the different governing forms (farms, business organizations, collective actions etc.) does not always mean a high efficiency and sustainability of the development. As North and Williamson have proved it the history of institutional development is full of examples of ―failures‖ while the organization modernization is usually a success story [North; Williamson]. Today ―multi-functionality‖ of agriculture is socially recognized, and the sustainability is considered both as a criteria and a goal (outcome) of the development. It is also recognized that sustainability cannot be effectively achieved as a ―side result‖ of totally decentralized actions (free market competition, contracting, collective initiatives). The sustainable development requires effective governing and enforcement mechanisms including a significant public involvement in market and private activities at local, national, transnational and global levels. Therefore, the analysis of the governance mechanisms for agrarian sustainability becomes essential both for defining the efficiency (potential and limits) of

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market competition and private sector initiatives as well as for designing the most effective modes for public (Government, international etc.) interventions in agrarian sector [Bachev, 2007].

THE MECHANISMS OF GOVERNANCE

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“Institutions Matter” Institutions are the ―rules of the game‖, and they determine the individuals‘ rights in society and the way the property rights3 are enforced [Furuboth and Richter; North]. The spectrum of rights could embrace the material assets, natural resources, intangibles, certain activities, labor safety, clean environment, food security, intra- and inter-generational justice etc. A part of the property rights are constituted by the formal laws, regulations, standards, court decisions etc. In addition, there are important informal rules determined by the tradition, culture, religion, ideology, ethical and moral norms etc. The enforcement of various rights is done by the state (administration, court, police) or other mechanisms such as community pressure, trust, reputation, private modes, self-enforcement etc. The institutional analysis is not interested in de-jure rights but de-facto rights individuals and groups possess. For instance, the ―universal principles‖ of sustainable development have been declared (1992 Rio Earth Summit) and accepted by most countries. However, the extend of adaptation and respecting of related rights, and their practical enforcement vary significantly among countries. The specific institutional environment affects human behavior and directs (governs) individuals‘ activities ―in a predictable way‖ [North]. It creates dissimilar incentives and restrictions for intensifying exchange, increasing productivity, inducing private and collective initiatives, developing new rights, decreasing divergence between social groups and regions, responding to ecological and other challenges. For example, (socially) acceptable norms for use of labor (employment of children, safety standards, minimum wages), plant and livestock (animal welfare, preservation of biodiversity, usage of GM crops), and environmental resources (water use rights; permissions for pollution), all they could differ even between various regions of the same country4. Namely the specific institutional structure eventually determines the potential for and the particular type of development in different communities, regions, and countries. The institutional ―development‖ is initiated by the public authority, international actions (agreements, assistance, pressure), and the private and collective actions of individuals. It is associated with the modernization and/or redistribution of the existing rights; and the evolution of new rights and the emergence of novel (private, public, hybrid) institutions for their enforcement. For instance, the sustainability initially evolved as ―movements‖ and a ―new ideology‖ in developed countries Afterward this ―new concept‖ extended and instituted in the body of formal laws, regulations and public support programs. Numerous initiatives of 3

While lawyers distinguish between property and human rights, for the economists all rights are propertory rights [Furuboth and Richter]. 4 In Valonia for instance, the environmental standards are much more restrictive than in other two Belgium regions - Flandria and Brussels [Sauvenier at al.]. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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producers and consumers have been wide-spreading in recent years (e.g. codes of ethical behavior, organic farming, system of fair-trade etc.) being an important part of (pushing up) the institutional modernization in the area. The diverse institutional environment contributes to a different extend to achieving economic, social, environmental etc. goals of the sustainable development. If for instance, the private rights are not well defined, enforced, or are restricted, that would limit the intensification of exchange and the overall economic development. Indeed the rights on major agrarian resources were not well defined during the post-communist transition in Bulgaria and that led to the domination of low productive, unsustainable and ―gray‖ structures; and ineffective use of large national resources; and serious economic, social and environmental problems in rural areas [Bachev, 2006]. The classical examples for the importance of institutional structure are associated with the ―tragedy of commons‖ and the negative externalities. Thus the ―institutions matter‖ and the analysis of sustainability is to be done in the specific institutional rather than in an unrealistic (―normative‖, desirable) context. The weakness of the later approach has been strongly criticized: ―The view that now pervades much public policy economics implicitly presents the relevant choice as between an ideal norm and an existing ―imperfect‖ institutional arrangement. This nirvana approach differs considerably from comparative institution approach in which the relevant choice is between alternative real institutional arrangements. In practice, those who adopt the nirvana viewpoint seek to discover discrepancies between the ideal and the real, and if discrepancies are found, they deduce that the real is inefficient. Users of the comparative institution approach attempt to asses which alternative real institutional arrangement seems best able to cope with the economic problem‖ [Demsetz]. Nevertheless, the institutional aspect is commonly missing in most of the suggested frameworks for analyzing and assessing agrarian sustainability. Accordingly, non-feasible norms rather than the real-life arrangements are used as criteria – e.g. the farming model in other (developed) countries, the assumption for perfectly defined and enforced property rights, the effectively working public (local, state, inter-governmental) organizations etc. Therefore, an analysis of the structure and the evolution of the real or other feasible institutional arrangements for carrying out the agrarian activities have to be included in the model [Bachev, 2004].

The Modes of Governance The New Institutional Economics gives a new insight on the efficiency of divers market, private, public and mix modes of governance, and their potential to deal with agrarian sustainability [Bachev, 2004; Bachev, 2007]. This new approach requires embracing all modes of governance affecting individuals behavior which includes: 

the institutional environment (the ―rules of the game‖) – that is the distribution of rights and obligations between individuals, groups, communities and generations, and the system(s) of enforcement of these rights and rules. In the modern society a great deal of the individuals activities and relations are regulated by some (general) formal and informal rules. However, there is no perfect system of preset outside rules

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that can govern effectively the entire activities of individuals in all possible (and quite specific) circumstances of their life and relations. 

the market modes – those are various decentralized initiatives governed by the free market price movements and market competition (e.g. spotlight exchanges, classical contracts, production and trade of organic products and origins, system of fair-trade etc.). The importance of the ―invisible hand‖ of market for the effective coordination and stimulation of individuals activities has been one of the fundamentals of the modern economy (and policies for development and globalization). However, there has been also a great number of ―market failures‖ compromising the sustainable development and leading to social crisis, economic crisis, ecological crisis, energy crisis etc.



the private modes (―private or collective order‖) – those are diverse private initiatives, and specially designed contractual and organizational arrangements governing bilateral or multilateral relationships between private agents (e.g. voluntary individual or collective actions, codes of professional behavior, environmental contracts, eco-cooperatives etc.). There has been emerging a great number of private and collective forms managed by the ―visible hand of the manager‖, collective decision-making, private negotiations etc. governing successfully various aspects (and challenges) of the sustainable development. Nevertheless, there exist abundant examples of ―private sector failures‖ (lack of potential to coordinate and stimulate sustainability) demonstrating the incapability to deal effectively with the problems of development.



the public modes (―public order‖) – these are various forms of a third-party public (Government, community, international) intervention in market and private sectors such as public guidance, public regulation, taxation, public assistance, public funding, public provision etc. The role of the public (local, national and transnational) governance has been increasing along with the intensification of the activity and exchange, and the growing interdependence of the social, economic and environmental activities (and related problems and risks). In many cases, the effective organization of certain activity through a market mechanism (price competition) and/or a private negotiation would take a long period of time, be very costly, could not reach a socially desirable scale, or be impossible at all. Thus a centralized public intervention could achieve the willing state of the system faster, cheaper or more efficiently. Nonetheless, there has been a great number of bad public involvements (inaction, wrong intervention, over-regulation etc.) leading to significant problems of the sustainable development around the globe.



the hybrid forms – some mixture combining features of the market and/or private and/or public governance (e.g. the state certifies the organic producers and enforces the organic standards, and thus intensifies the development of organic markets and environmental sustainability).

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NATURE

Public governance

Socio-economic development

Hybrids Market governance

Institutional environment

Private governance INDIVIDUALS

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Figure 1. Governing mechanisms for agrarian sustainability.

In one person world there is no need for (any) governance since the sustainable relations between that person and the nature are achieved through a simple (production and/or consumption) management (―self-governance‖). However, in the real world of limited resources, complex social interactions between many individuals (division, specialization and cooperation of labor, intensive exchanges) and conflicting interests, there is a need for a special governing mechanism to direct, coordinate, stimulate, induce and enforce individuals efforts to accomplish a sustainable development. The achievement of the state of an overall efficiency (the maximum social welfare, sustainability) is driven by various social arrangements – preset formal and informal rules (institutional environment), competition, contracting, cooperation, profit-making or non-for profit activity, collective actions, pure private order, public order, voluntary initiatives, mixed modes etc. Depending on the efficiency of the system of governance which is put in place, the outcome of the development is quite different (Figure 1). Therefore, all systems for the assessment of sustainability must include not only the outcome(s) of the process, that is the ―current‖ level (the state) of sustainability. The evaluation is to embrace the system of governance put in place, that is the social mechanism responsible for the outcome. Otherwise, mere analysis of the state or trend indicators would give no adequate picture for the ability of the system to improve, sustain, or adapt to a new sustainable level. Thus the problem for assessing the efficiency of individual governing mechanisms and for selecting the most efficient one(s) is very important. The New Institutional Economics gives us a good framework to answer this key question.

The Costs of Governance Transaction costs are the costs associated with the protection and the exchange of individuals‘ rights [Furuboth and Richter]. In addition to the production costs, the economic

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agents make significant costs for the coordination of their relations with other individuals5: for finding best prices and partners for land, inputs and labor supply, financing, and marketing of outputs and services; for negotiating the conditions of exchange; for completing and ―writing down‖ contract or setting up a partnership organization (coalition); for coordination through a collective decision-making or direct managerial orders; for enforcing negotiated terms through monitoring, controlling, measuring and safeguarding; for disputing through a court system or another way; for adjusting or termination along with the changing conditions of exchange. The institutional environment and its development also impose significant transaction costs to individuals – e.g. for studying out and complying with various institutional restrictions (community or state norms, regulations, standards etc.), formal registration of contracts and entities, efforts to deal with bureaucracy etc. A good example in this respect are current problems of many Bulgarian farms to meet the new EU requirements (―institutionally determined‖ costs) related to new product quality, food safety, labor, environmental, animal welfare etc. standards [Bachev, 2008]. The transaction costs have two behavioral origins: individual‘s bounded rationality and tendency for opportunism [Williamson]. The economic agents do not possess full information about the system (price ranges, trade opportunities, adverse effects of their activities on others, trends in development) since the collection and the processing of such information would be either very expensive or impossible (e.g. for future events, for partners intention for cheating, time and space discrepancy between individual action and adverse impacts on others etc.). In order to optimize decision-making (to reach the state of efficiency and sustainability) they have to spent costs for ―increasing their imperfect rationality‖ - for data collection, analysis, forecasting, training etc. The individuals are also given to opportunism and if there is an opportunity for some of the transacting sides to get non-punishably an extra rent from the exchange (performing unwanted exchange) he will likely ―steal‖ the rights of others. Two major forms of opportunism can be distinguished: pre-contractual (―adverse selection‖) - when some of the partners use the ―information asymmetry‖ to negotiate better contract terms; and postcontractual (―moral hazard‖) - when some counterpart takes an advantage of impossibility for full observation on his activities (by another partner or by a third party) or when he take ―legal advantages‖ of the unpredicted changes in transacting conditions (costs, prices, environment etc.). A special third form of opportunism occurs in the development of large organizations (known as ―free-riding‖). Since the individual benefits are often not proportional to the individual efforts, everybody tends to expect others to invest costs for the organizational development and later on to benefit (―free riding‖) from the new organization [Olson]. Commonly, it is very costly or impossible to distinguish the opportunistic from nonopportunistic behavior (because of the bounded rationality). Therefore, agrarian agents have to protect their transactions and rights from the hazard of opportunism through: ex ante efforts to protect their ―absolute‖ (given by dominating institutions) rights, and find a reliable counterpart and to design an efficient mode for partners credible commitments to the 5

The production costs are the cost associated with the proper technology (combination of production factors) of certain farming, servicing, environmental, community development etc. activity. The transaction costs are the costs for governing the economic and other relations between individuals.

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―contracted‖ (voluntary transferred) rights; and ex post investments for overcoming (through monitoring, controlling, stimulating cooperation) of possible opportunism during contract execution stage. If transaction costs were zero then the mode of the governance would not be of economic importance. In such a world the individuals would manage their relations with an equal efficiency though free market, or through private organizations of different types, or in a single nationwide company. All information for the effective potential of transactions (exploration of technological opportunities, satisfying various demands, respecting assigned and transferred rights) would be costlessly available. And the individuals would costlessly protect their (absolute and contracted) rights, and trade owned resources in mutual benefit until exhausting the possibilities for increasing productivity, maximizing the consumption, and the sustainable development6. However, very often the high costs make it difficult or block otherwise efficient (mutually beneficial) transactions. We have already mentioned the textbook cases of ―market failure‖ connected with the negative and positive externalities. Since free-market prices do not reflect the effect on the third party‘s welfare they cannot govern effectively the relations between individuals. The maximization of the social output (welfare) is not achieved, and inefficient allocation of resources and activities, and unsustainable development arrives. Hence farmers will over-produce ―public bads‖ (noise, air, and water pollution) and underproduce ―public goods‖ (rural amenities, ecological and cultural services; habitat for wildlife, biodiversity). That necessitates a ―Government intervention‖ to eliminate the differences between the social and the private prices (an ―internalization of externalities‖ through taxes, norms etc.). The problem of ―social costs‖ does not exist in the world of zero transaction costs and well-defined private rights [Coase]. Here the situation of maximum efficiency is always achieved independent of the initial allocation of rights. However, when transaction costs are significant, then costless protection, negotiation and exchange of rights is impossible. The initial allocation of property rights between individuals is critical for the overall efficiency and sustainability. Moreover, if rights on important resources are not well-defined (e.g. rights on clean air and water) that creates big difficulties in effective allocation (e.g. unsolvable costly disputes between polluting farmers and neighborhood). Consequently, some essential activities (and transactions) are not carried out at socially effective scale, and the existing governing structures less contribute to sustainable development [Bachev, 2007]. Thus the type of the governance becomes crucial since various modes give unequal possibilities for participants to coordinate activities, and stimulate an acceptable behavior of others (counterparts, dependents), and protect their contracted and absolute rights from unwanted expropriation [Williamson]. In the world of positive transaction costs the rational agrarian agents will seek, chose, and develop such modes for governing of their activities and relations with others which maximize their benefits and minimize their total (production and transacting) costs. In the long run only efficient modes for governing of different activities will prevail (sustain) in agriculture [Bachev, 2004].

6

Currently, there is a principle agreement (a‖ social contract‖) for a global sustainable development.

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However, the sustainability of agrarian structures is a necessary7 but not a sufficient condition for the sustainable development [Bachev and Peeters]. The overall goals of sustainable development cannot be automatically achieved through totally decentralized actions (free market competition, private initiatives). There is a need for a special (designed and installed) governance which include a significant public (community, national, transnational, global) intervention in the agrarian sector. There is not a singe (universal) mode for an effective organization of all type of agrarian activity in any possible natural, institutional, and economic surroundings [Bachev, 2004]. The individual governing forms have distinct features (different advantages and disadvantages) to protect rights and to coordinate and stimulate the socially desirable activities. Besides, the agents have specific personal characteristics – different awareness, entrepreneurships, preferences, risk aversion, tendency for opportunisms etc. Furthermore, efficiency of the governing mode will depends on the specific attributes of each activity and transaction. Therefore, the individual transaction and the transaction costs is to be put in the centre of the analysis, and the comparative efficiency of the feasible modes for governing of socially desirable activities assessed [Bachev, 2007].

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The Principle Governance Matrix Generally, every agrarian activity and transaction could be governed through a great variety of alterative forms. For instance, a supply of environmental preservation service could be governed as: a voluntary activity of a farmer; though private contracts of the farmer with interested or affected agents; though an interlinked contract between the farmer and a supplier or a processor; though a cooperation (collective action) with other farmers and stakeholders; though a (free) market or assisted by a third-party (a certifying and controlling agent) trade with special (eco, protected origins, fair-trade etc.) products; though a public contract specifying farmer‘s obligations and compensation; though a public order (regulation, taxation, quota for use of recourses or emissions); within a hierarchical public agency or by a hybrid form. The different governance modes are alternative but not equal modes for the organization of activities. The free market has a big coordination and incentive advantages (―invisible hand‖, ―power of competition‖), and provides ―unlimited‖ opportunities to benefit from the specialization and the exchange. However, market governance could be associated with a high uncertainty, risk, and costs due to the price instability, the great possibility for facing an opportunistic behavior, the ―missing market‖ situation etc. The special contract form (―private ordering‖) permits a better coordination, intensification, and safeguard of transactions. However, it may require large costs for the specification of contract provisions, for adjustments with constant changes in the conditions, for enforcement and disputing of negotiated terms etc. The internal (ownership) organization allows a greater flexibility and control on transactions (direct coordination, adaptation, enforcement, and dispute resolution 7

According to the most opinions the sustainability of farms is one of the major criteria (and an indicator) for the sustainable agrarian development [Sauvenier at al.]. In fact, the experience of beef, pig, and poultry sectors of developed countries shows that financial stability (security) for farmers increases after transformation from the independent operators (traditional family farm) into hired laborers of the vertically integrated industries [Martinez; Sporleder].

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by a fiat). However, the extension of the internal mode beyond the family and smallpartnership boundaries (allowing achieving the minimum technological or agronomic requirements; exploration of technological economies of scale and scope) may command significant costs for development (initiation and design, formal registration, restructuring), and for current management (for collective decision making, control on the coalition members opportunism, supervision and motivation of hired labor etc.). In order to select the best (most efficient) form for governing of a particular activity we have to assess the comparative advantages and disadvantages of practically possible forms for governance of that activity. In some cases the advantages of a certain mode of governance are not difficult to verify - e.g. when it gives bigger benefits (achieves the socially desirable/effective scale) or commands minimum total costs etc. In such cases the choice of the most effective form of governance is easy since we can compare directly costs and benefits of alternatives. For instance, in most countries much of the agrarian activity is commonly governed in some sort of family farm, the supply of inputs or exchange of farm output are governed my market modes etc. However, in many instances, the direct assessment (the comparison) of the costs and the benefits of the alternative governing arrangements are difficult or impossible to make. That is particularly true for some elements of the transaction costs related to divers governance structures. In the later group we can include the costs for finding best partners, for negotiation, for controlling and enforcement of contractual terms, for organizational development, for interlinked transacting, for unrealized (failed) deals etc. [Bachev, 2004]. The discrete structural analysis is suggested to evaluate the comparative efficiency of the alternative governing forms [Williamson]. Here the assessment of the absolute levels of transaction costs of the alternative governing structures is not necessary. This approach aims to evaluate the relative levels of transacting costs between alternative modes of governance, and selecting that one which most economize on transacting costs. Following that framework first we have to identify the ―critical dimensions‖ of transactions responsible for the variation of transaction costs. The ―frequency‖, ―uncertainty‖, and ―asset specificity‖ have been identified as critical factors of the transaction costs by Williamson [Williamson] while the ―appropriability‖ has been added by Bachev and Labonne [Bachev and Labonne]. When the recurrence of transactions between the same partners is high, then both (all) sides are interested in sustaining and minimizing costs of their relations (avoiding opportunism, building reputation, setting up adjustment mechanisms etc.). Besides, the costs for development of a special private mode for facilitating bilateral (or multilateral) exchange could be effectively recovered by frequent exchange. When the uncertainty, which surrounds transactions increases, then costs for carrying out and secure the transactions go up (for overcoming information deficiency, safeguarding against risk etc.). Certain risks could be diminished or eliminated by a production management or through a special market mode (e.g. purchase of an insurance). However, the governance of most transacting risk would require a special private forms – e.g. trade with origins; providing guarantees; using share-rent or output-based compensation; employing economic hostages; participating in a risk-pooling, inputs-supply or marketing cooperative; a complete integration [Bachev and Nanseki].

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The transaction costs get very high when specific assets for the relations with a particular partner are to be deployed8. The relation specific investments are ―locked‖ in transactions with a particular buyer or seller, and cannot be recovered through a ―faceless‖ market trade. Therefore, dependant investment (assets) have to be safeguarded by a special form such as long-term contract, interlinks, hostage taking, joint investment, or ownership integration. The transacting is particularly difficult when the appropriability of rights on products, services or resources is low. ―Natural‖ low appropriability has most of the agrarian intellectual products - agro-market information, agro-meteorological forecasts, new varieties and technologies, software etc. Besides, all products and activities with significant (positive or negative) externalities are to be included in this group. If the appropriability is low the possibility for unwanted (market or private) exchange is great, and the costs for protection of private rights (safeguard, detection of cheating, disputing) extremely high. The agents would either over produce (negative externalities) or under organize such activity (positive externalities) unless they are governed by an efficient private or hybrid mode (cooperation, strategic alliances, long-term contract, trade secrets, or public order). Secondly, we have to ―align transactions (differing in their attributes) with the governance structures (differing in their costs and competence) in discriminating (mainly in transaction cost economizing) way‖ [Williamson]. According to the combination of the specific characteristics of each transaction, there will be different the most effective form for governing of activity (Figure 2). Agrarian transactions with a good appropriability, high certainty, and universal character of investments (the partner can be changed anytime without significant additional costs) could be effectively carried across the free market through spotlight or classical contracts. Here the organization of transactions with a special form or within the farm (firm) would only bring extra costs without producing any transacting benefits. The recurrent transactions with low assets specificity, and a high uncertainty and appropriability, could be effectively governed through a special contract. The relational contract is applied when detailed terms of transacting are not known at outset (a high uncertainty), and a framework (mutual expectations) rather than a specification of the obligations is practiced. The partners (self)restrict from opportunism and are motivated to settle the emerging difficulties and continue relations (the situation of a frequent bilateral trade). Besides, no significant risk is involved since investments could be easily (costlessly) redeployed to another use or users (no assets dependency exist). A special contract forms is also efficient for rare transactions with a low uncertainty, high specificity and appropriability. The dependent investment could be successfully safeguarded through the contract provisions since it is easy to define and enforce the relevant obligations of partners in all possible contingencies (no uncertainty surrounds transactions). Here the occasional character of the transactions does not justify the internalization within the farm (firm).

8

Specificity is not a technological but transacting characteristic of the assets. In one situation a particular capital (investment) could be highly universal (easy deployment to another internal usage or outside trade) while in others - highly specific (a big dependency from the relations with a certain counterpart (buyer or seller).

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Mechanisms of Governance of Agrarian Sustainability Generic modes

Critical dimensions of transactions Appropriability High Low Assets Specificity Low High Uncertainty Low High Low High Frequency High Low High Low High Low High Low        

Free market Special contract form Internal organization Third-party involvement Public intervention  - the most effective mode;  - a necessity for a third party involvement

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Figure 2. Principle modes for governing of agrarian transactions.



9

The transactions with a high frequency, a big uncertainty, a great assets specificity (dependency), and a high appropriability, have to be organized within the farm/firm (the internal ownership mode). For instance, the managerial and the technological knowledge is quite specific to a farm, and its supply has to be always governed through a permanent labor contract and coupled with the ownership rights [Bachev, 2004]. The capital investments in land are to be made on owned (or long-leased) rather than a seasonally rented land (high site and product specificity). All ―critical‖ to the farm material assets will be internally organized - production of forage for animals; important machineries; water supply for the irrigated farming etc. While the universal capital could be effectively financed by a market form (e.g. a bank credit), the highly specific investments can be only made through an internal funding (own funds, equity sell, joint venture). According to the personality of resource owners and the (transacting) costs of their coalition, different type of farm (agro-firm) will be efficient - one-person farm, family farm, partnership, cooperative farm, and corporative farms [Bachev, 2004]. If the specific and specialized capital cannot be effectively organized within the farm (economy of scale and scope explored, funding made)10, then an effective governing form outside farm-gates is to be used - group farming, joint ownership, interlinks, cooperative, lobbying for a public intervention. When the strong assets (capacity, time of delivery, site, branding) interdependency with an upstream or downstream partner exists, then it is not difficult to govern transactions through a contract modes (strong mutual interests for cooperation and restriction of opportunism). For instance, in Germany and some other developed countries the effective 9

The differences in the personal characteristics of the agents are disregarded. Only the extreme levels (high-low) of the critical factors of transactions are considered. In the real agrarian economy there is a big variation of the critical dimensions, and thus of the effective governing forms (including mixed, hybrid, interlinked etc. governance). 10 The integration of transactions would either increase the management costs (needs to buy from or sell to a competitor) or it would be loss-making comparing to the outside production costs (price) competition.

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cooperative agreements between farmers and drinking water companies are widely used (symmetrical dependency) and led to production methods protecting water from pollution [Hagedorn]. However, very often farmers face a unilateral dependency and need an effective (ownership) organization to protect their interests. The transacting costs for initiation and maintaining of such ―collective organization‖ is usually great (big number of the coalition, different interests of the members, opportunism of ―free-riding‖ type) and it is either unsustainable or does not evolve at all. That creates serious problems for the efficiency (and sustainability) of individual farms - missing markets, monopoly or quasi-monopoly situation, impossibility to ―induce‖ a public intervention etc. Third, we have to identify the situations of market and private sector failures – that is the critical points for the sustainable development. Serious transacting problems arise when the condition of assets specificity is combined with a high uncertainty, low frequency, and good appropriability (Figure 2). Here the elaboration of a special governing structure for a private transacting is not justified, the specific investments are not made, and the activity (or restriction of activity) fails to occur at an effective scale (―market failure‖ and ―contract failure‖). Similar difficulties are also encountered for rare transacting associated with a high uncertainty and appropriability. In these cases, a third part (private agent, NGO, public authority) involvement in transactions is necessary (through assistance, arbitration, regulation) in order to make them more efficient or possible at all. For instance, when State establishes and enforces quality and safety standards for farm inputs (chemicals, machinery) and produces, or certify providers of agrarian services, or regulate employment relations, or guarantee minimum price for farmers, all that considerably facilitates and intensifies (market and private) transactions and increases farm sustainability. The emergence and unprecedented development of the organic farming and the system of fair-trade are also good examples in that respect. There is an increasing consumer‘s demand (a price premium) for the organic, semi-organic and fair-trade products in developed countries. Nevertheless their supply could not be met unless effective trilateral governance (including an independent certification and control) has been put in place. When the appropriability associated with a transaction is low, there is no pure market mode to protect and carry out activity effectively. Nevertheless, the respecting others rights (unwanted exchange avoided) or the ―granting‖ additional rights to others (needed transactions carried) could be governed by a ―good will‖ or charity actions of individuals, NGOs, government or international organizations. For instance, a great number of voluntary environmental initiatives (agreements) have emerged driven by the competition in the food industries, the farmers‘ preferences for eco-production, and the responds to the public pressure for a sound environmental management11. However, the environmental standards are usually ―process-based‖, and ―environmental audit‖ is not conducted by an independent party, which does not guarantee a ―performance outcome‖. Therefore, most of these initiatives are seeing as a tool for the external image manipulation. Recent huge food safety, animal safety, and eco-scandals have demonstrated that such private schemes could often fail (high bounded rationality and possibility for opportunism).

11

Unprecedented development of the ―codes of behaviors‖, eco-labeling and branding, environmental cooperatives, and ―green alliances‖, all they are good examples in that respect.

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In any case, the voluntary initiatives could hardly satisfy the entire social demand especially if they require significant costs. Some private modes could be employed if a high frequency (a pay-back on investment is possible) and a mutual assets dependency (thus an incentive to cooperate) exists12. In these instances, unwritten accords, interlinking, bilateral or collective agreements, close-membership cooperatives, codes of professional behavior, alliances, internal organization etc. are used. However, emerging of special large-members organizations for dealing with low appropriability (and satisfying the entire ―social‖ demand) would be very slow and expensive, and they unlikely be sustainable in a long run (―free riding‖ problem). Therefore, there is a strong need for a third-party public (Government, local authority, international assistance etc.) intervention in order to make such activity possible or more effective [Bachev, 2004]. For example, the supply of environmental goods by farmers could hardly be governed through private contracts with the individual consumers because of the low appropriability, high uncertainty, and rare character of transacting (the high costs for negotiating, contracting, charging all potential consumers, disputing etc.). At the same time, the supply of additional environmental protection and improvement service is very costly (in terms of production and organization costs) and would unlikely be carried out on a voluntary basis. Besides, the financial compensation (price-premium) of farmers by the willing consumers through a pure market mode is also ineffective due to the high information asymmetry, massive enforcement costs etc. A third-party mode with a direct public involvement would make that transaction effective: on behalf of the consumers the Government agency negotiates with the individual farmers a contract for ―environment conservation and improvement service‖, coordinates activities of various agents (including a direct production management), provides public payments for the compensation of farmers, and controls the implementation of negotiated terms[13].

Farm as a Governing Structure A significant amount of the agrarian activities is organized by different type farms and farming organizations. The New Institutional Economics gives a new insight for understanding the role of the farm and its sustainability [Bachev and Peeters]. The sustainability of a farm is to characterize farm‘s ability to maintain (continue) over time. Since no economic organization would exist in a long-term if it were not efficient (otherwise it would be replaced by more efficient arrangement), the problem of assessment of sustainability of farms is directly related to estimation of the factors and the level of farm efficiency. In the traditional (Neoclassical) framework, the farm is presented as a ―production structure‖ and the analyses of efficiency are restricted to the production costs (―factors productivity‖, ―optimization of technological factors according to marginal rule‖). This 12

For instance, inter-dependency between a dairy farm and a milk processor in a remote region (capacity and site dependency); or a bee keeper and a neighboring orchard farm (symmetric dependency between needs of flower and needs for pollination). 13 Namely, public environmental contracts with individual farmers have been broadly used in EU as an effective form for governing the supply of environmental preservation and improvement services [EC].

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approach fails to explain why (in any given country) for a long period of time there exist so many farms with different levels of ―efficiency‖ (productivity). In Bulgaria for instance, the level of profitability and productivity in cooperative farms has been 5 times lower than in private farms. Besides, there have been one million highly sustainable subsistent and nonprofit making farms in the country [Bachev, 2006]. In addition to the production costs, the modern farming is also associated with significant transaction costs. Therefore, the ―rational‖ agrarian agents will seek, chose and/or develop the most effective (less expensive) mode for organization of their transactions that minimize their bounded rationality, and safeguard their investments and rights from the hazard of opportunism. When transaction costs are high, they could block otherwise effective transactions, and restrict the farm size far bellow the technologically optimal level. Very often the high costs for market trading (e.g. for finding a credit; marketing of output) and/or internal governance (e.g. deficiency of low transacting cost labor) limit the farm size to miniature subsistent farming or family borders [Bachev, 2004]. In other instances, the existing effective potential to economize on market transacting costs could cause a vast extension of farm size through a backward, lateral or forward integration of transactions. For example, the high costs for market and contract trading after 1990 has turned the subsistent farming into the most effective (or only possible) forms for organization of available agrarian assets (farmland, livestock etc.) of more than a million Bulgarians (Bachev, 2006). On the other hand, the enormous costs of market trading have caused a domination of integrated and interlinked modes of transacting, and a concentration of commercial farming in few thousands large agro-firms and cooperatives. Thus in the world of positive transaction costs, farms and other agrarian organizations have a significant economic role to play. They are not only production but also a major governing structure – a form for organization of transactions and for minimization of transacting costs. Therefore, sustainability of different farms cannot be correctly understood and estimated without analyzing their comparative production and governance potential [Bachev and Peeters]. Generally, every farm related transaction could be governed through a great variety of alterative market, contract, integral etc. forms. Each of these governing modes gives individuals dissimilar opportunities to coordinate, stimulate, and control transactions, safeguard their investments from an opportunistic expropriation, and profit from the specialization, cooperation and exchange. For instance, one-person farm (firm) has zero internal transaction costs (one agent), but limited possibility for investment in specialized (and specific) human and material capital. The ―internal‖ opportunities for increasing productivity (through investments, exploring economy of scale and size) increases along with the extension of the members of coalition (group farm, partnership). However, the later is also associated with an enlargement of the costs for making the coalition (finding complementary and reliable partners) and the internal costs for managing the coalition (for coordination, reducing bounded rationality, controlling opportunism etc.). The separation of ownership from the management (cooperative, corporation) gives enormous opportunities for productivity growth but it is connected with huge transacting costs (for decreasing information asymmetry between management and shareholders, for decision making, for adaptation, for controlling opportunism of hired labor and between partners etc.). The special contract form combines the potential for a greater ―control‖ on transactions with possibility to explore advantages of further specialization of activity.

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Nevertheless, it could be connected with large costs for preparing and enforcement of contracts for complex occasional transactions with high unilateral dependency. Free market has big coordination and incentive advantages (―invisible hand‖, ―power of competition‖), and provides ―unlimited‖ opportunities to benefit from specialization and exchange. However, market governance could be associated with high uncertainty, risk, and costs due to price instability, great possibility for facing opportunistic behavior, ―missing market‖ situation etc. Protection of rights and economic exchanges let more profitable use of resources but also require additional costs. Farmers and other economic agents (resource owners, consumers) will tend to govern their activity and relations though the most effective forms – that which maximize their benefits and minimize their costs. Therefore, the most effective form and size of farm will be determined through optimization of total (production and transacting) costs, and trade-offs between the gain in the productivity/benefits and the gain in transacting costs. Hence farm will be efficient (sustainable) if it manages all transactions in the most economical for the owner(s) way – that is the situation when there exist no activity which could be carried out with a net benefit [Bachev, 2004]. If a farm does not govern activity or transactions effectively, it will be unsustainable since it experiences high costs and difficulties using institutions (possibilities, restrictions) and carrying out activity and transactions comparing to other feasible organization. In that case, there will be strong incentives for exploring the existing potential (adapting to a sustainable state) through reduction or enlargement of farm size, or via reorganization or liquidation of the farm. Thus either alternative farm or non-farm application of resources; or farm expansion through an employment of additional resources; or trade instead of internal use of owned land and labor; or taking over by (or merger with) another farm or organization14, will take place. Furthermore, the transacting modes and the acceptable net benefits will vary according to the individual’s preferences, entrepreneurship ability, risk aversion, opportunity costs of owned resources etc. Depending on the personality of resource owners and the (transacting) costs and benefits of their coalition, different type of farm will be preferred - one-person farm (firm), family farm (firm), group farm or partnership (firm), cooperative farm, and corporative farms [Bachev, 2004]. Expected benefits for farmers could range from the monetary or non-monetary income; profit; indirect revenue; pleasure of self-employment or family enterprise; enjoyment of agricultural activities; desire for involvement in environment, biodiversity, or cultural heritage preservation; increased leisure and free time; to other noneconomic benefits15. Moreover, in the specific institutional environment (legal framework, support policies, tradition, access to new technology, level of transacting costs) various types of farm will have quite different effective horizontal and vertical boundaries. For instance, in transitional conditions of high market and institutional uncertainty, and inefficient property rights and contract enforcement system, most of the agrarian investments happened to be in a regime of high specificity (dependency). As a result (over)integrated modes such as low productive subsistent household and group farming, or large production cooperatives and agro-companies, have been dominating in Bulgaria and East Europe [Bachev, 2006]. 14

15

In most developed countries, the sustainable development has been associated with the disappearance of the traditional farming organization in major sectors (poultry, beef, pig) which is taken over by or integrated into related industries. A ―desire for preservation of the farm for future generation‖ has been a major reason for the persistence (sustainability) of a great number of part-time farms in Japan [Bachev and Petters].

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Functional areas

Alternative governing modes Market contract

Special organization Cooperation Partnership

Supply of land and other natural resources Labor supply

Purchase Short-term lease

Long-term lease with a fix rent Long-term lease with a share rent Long-term lease with a market rent

Daily hire Seasonal hire

Partnership Cooperation

Supply of short-term material assets Supply of long-term material assets Service supply

Purchase with a spotlight contract Standard contract

Permanent labor contract with a fix remuneration Permanent labor contract with result based payment Long-term procurement contract Supply contract interlinked with a credit supply, service supply, and/or marketing of farm produce Long-term lease contract Contract for purchase interlinked with crediting (leasing) and/or services Long-term supply contract Supply contract interlinked with other services, products or crediting Long-term supply contract Supply contract interlinked with supply of material assets and/or crediting

Partnership Cooperation

Co-investment Crediting interlinked with supply of material assets and services Contract with a public funding program Insurance contract interlinked with material assets Long-term insurance contract

Partnership Cooperation

Long-term contract for marketing Marketing contract interlinked with crediting, supply of material assets and/or services

Partnership Cooperation

Innovation and knowhow supply

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Special contract form

Financing

Insurance

Marketing of products and services

Purchase with a spotlight contract Standard contract Purchase with a spotlight contract Standard contract Purchase with spotlight contract Standard contract Free consultation in the farm advisory system Bank loan Loan from an individual agent Loan from a private organization Purchase of insurance Purchase of ―assurance service‖ Retail sale Wholesale trade Standard contract

Cooperation

Partnership Cooperation

Cooperation

Cooperation

Figure 3. Principle governing forms for functional areas of Bulgarian farms.

Alternatively, in more matured economies, where markets are developed and institutions stable, the agrarian assets are with more universal character. Therefore, farm borders are greatly determined by the family borders, and more market and mixed (contract rather than entirely integrated) forms prevail.

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In order to assess the farm‘s efficiency and sustainability we have to put the individual transaction in the centre of analysis, and assess the level of associated costs and benefits. The major types of farm transactions are associated with: the know-how supply, innovation supply, land supply, labor supply, inputs supply, service supply, finance supply, insurance supply, and marketing of services and products (Figure 3). The analysis is to embrace the comparative efficiency of the organization (governance) of every major transaction of the farm. If significant costs (difficulties) of some type of transacting in relation to the feasible alternatives is in place, then farm is to be considered as non-sustainable. Given the fact that an alternative form often diminish one type while increasing the other kind of transacting costs, and the widespread application of complex modes (e.g. interlinking credit supply with inputs supply and/or marketing), the overall (internal and external) governance costs of the farm has to be taken into account. Next, farm‘s potential (incentives, ability) for adaptation to the evolving market, institutional and natural environment through effective changes in the governing forms (saving on transacting costs) and the production structure (exploring technological possibilities for growth in productivity) is to be estimated. Thus if a farm does not have a potential to stay at or adapt to new more sustainable level(s) it would be either liquidated or transformed into another type of farm. For instance, if a farm faces enormous difficulties meeting institutional opportunities and restrictions (e.g. new quality and environmental standards, production quotas); or it has serious problems supplying managerial capital (as it is in a one-person farm when an aged farmer has no successor), or supply of needed farmland (a big demand for non-agricultural use of land), or funding activities (insufficient own finance, impossibility to sell equity or buy credit), or marketing output (a changing demand for certain products, strong competition with the imported products), then it would not be sustainable despite the high historical or current efficiency. Currently there are numerous unsustainable farms in most EU countries, which can hardly adjust to the fundamental changes in CAP and associated enhanced competition and new food safety, environmental, animal welfare etc. standards. Our new approach makes it clear that sustainable development does not mean sustainable farms and agrarian structures [Bachev and Peeters]. The farms and other modes of governance evolve (modernize, adapt, transfer, disappear) according to the changes in the social and natural environment. The development of the governance must be judged depending on the contribution of dominating and newly emerging forms of governance to achieving various (social, economic, environmental etc.) goals of sustainable development. Our approach also proves inadequacy of widely used indicators for productivity of ―production costs and resources‖ for the assessment of the efficiency (viability, sustainability) of different farming organizations. Actually it is to be expected a significant differences in the rate of profitability on investments in an agro-firm (a ―profit making organization‖) from the ―pay-back‖ of expenditures and resources in a cooperative (―member oriented organization‖), a public farm (a ―non-for profit organization‖) or in a self-consistent farm (giving opportunity for productive use of otherwise ―non-tradable‖ resources such as family labor, land etc.) [Bachev, 2004]. It is obvious that traditional statistical, accountancy and other data are little suitable to test and broadly apply our new approach for assessing efficiency (and sustainability) of farms. Here it is necessary to get micro-economic data for the different transactions governed by

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various types of farms as well as for the costs and benefits associated with alternative governing structures.

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The Effective Modes for Public Intervention There is a big variety of possible forms for public intervention in the market and private activities. The comparative analysis is to extend to the public modes and include: firstly, the correspondence of the public involvement to the real needs of development – the identified needs for a third-party intervention from Figure 2. Secondly, an assessment of the comparative advantages of the alternative modes for public involvements comprising all costs – the direct (tax payer, assistance agency etc.) expenses, and the transacting costs of bureaucracy (for coordination, stimulation, mismanagement), and the costs for individuals‘ participation and usage of public modes (expenses for information, paper works, payments of fees, bribes), and the costs for community control over and for reorganization of the bureaucracy (modernization and liquidation of public modes), and the (opportunity) costs of public inaction. And third, estimation of the comparative efficiency of selected form and the other practically possible (feasible) modes of governance of socially desirable activity such as partnership with private sector; property rights modernization etc. Accordingly, a public intervention is to be initiated only if there is overall net benefit - when the effects are greater than additional (individual and social) costs for the third-party involvement [Bachev, 2007]. Depending on the uncertainty, frequency, and necessity for the specific investment of public involvement, there will be different the most effective forms. Figure 4 presents an example with the public modes for effective interventions in the ―environmental transactions‖. Principally, the interventions with a low uncertainty and assets specificity would require a smaller Government organization (more regulatory modes; improvement of the general laws and contract enforcement etc.). When uncertainty and assets specificity of the transactions increases a special contract mode would be necessary – e.g. employment of public contracts for provision of private services, public funding (subsidies) of private activities, temporary labor contract for carrying out special public programs, leasing out public assets for private management etc. And when transactions are characterized with a high assets specificity, uncertainty and frequency then an internal mode and a bigger public organization would be necessary — e.g., permanent public employment contracts, in-house integration of crucial assets in a specialized state agency or public company etc. In the beginning, the existing and emerging problems (difficulties, costs, risks, failures) in the organization of market and private transactions have to be specified. The appropriate government involvement would be to create an environment for: decreasing the uncertainty surrounding market and private transactions, and increasing the intensity of exchange, and protecting private rights and investments, and making private investments less dependent etc. For instance, the State establishes and enforces quality and safety standards for farm inputs and produces, certifies service providers, regulates employment relations, transfers water management rights to farms associations, sets up minimum farm-gate prices etc. All that facilitates and intensifies (market and private) transactions and increases sustainability.

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Low

Level of Uncertainty, Frequency, and Assets specificity -----------------------------------

High

New property rights

Regulations

Taxes

Assistance and support

Public provision

Rights for clean, beautiful environment, biodiversity; Private rights on natural, biological, and environmental resources; Private rights for (non) profit management of natural resources; Tradable quotas (permits) for polluting; Private rights on intellectual agrarian property, origins, (protecting) ecosystem services; Rights to issue eco-bonds and shares; Private liability for polluting

Regulations for organic farming; Quotas for emissions, and use of products and resources; Regulations for introduction of foreign species, and use of GM crops; Bans for certain activity, and use of some inputs and technologies; Norms for nutrition and pest management; Regulations for water protection against pollution by nitrates; Regulations for biodiversity and landscape management; Regulations for trading of protection of ecosystem services; Licensing for water or agrosystem use; Quality and food safely standards; Standards for good farming practices; Mandatory (environmental) training; Certifications and licensing; Compulsory environmental labeling; Designating environmental vulnerable and reserve zone; Set aside measures; Inspections, fines and, ceasing activities

Tax rebates, exception, and breaks; Ecotaxation on emissions or products (pesticide, fertilizers); Levies on manure surplus; Tax or levies schemes on farming or export for funding innovation and extension; Waste tax

Recomendation and information; Demonstration; Direct payments and grants for environmental actions of farms, farmers and community organizations, businesses; Preferential credit programs; Public environmental contracts; Government purchases (water and other limited resources); Financial and price support for organic and ecoproduction, and special origins; Funding of environment and management training programs; Assistance in farm and ecoassociations Collecting fees for paying ecosystem service providers

Research and development; Extension and advise; Agro-market and knowhow information; Agrometeorologica l forecasts; Sanitary and veterinary control, vaccination, prevention measures; Specialized public agency (company) for important ecosystems; Pertaining ―precaution principle‖ Ecomonitoring; Eco-foresight; Risk assessment

Figure 4. Effective modes for public intervention in environmental transactions.

*

Next, practically possible modes for increasing appropriability of transactions have to be considered. The low appropriability is often caused by unspecified or badly specified private rights [Bachev, 2004]. In some cases, the most effective government intervention would be to *

The environmental transactions are associated with respecting the environmental rights and improving the environmental performance of individual agents. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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introduce and enforce new private property rights – e.g. rights on natural, biological, and environmental resources; tradable quotas for polluting; private rights on intellectual agrarian property and origins etc. That would be efficient when the privatization of resources or the introduction (and enforcement) of new rights is not associated with significant costs (uncertainty, recurrence, and level of specific investment are low). That Government intervention effectively transfers the organization of transactions into the market and private governance, liberalizes market competition and induces private incentives (and investments) in certain activities (the relevant part in Figure 2). For instance, tradable permits (quotas) are used to control the overall use of certain resources or level of a particular type of pollution16. They give flexibility allowing farmers to trade permits and meet their own requirements according to their adjustment costs and specific conditions of production. That form is efficient when a particular target must be met, and the progressive reduction is dictated through permits while trading allows the compliance to be achieved at least costs (through a private governance). The later let also a market for environmental quality to develop17. In other instances, it would be efficient to put in place regulations for trade and utilization of resources and products – e.g. standards for labor (safety, social security), product quality, environmental performance, animal welfare; norms for using natural resources, GM crops, and (water, soil, air, comfort) contamination; a ban on application of certain chemicals or technologies; foreign trade regimes; mandatory training and licensing of farm operators etc. The large body of environmental regulations in developed countries aim changing the farmers behavior and restricting the negative externalities18. It makes producers responsible for the environmental effects of their products or the management of products uses (e.g. waste). This mode is effective when a general improvement of the performance is desired but it is not possible to dictate what changes (in activities, technologies) is appropriate for a wide range of operators and environmental conditions (high uncertainty and information asymmetry). When the level of hazard is high, the outcome is certain and the control is easy, and no flexibility exists (for timing or the nature of socially required result), then the bans or strict limits are the best solution. However, the regulations impose uniform standards for all regardless of the costs for compliance (adjustment) and give no incentives to over-perform beyond a certain level. In other instances, using the incentives and restrictions of the tax system would be the most effective form for intervention. Different sorts of tax preferences (exception, breaks, credits) are widely used to create favorable conditions for the development of certain (sub)sectors and regions, forms of agrarian organization, segment of population, or specific types of activities. The environmental taxation on emissions or products (inputs or outputs of production) is also applied to reduce the use of harmful substances. For instance, taxes on pesticides and fertilizer are used in Scandinavian countries and Austria to decrease their

16

E.g. manure production quotas in Holland until recently, water abstraction licenses and water rights trading in UK and Australia, nutrition trading schemes in some US river catchments etc. 17 Permits can be taken out of market in order to raise the environmental quality above the ―planned‖ (by the Government) level. 18 For instance, in EU there is a ban for spraying pesticides by airplane, burning after harvest, overhead irrigation of grassland; detailed regulations for nutrition and pest management, water protection against pollution by nitrates, biodiversity and landscape management; licensing for water use etc. Each country develops a system of ―good farming practices‖ to set up specific codes for sustainable farming.

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application and environmental damaging impact19. In Holland, levies on manure surplus were introduced in 1998 based on levies for nitrogen and phosphorus surpluses above a levy free surplus per hectare. The system creates strong incentives to minimize the leakages (and not just usage), and reduce the flexibility to substitute taxable for non-taxable inputs. However, it is associated with significant administrative and private costs20. The environmental taxes impose the same conditions for all farmers using a particular input and give signals to take into account the ―environmental costs‖ inflicted on the rest of the society. Taxing is effective when there is a close link between the activity and the environmental impact, and when there is no immediate need to control the pollution or to meet the targets for reduction. Tax revenue is also perceived to be important to maintain budget and activities of special (e.g. environmental) programs. However, an appropriate level of the charge is required to stimulate a desirable change in farmers behavior21. Furthermore, the nitrogen emission can vary according to the conditions when nitrates are applied and attempting to reflect this in tax may result in complexity and high administrating costs. Besides, the distribution impact of such taxes must be socially acceptable, and the implications for international competitiveness also taken into account. In some cases, a public assistance and support to private organizations is the best mode for intervention. Large agrarian and rural support and development programs have been widely used in all industrialized countries. They let a ―proportional‖ development of agriculture, improvement of farmers welfare (―income parity‖), and in some instances undesired effects such as over-intensification, environmental degradation, and market distortions. The public financial support for the environmental actions is the most commonly used instrument for the improving environment performance of farmers in the EU and other developed countries22. It is easy to find a justification for the public payments as a compensation for the provision of an ―environmental service‖ by farmers. All studies shows that value placed upon landscape exceed greatly the costs of running the schemes. However, the share of farms covered by various agri-environmental support schemes is not significant [EC]. That is a result of the voluntary (self-selection) character of this mode which does not attract farmers with the highest environment enhancement costs (most intensive and damaging environment producers). In some cases, the low-rate of farmers‘ compliance with the environmental contracts is a serious problem23. The later cannot be solved by augmented administrative control (enormous enforcement costs) or introducing bigger penalty (politically and juridical intolerable measure). A disadvantage of ―the payment system‖ is that once introduced it is practically difficult (―politically unacceptable‖) to be stopped when 19

In Sweden tax is imposed on manufactures and importers at a fixed rate for active ingredient, and represents 20% of the fertilizers prices. In Denmark a different rate of sale tax is applied on retail prices of chemicals representing an average of 37% of the wholesale prices [ECOTEC]. 20 Annual revenue of 7,3 millions Euro against the administration costs of 24,2 millions and compliance expenses at farm level between 220-580 per farms [ECOTEC]. 21 In Scandinavia the introduction of such tax brought about a reduce use of pesticide. In contrast, doubling the tax rate in California had no discernable effect on sales [ECOTEC]. 22 In EU, USA, and Japan the public environmental contracts are mostly with the individual farmers while Canada, Australia, and New Zealand direct support to community (collective) actions. 23 A study in France shows that 40% of the farmers face some difficulties to enforce contracts in their parts of the environmental impact [Dupraz et al.].

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goals are achieved or there are funding difficulties. Moreover, an withdraw of the subsidies may lead to further environmental harm since it would induce the adverse actions such as intensification and return to the conventional farming. The main critics of the subsidies are associated with their ―distortion effect‖, the negative impact on ―entry-exit decisions‖ from polluting industry, the unfair advantages to certain sectors in the country or industries in other countries, not considering the total costs (transportation and environmental costs, and ―displacement effect‖ in other countries). It is estimated that the agri-environmental payments are efficient in maintaining the current level of environmental capital but less successful in enhancing the environmental quality [EC]. Often providing public information, recommendations, training and education to farmers, other agrarian and rural agents, and consumers are the most efficient form. In some cases, a pure public organization (in-house production, public provision) will be the most effective as in the case of agrarian research and education, agro-market information, agro-meteorological forecasts, border sanitary and veterinary control etc. Usually, the specific modes are effective if they are applied alone with other modes of public intervention. The necessity of combined intervention (a governance mix) is caused by: the complementarities (joint effect) of the individual forms; the restricted potential of some less expensive forms to achieve a certain (but not the entire) level of the socially preferred outcome; the possibility to get an extra benefits (e.g. ―cross-compliance‖ requirement for participation in EU support programs); the particularity of the problems to be tackled; the specific critical dimensions of the governed activity; the uncertainty (little knowledge, experience) associated with the likely impact of the new forms; the practical capability of Government to organize (administrative potential to control, implement) and fund (direct budget resources and/or international assistance) different modes; and not least important the dominating (right, left) policy doctrine [Bachev, 2007]. Besides, the level of an effective public intervention (governance) depends on the kind of the problem and the scale of intervention. There are public involvements which are to be executed at local (community, regional) level, while others require nationwide governance. And finally, there are activities, which are to be initiated and coordinated at international (regional, European, worldwide) level due to the strong necessity for trans-border actions (needs for a cooperation in natural resources and environment management, for exploration of economies of scale/scale, for governing of spill-overs)24 or consistent (national, local) government failures. Very frequently the effective governance of many problems (risks) requires multilevel governance with a system of combined actions at various levels involving diverse range of actors and geographical scales. The public (regulatory, inspecting, provision etc.) modes must have built special mechanisms for increasing the competency (decrease bounded rationality and powerlessness) of the bureaucrats, beneficiaries, interests groups and public at large as well as restricting the possible opportunism (opportunity for cheating, interlinking, abuse of power, corruption) of the public officers and other stakeholders. That could be made by training, introducing new assessment and communication technologies, increasing transparency (e.g. independent assessment and audit), and involving experts, beneficiaries, and interests groups in the management of public modes at all levels [Bachev, 2007]. Furthermore, applying ―market

24

Recent epidemic of avian infection is a good example in that respect.

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like‖ mechanisms (competition, auctions) in the public projects design, selection and implementation would significantly increase the incentives and decrease the overall costs. Principally, a pure public organization should be used as a last resort when all other modes do not work effectively [Williamson]. The ―in-house‖ public organization has higher (direct and indirect) costs for setting up, running, controlling, reorganization, and liquidation. What is more, unlike the market and private forms there is not an automatic mechanism (such as competition) for sorting out the less effective modes25. Here a public ―decision making‖ is required which is associated with high costs and time, and it is often influenced by the strong private interests (the power of lobbying groups, policy makers and their associates, employed bureaucrats) rather than the efficiency. Along with the development of general institutional environment (―The Rule of Law‖) and the measurement, communication etc. technologies, the efficiency of pro-market modes (regulation, information, recommendation) and contract forms would get bigger advantages over the internal less flexible public arrangements [Bachev, 2007]. Usually hybrid modes (public-private partnership) are much more efficient than the pure public forms given the coordination, incentives, and control advantages. In majority of cases, the involvement of farmers, farmers organizations and other beneficiaries increase efficiency - decrease asymmetry of information, restrict opportunisms, increase incentives for private costs-sharing, reduce management costs etc. [Bachev, 2007] For instance, a hybrid mode would be appropriate for carrying out the supply of non-food services by farmers such as the preservation and improvement of biodiversity, landscape, and historical and cultural heritages.26 That is determined by the farmers information superiority, the strong interlinks of that activity with the traditional food production (economy of scope), the high assets specificity to the farm (farmers competence, high cite-specificity of investments to the farm and land), and the spatial interdependency (a need for cooperation of farmers at a regional or wider scale), and not less important – the farm‘s origin of negative externalities. Furthermore, the enforcement of most labor, animal welfare, biodiversity etc. standards is often very difficult or impossible at all. In all these cases, stimulating and supporting (assisting, training, funding) the private voluntary actions are much more effective then the mandatory public modes in terms of incentive, coordination, enforcement, and disputing costs [Bachev, 2004]. Anyway, if there is a strong need for a third-party public involvement but an effective government intervention is not introduced in a due time, the agrarian ―development‖ would be substantially deformed. Thus the Government failure is also possible and often prevails. In Bulgaria for instance, there have been a great number of bad examples for Government under- and over-interventions in agrarian sector during post-communist transition now [Bachev, 2006]. Consequently, a primitive and uncompetitive small-scale farming; predominance of over-integrated and personalized exchanges; ineffective and corrupted agrarian bureaucracy; blocking out of all class of agrarian transactions (such as innovation and extension supply, long-term credit supply, supply of infrastructure and environmental goods); and development of a large informal (gray) sector, all they have come out as a result.

25 26

It is not rare to see highly inefficient but still ―sustainable‖ public organizations around the world. The environmental cooperatives are very successful in some EU countries like Holland and Finland [Hagedorn].

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Hrabrin Bachev Assessing sustainability level of agricultural systems, and identification of sustainability problems and risks Assessing efficiency and sustainability of existing and other feasible modes of governance Identifying needs for public intervention

Assessing comparative efficiency of different modes for public intervention and selecting the best one(s)

Figure 5. Steps in analysis and improvement of governance of agrarian sustainability.

Stages for Analyzing and Improvement of the Governance

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The analysis and the improvement of the governance of agrarian sustainability have to go though following major steps: Firstly, an assessment is to be made on the economic, social, environmental etc. sustainability of different agricultural systems (parcel27, farm, eco-system, regional, national etc.), and the existing and emerging problems and risks are to be identified (Figure 5). There are developed and practically used a great number of holistic systems for assessing the sustainability level of divers agricultural systems [Sauvenier et al.; OECD, 2008; VanLoon]. The identified problems of sustainability could be internal for a particular agricultural system or caused by other or larger systems28. In any case, a persistence of serious environmental, social and economic challenges (problems, conflicts, risks) is a credible indicator that an effective system of governance is not put in place29. The modern science increasingly offers quite precise methods both: to detect various (ecological, social etc.) problems and risks associated with the agriculture as well as to improve farming systems in order to mitigate environmental and other hazards caused by agriculture and other (man-made or natural) factors. Secondly, the spectrum of existing and other practically possible modes of governance (institutions; market, private, public and hybrid forms) employed in agriculture has to be identified, and their efficiency and sustainability assessed. The evaluation of efficiency of individual modes will show their ability (potential) to deal with various challenges of and contribute to agrarian sustainability at different levels. In addition, the assessment of 27

Commonly, the parcel is defined as the smallest (the lowest level) agricultural system [Sauvenier et al.; VanLoon]. However, the parcel management is an integral part of the farm governance. That is why detected sustainability problems at parcel level could only be tackled with farm and/or higher level governance. 28 In globalise economy many of the factors affecting adversely agrarian sustainability are external for agriculture global warning, global financial and economic crisis, regional water crisis etc. 29 It shows that needed social, economic, environmental preservation etc. activity is not carried at effective (socially desirable) scale.

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sustainability of existing governing structure is necessary to get an idea about its ―internal‖ potential to adapt (evolve, modernize, transform) to dynamic economic, institutional and natural environment, and meet effectively the new (future) challenges and goals of sustainable development30. All these would let us know whether (and the extend to which) there will be an efficient response to sustainability objectives and challenges within the existing system of governance.

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Third, the serious deficiencies (failures) in dominating market, private, and public modes to solve existing and emerging problems (risks, goals) of agrarian sustainability are to be specified, and the needs for a (new) public intervention identified. That step is to include an analysis of the structure and factors of transaction costs at nationwide (social) scale, which eventually slow down the sustainable growth of agrarian sector and different regions, and lead to insufficient and unsustainable use of resources, underinvestment and low productivity in production, lack of innovations, holdup of social cohesion of agrarian actors etc. Finally, the alternative modes for public intervention to correct the existing market, private sector and public sector failures have to be identified (e.g. assistance, regulation, property rights modernization etc.); and their comparative efficiency assessed in terms of contribution to sustainability and minimization of total social costs; and the most efficient one(s) selected. It is essential to assess the comparative efficiency of practically possible (feasible) and alternative forms of governance. Thus, the additional benefits (problems to be solved, risks to be overcome, new goals to be achieved), and the costs, and the modes for a new public intervention must be socially admissible (acceptable). If different forms permit achieving the same goals, tackling the same problems, overcoming the same risks etc., the analysis is to focused on the selection of the mode minimizing the total (implementing and transacting) costs. Moreover, a form having the same (or less) costs as the alternatives is to be chosen if it provides more benefits or it is (socially, politically, technically) more preferable than other arrangements. If one of the possible forms provides more benefits at the expense of more costs, then the selection is to be made depending on whether the additional costs for that public intervention are socially acceptable (and feasible) or not. Similarly, if there is a single (only one) mode available for governing a particular intervention (achieving a certain sustainability goal) it would be introduced only if associated implementing and transacting costs are socially admissible (and feasible). At this final stage, our comparative analysis let us improve the design of the new forms of public intervention according to the specific market, institutional and natural environment of a particular country, region, sub-sector31, and in terms of perfection of the coordination, adaptation, information, stimulation, restriction of opportunism, controlling (in short – minimization of transaction costs) of participating actors (decision-makers, implementers, beneficiaries, other stakeholders). What is more, it also unable us to predict likely cases of new public (local, national, international) failures due to impossibility to mobilize sufficient political support and necessary resources and/or ineffective implementation of otherwise 30

Often some governing modes are highly efficient in ―current‖ economic, social and natural environment but unable to adapt (sustain) to evolving new (future) challenges of sustainable development. 31 The effective institutions can not be ―imported‖ but must be designed for the specific conditions of different countries, regions, sectors etc. [North]. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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―good‖ policies in the specific economic and institutional environment of a particular country, region, sub-sector etc. Since the public failure is a feasible option its timely detection permits foreseeing the persistence or rising of certain problems of agrarian sustainability, and informing (local, international) community about associated risks32.

ENVIRONMENTAL GOVERNANCE IN BULGARIAN AGRICULTURE

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Institutional Environment There has been a fundamental post-communist transformation of Bulgarian agriculture after 1989 [Bachev, 2006]. New private rights on major natural resources (farmland, forestry, water, origins) has been introduced or restored, markets and trade liberalized, and modern public support and regulations introduced. During most of the transition diverse environmental rights (on clean and athetie nature; preservation of natural resources, biodiversity etc.) were not defined or were badly defined and enforced [Bachev, 2008]. Furthermore, inefficient public enforcement of laws and absolute and contracted rights has been common during transition now33. Besides, out-dated system of public regulations and control dominated until recently which corresponded little to the contemporary needs of environmental management. Besides, there was no modern system for monitoring the state of soil, water, and air quality, and credible information on the extent of environmental degradation was not available. What is more, there existed neither social awareness of the ―concept‖ of sustainable development nor any ―needs‖ to be included in public policy and/or private and community agenda. The lack of culture and knowledge of sustainability has also impeded the evolution of voluntary measures, and private and collective actions (institutions) for effective environmental governance. In the last few years before EU accession, country‘s laws and standards were harmonized with the immense EU legislation34. The Community Acquis have introduced a modern framework for the environmental governance including new rights (restrictions) on protection and improvement of environment, preservation of traditional varieties and breeds, biodiversity, animal welfare etc. However, a good part of these new ―rules of the game‖ are not well-known or clearly understood by the various public authorities, private organizations and individuals [Bachev, 2008]. Generally, there is not enough readiness for an effective implementation of the new public order because of the lack of experience in agents, adequate administrative capacity, and/or practical possibility for enforcement of novel norms (lack of comprehension, deficient court system, widespread corruption etc.). In many instances, the enforcement of environmental standards is difficult (practically impossible) since the costs for detection and penalizing of offenders are very high, or there is no direct links between the performance and the environmental impact. For example, 32

For instance, most countries have declared a ―green recovery strategy‖ for overcoming the current financial and economic crisis. However, only few of them actually take the appropriate measures and put needed resources in than direction. 33 Requirements for fighting against corruption and reforming administration and juridical system have been underlined by the European Commission (EC) Monitoring Reports and closely scrutinized after EU accession. 34 The Acquis Communitaire adapted before EU accession (January 1, 2007) contains 26000 pieces of legislation accounting for 80000 pages.

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although the burning of (stubble) fields has been banned for many years (2000 Law for Agricultural Land Protection) yet this harmful for the environment practice is still widespread in the country. Subsequently, a permanent deterioration of soil quality35, wasting the accumulated through photosynthesis soil energy, an extermination of soil micro flora and other habitats, a significant contribution to green-house emissions36, multiplying instances of forests fires, diminishing visibility and increasing traffic accidents, all they come out as a result [EEA]. The harmonization with the EU legislation and the emergence of environmental organizations also generate new conflicts between private, collective and public interests. However, the results of the public choices have not always been for the advantage of the effective environmental management. For instance, the strong lobbying efforts and profitmaking interests of particular individuals and groups have led to 20% reduction in numbers and 50% reduction in area of initially identified sites for the pan European network for preservation of wild flora, fauna and birds NATURA 2000.

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Private Modes of Governance During much of the transition newly evolving market and private structures have not been efficient in dealing with various environmental issues. The privatization of agricultural land and other non-land assets of ancient public farms took almost 10 years to complete37. During a good part of that period, the governance of a critical agrarian resource was in ineffective and ―temporary‖ structures (such as Privatization Boards, Liquidation Councils, Land Commissions etc.). Sales and long-term lease markets for farmland did not emerge until 2000, and leasing on an annual base was a major form for the extension of farm size until recently. That was combined with a high economic and institutional uncertainty, and a big inter-dependency of agrarian assets [Bachev, 2006]. Consequently, most of the farming activities have been carried out in less efficient and unsustainable structures such as part-time and subsistence farms, production cooperatives, and huge business farms based on provisional lease-in contracts (Table 1). Furthermore, market adjustment and intensifying competition has been associated with a significant decrease in number of unregistered farms (74%) and cooperatives (51%) since 1995. Post communist transformation has also seen a significant change in the governance of livestock activity. The specialized livestock farms comprise a tiny portion of all farms (Table 2) while 97% of the livestock holdings are miniature ―unprofessional farms‖ breading 96% of the goats, 86% of the sheep, 78% of the cattle, and 60% of the pigs in the country [MAF].

35

Losses reach up to 80% of the organic carbon and nitrogen, and up to 50% of the remaining main nutrition elements in the soil [EEA]. 36 According to estimates they account for 5793 tons methane, 1883 tons carbon oxide, 4344879 tons carbon dioxide, and 3621 tons nitrogen oxide in 2006 [EEA]. 37 During the Communist period farming was carried in few large public farms (agro-industrial complexes, state and collective farms) averaging tens of thousands hectares and livestock heads. Besides, there were more than a 1.5 million small ―personal plots‖ (farms).

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Table 1. Number, size and importance of different type farms in Bulgaria Public farms Unregistered Cooperatives Agro-firms Number of farms 1989 2101 1600000 na na 1995 1002 1772000 2623 2200 2000 232 755300 3125 2275 2005 515300 1525 3704 2007 458617 1281 5186 Share in number (%) 1989 0.13 99.9 1995 99.7 0.1 0.1 2000 99.3 0.4 0.3 2005 99.0 0.3 0.7 2007 98.6 0.3 1.1 Share in farmland (%) 1989 89.9 10.1 1995 7.2 43.1 37.8 11.9 2000 1.7 19.4 60.6 18.4 2005 33.5 32.6 33.8 2007 32.2 24.7 43.1 Average size (ha) 1989 2423.1 0.4 1995 338.3 1.3 800 300 2000 357.7 0.9 709.9 296.7 2005 1.8 584.1 249.4 2007 2.2 613.3 364.4 Source: National Statistical Institute and Ministry of Agriculture and Food

Total 1602101 1777000 760700 520529 465084 100 100 100 100 100 100 100 100 100 100 3.6 2.8 4.7 5.2 6.8

Dominating modes for carrying out farming activities have had little incentives for longterm investment to enhance productivity and environmental performance [Bachev, 2006]. The cooperative‘s big membership makes individual and collective control on management very difficult (costly). That focuses managerial efforts on current indicators, and gives a great possibility for using coops in the best private (managers) interests. Besides, there are differences in the investment preferences of diverse coops members due to the non-tradable nature of the cooperative shares (―horizon problem‖). Given the fact that most members are small shareholders, older in age, and non-permanent employees, the incentives for long-term investment for land improvement and renovation of material and biological assets have been very low. Last but not least important, the ―member-oriented‖ (non-for-profit) nature of the cooperatives prevents them to adapt to diversified needs of members and market demand and competition.

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Mechanisms of Governance of Agrarian Sustainability Table 2. Number and size of livestock holdings in Bulgaria (November 2007) Share Share farms heads farms heads 1-2 3-9 Dairy cows 79.8 36.1 16 25.2 Buffalo cows 69.9 19 17.7 13 1-9 10-49 Ewes 85 37.1 12 24.5 She-goats 97.1 75.3 2.7 17.4 1-2 3-9 Breeding pigs 78.8 12.8 14.9 8.8 Source: MAF Agro-statistics

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Type of holdings

Share Share farms heads farms heads 10-19 20 and > 2.5 11.8 1.6 26.8 7.2 15.5 5.2 52.5 50 -99 100 and > 2 15 1 23.4 0.2 4.1 0.1 3.2 10-199 200 and > 5.8 21.1 0.5 57.4

Average heads 2.7 5.1 8.6 2.8 7.8

On the other hand, small-scale and subsistent farms38 possess insignificant internal capacity for investment, and small potential to explore economy of scale and scope (big fragmentation and inadequate scale). Besides, they have little incentives for non-productive (environment conservation, animal welfare etc.) investment. Moreover, there has been no state administrative capacity nor a political will to enforce the quality and eco-standards in that vast informal sector of the economy. Likewise, the larger business farms operate mainly on leased land and concentrate on high pay-off investment with a short pay-back period (cereals, sunflower). That has been coupled with ineffective outside pressure (by authority, community) for respecting the official standards for ecology, land use (crop rotation. nutrition compensation), biodiversity etc. In general, survivor tactics and behavior rather than a long-term strategy toward farm sustainability has been common among the commercial farms. Furthermore, during the entire transition the agrarian long-term credit market was practically blocked due to the big institutional and market uncertainty, and the high specificity of much of the farm investments [Bachev and Kagatsume]. In addition, newly evolving Bulgarian farming has been left as one of the least supported in Europe39. Until 2000 the public aid was mainly in the form of preferential short-term credit for the grain producers and insignificant support to capital investments. That policy additionally contributed to the destructive impact for unbalanced unilateral N fertilization by the biggest producers having access to the programs. Despite the considerable progress in the public support since 2000 (EU Special Assistance Program for Agriculture and Rural Development - SAPARD, CAP measures) the overall support to agriculture is estimated very little [Bachev and Kagatsume]. In addition, only a small proportion of the farms benefits from some form of public assistance most of these farms being large enterprises from regions with less socio-economic and environmental problems. Basically, a publicly supported farm must meet the requirements for the good environmental performance. However, the minor amount of actually supported

38

Subsistence and semi-subsistence farms comprise the best part of the farms as almost 1 million Bulgarians are involved in farming mostly on a part-time base and for ―supplementary‖ income [MAF]. 39 Estimates demonstrate that the Aggregate Level of Support to Agriculture before 2000 was very low, close to zero or even negative [OECD, 2000]. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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farms, and the deficiency of clear criteria for eco-performance, and the lack of effective control, have contributed barely to overall improvement of environmental situation. Hence, since 1990 the entire ―environmental management‖ has been left on the farmers ―good will‖ and the ―market signals‖. Market governance (competition, marginal rule) has led to a sharp decline in all crop (but sunflower) and livestock (but goat) productions40. The smaller size and owner operating nature of the majority of farms avoided certain problems of the large public enterprises from the past such as lost natural landscape, biodiversity, nitrate and pesticide contamination, huge manure concentration, uncontrolled erosion etc. Subsistent and small-scale farming has also revived some traditional (and more sustainable) technologies, varieties and products. In additions, the private mode has introduced incentives and possibilities for an integral environmental management (including revival of eco- and cultural heritage, anti-pollution, esthetic, comfort etc. measures) profiting from the interdependent activities such as farming, fishing, agro-tourism and recreation, processing, trade etc. Last but not least, there are good examples for foreign direct investment in cereals, oil crops, and integrated with farming vine and food processing, which introduce modern (western) governance, technologies, and quality, labor and environmental standards. A by-product from dominating ―market and private governance‖ was a considerable desintensification of the agriculture, and an ease of the general environmental pressure and pollution comparing to the pre-reform level. For instance, the total amount of used chemical fertilizers and pesticides has declined considerably, and now their per hectare application represent merely 22% and 31% of 1989 level (Figure 6). That sharp reduction in chemical use has diminished drastically the risk of chemical contamination of soils, waters, and farm produce. Consequently, a good part of the farm production has got unintended ―organic‖ character obtaining a good reputation for products with a high quality and safety. Nonetheless, a negative rate of fertilizer compensation of N, P and K intakes dominate being particularly low for phosphorus and potassium (Figure 6). Accordingly, an average of 23595,4 t N, 61033,3 t P205 and 184392 t K20 have been irreversibly removed annually from soils since 1990 [MAF]. Furthermore, an unbalance of nutrient components has been typical with application of 5,3 times less phosphorus and 6,7 times less potassium with the appropriate rate for the nitrogen used during that period. Moreover, a monoculture or simple rotation has been constantly practiced by most large operators concentrating on few profitable crops (such as sunflower and wheat). All these practices further contributed to deterioration of soil quality and soil organic matter content. There has been also a considerable increase in agricultural land affected by acidification (Figure 7). It has been a result of a long-term application of specific nitrate fertilizers41 and unbalanced fertilizer application without adequate input of phosphorus and potassium. Currently almost a quarter of soils are acidified as percentage of degraded farmland acidified soils reach 4,5% of total lands. After 1994 the percentage of acidified soil began to decrease, however, in recent years there is a reverse tendency along with the gradual augmentation of

40

For potatoes by 33%, wheat 50%, corn and burley 60%, tomatoes, Alfalfa hay and table grape 75%, apples 94%, pig meat 82%, cattle meat 77%, sheep and goat meat 72%, poultry meat 51%, cow milk 45%, sheep milk 66%, buffalo milk 59%, wool 85%, eggs 45%, honey 57% [NSI]. 41 Consisting mostly of ammonium nitrate (70-80%) and carbamide (20-30%) [EEA]. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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use of nitrates. During the entire period no effective measures have been taken to normalize soil acidity and salinity42. 120

800

100

600 80

percent

N compensation (%)

700 500

60

P compensation (%) K compensation (%)

400 300

40

200 20

Irrigated area (000 ha) Pesticides (00 t)

100

0

Fertilizers (000 t)

0 1989 1991 1994 1997 1999 2001 2003 2005 2007

Source: National Statistical Institute and Ministry of Agriculture and Food Figure 6. Irrigation, chemical application, and rate of fertilizer compensation in Bulgarian agriculture.

2004

Heavy metals

1999

Saltified

1994

Acidificated

1985

Eroded 0

10

20

30

% 40

50

60

70

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Source: Executive Environment Agency Figure 7. Share of degradated agricultural lands in Bulgaria.

Erosion has been another major factor for land degradation since 1990 (Figure 7). Due to ineffective management around one-third of the arable lands are subjected to wind erosion and 70% to water erosion as total losses varies from 0,2 to 40 t/ha in different years45. The progressing level of erosion is a result of the extreme weather but it has been also adversely affected by dominant agro-techniques, deficiency of anti-erosion measures, and uncontrolled deforestation [EEA].

42

For instance, limed acidificated lands comprises far bellow 2 % of the areas limed until 1990. And no chemical melioration or drainage of salinified land has been effectively implemented [MAF]. 45 Annual losses of earth masses from water erosion are estimated at 136 Mt while wind erosion deflates between 30-60 Mt. Two-third of the former and almost all of the later come from the arable land [EEA]. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Hrabrin Bachev 120

Agriculture % in total

100

Agriculture % in N2O

80 60

Agriculture % in CH4

40

Agriculture 1988=100 20

National 1988=100

0 1988 1991 1993 1995 1997 1999 2001 2003 2005

Source: Vassilev et al.

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Figure 8. Trend and components of green-house gas emissions from Bulgarian agriculture.

There has been also a sharp reduction of irrigated farmland as merely 2-5% of existing irrigation network46 has been practically used (Figure 6). Consequently, irrigation impact on erosion and salinization has been significantly diminished. However, the decline in irrigation has had a direct negative effect on crop yields and structure of the crop rotation. In addition, irrigation has not been effectively used to counterbalance the adverse effect of global worming on farming (extension of farm season, increased water requirements, fall of rainfalls) and the further degradation of agricultural land. There has been a significant reduction of overall green-house gas (GHG) emissions from agriculture as well (Figure 8). Moreover, the decline in the sector's contribution has been higher than the national. The N2O emissions comprise 59% of the total emissions from agriculture and there is a slight enlargement of the share in last 5 years. Besides, agriculture has been a major ammonia source accounting for two-third of the national emission. After 2000, the majority of NO2 emissions come from agricultural soils (87%), and manure management and burning of stubble fields (13%). The methane emission from agriculture represents about a quarter of the national. After 2000 the biggest portion of CH4 comes from fermentation from domestic livestock (72%) and manure management (24%). The new private management has led to an improved environmental stewardship on owned resources but has not extended to the nature in general (low appropriability of rights). It has been often associated with less concern to the manure and garbage management, overexploitation of leased and common resources, and contamination of air and groundwater. For instance, the illegal garbage yards in rural areas have noticeably increased47. Farms contribute extensively to waste ―production‖ with both organic and industrial materials, leading not only to negative changes in the beauty of scenery but also bring about air, soil and water pollution. Pollution of soil and water from industrial activities, waste management, and inproper farming activities still presents risk for the environment and human health48. Data shows that in 7% of the tested soils, concentration of pollutants is higher than the contamination critical limits [EEA]. 46

Since 1990 a considerable physical distortion of irrigation facilities has also taken place affecting 80% of the internal canals [MAF]. 47 The official figure for major illegal garbage locations is 4000 [EEA]. The actual figure is far bigger than the official one. 48 Areas of agricultural land industrially polluted by heavy metals have fallen after 1990, they are not significant, and only about 30% of the affected soils need special monitoring [EEA].

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Furthermore, around a quarter of the riverlength does not meet the normal standards for good water quality [MAF]. Monitoring of water for irrigation shows that in 45% of water samples, the nitrates concentration exceeds the contamination limit value by 2 to 20 folds [MAF]. Nitrates are also the most common polluter of underground water for the last 5 years49 with a slight excess over the ecological limit [EEA]. In addition, there has been reported general levels of pollutants exceeding the ecological limit value for triasine pesticides in underground water which is a consequence of the increased use of these chemicals. The lack of effective manure storage capacities and sewer systems in majority of farms contribute significantly to the persistence of the problem. A major part of the post-communist livestock activity is carried out by a great number of small and primitive holdings often located within village and town borders. Merely 0,1% of the livestock farms possess safe manure-pile sites, around 81% of them use primitive dunghills, and 116 thousands holdings have no facilities at all [MAF]. All that contributes significantly to pollution of air, water and soils, and disturbing population comfort (unpleasant noise and odor, dirty roads etc.). There have been also significant degrading impacts of agriculture on biodiversity. According to the official data all 37 typical animal breeds have been endangered during the last several decades 50 as 6 among them are irreversibly extinct, 12 are almost extinct, 16 are endangered and 3 are potentially endangered [MEW]. Since 1990 a considerable portion of agricultural lands have been left uncultivated for a long period of time or entirely abandoned51. The later has caused uncontrolled ―development‖ of species allowing development of some of them and suppressing others. Besides, some of the most valuable ecosystems (such as permanent natural and semi-natural grassland) have been severely damaged 52. Part of the meadows has been left under-grazed or under mowed, and intrusion of shrubs and trees into the grassland took places. Some of fertile semi-natural grasslands have been converted to cultivation of crops, vineyards or orchards. This has resulted in irreversible disappearance of plant species diversity. Meanwhile, certain public (municipal, state) pastures have been degraded by the unsustainable use (over-grazing) by private and domestic animals. In addition, a reckless collection of some valuable wild plants (berries, herbs, flowers) and animals (snail, snakes, fish) have led to destruction of all natural habitats. Above and beyond, some genetically modified crops have been introduced without an independent assessment of possible hazards for traditional and organic production and human health, or providing appropriate safeguards and proper information.

Market Modes A market driven organic farming has emerged in recent years in the country (Figure 9). It is a fast growing approach but it is restricted to 432 farms, processors and traders, and covers 49

Nitrate Vulnerable Zones cover 60% of country‘s territory and less than 7% of agricultural land use. The policy toward intensification and introduction of foreign varieties and breeds during communist period, and the lack of any policy toward protection of biodiversity afterwards have largely contributed to degradation of the rich diversity of local plants and animal breeds. 51 Currently, almost 10% of all agricultural lands is unutilized farmland. In addition, fallow land accounts for 9,5% of arable land. In some years of transition abandoned land reached a third of total agricultural land [MAF]. 52 Approximately 20% of the agricultural lands of Bulgaria are lands of High Nature Value [MAF]. 50

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less than 3% of the Utilized Agricultural Area [MAF]. There are only few livestock farms and apiaries certified for bio-production. In addition, 242677 ha have been approved for gathering wild organic fruits and herbs. The organic form has been introduced by business entrepreneurs who managed to organize and fund this new venture arranging needed independent certification 53 and finding potential buyers for the highly specific output. Produced bio fruits, vegetables, essential oil plants, herbs, spices, and honey are entirely for export since only a tiny internal market for organic products exists in the country. The slow development of organic market is not only because of the higher prices of organic products but also because of the limited consumer confidence in the authentic character of products and certification 54. In addition, eco-labeling of processed farm products (relying on self-regulation) have appeared which has been more a part of the marketing strategy of certain companies rather than a genuine action for environmental improvement. Since 2001 the assets of public owned irrigation companies were transferred to the newly evolving Water Users Associations. However, expected ―boom‖ in efficiency (quantity, productivity) from a collective management of irrigation activities have not been materialized. That is because of the semi-monopoly situation of regional state water suppliers (monopoly terms and pricing), little water-users incentives to innovate facilities and expand irrigation, and still uncompleted privatization of state irrigation assets. Generally, an initiation, development and maintenance of an organization of large group is very costly, and such a coalition is not sustainable for a long time (―free rider‖ problem). In Bulgaria, the evolution of farmers and environmental associations has been additional hampered by the big number of rural agents and their diversified interests (size of ownership and operation, type of farming, individual preferences, different age and horizon etc.) [Bachev, 2006].

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Public Modes Market and private sector have failed to govern effectively the environment related activities in agriculture and there has been a need for a third-party public intervention. However, the Government and local authority involvement has not been significant, comprehensive, sustainable, or even related to the matter [Bachev, 2008]. The total budget of the Ministry of Water and Environment accounts for just 1,5% of the National Budget, and the agricultural sector gets a tiny portion of all public eco-spending [MWE]. Similarly, recultivation of degradated farmlands by the MAF has been under way recently but it accounts for merely 200-250 ha per year [MAF]. In the passed several years a number of programs have been developed to deal with the specific environmental challenges55. In addition, national monitoring systems of environment and biodiversity have been set up and a mandatory ecological assessment of public programs 53

A good part of the certification has been done by foreign bodies since until recently no Bulgarian certification institutions existed. 54 Numerous fake labeling as organic or traditional products have been detected by the Organization for Consumer Protection and reported daily in media. 55 National Strategy for Preservation of Biodiversity (1999); National Strategy for Environment (2000); National Plan for Agrarian and Rural Development (2000); National Programme for Limitation of Total Emissions of Sulphur Dioxide, VOC, and Ammonia (2002); National Program for Waste Management Activities (2002); Environmental Strategy for the Instruments of ISPA (2003), National Strategy for Management and

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introduced. Nevertheless, the actual eco-policies rest fragmented and largely reactive to urgent environmental problems (natural disasters such floods, storms, drought) rather that based on a long-term strategy for sustainable development. Moreover, there is no efficient coordination between different programs and management levels. The programs and action plans are usually developed and executed in a highly centralized manner (by bureaucrats, foreign experts, and profit-making companies) without involvement of independent local experts, stakeholders and pubic at large. In addition, there is considerable deficiency in administrative capacity at local level in terms of staff, qualification, material and financial means. As a result of all of these, inefficiency in priority setting and management (incompetence, corruption), and a minor impact of the public programs prevails [Bachev, 2008]. Moreover, a multifunctional role of farming has not been effectively recognized; and proper system for its assessment (data, indicators) introduced; and provision of a public service ―environmental preservation and improvement‖ funded by the society. For instance, a measure ―Agro-ecology‖ of the SAPARD was not approved until the middle of 2006 and a few projects have been funded since 200756. Neither, the essential public institutions and infrastructure crucial for the sustainable farming development have been built: public system for enforcement of laws, regulations, and contracts does not work well; essential property rights (on environmental resources and biodiversity, special and organic products, GM products and intellectual agrarian property) are not well defined and/or properly enforced; public support programs are rarely governed effectively and in the best interest of the legitimate beneficiaries; agricultural research is under-funded and can hardly perform its function for innovation and independent expertise; newly established agricultural advisory system does not serve the majority of farms and include rural development and environmental issues; urgently needed public system for agrarian insurance has not been introduced; crucial agrarian and rural infrastructure (wholesale markets, irrigation, roads, communications) has not been modernized; public support for initiating and developing farming associations has not been given etc. A serious environmental challenge is still caused by the state deficiency in storing and disposal of the out-of-dated or prohibited pesticides of the ancient public farms. Currently those chemicals account for 11079 t and a good proportion of them are not stored in safe places. There are registered 477 abandoned storehouses for such pesticides, situating in 460 locations around the country, and just 38% of them are guarded [EEA]. What is more, as much as 82% of all polluted localities in the country are associated with these dangerous chemicals, and only a tiny portion of them have gone through the entire cycle of examination. A great number of international assistance projects (funded by the UN agencies, EU, Foreign Governments, NGOs etc.) have been carried out to ―fill the gap‖ of the national government failures. They either focus on a specific issue (sustainable agriculture, desertification etc.) or mobilize local actors for sustainable development. These programs introduce western experiences in governance and try to make a difference. However, they are Development of Water Sector (2004); Strategy for Developing Organic Agriculture (2005); National Plan for Agrarian and Rural Development (2007) etc. 56 Due to the mismanagement and corruption SAPARD was suspended by the EC in 2008, and a considerable EU funding under that scheme lost.

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limited in scale and unsustainable in time; in some cases overtaken by the local groups and funding improperly used; and above all with no significant impact. The endurance of environmental and other challenges demonstrates that an effective system of governance has not been put in place. Subsequently, the modernization of Bulgarian farms according to the EU (quality, safety, environmental, animal welfare etc.) standards has been delayed; and growth in farms productivity, competitiveness and sustainability severely restricted; and technological, income and eco-disparity between farms of different type, sub-sectors and regions broadened [Bachev and Kagatsume]. 180000

3

160000

2,5

140000

ha

120000

2

100000

Organic area

1,5 %

80000 60000

1

40000

Share in farmland

0,5

20000 0

0 1999

2000

2001

2002

2003

2004

2005

2006

2007

Source: Ministry of Agriculture and Food Figure 9. Development of organic farming in Bulgaria.

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Environmental Governance in Conditions of EU CAP Implementation The EU integration and CAP implementation provides new opportunities for Bulgarian farms. The EU funding alone, which agriculture receives from 2007 on is 5,1 times higher than the overall level of support to farming before acceding 57. Besides, the EU accession introduces and enforces a ―new order‖ - strict regulations and control; tough quality, food safety, environmental etc. standards; financial support and protection against market instability etc. The external monitoring, pressure and likely sanctions by the EU leads to better enforcement of laws and standards in the country. For instance, in 2007 the EC started a procedure for sanctions for not reducing emissions of greenhouse gasses according to the EU Program for Environment and Combating Adverse Climate Changes. In 2008 EC blocked payments for SAPARD and other programs because of a considerable mismanagement and corruption. Furthermore, huge EU markets is opened which enhances competition and let Bulgarian farms explore their comparative advantages (low costs; high quality, specificity and purity of produce). The novel conditions of market competition and institutional restrictions also give strong incentives (pressure) for new investments for increasing productivity and conforming to higher product, technology and environmental standards.

57

For 2007-2009 the EU funds allocated for ‖agrarian and rural development‖ are €733 million, for ―direct payments‖ 722 million, and for ―market support‖ €388 million. Besides, Bulgarian agriculture receives funding from the EU Structural Funds and the national budget.

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The larger and business farms are most sensitive to new market demand and institutional regulations since they largely benefit (or lose) from timely adaptation to new environmental regulations. Besides they have higher capacity to generate resources and find outside (credit, equity, public) funding to increase competitiveness and meet new institutional requirements [Bachev, 2006]. The process of adaptation has been associated with appropriate land management and the intensification of production. The later could revive or deepen some of the environmental problems (erosion, acidification, pollution) unless pro-environmental governance (public order, regulation etc.) is put in place to prevent that from occurring. Table 3. Share of EU and national support in Net Income of different Bulgarian farms in 2008 (percent) Type of farm

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Field crops Horticulture Permanent crops Livestock Source: MAF Agro-statistics

Share of subsidies in farms Net Income Current subsidies Investment subsidies 63.2 2.1 1.3 1.8 0.4 2.2 0.3 0

On the other hand, small-scale producers and most livestock farms are having a hard time adapting to new competition pressure, investment needs, and new food safety, environmental, animal-welfare etc. standards [Bachev and Nanseki]. Diary farming is particularly vulnerable, since, only 1,4% of the holdings with 17% of the cows in the country meet EU quality, hygiene, veterinary and building standards [MAF]. A part of the farms is qualified to receive ―area based‖ direct payments from EU. In view of the current (low) level of support, the direct payments augment farm sustainability and give means for adaptation to the new standards. On the other hand, this mode support less productive structures (smaller-scale, part-time, cooperative farms) and non-market forms (subsistence, cooperative farming). As a result, sustainability of these farms will increase – small-scale operations become viable; cooperatives are able to pay rent; subsistence farming become more profitable etc. Furthermore, direct payments cause an increase of farmland price and rent, and thus enlarge costs for land supply in the largest farms. In contrast, smaller-scale operators retain entire subsidies and see their income increased. Subsequently, the transformation of land management to the most effective forms and restructuring of farms is further delayed 58. However, the EU support benefit unevenly different farms as the bulk of the public subsidies actually go to few farms - the larger operators (agri-firms and cooperatives) specialized in field crops. At the same time, many effective small-scale farms and livestock farms 59 receive no or only a tiny fraction of the direct payments. For instance, in 2008 less than 16% of all farms got area based payments averaging 2226,1 Euro per farm and 50,4 Euro per ha [MAF]. In addition, around 13% of the farms received national top-ups averaging 910 58

In some instances (subsistence and semi-subsistent farms, member oriented cooperatives), EU funds is used effectively to subsidize food self-supply of population. 59 Livestock farms are not eligible to receive any direct payments under the ―area based scheme‖. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Euro per farm and 203,3 Euro per ha. Typically, the same farms touch both types of payments as farms specialized in field crops get the largest public support (Table 3). Furthermore, the most of the subsidies go to the more developed regions where the biggest farms and utilized farmland are located. That further fosters the disparity in income and efficiency among different farms and sub-sectors. There are also significant EU funds for rural development exceeding 4,7 times the relevant pre-accession level. This amount of resources let more and relatively smaller farms to get access to public support scheme and invest in modernization of enterprises. Furthermore, new essential activities are effectively funded such as: commercialization and diversification of farming; introduction of organic farming; maintaining productivity, biodiversity; agri-environment of protection, animal welfare; support for less-favored areas and regions with environmental restrictions etc. All these would help bringing additional employment and income for farmers, and increasing economic and environmental sustainability of farms. Similarly to the past60, mostly bigger farms participate in public support programs because they have a superior managerial and entrepreneurial experience, available resources, possibilities for adaptation to new requirements for quality and other standards, potential for preparing and wining projects etc Besides, despite the strong EU (and internal pressure) it has been impossible to reform the inefficient system of governance of public programs. Consequently, a significant EU funding has been blocked while other support (such as SAPARD) irreversibly lost. Therefore, agrarian and rural development funds will probably continue to benefit exclusively the largest structures and the richest regions of the country; and more abuses will take place; and CAP support will not contribute to decreasing economic and eco discrepancy between farms, sectors, and regions. The CAP implementation improve the environmental performance of commercial farms. There is a mandatory requirement for farms to ―keep the farmland in a good agricultural and environmental status‖ in order to receive direct payments and participate in public programs. Moreover, direct payments induce farming on previously abandoned lands, and improve environmental situation and biodiversity. Furthermore, there is a huge budget allocated for special environmental measures (going beyond the ―good farming practices‖)61. Therefore, a number of farms taking part in various agri-environmental programs will gradually increase in future62. Our recent survey has found out that for most farms the ―economic‖ sustainability (―concentration on products with secure marketing‖) is still the dominant strategy (Figure 10). At the same time, a good portion of cooperatives and most part of non-cooperative farms do not implement long-term strategies for keeping ecological sustainability through preserving soil fertility, observing crop rotation and agro-techniques requirements etc. The CAP measures would affect positively the environmental performance of large business farms and cooperatives. Namely these enterprises (and potential big polluters) are 60

SAPARD and other public programs benefited predominately large farms, cooperatives and agri-firms [Bachev and Kagatsume]. Likewise, in 2008 the biggest part of funded projects under measure ―Modernisation of farms‖ of Agrarian and Rural Development Program were for agro-firms (57%) and cooperatives (15%) [MAF]. 61 The National Plan for Agrarian and Rural Development (2007-2013) allocates budget for ―preservation of national resources and improvement of countryside‖ amounting € 623.3 million (27,1% of the total funding). 62 In 2008 there are only 27079 approved projects supporting farms from ―unfavarable‖ regioms [MAF].

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under constant administrative control and severe punishment (fines, losing licenses, and ceasing activities) for obeying new environment and animal welfare standards. Therefore, they are strongly interested in transforming their activities according to the new eco-norms making necessary eco-investments, changing production structures etc. Moreover, larger producers are motivated to participate in special agro-environmental and biodiversity programs, since they have lower costs (potential for exploring economies of scale and scope) and higher benefits from such long-term public contracts. Try to keep soil fertility Interested only in current yield Cooperatives

Put fertilizers and keep rotation Use specialized experts assistance

Private farms

Follow agro-techniques Produce products with secure marketing 0

10

20

30

40

50

60

70

80

percent

Source: Survey data

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Figure 10. Share of Bulgarian farms implementing different production strategies (%).

The experience of other EU countries demonstrates that some of the terms of the specific contracts for environment and biodiversity preservation, animal welfare, keeping tradition etc, all they are very difficult (expensive) to enforce and dispute. In Bulgaria the rate of compliance with these standards would be even lower because of the lack of readiness and awareness, insufficient control, ineffective court system, domination of ―personal‖ relations and bribes etc. Correspondingly, more farms than otherwise would enroll will participate in such schemes (including the biggest polluters and offenders). Subsequently, the outcome of implementation of that sort of instruments would be less than the desirable (―European‖) level. More to the point, direct costs and lost income for conforming to the requirements of the special programs in different farms vary considerably, and they have unequal incentives to participate. Having in mind the voluntary character of the most CAP support instruments, we should expect that the biggest producers of negative impacts (large polluters and noncompliant with modern quality, agronomic, biodiversity, animal welfare etc. standards) would stay outside of these schemes since they have the highest environment enhancement costs. On the other hand, small contributors would like to join since they do not command great efforts (and additional costs) comparing to the supplementary net benefit. Moreover, the Government is less likely to set up high performance standards because of the perceived ―insignificant‖ environmental challenges, the strong internal political pressure from farmers, and the possible external problems with the EU control (and sanctions) on cross-compliance. Therefore, CAP implementation will probably have a modest positive impact on the environment performance of Bulgarian farms. The public support and new public demand give a push to further development of market modes such as organic farming, industry driven eco-initiatives (eco-labeling, standards,

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professional codes of behavior), protected high quality products63, system of fair-trade, production of alternative (wind, manure) energy at farm etc. For instance, the significant EU market and lower local costs create strong incentives for investment in organic and specific productions by the large enterprises - farms, partnerships and joint ventures (including with non-agrarian and foreign participants). Similarly, new incentives for production of bio-fuel and clean energy would induce development of a new area of farm activity (new sub-sectors) associated with that new public and market demand. Principally, the small farms have less capacity to put together or find necessary capital and expertise for initiating, developing, certifying and marketing in all these new venture. Besides, the coalition (development, management, and exit) costs between small-scale producers are extremely high to reach the effective operation level (allowing exploring technological economies of scale and scope or technologically required minimum of inputs). Therefore, the later either stay out of these new businesses or have to integrate into larger or non-farm ventures. However, assuring the effective traceability of the origin and quality for small farms is very costly and they are not preferable partner for integrators (processor, retailers, and exporters). What is more, the internal market for organic and specialized farm products would unlikely develop fast having in mind the low income of population and the lack of confidence in public and private system of control. Some economic and/or ecological needs (such as economizing on scale and scope or high interdependency of assets) would continue to bring about a change in size and governance of individual farms and/or evolution of group organization, cooperation, and joint ventures. For instance, a big interdependency of activities require concerted actions for achieving certain eco-effect; a high asset dependency between livestock manure (over) supplier and nearby (manure demanding) organic crop farms necessitate a coordination etc. A special governing size and/or mode is also imposed by some of the institutional requirements. For example, a mandatory minimum scale of activities is set for taking part in certain public programs (e.g. marketing, agri-ecology, biodiversity, organic farming, tradition and cultural heritage); signing a 5 year public environmental contract dictate a long-term lease or purchase of managed land etc. Our recent survey has proved that as much as 41% of the non-cooperative farms and 32% of the cooperatives are in the middle of investigation of possible membership in a professional organization. Producers grouping are further stimulated by the available new public support (training, advising, funding) for farmers association. Some of the existing production cooperatives would also profit from their comparative advantages (interdependency and complementarily to individual farms, potential for exploring economy of scale and scope on institutionally determined investment, adapting to formal requirements for support, using expertise, financing and executing projects, non-forprofit character etc.), and extend their activities into eco-projects, environmental services, eco-mediation between members etc. Thus an immediate result of the new market and public opportunities for getting additional benefits (income, profit) from environmental products and services will be an amelioration of the economic performance and overall sustainability of a number of farms and rural households. 63

Such as Protected Designation of Origin, Protected Geographical Indication, and Traditional Specialty Guaranteed.

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Mechanisms of Governance of Agrarian Sustainability

The CAP implementation will push modernization of farms structures through widening the variety of contractual and organizational innovations - specific sort of contracts, new types of producers associations, spreading vertically-integrated modes etc. Special forms are also emerging, allowing agents to take advantage of large public programs which specialize in project preparation, management, and execution; invest in ―relations capital‖ or ―negative‖ entrepreneurship; form modes for lobbying and representation; make coalitions for complying with formal criteria (e.g. minimum size of utilized agricultural area for direct payments, membership requirements for producers‘ organizations) etc. Table 4. Share of farms with big and good capacity for adaptation to EU requirements for dairy sector (per cent) Farms capacity Extend of knowledge on new requirements Available skills and knowledge for adaptation Available production capacity Improvement of quality and hygiene standards Improving animal welfare Improving environmental performance Finding necessary investment Source: survey data

Unregistered

Firms

Coops

Total

22.7 22.7 27.3 36.4

63.6 54.5 45.4 72.7

100 100

38.2 35.3 32.3

31.8 31.8 9.1

100 50.0 44.1 38.2 14.7

72.7 54.5 27.3

Table 5. Expectation for impact of EU CAP implementation on your farm (% of farms)

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Impact on: Volume of production Income of farm Technology of production Investment Products quality Access to public programs Improvement of animals care Improvement of care for environment Development of infrastructure

Unregistered + 22.7 9.1 22.7 9.1 13.6 4.5 18.2 4.5 18.2 0 9.1 4.5 13.6 0 9.1 0 9.1 0

Opportunities for new income 18.2 9.1 Social status of your household 13.6 4.5 Source: survey data (+) - positive impact; (-) - negative impact

Firms + 36.4 27.3 45.4 18.2 54.5 9.1 45.4 18.2 45.4 0 54.5 9.1 45.4 9.1 54.5 9.1 54.5 9.1

+ 26.5 29.4 26.5 26.5 26.5 23.5 26.5 23.5 23.5

14.7 14.7 5.9 8.8 0 8.8 2.9 2.9 2.9

36.4 45.4

23.5 23.5

8.8 11.8

9.1 27.3

Total

CAP measures and enhanced competition foster the restructuring of commercial farms according to modern market, technological, and institutional standards. A large part of agrarian inputs, technologies, and outputs is increasingly having a ―mass‖ (standardized) character, and market transacting dominate at farm gates. There is also a parallel tendency toward specialization into productions for ―niche markets‖ and products with special quality -

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specific origins, special technologies, special quality etc. All that requires investments with higher specificity to a particular buyer(s), and ―integrated‖ management of activity in farming, processing, retailing and exporting [Bachev, 2006]. Besides, some diversification of enterprises into related activities (trade with origins, agro-tourism) for dealing with market risk is to grow. All these bring more new, special modes for private governance such as longterm contracts, collective agreements (codes of professional behavior), trilateral modes (independent third-party certification/control), ―quasi‖ or complete integration. In the new market and institutional environment many livestock farms are less sustainable because of the low productivity and competitiveness, and non compliance with the EU quality, hygiene, animal welfare and eco-standards. That is particularly truth for the small-scale unregistered producers which dominate the sector (Table 4). What is more, only a third of dairy holdings believe their production capacity corresponds to the modern requirements of competition, productivity, and justification of improvement of environmental performance and animal welfare. Nevertheless, merely one-seventh of dairy farms have potential (internal capacity, access to outside sources) to fund necessary investment associated with the adaptation to new norms and standards. Our survey of dairy farms has found out that the greatest part of unregistered farms believes that CAP measures would have a ―neutral impact‖ on their income, volume and technology of production, investment level, product quality, access to public programs, improvement of environmental care, improvement of animal welfare, development of infrastructure, possibilities for new income generation, and social status of farm households (Table 5). A bulk of firms expects a ―positive‖ effect in all above directions while cooperatives are optimistic for improvement of animal welfare and pessimistic for the impact on income and access to public programs. A few livestock farms will be able to adapt through specialized investment for enlargement and conforming to the new institutional restrictions by the deadline for full compliance in the end of 2009. Meanwhile, the EU and public pressure for enforcement of standards in commercial sector increases and leads to closure or take-over of a greater part of livestock farms. The related reduction of farms and animals, and improved manure management, is associated with a drop of the environmental burden by the formal sector (less over-grazing, fewer manure production and mismanagement etc.). We estimated that few subsistence farms would undertake market orientation and extend their present scale because of the high costs for farm enlargement and adjustment - no entrepreneurial capital and resources available, low investment and training capability of aged farmers, and insufficient demand for farm products [Bachev, 2006]. Newly introduced specific support to ―semi-market‖ farms would have no considerable impact on subsistency because of the inappropriate criteria64 and the insufficient level of support. Besides, this measure focus on less prospective structures (small semi subsistence holdings) with low potential for adaptation to volume, quality, safety, animal welfare and environmental requirements, and needs of processors and distributors. On the other hand, for the authority is practically (technically, politically) impossible to enforce the official standards in that huge informal sector of the economy. Therefore, massive (semi) subsistence farming with primitive

64

The same criteria (as in other EU countries) for defining ―semi-market farms‖ is used – farms with size of 1-4 European Size Units (1ESU=1200 Euro). However, for the Bulgarian conditions an income within this range

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technologies, poor food safety, environmental and animal welfare standards will continue to exist in years to come. We have already demonstrated that, the hybrid modes (public-private; public-collective) are much more efficient than the pure public forms given the coordination, incentives, and control advantages. Moreover, enforcement of most labor, animal welfare, biodiversity etc. standards is very difficult or impossible at all. That is particularly truth for the huge informal sector of the economy. Here individual ―punishments‖ do not work well while overall damages from the incompliance are immense. That is why policies should be oriented to market orientation of subsistence farms, support and incentives for collective modes, and ecoprograms for informal farms and groups. Principally, public support to voluntary environmental initiatives of farmers and rural organizations (informing, training, assisting, funding) would be much more effective than mandatory public modes in terms of incentive, coordination, enforcement, and disputing costs. Furthermore, involvement of farmers, farmers organizations, and interests groups in priority setting and management of public programs at different level is to be institutionalized in order to decrease information asymmetry and possibility for opportunism, diminish costs for coordination, implementation and control, and increase overall efficiency and impact. All surveys show that many of the specific EU regulations are not well known by the implementing authorities and majority of farmers [Bachev, 2008]. What is more, our recent survey indicates that as much as 47% of non-cooperative farms and 43% of cooperatives are still ―not aware or only partially aware‖ with the support measures of CAP different from the direct payments. Furthermore, as much as 62% of the farms report that they will not apply for such support due to the ―lack of financial resources‖ (26%), ―not compliance with formal requirements‖ (18%), and ―clumsy bureaucratic procedure‖ (17%). In addition, there are still a number of ―blank points‖ in adaptation of EU regulations in Bulgarian agriculture. For instance, ―the whole farm‖ is a subject of support in agrienvironmental measures (e.g. organic farming) but its borders are not defined at all in the national legislation. That creates serious difficulties since land and other resources of the majority of farms are considerably fragmented and geographical dispersed. Above and beyond, most of the farm managers have no adequate training and managerial capability, and are old in age with a small learning and adaptation potential. For instance, the average age of the farm managers is 61 as 70% of them are older than 55 [MAF]. The lack of readiness, experiences, and potential for adaptation in public and private sectors alike would require some time lag until the ―full‖ implementation of the CAP in ―Bulgarian‖ conditions. The later will depend on the pace of building an effective public and private capacity, and training of (acquiring learning by doing experience by) bureaucrats, farmers, and other agrarian agents. As a consequence of the internal and external for farms factors farms modernization and adaptation will be delayed, and their competitiveness and sustainability diminished. Moreover, there will be significant inequalities in application (and enforcement) of new laws and standards in diverse regions of the country and sectors of agriculture, and farms of different type and size. Last but not least important, there is a growing competition for environmental resources between different industries and interests. That push further overtaking the natural resources is quite big (above the average for agriculture and other sector of the economy) to be considered as ―semimarket‖ activity.

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away from the farm governance and change into non-agricultural (urban, tourism, transport, industry etc.) use. The needs to compete for and share resources would deepen conflicts between various interests and social groups, regions, and even with neighboring states. All that would require a special governance (cooperation, public order, hybrid form) at local, national and transnational scales to reconcile conflicts in the benefit of an effective environmental management. 90

120

80 100 70 60

Share in SGM < 2 ESU

80

50 60

Share in SGM > 100 ESU

40 30

40

Share in farms < 2 ESU

20 20 10 0

0 Field crops Horticulture Permanent Grazing crops livestock

Pigs & poultry

Mixed cropping

Mixed livestock

Share in farms > 100 ESU

Mixed crops & livestock

Source: Ministry of Agriculture and Food Figure 11. Share of farms with SGM smaller than 2 ESU and bigger than 100 ESU in total SGM and farms with different specialization (percent).

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Sustainability of Farm Structures The last stage of analysis is to assess the sustainability of different type of farming organization. Large business farms govern a significant part of the activity in cereals, industrial crops, permanent crops, poultry and pigs. Most of them are registered as some type of agro-firms Sole Traders (58,3%), Companies (35,4%), and Associations (6,3%). Big farms account for a tiny portion of all farms, but concentrate a significant part of UAA (Table 1) and produce the bulk of the Standard Gross Margin (SGM) in major sub-sectors (Figure 11). Business farms are commonly large specialized enterprises. Most of them were set up as family and partnership organization during first years of transition by younger generation entrepreneurs. Specific management skills and ―social‖ status, and a combination of partnership assets (technological knowledge, business and other ties, available resources) led to the rapid extension of farms through an enormous concentration of (management, ownership of) resources, exploration of economy of scale and size, and modernization of enterprises [Bachev, 2006]. During the long period of institutional and market transformation (unsettled rights on resources, imperfect regulations, huge uncertainty and instability) the personal relations and ―quasi‖ or entirely integrated modes were extensively used to overcome transaction difficulties. In addition, some state companies were taken over by managers and registered as shareholdings. Joint ventures with non-agrarian and foreign

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capital have been increasingly set up as well. Business farms have been constantly extending their share in managed agrarian (and related) resources and output taking over smaller farms, incorporating new types of activities and applying new organizational schemes. Business farms are profit-oriented organizations, and farmer(s) have great incentives to invest in farm-specific (human, material, intangible) capital because they are the sole owners of residual rights (benefits) of the farm. Owners are family members or close partners, and the internal transaction costs for coordination, decision-making, and motivation are not high. Increased number of coalition (partnership) gives additional opportunity for internal division of labor and profiting from specialization (e.g. full-time engagement in production management, market relations, paper work, technological development etc.). The organizational style of a firm is more and more preferred since it provides the opportunity to overcome coalition difficulties (e.g. forming joint ventures with outside capital, disputed ownership rights through the court system); to diversify into farm related or independent businesses (trade, agro-tourism, processing); to develop firm-specific intangible capital (advertisement, brand names, public confidence) and its extension into a daughter company, trade (sell, licensing), and transfer through generations (inheriting); to overcome existing institutional restrictions (e.g. for direct foreign investments in farmland and engaging in trade with cereals, vine, dairy); to provide explicit rights for taking part in particular types of transactions (such as export licensing, privatization deals, assistance programs etc.). Their large size and reputation make business farms preferable partners in inputs supply and marketing deals. Besides, business farms have giant negotiating power and effective economic and political mechanisms to enforce contracts. They also possess great potential to collect market information, search for the best partners, use experts and innovation, meet special (collateral) requirements and bear the risk and costs of failures. Large farms have strong incentives and potential for innovation – available resources to test, adapt, buy, and introduce new methods, technologies, varieties; possibility to hire leading experts and arrange direct supply from consulting companies or research institutes. In addition, they could explore economy of scale and scope on production and management (e.g. ―package‖ arrangement of credits for many projects and interlinking inputs supply with know-how supply, crediting and marketing). They are also able to invest considerable relation-specific capital (information, expertise, reputation, lobbying, bribing) for dealing with funding institutions, agrarian bureaucracy, and market agents at national or even international scale. Furthermore, they have enormous political power to lobby for Government support in their best interests. All these give considerable advantages of business type farming organization. Under the conditions of non-working court and contract enforcement systems, all critical transactions are governed (controlled, protected) through internal modes. Farm-specific assets such as critical machinery, vineyards, orchards, animals, processing facilities, and adjoining land, are all safeguarded by ownership. Low cost standard (one-season, share rent) lease-in contracts are widely used to govern land supply from tens and hundreds of proprietors. Critical transactions are integrated through extensive labor employment. Besides, core labor (specialists, mechanists) is hired on a permanent basis and special forms such as output-based compensation, interlinking (housing, services), social disbursements, paid holidays etc, are further used to enhance motivation. Own supply (making) rather than outside procurement is typical for the essential services and inputs which prevents risk from unilateral dependency (opportunism of supplier) or missing market situation. In the case of high asset interdependency (product specificity;

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quality and quantity dependency) with a downstream partner‘s reciprocal supply of inputs against marketing is applied. Funding is secured through an effective combination of equity, debt, public and hybrid modes. Standard activities and assets are financed by bank credit since it is easy to arrange a loan. Alternatively, farm-specific investments are financed through private modes - own sources, ―personal‖ loans and co-investment. Also, special contract modes are used to mitigate funding difficulties (e.g. shortage of working capital) or to facilitate mutuallydependent relations with buyers and suppliers, such as delayed payments for inputs supply (zero interest, ―loans in kind‖), interlinking credit with inputs supply and marketing, leasing or accepting outside investment (―hostage taking‖, joint ownership) of long-term assets. Business farms have been quite successful in benefiting from the various preferential public support programs (SAPARD, State Fund Agriculture) developing good proposals, meeting formal requirements, dealing with complicated paper work, and ―arranging‖ selection of their projects for modernization and expansion of enterprises, diversifying into related businesses, improving environmental performance etc. Furthermore they get the greatest share of EU CAP support measures (direct payments, agrarian and rural development support etc.) which enhance additionally their efficiency. In marketing farm output and services, classical trade across the market (sells on wholesale market; business with market agents) dominates. Since the main part of a farm‘s product has a standardized (commodity) character, market prices and competition effectively govern relations with partners. However, when specificity of output to a particular buyer (processor, retailer) is high (technology, quality, packaging, time of delivery, origin, sitespecificity) then delivery contracts with a respective partner are employed to tailor or protect transactions. Intra-firm processing and retailing is practiced by some farms. Larger operational size and frequency of transacting provide an economic opportunity for the internal exploration of interdependent assets in farming-processing-retailing. Vertical integration helps protect dependent investments and payoffs from marketing processed and retail products - e.g. getting the entire profit (value-added and final products), brand name trade, lessened market dependency (easy storage and transportation) etc. Large business farms have significant comparative advantages in terms of adaptability, governance, and productivity. That leads to further redistribution of farming activities into this effective and perspective structures. Accordingly, agricultural is increasingly characterized by the domination of larger and highly competitive business enterprises, which will take over and concentrate most activities in all sub-sectors. Business farms will sustain in future maintaining (enhancing) their comparative advantages in terms of adaptability, governance, and productivity by having greater access to EU markets and opportunities to benefit from the large public support programs for agrarian and rural development. The cooperatives concentrate a major part of cereals, oil and forage crops, orchards and vineyards, and they are key service providers for their members and rural agents. Long-term cooperative tradition was an important factor for emergence of more than 3000 ‗new type‖ production cooperatives during and after the liquidation of old ―cooperative‖ structures. Furthermore, often the cooperative was the single form for farming organization in the absence of settled rights on main agrarian resources and/or inherited high interdependence of acquired by individuals assets [Bachev, 2006]. More than 2 millions Bulgarians have got individual stakes in the assets of liquidated ancient public farms. In addition to their small

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size, a great part of these shares were in indivisible assets (large machinery, buildings, processing and irrigation facilities). Therefore, new owners had no any alternative but liquidate (sales, consumption, distortion) or keep them up as a joint (cooperative) ownership. In many cases, ownership on farmland was restituted with adjoined fruit trees and vineyards, and much of the activities (e.g. mechanization, plant protection, irrigation) could be practically executed solely in cooperation. Most of landowners happened to live away from rural areas, have other business, be old of age, or possess no skills or capital to start own farms. In the absence of big demand for farmlands and/or confidence in emerging private farming, new evolving cooperatives have pulled land plots of more than 40% of novel proprietors in 1990s. The cooperative rather than other formal collective (e.g. firm) mode has been mostly preferred. It allows individual members easy (low costs) entree and exit from the coalition, preservation of full control on a major private resource such as land, and democratic participation in (and control on) management (―one member-one vote‖ principle). Besides, cooperative form gives some important tax advantages such as tax exemption on sale transactions with individual members and on received rent in kind (Double-taxation Law). Also there are possibilities for organization of transactions which are not legitimate for other modes such as credit supply, marketing, and lobbying at nation-wide scale (Antimonopoly Law). Moreover, most of cooperatives develop along with or after emergence of small-scale and subsistent farming. Namely, ―non-for-profit‖ character and strong member (rather than market) orientation attracted membership of many households. Production coops have been perceived as an effective (cheap and stable) form for supply of highly specific to individual farms inputs and services (production of feed for animals; mechanization of major operations; storage, processing, and marketing of farm output), and/or food for household consumption. Relatively bigger operational size of cooperatives gives them great opportunity for efficient use of labor (teamwork, division and specialization of work), farmland (cultivation in big consolidated plots, effective crop rotation, application of chemicals and irrigation), and material assets (exploration of economy of scale and scope on large machinery and equipment). In addition, they have superior potential to minimize market uncertainty (―risk pooling‖, advertisement), and organize some critical transactions (better access to agrarian credit; stronger negotiating positions in input supply and marketing, facilitate land consolidation through lease-in and lease-out deals; introduce technological innovations, effective environmental management), to invest in intangible capital (reputation, brand names, labels, origins) etc. In situation of ―missing markets‖, the cooperative mode has been the single form for organization of certain transactions in villages and rural areas undertaking bakery, processing, retail trade etc. Cooperative activities are not difficult to manage since internal (members) demand for output and services is known and ―marketing‖ secured. In addition, coops concentrate on a few highly standardized products (wheat, sunflower) with a stable market and good profitability. All this assists financing, as advance funding of activities commissioned by members is commonly practiced, while producing universal (mass) commodities is easily financed by public programs or commercial credit. Furthermore, coops offer low-cost, longterm leasing of land. That is often coupled with simultaneous lease-out deals as a specific mode for cashing coops output or facilitating relations between landlord and private farms. The cooperatives broadly practiced an integral organization of critical ―services‖ and inputs

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supply benefiting from internal specialization and division of activity. Marketing of risky output is governed by effective delivery contracts or integrated into own processing. Output-based payment of labor is common, which restricts opportunism and minimizes internal transaction costs. Besides, production cooperatives provide employment for members who otherwise would have no other job opportunities - housewives, pre-retired or retired persons. They are preferable employer since they offer relatively high job security, social and pension payments, day-offs and paid annual holidays, and opportunity for professional (including career) development. Given the considerable transacting benefits, most of the coop members accept lower than market returns on their resources - lower wages, inferior or no rent for land and dividends for There have been some adjustments of size, memberships, and production structure in cooperatives (Table 1). A number of them have moved toward more ―business like‖ governance applying market orientation, profit-making goals, close and small-membership policy, complex joint-ventures with other organizations etc. That has been a result of overtaking the coops management by younger entrepreneurs, improving the governance, taking advantage from new market opportunities and public support programs, and establishing of some of them as key regional players. At the same time, traditional cooperative has shown certain disadvantages as a form for farm organization. A large coalition (averaging 240 members) makes individual or collective control on management very difficult and costly. That gives great possibility for mismanagement and/or let using coops in best interests of managers and groups around them (on-job consumption, unprofitable for members deals, transfer of profit and property, corruption). Besides, there are differences in investment preferences of diverse members due to the non-tradable character of cooperative shares. While working and younger members are interested in long-term investments and growth of salaries, income in kind, other on-job benefits, older and no working members favor current gains (income, land rent and dividend). Given the fact that most of the members are older in (pre-retired and retired) age, smallholders, and non-permanent employees, incentives for long-term investment in cooperatives have been very low. Finally, many co-ops fall short to adapt to diversified (service) needs of members and explore the potential of inter-cooperative modes (joint ventures, associations). Accordingly, long-term comparative efficiency of cooperatives diminishes considerably in relation to other modes for organization (market, contracts, partnerships, alliances), and 59% of them have gone bankrupt or ceased to exist after 2000. Most of the existing cooperatives will sustain in years to come since they will keep their production and organizational advantages to a large number of petite landowners, rural labor, small and subsistent farms. What is more, they have a greater potential to explore economies of scale and scope on institutionally-determined investment, adapt to formal requirements for support, and use expertise and finance to execute public projects. Furthermore, diverse and considerable CAP support measures (direct payments, investment subsidies, rural development projects) give a new opportunity to mitigate the coops funding problem. Direct payments for instance, allow the extension of activities and offer attractive rent, while access to investment subsidies let modernize farms and enhance competitiveness. Besides, some environmental, infrastructural, and rural development projects, which require large collective actions and coalition of resources, could be effectively initiated, coordinated, and carried by the existing cooperatives or mix (coop-private, coop-public) modes. That will extend and intensify transactions governed by existing cooperatives. Adaptability of cooperative to new

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challenges would be significantly increased through public training of their staff in business and agro-environmental management, carrying out an effective control on coops activities, and providing assistance in farm and cooperative associations. Unregistered holdings are predominantly small-scale farms comprising the biggest portion of all farms (Table 1 and Figure 11) and agricultural employment 65. Most private farms evolved after 1989 when agricultural land was restituted, and assets of large public farms distributed or privatized. Agrarian reform turned most households into owners of farmland, livestock, equipment etc. Internal organization of available household resources in an own farm was an effective way to overcome great institutional and economic uncertainty, and minimize costs of transacting [Bachev, 2006]. Private rights on most of farmlands were not entirely restituted until 2000 making market trade with land very difficult or impossible. Besides, there was ―oversupply‖ of farmland and the effective demand was not immense. In the meantime, many Bulgarians lost their jobs as a result of privatization of public farms and industrial companies. Starting up an own farm was the most effective (or only) mode for productive use of available resources (free labor, land, technological knowhow). Moreover, a large portion of people was at pre-retired or retired age and had no other job alternatives. For others farming was a stable ―temporary‖ or secondary employment in conditions of high insecurity of job market. Diversification into farming took place and now farming is ―sole or major employment‖ just for a quarter of ―engaged persons in agriculture‖ while for almost 1 million it is an ―additional source of income‖ [MAF]. During transition, market or contract trade of household capital (land, labor, money) was either impossible or very expensive due to ―missing‖ markets, high uncertainty, risk, asymmetry of information, opportunism in time of hardship, little job opportunities and security. Moreover, low payoff from outside trade (high inflation; non- or delayed payment of pensions, wages, rents) was combined with an increased share of households‘ food costs. Therefore, internal organization was the most effective way of protecting and getting a return on resources and securing a stable income. Long-term tradition with ―personal plots‖ during communist period, and insignificant costs for acquiring specialized knowledge (information, training, learning by doing experience) made development costs for own farm accessible for everybody. In addition, there has been a great (price, quantity, quality) uncertainty associated with market supply of basic foods (many new suppliers, no reputation built, poor assortment, insufficient enforcement of quality and safety standards). For lots of consumers an internal organization (own production) has been an effective mode to guarantee cheep, stable, safe, and high quality delivery of food. Also, for many Bulgarians, farming activity happens to be a favorable full-time or free-time occupation. Unregistered farms are not a unified group since there are numerous subsistent and semimarket farms as well as highly-commercialized small to middle-size enterprises. The best part of Bulgarian farms are subsistent and semi market farms. According to the last census less than 39% of unregistered farms reportedly sell products, and in more than 50% of the cases, those are surplus, not consumed by households [MAF]. Consequently, a significant portion of the entire output of vegetables, fruits, vine and livestock is for ―self consumption‖. Governing of small-scale and subsistent farms is not associated with significant costs. Unregistered farms are predominately individual or family holdings, and farm size is exclusively determined by the available household resources – family labor, own farmland 65

Accordingly 95% of the employed persons and 92% of the Annual Work Units of the sector [MAF].

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and finance. Internal governing costs are insignificant because transactions are between family members (common goals, high confidence, and no cheating behavior dominates) or non-existent (one-person farm). Costs for coordination and organization of activities are not big as primitive technologies are applied; (internal) demand and potential are known; and common objectives, cooperating behavior, and high trust govern relations between family members. A small collective organization for some activities is also practiced - e.g. group pasture of animals, common guarding of yields, common processing and marketing. That allows a partial specialization and division of labor, exploration of economies of scale and scope, and/or makes part-time farming possible. This form is cost-effective since transactions are not complicated, easily controlled, and between close friends, neighbors, and relatives (here mutual trust and self-restriction of opportunism govern relations). Occasional outside supply of some inputs (seeds, chemicals) and services (veterinary) take place but they are not connected with significant costs because of highly standardized and not farm-specific character (many suppliers). On the other hand, highly specific to farm transactions (feed supply for animals, mechanization and irrigation services) are effectively secured through a joint ownership mode such as cooperative or group farming. ―Marketing‖ of the output for subsistent and semi-subsistent farms is not associated with considerable costs because most of it is for internal household consumption or processing. Exceeds are exchanged with relatives and friends, or sold at local (farmers, street) market, to regional middleman or processor. In any case, low volume, high frequency, and personal character of the transactions (clientalization) minimize the costs of marketing. There are also a good number of small-scale commercial (market oriented) farms among the unregistered holdings. They are mainly in labor-intensive productions such as vegetables, tobacco, vineyards, berries, melons, flowers, mushrooms, medicinal and aromatic crops, livestock, sericulture, bee kipping, and in natural meadows. Those are individual or family enterprises, and farmers have strong incentives to adapt to market demand and increase productivity (through intensification of work, investments in human and material assets) since they own the whole residuals (income). Own farm enterprise has been a secure mode for providing (full or part-time) employment for household members (including retired, housewives, children). Family organization is also an effective form for intergeneration transfer of farm-specific intangible assets such as know-how, learning by doing experience, reputation etc. The extension of farms through outside supply of labor and services is restricted since directing, monitoring, and disputing costs are extremely high in labor demanding and spatially dispersed productions. External financing of farming via debt, equity sell-off, or preferential public programs have been out of reach because of the high costs for preparing project proposals; for meeting formal (paperwork, ownership, co-financing) requirements; and for ―arranging‖ funding. That has been additionally complicated by the big transacting uncertainty, asymmetry of information, and strong specificity (―berried in land‖) and risk (―mobile character‖) of investments in agriculture. Thus, possibility for effective farm enlargement and growth in productivity through mechanization, application of chemicals and innovation is limited by the small internal investment capacities (savings, profit). As a result, outdated technologies, low productivity, and poor quality, labor, animal-welfare, and environmental standards prevail.

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Low cost outside land supply (leasing) is practiced to explore economies of scale on existing assets, and integrate the critical inputs supply (such as forage for livestock). For external supply of indispensable inputs and services market supplier or ownership modes (cooperative, group farming) is typically used according to the level of specificity of supply. In many instances, they are not provided at efficient scale due to the enormous costs of delivery as it is for pesticides, fertilizers, irrigation, extension etc. In some intensive areas (e.g. off-season vegetables and fruits, horticulture, melons) smallscale farming has been quite effective in quality and price competition bringing good income for households. Profitability of these farms has been especially big when there exist special nationwide organization for marketing (e.g. bee honey); production planning and price support (e.g. quotas and guaranteed prices for tobacco); inputs supply and marketing (e.g. sericulture). When symmetrical (capacity, quality, time of delivery) dependency is in place then tight marketing or interlinked 66 contracts with downward partners (processors, supermarkets, exporters) have developed which govern transactions effectively (in dairy, vegetables). Principally marketing of output is not associated with considerable costs for commodity and locally-demanded produces because of short distance, low volume, high frequency, and personal character of transactions. Besides, some produces of small farms (fresh fruits and vegetables, dairy and meat products) enjoy increasing demand because of the low level of intensification (reduced or no chemical use, extensive breeding of animals), high quality, freshness and good taste, authentic local varieties, bigger confidence of consumers about safety and origin. Nevertheless, the majority of small commercial farms is vulnerable and has poor mechanisms to protect from outside institutional, market and natural disturbances. Most of them have little ability to meet institutional and market restrictions, bear risks, and safeguard against natural and market hazard (buying insurance, diversifying, or cooperating). All these result in significant income variation for individual farms, (sub) sectors, and different years. A great number of small-scale farms face great transacting difficulties in marketing of their output. Most often they are not preferable partners for big buyers because of small volume and less-standardized character of output, and impossibility (unaffordable costs) to verify quality of products through laboratory tests, and certificates. On the other hand, official wholesale markets have been inaccessible for these farms for the reason of great distance; high fees; requirements for volume, special preparation, certification etc. Besides, small farms frequently experience problems with meeting contractual terms (none or delayed payment), huge market price fluctuation, (quasi-) monopolistic situations, and missing markets in remote regions. In order to protect transacting and avoid unwanted exchanges the primitive forms for risk minimization is commonly used - investment in more universal but less profitable assets, diversification of production, informal cash and carry deals, direct retail marketing etc. With exception of tobacco producers67 development of effective collective organizations for risk sharing, price negotiation, marketing, or lobbying for public support have been difficult because of high transacting costs and diversified interests of individual farmers (old-young; larger or smaller size; specialized or diversified etc.).

66 67

Typically marketing against credit, inputs and/or extension supply. having a significant political representation.

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Different fractions of the unregistered farms are with unequal sustainability. Unlike other forms of organization the life cycle of one-person (family) farm is greatly determined by the age of the entrepreneur. Thus, farms are unsustainable when farmers are close to the end of working age, and they have no heir wishing to take up the farm or have more than one successor wanting to get the enterprises68. Moreover, incentives for long-term investment in specialized assets for increasing sustainability is low for older farmers since there is no secondary market for farm-specific assets (such as investments in human capital, training, know-how, good reputation, organizational modernization, positive externalities). For that reason a good number of small-scale commercial farms will operate at low sustainable level (at present or smaller scale) given that most of farm managers and laborer are old in age 69. The EU integration and CAP implementation will also foster the restructuring of commercial farms according to modern market, technological, and institutional standards. Most small-scale livestock farms will hardly meet the EU (hygiene, quality, veterinary, phitosanitary, environmental, animal welfare) standards and have to cease the formal commercial activity by the end of 2009. Only few livestock farms will be able to increase their present size with additional specialized investments in modern technologies, food safety, animal welfare and environmental protection. That would enhance their capability to compete, meet strict institutional restrictions, and participate in various public support programs. Increased scale of operations will also require some stable forms for governing of marketing such as cooperation or tight contracts with dairy and meat processing industries. A process of consolidation and modernization is taking place in some horticultural farms as well. In years to come market, contract, and institutional uncertainty will be steadily diminishing while access to public support programs augmenting with application of CAP measures. That will further enhance sustainability of smaller-scale intensive family operations. In some cases, small partnership, group farming or vertical integration by buyer (e.g. processor, exporter) will be used to achieve rapid concentration of capital and labor. Tobacco farms are located in mountainous and less-developed regions with little farmland and no alternative job opportunities. They will continue to enjoy high public support because of the political power (preferential production or regional support policies). However, due to the global tendency for declining demand and restriction in production (quotas) the restructuring of this sub-sector is inevitable. Thus modernization and diversification with no significant changes in mode of organization (specialized small-scale family operation) will occur. The strong competition will be predictably connected with decreasing the number of small commercial farms of various types as a result of take-overs, joint ventures, failures, or non-market orientation. There will be also a parallel tendency toward specialization into productions for ―niche markets‖ and products with special quality (specific origins, organic products, eggs from freely-breed chicken, meat with low fat level, grape for special wines). That will require investments with increasing or high specificity to a particular buyer(s), and ―integrated‖ management of farming, processing industries, food chains, exporting (associated with specification of production technologies, products quality and quantity, time of harvesting and delivery etc.). Besides, some diversification of enterprises into related 68

Disputes between heirs about agricultural lands are widespread and that is a major factor for the big fragmentation of land ownership and farms in Bulgaria. 69 Farm managers older than 45 and 65 are 85% and 40% accordingly [MAF]. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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activities (trade with origins, agro-tourism etc.) as mode for dealing with market risk should be expected. And finally, high inter (cite, capacity, quality etc.) dependency will require expansion of the modes for vertical integration with downstream industries [Bachev and Nanseki]. Preliminary assessments of likely impact of CAP implementation in Bulgaria indicate that income, technological, environmental and social discrepancies between farms in different sub sectors and regions, and between small holdings and larger operators, will further augment [Bachev, 2008]. The enhancement of sustainability of small-scale commercial farms would be considerably accelerated through a third-part public involvement in training and extension education, assisting in farm association, and increasing accessibility to various support programs (improving transparency, decreasing bureaucratic procedures, providing preferences for small-scale enterprises and disadvantages regions). At the same time, restructuring a large portion of smaller-scale and subsistent farms will have no positive effect. There has been a significant diminution of institutional and market uncertainty in recent years. However, most of the factors that brought to existence subsistent and semi-market farming persist – high economic insecurity and unemployment, low income and purchasing power of households, limited demand for agrarian resources and products, uncertainty associated with market supply of food (freshness, safety, quality, price). The situation has even worsened as a result of the present global economic and financial crisis. Most subsistent farms have no intention of increasing their size because of other major occupations and income source, limits of household demands and resources, the advanced age of farmers etc. Transaction costs to enlarge farms through outside supply of additional land, labor, finance and marketing are extremely high (no entrepreneurial capital exists). Vast costs for studying and respecting new institutional restrictions (laws, regulations; quality, veterinary, eco, animal welfare etc. standards) and for establishing ―relations‖ with agrarian bureaucracy (registrations, certifications, paper works) is also restrictive. Moreover, more than a half of employed in agriculture are in pre-retirement or retirement age [MAF]. That puts serious restrictions on effective farm adjustment and enlargement - low investment activity and entrepreneurship, limited training capacities, no alternative employment opportunities. On the other hand, it is practically impossible for Government to enforce the official standards in that huge informal sector of the economy. What is more, there is a strong political pressure to relax application of EU rules in non-market farm transacting (respect voters interests). Therefore, the majority of subsistent farms will be highly sustainable in years to come.

CONCLUSION Deepening the labor specialization and exchanges between agents opens up enormous opportunities for economic growth. However, it is also associated with significant transaction costs which might disturb sustainable development. In the traditional (Neoclassical Economics) framework with no transacting costs, there is only one mechanism for governing of agrarian development. ―Free market prices‖ (and market competition) effectively coordinate and stimulate the entire activity of resource owners, entrepreneurs, and consumers.

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Accordingly all farms constantly ―adapt‖ to price movements and social demand being equally efficient and sustainable. Rare cases of market ―failures‖ are also recognized (―negative externalities‖, ―tragedy of commons‖) but a perfect ―government intervention‖ is seen as a remedy. All that leads to an interrupted global sustainable development. In the real economy, there are additional important factors affecting individual choices and agrarian sustainability (namely institutions and transacting costs), and a great variety of effective governing mechanisms. The institutional environment is a crucial factor, which eventually determines the ―type‖ of development and the ―level‖ of agrarian sustainability. The individual agents tend (have) to govern available resources in the most economical way adapting to institutional environment and minimizing total (production and transaction) costs. Depending on personal characteristics of agents and the critical attributes of each activity, there will be a spectrum of effective structure for organization of agrarian resources, activities and exchanges—some will be governed by ―invisible market hand‖, others by special contract forms, some by ―visible manager hands‖ or within complex hierarchies, others will be supported by a third-party, etc. Accordingly, at any given period of time, farms and agrarian organizations of various type and size would persist (sustain) in agriculture—subsistent, family, cooperative, corporative, etc. Furthermore, the sustainable development does include a fundamental modernization of farming structures—size adjustment, transformation, coalition, and disappearance of farms. Our new framework helps us better understand the factors for sustainable development and the ―Government‘s role‖ as well. The analyses of transaction costs identify an immense range of ―market failures‖ associated with unspecified or badly specified property rights; inefficient systems for enforcement of absolute and contracted rights; high uncertainty and dependency of activity, and low appropriability of rights. The economic agents deal with market deficiency developing different non-market forms for effective governance (contracts, internal modes, collective actions, etc.). Nonetheless, the private sector also ―fails‖ to safeguard individual rights and carry out certain activities at an effective scale. That is particularly true for human and eco-rights, technological and infrastructural development, environmental conservation activity, etc. Thus there is a strong need for a third-party public involvement in market and private transactions though institutional modernization, assistance, regulation, hybrid or public organization. However, diverse forms of public interventions have unequal efficiency, and the most efficient one is to be selected taking into account the overall transaction costs and contribution to sustainable development. What is more, at the present stage, most public interventions increasingly require concerted actions (multilateral and multilevel governance) at local, regional, national, transnational, and global scale. Nevertheless, ―government failure‖ is also possible, and inappropriate involvements, under- or over-regulations, mismanagement, corruption, etc., are widespread around the world. Agrarian sustainability is significantly compromised when market and private sector fails, and no effective public intervention takes place. The comparative institutional and transaction costs analysis of the environmental governance in Bulgarian agriculture let us specify the driving factors for emergence and persistence of environmental problems (risks), and make a more realistic forecast about the eco development. Contemporary development of agriculture is associated with specific (and quite different from other European states) environmental challenges, some of them reaching up to the point of no or limited management. That has been a result of the specific

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institutional and governing structure evolving in the sector during the past 20 years. Our analysis also shows that implementation of the common EU policies will have unlike results in ―Bulgarian‖ conditions. In short and medium term it will enlarge income, technological, social and environmental discrepancy between different farms, sub-sectors and regions. In a longer-term environmental hazard(s) caused by the agricultural development will enlarge unless effective public and private measures are taken to mitigate the existing environmental problems. What is more, the specific structures for effective governance of farming (such as subsistence farming, production cooperatives, small-scale commercial farms, and large business firms) will continue to dominate in years to come. Nevertheless, a significant improvement of public (Government, EU, etc.) interventions is needed in order to enhance sustainability of prospective farms and sustainable agrarian development. The identification of efficiency, complementarities, and sustainability of different modes of environmental governance has a substantial importance for amelioration of public policies and individuals and collective actions. Firstly, it helps anticipate possible cases of market, private sector, and public (community, Government, international assistance) failures, and design appropriate modes for public intervention. In particular, it facilitates formulation of specific policies and institutional framework to overcome the existing environmental problems, and safeguard against the possible eco-risks, and avoid the severe environmental challenges in other developed countries. Next, it could assist individual and collective actions and organizational modernization in the agrarian sphere for successful adaptation to a changing economic, institutional and natural environment.

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REFERENCES Bachev, H. (2004). Efficiency of Agrarian Organizations, Farm Management and Rural Planning No 5, Fukuoka: Kyushu University Press, 135-150. Bachev, H. (2006). Governing of Bulgarian Farms – Modes, Efficiency, Impact of EU Accession, in J., Curtiss, A., Balmann, K. Dautzenberg & K. Happe (editors), Agriculture in the Face of Changing Markets, Institutions and Policies: Challenges and Strategies‖ (133-149). Halle (Saale): IAMO. Bachev, H. (2007). Governing of Agrarian Sustainability, ICFAI Journal of Environmental Law, Vol.VI, No 2, Hyderabad: ICFAI University, 7-25. Bachev, H. (2008). Management of Environmental Challenges and Sustainability of Bulgarian Agriculture, in P., Liota, D., Mouat, W. Kepner, & J. Lancaster, (editors), Environmental Challenges and Human Security: Recognizing and Acting on Hazard Impacts, (117-142). The Netherlands: Springer. Bachev, H. (2009). Governing of Agro-ecosystem Services. Modes, Efficiency, Perspectives. Saarbrucken: VDM Verlag Dr.Muller Aktiengesellscaft & Co. KG. Bachev, H. & Kagatsume, M. (2006). Assessment of Farm Support Policies and Likely Impact of CAP Implementation on Farm Structures and Sustainability in Bulgaria, The Natural Resource Economics Review No 11, Kyoto: Kyoto University Press, 173-192. Bachev, H. & Labonne, M. (2000). About Agrarian Innovations, Montpellier: INRA. Bachev, H. & Nanseki, T. (2008). Risk Governance in Bulgarian Dairy Farming, paper presented at the 12th Congress of the European Association of Agricultural Economists

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―People, Food and Environments – Global Trends and European Strategies‖, 26-29 August, 2008, Ghent. http://ageconsearch.umn.edu/bitstream/44136/2/240.pdf Bachev, H. & Peeters, A. (2005). Framework for Assessing Sustainability of Farms, Farm Management and Rural Planning No 6, Fukuoka: Kyushu University, 221-239. Berge, E. & Stenseth, N. (editors). (1998). Law and the Governance of Renewable Resources. Studies from Northern Europe and Africa, Oakland: ICS Press. Coase, R. (1960). The Problem of Social Costs, Journal of Law and Economics, 3, 1-44. Demsetz, H. (1969). Information and Efficiency: Another Viewpoint, Journal of Law and Economics, 12, 1-22. Dupraz, P., Latouch, K. & Bonnieux, F. (2004). Economic Implications of Scale and Threshold Effects in Agri-environmental Processes, paper presented at the 90 EAAE Seminar, 27-29, October, 2004, Rennes. Edwards, C., Lal, R., Madden, P., Miller, R. & House, G. (editors). (1990). Sustainable Agricultural System, Iowa: Soil and Water Conservation Society. EEA. (2007). Annual State of the Environment Report 2006. Sofia: Executive Environment Agency. EC. (2005). Agri-environment Measures, Overview on General Principles, Types of Measures, and Application. Evaluation of Measures applied to Agriculture Studies. European Commission, Directorate General for Agriculture and Rural Development. ECOTEC, (2001). Study on the Economic and Environmental Implications of the Use of Environmental Taxes and Charges in the EU and its Member Sates. Brussels: ECOTEC Research and Consulting. Furuboth, E. & Richter, R. (1998). Institutions and Economic Theory: The Contribution of the New Institutional Economics. Ann Arbor: The University of Michigan Press. Hagedorn, K. (editor). (2002). Environmental Cooperation and Institutional Change. Cheltenham: Edward Edgar. Hardin, G. (1968). The Tragedy of the Commons, Science, Vol. 162. no. 3859, 1243 -1248. Martinez, S. (2002). A Comparison of Vertical Coordination in the U.S. Poultry, Egg, and Pork Industries, Current Issues in Economics of Food Markets, Agriculture Information Bulletin No. 747-05, U.S. Department of Agriculture, Economic Research Service. MAF. (2008). Agrarian paper. Sofia: Ministry of Agriculture and Food. MEW. (2008). Official papers. Sofia: Ministry of Environment and Water. Mirovitskaya, N. & Ascher, W. (editors). (2001). Guide to Sustainable Development and Environmental Policy. London: Duke University Press. NSI. (2008). Statistical Book. Sofia: National Statistical Institute. North, D. (1990). Institutions, Institutional Change and Economic Performance. Cambridge: Cambridge University Press. Olson, M. (1969). The Logic of Collective Actions: Public Goods and the Theory of Groups. Cambridge: Harvard University Press. Ostrom, E. (1990). Governing the Commons: The Evolution of Institutions for Collective Action. Cambridge University Press. OECD. (2000). Review of Agricultural Policies in Bulgaria. Paris and Sofia: OECD. OECD. (2001). Multifunctionality: Towards an Analytical Framework. Paris: OECD. OECD. (2008). Conducting Sustainability Assessments. Paris: OECD. Pigou, A. (1920). Economics of Welfare. London: Macmillan and Co.

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Raman, S. (2006). Agricultural Sustainability. Principles, Processes and Prospect, New York: The Haworth Press Inc. Sauvenier, X., Valekx, J., Van Cauwenbergh, N., Wauters, E., Bachev, H., Biala, K., Bielders, C., Brouckaert, V., Garcia-Cidad, V., Goyens, S., Hermy, M., Mathijs, E., Muys, B., Vanclooster, M. & Peeters, A. (2005). Framework for Assessing Sustainability Levels in Belgium Agricultural Systems – SAFE. Final Report. Brussels: Belgium Science Policy. Sporleder, T. (1992). Managerial Economics of Vertically Coordinated Agricultural Firms, American Journal of Agricultural Economics, Vo l 74, No 5, 1226-1231. UN. (1992). Report of the United Nations Conference on Environment and Development, 314, June, 1992, Rio de Janeiro: UN. VanLoon, G., Patil, S. & Hugar, L. (2005). Agricultural Sustainability: Strategies for Assessment. London: SAGE Publications. Vassilev, HR., Christov, C., Hristova, V. & Neshev, B. (2007). Greenhouse Gas Emissions in Republic of Bulgaria 1988, 1990-2005, National Inventory Report 2005, Sofia: Ministry of Environment and Water. Williamson, O. (1996). The Mechanisms of Governance. New York: Oxford University Press.

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In: Sustainable Agriculture Editors: A. Salazar, I. Rios, pp. 145-176

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Chapter 3

THE ROLE OF PLANT GENETIC RESOURCES IN THE SUSTAINABLE AGRICULTURE J.B. Alvarez1, M.A. Martín1, L. Caballero2, and L.M. Martín1 1

Departamento de Genética, Escuela Técnica Superior de Ingenieros Agrónomos y de Montes, Edificio Gregor Mendel, Campus de Rabanales, Universidad de Córdoba, ES14071 Córdoba, Spain. 2 Departamento de Mejora Genética Vegetal, Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Apdo. 4084, ES-14080 Córdoba, Spain.

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ABSTRACT The sustainability is defined as the use of natural resources without risking their exploitation by future generations. Agriculture can only be considered as sustainable if it includes a suitable system of plant genetic resources conservation. Modern agriculture has caused a drastic reduction of fields‘ biodiversity. Over the last four decades, considerable efforts in collecting, characterizing and conserving crops genetic diversity have been carried out, although for minor crops this conservation has been sensitively lower. The genetic resources of the crops include both the old and neglected varieties and the relative species. The conservation of plant genetic resources can be achieved by different ways: ex-situ conservation, in-situ conservation and on-farm conservation. This last type of conservation has increasing attention, since conserves the dynamic process of crop evolution and includes the traditional knowledge associated with its use. Our group is working in the evaluation and characterization of on-farm conservation systems in Spain, both on neglected crops and agroforestry crops. Among the neglected crops, the hulled wheats (einkorn, emmer and spelt) present a new revival in diverse regions of the World. In Spain, spelt continues being cultivated in Asturias (Northern of Spain) where it is associated to traditional and sustainable agricultural systems. Other crop with traditional management and use in Spain is the chestnut, which is associated to regions with special environmental interest (Natural Parks). Our studies have indicated that both cases are valued systems of on-farm conservation. The recognition of this fact could allow increasing the economic and social sustainability of these traditional agricultural systems.

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INTRODUCTION The biodiversity term was introduced in the scientific discussion in the late 80‘s by Edward O. Wilson as a shortening of the term biological diversity (Wilson 1988). This is defined as the variation of all living organisms at all levels, divided in three categories: genetic diversity, species diversity and ecosystem diversity. It is common that most of the references on biodiversity are sustained in the second level and the rest preferably on the third one, being those based in the first case, purely testimonials. On the other hand, there is a widespread tendency of do not integrate in these studies the domesticated plants and animals, which has entailed that the studies on biodiversity are relegated to the wild plants and animals. This problem is major when it studies the forest species, which have been excluded of both classifications; although the maintenance of their genetic diversity is equally important (White et al. 2007). In response to this, the concept arises from agricultural biodiversity or agrobiodiversity that is defined as: «…that part of biodiversity which nurtures people and which are nurtured by people…» (FAO, 1995).

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Consequently, agrobiodiversity refers mainly to genetic variability in cultivated plants and domesticated animals together with their progenitors and closely related wild species, maintained within agroecosystems and surrounding natural environments (Qualset et al. 1995; Hammer et al. 2003). Thus, plants and animals harvested from the wild are also included in this term (Thrupp, 1998). The Subsidiary Body of Scientific, Technical and Technological Advice (SBSTTA) of the Convention of Biological Diversity in its fifth meeting (2000) defined the scope of agrobiodiversity, as: «all components of biological diversity of relevance to food and agriculture, and all components of biological diversity that constitute the agroecosystem: the variety and variability of animals, plants and microorganisms, at the genetic, species and ecosystem levels, which are necessary to sustain key function of the agroecosystem, its structure and processes» (UNEP 2000).

The sustainability is defined as the use of natural resources without risking their exploitation by future generations (World Commission on Environment and Development 1987). On the other hand, sustainable agriculture has been defined as the use of farming systems and practices that maintain or enhance the economic viability of agricultural production, the natural resource base, and other ecosystems that are influenced by agricultural activities (Dore 1997). The genetic diversity of the crops and relatives is a natural resource, together with a basic element that use the plant genetic improvement for the assessment of new cultivars adapted to actual conditions of Agriculture. Consequently, any agriculture can be considered sustainable if it does not include a suitable system of plant genetic resources conservation. There are approximately 400,000 species in the Earth, 7,000 out of them (2.5%) have been sometime collected or cultivated by humans (Wilson 1992). Nevertheless, although only 30 crops constitute the World food base, there are three major crops (wheat, rice and maize) that supply more than 55% of the global food energy derived from crops (FAO 1996). It is

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noteworthy that due to their importance, 25% of the approximately six millions of accessions stored in Germplasm Banks are of these three crops, whereas minor crops and wild relatives crops are poorly represented (Padulosi et al. 2002). However, the great underlying problem is not only that few crops are used, but also that in many cases, the genetic base of them is considerably narrow, which supposes a real danger for the crops making them more vulnerable. In 1970s, more than half of the maize grown in the Southern of United States was destroyed by corn leaf blight (Helminthosporium maydis Nisikado & Miyake). When this problem was analysed, data confirmed that this disease susceptibility was related with a mitochondrial genetic factor present in the ―Texas‖ cytoplasm, which was present in all andro-sterile lines using for assessment of the maize commercial hybrids. The US National Academy of Sciences carried out diverse studies that demonstrated that all-important crops of the country are represented by a few genotypes (National Research Council 1972). On the other hand, this suggested that a similar vulnerability by genetic narrowing or genetic uniformity was the cause of the pandemic potato blight (Phytophtora infestans Mont. em. de Bary) in Ireland in the 1840s, which triggering one of the major famines of this country with a million of deaths and two millions of emigrates. Furthermore, modern plant breeding based in high-yielding cultivars, has also contributed to the narrowing of the crops genetic base, causing that great part of the modern cultivars are close related (Esquinas-Alcázar 2005). This could even be increased with the use of transgenic cultivars, where only the presence of one or other transgen would be the difference in the gene pool among these cultivars (Gepts and Papa 2003; Hammer et al. 2003). This supposed the identification of the genetic uniformity as cause of the crop vulnerability to the biotic and abiotic stresses; and, consequently, the necessity of the search and conservation of the plant genetic resources for enlarging the genetic pool of the crops. For the conservation of these resources, there are three fundamental questions. The accomplishment of collecting missions that allow their cataloguing, its maintenance on the land (in-situ) or in Germplasm Banks (ex-situ) and, very important, its evaluation and characterization that allows a sustainable use of them (Esquinas-Alcázar 2005). Conservation systems of plant genetic resources can be very varied, depending on the nature of the materials to conserve. For ex-situ conservation, the possibility or not of storing their seeds at low temperature and low moisture content, will be an important factor for determining the conservation way. The plants that have seeds that tolerate the storage in dry at low temperature, termed as ―orthodox seeds‖, can be conserved in Germplasm Banks into hermetically sealed containers at -18C or cooler (FAO and IPGRI 1994). Conversely, the plants without orthodox seeds, termed in this case as ―recalcitrant seeds‖, must be conserved as living plants collection (arboretum) or by cryopreservation of in vitro cultured material (Engelmann and Engels 2002). It is therefore necessary to evaluate the sexual or clonal nature of the individuals, since the conservation of the chosen genotypes depends on them. This conservation type would have to be understood as a static conservation of the genetic patrimony of the species (Bretting and Duvick 1997). This can entail problems of genetic erosion by drift due to the handling taken place, mainly when seeds are used (Hammer 2003). This is a process already described, arisen in the Germplasm Banks. Now, some experts suggest that this static conservation (ex-situ conservation) would have to be complemented by a dynamic conservation (in-situ and on-farm conservation), where the farmers and traditional communities could play an important role (Brush and Stabinsky

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1996). This type of conservation is denominate on-farm conservation, and constitutes a way of maintenance of the evolutionary potential of the crops (Maxted et al. 1997; Brush and Meng 1998; Zeven 2000). Against this background, farmer goes from passive agent of the conservation to active and necessary agent. It should be stressed that the crop knowledge also rests in these traditional communities (Mauro and Hardison 2000; Brookfield et al. 2002; Posey 2002). The main milestones developed in the conservation of the plant genetic resources for Food and Agriculture are the Convention on Biological Diversity and the International Treaty for Plant Genetic Resources for Food and Agriculture. The former was signed in Rio in 1992, which came into force in 1993; whereas the latter was signed in Rome in 2001 that came into force on June 2004, and, now, ratified by 120 countries (FAO 2001; Esquinas-Alcázar 2005). In first, the references to Food and Agriculture were scarce, which was the main cause for the development of the second ones. Consequently, also definition tends to establish special for those Plant Genetic Resources for Food and Agriculture (PGRFA), which is associated to the materials that work the agriculturists and those relative wild species, along with the material conserved in the Germplasm Banks. In the case we are concerned with, our interest focuses on the crops agrobiodiversity, which displays a clear narrowing of the diversity, given the special characteristics of these materials. As abovementioned, plant genetic resources can be used for the enlarging of genetic background of the modern cultivars; although, in many cases, these materials are underutilized or neglected crops that could be recuperated for new agriculture. Some of these materials are always used by rural communities, which continue to grow them by traditional techniques. In this case, their conservation implies the necessity of larger cooperation between the scientists and technicians with the farmers, in the form of one participative research where all implied agents can contribute with their knowledge on the crops (Ceccarelli and Grando 2007). Likewise, the diversification of the culture zones, where the above-mentioned dangers can be minimized, must be one priority of these agricultural systems if we whish that it is sustainable. This last type of conservation comes explicitly supported by the International Treaty on Plant Genetic Resources for Food and Agriculture (FAO 2001, Article 5.c): «Promote or support, as appropriate, farmers and local communities’ efforts to manage and conserve on-farm their plant genetic resources for food and agriculture».

In addition, this Treaty, established some farmer‘s rights as: «protection of traditional knowledge relevant to plant genetic resources for food and agriculture» (FAO 2001, Article 9.2.a).

Of this traditional knowledge formed part the information on crop landraces and their agronomic and culinary characteristics, together with the medical properties of native species. It is the consequence of intimate contact of the indigenous communities with these species during generations (Mauro and Hardison 2000); being fundamental the apprenticeship with elders or specialists and the oral tradition.

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It is important to emphasise that this traditional knowledge is not exclusive of indigenous communities (defined as descendants of preconquest people of certain geographic area with a common history, culture, language and customary law), but must also include rural communities of modern societies (Gepts 2004). Nevertheless, one aspect of this Treaty directly related to the sustainable use of the plant genetic resources is established in the Article 6.2.c:

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«…supporting, as appropriate, the wider use of diversity of varieties and species in onfarm management, conservation and sustainable use of crops and creating strong links to plant breeding and agricultural development in order to reduce crop vulnerability and genetic erosion, and promote increased world food production compatible with sustainable development» (FAO 2001).

For this, for having successful possibilities it would be necessary the revitalization of the on-farm conservation by rural families, which must be rewarded by economic incentive systems that compensate them for the loss of yield (Swaminathan 2002; Gepts 2004). This economic compensation is only one act of equity and justice with these communities, given that they develop an important service of conservation of plant genetic resources. In the European Union, some initiatives for compensating these services have been established (OJEU 2004). The election is simple, if any compensation type is developed, the farmers could opt for new modern varieties, neglecting the traditional materials that could irremissibly be lost. Nevertheless, the regions with high levels of agrobiodiversity are not, in general, zones with high agronomical yields; whereas the regions with high yields present important diversity erosion due to the tendency of growing few crops with few cultivars by crop. On the other hand, the loss of profit associated to these less-yields could led to neglect the agricultural activities and to the rural exodus to the cities with the social implications that it implies. Our group is working in the evaluation and characterization of on-farm conservation systems in Spain, both on neglected and agroforestry crops. Among the neglected and underutilized crops are the hulled wheats (einkorn, emmer and spelt) that present a new revival in diverse regions of the World. In Spain, these old crops, mainly spelt, are grown in Asturias (Northern of Spain) where it is associated to traditional and sustainable agricultural systems and a traditional food. The chestnut is an agroforestry crop that can have a double purpose: production of fruit and timber, and it is associated to regions with special environmental interest (Natural Parks). In this chapter, we argue how on-farm conservation has a direct effect on the maintenance of genetic resources and the traditional systems where it is practised. For this aim, we propose two examples of crops, hulled wheats and chestnut, related to this sustainable agricultural system.

HULLED WHEATS The wheat origin and domestication are placed in the Near East, in the well-known zone as Fertile Crescent (Zohary and Hopf, 1988). The wheat is a complex polyploid formed by multiple species of different ploidic level, consequence of the merge of genomes come from

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species of the Triticeae tribe, Poaceae family (Figure 1). Thus, it can be found diploid (2n = 2 = 14, AA), tetraploid (2n = 4 = 28, AABB) and hexaploid species (2n = 6 = 42, AABBDD). Within the wide complex of the wheats, there is a group defined as hulled wheats. This denomination makes reference to that their glumes remain adhered to the grain after threshing. This is, however, a controversial term since it includes in broad-sense many species within the genetic complex of the wheat as species of the genus Haynaldia, Aegilops or Agropyron among others. In certain works, the Italian term farro has been indifferently applied to the species: T. monococcum L., T. dicoccon Schrank and T. spelta L., although the problem subsists, since also exists T. monococcum of naked grain (ssp. sinskajae A. Filat. et Kurk.). In the context of this work, the term hulled wheats would be applied to three concrete crops (Figure 2): einkorn (T. monococcum L. ssp. monococcum), emmer (T. turgidum ssp. dicoccum Schrank em. Thell.) and spelt (T. aestivum ssp. spelta L. em. Thell.), which were cultivated in Spain some time ago and which, at now, could be catalogued as neglected or underutilized crops. Morphological characteristics as spike shape, hulled grain or brittle rachis are controlled by diverse genes, although one of them, Q locus or spelt factor, is the most important. This locus is located on the long arm of the chromosome 5A (Kato et al. 1998), and it is the q mutation the responsible of the non-free-threshing in the hulled wheats (Muramatsu 1963; Kerber and Rowland 1974). Likewise, the Tg1 and Tg2 genes, located on the short arms of the chromosomes 2D and 2B, respectively, control the tenacious glumes. Consequently, the naked wheats must be recessive for the Tg genes and dominant for Q gene, whereas the hulled wheats present the inverse combination (Luo et al. 2000; Salamini et at. 2002).

Figure 1. The wheat complex. The species in gray are or have been cultivated by humans. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Figure 2. Hulled wheats. Left to right: T. monococcum ssp. monococcum; T. turgidum ssp. turgidum; and T. aestivum ssp. spelta.

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- Triticum monococcum ssp. monococcum This cereal was one of first used by humans and comes from domestication of T. monococcum ssp. boeoticum Boiss. in the zone of the Fertile Crescent, although its cultivation began to be abandoned in the Bronze Age (Nesbitt and Samuel 1996). During long time this species has been associated to the donor of the genome A of the tetraploid and hexaploid wheats; however, the last investigations at this respect have discarded this possibility in favour of another diploid species, also present in the Fertile Crescent as is T. urartu Thum ex- Gandil. - Triticum turgidum ssp. dicoccum This species, domesticated from the wild progenitor T. turgidum L. ssp. dicoccoides (Körn. ex Asch. & Graebn.) Thell., is between the first cultivated wheats, having documents that suggest the exclusive preference of some nations by it. Thus, Herodotus in his History comments in relation to the nutritional customs of the Egyptians: «…while other nations live on naked wheat and barley, it is considered in Egypt the greatest shame to live on them; they prepare their bread from olýra which some call zeía…» (Herodotus, II, 36).

The problems begin here, since zeía () it can generally be translated as emmer, whereas olýra or alura () talk about as much to emmer as to spelt. In this respect, Harlan (1981) indicates that the species used by ancient Egyptians was emmer and not spelt. Other authors mention that the crop is spelt, although indicating that is the same species. However, it is more probable that this confusion comes from an error in the form to define

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this type of wheat, since the morphology of spelt spike is very different from the one from the naked wheats; however, emmer is more similar to modern naked wheats. - Triticum aestivum ssp. spelta All the indications suggest that spelt could be the species produced by the spontaneous crossover between emmer and Aegilops tauschii Coss. ssp. strangulata (Eig) Tzvel. (McFadden and Serars 1946; Kerber and Rowland 1974). This wheat is of Iranian origin, although the word ―spelt‖ is of Germanic origin; appearing the first written reference in the Edict of Diocletian (301 AC), a relation becomes of the price of foods and agrarian products. In fact, spelt was not introduced in Italy until the invasion of the Germanic tribes, whereas emmer was the food base of Rome during at least 300 years from its foundation.

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Uses of the Naked and Hulled Wheats In the Mediterranean region, the culture of the wheat is linked to its flour transformation and its consumption. The original consumption of the flour was in the form of porridge, since it does not require special conditions for its elaboration (Harlan 1981). A more elaborated use is the bread, whose first written references go back to 2600 years BC; although, the archaeological findings indicate the possibility that it was already known in Babylon 4000 years BC. However, the baking process was developed in the Ancient Egypt where began to use the beer yeast (Sacharomyces cerevesiae L.) to ferment the dough (Kemp 2005). However, the bakeries at commercial scale were developed by the Romans, who founded the first organization of bakers, the collegium pistorum. This name derives from the used name to designate to the bakers as pistores (from the verb pinsere, -to pound-), because emmer was traditionally de-glumed by striking within a mortar until glumes separated. The Romans, in fact, used during long time, as the Egyptians, emmer that they denominated of several forms: semen adoreum or ador of where it derives the word «glory», and far from where it derives the word farina (flour). Another important fact in this respect is that the emmer flour mixed toast and with salt was used to make a sauce with that covered the offers to the Gods. This sauce denominated mola, where derived the term immolate. Although the use of emmer began to decrease slowly face to common wheat (T. aestivum ssp. aestivum L. em. Thell), being relegated to its religious use; during almost 300 years, this was the unique cereal that was used in Rome; having established Numa Pompilio (785-672 BC) an annual celebration called the Feast of the Ovens (Fornacalia), in which the emmer flour was toasted for its use as sacramental food. In fact, one the marriage forms named confarreatio had as fundamental part where the partners consumed ritually a special wedding cake (farreum) made with flour far. With the Industrial Revolution and the mechanization of many of the baking processes, previously made by hand, greater products diversity began to be generated. Nevertheless, the use of machinery in the baking processes forced to look for varieties with very concrete aptitudes. The dough done with these flours must have a certain tolerance to the mixing and the over-mixing mechanic, whose development was well different from the manual process. Consequently, many of the traditional wheats are neglected; due mainly to their smaller yields and in many cases their difficult mechanization. The hulled wheats were completely

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substitute by the naked wheats, and the use of the tetraploid wheats (durum wheat) was associated to the pasta products, while the hexaploid wheat (common wheat) was to the baking industry in the Western countries. These new circumstances generate the study on the nature of the dough, and the proteins involved in it. The endosperm storage proteins were studied since three centuries in the last, from the isolation of the gluten obtained for the first time by Iacopo Bartolomeo Beccari in 1728 (Beccari, 1745). These proteins have been widely studied and associated with the breadmaking properties of the wheat flour. Actually, there is a good knowledge of the regulation and gene location of these proteins; as well as, of which the elastic properties of the dough are employees of the interactions between the diverse components. These interactions mainly pronounce as covalent unions by disulphide bonds (Cys-S-S-Cys). Two main groups (gliadins and glutenins) have been identified among these proteins according to their molecular characteristics (Payne 1987). Glutenins are also divided in high-molecular-weight (HMWGs) and low-molecular-weight (LMWGs) subunits (Singh and Shepherd 1988; Pogna et al. 1990). The HMWGs are coded at the Glu-1 loci located on the long arm of group-1 homoeologous chromosomes, whereas on the short arm are located the Glu-3 loci that codes for the LMWGs and the Gli-1 loci that controls the synthesis of -, - and some -gliadins. On the short arm of group-6 homoeologous chromosomes are located the Gli-2 loci that code mainly for components present in the  region and some -gliadins (Metakovsky et al. 1984). Because of the action of all these loci, duplicated in tetraploid wheats and triplicate in the hexaploid ones, the seed storage proteins are formed by high number of subunits. Given that these loci are very polymorphic, the diversity for storage proteins can be used as genetic diversity marker in studies on genetic resources and the varietal identification (Bushuk and Zillman 1978). Furthermore, the HMWGs allelic diversity has been associated with diversity for baking characteristics and the LMWGs allelic diversity with diversity for pasta characteristics (Wrigley et al. 2006); being this diversity used in the plant breeding programmes.

The Hulled Wheats in Spain: Past and Present Einkorn (escaña in Spanish) is considerate practically disappeared in Spain. In fact, its use declined quickly with the irruption of the tetraploid wheats, being exclusively used for feeding animal; although its straw, given is massive, has been using for the accomplishment from utensils and in certain zones as ceiling in huts. In Spain, emmer and spelt form a complex denominate escanda (Latin: ―scandŭla‖), although it is possible that other less-known species have been including between the same due to their similarity with some of the species of these complex. Emmer is also named povia or pavida; whereas spelt is named Asturian fisga. However, actually, given that emmer is practically missing, the denomination escanda is exclusive for spelt. In Spain, both einkorn and emmer seem to have been present from the Neolithic period, although never as a main crop. Spelt, on the contrary, appeared since the Iron Age in areas of northern Spain (Buxó i Capdevila et al. 1997). Afterwards, references on its cultivation can be found along the Middle Age both in Christian texts as the ―Cronicon Albendense‖ dated in

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883 and in Arab agronomic treatises as the ―Agriculture‘s Book‖ of Ibn Al Awam (Cubero, ed. 2000). During the Nineteenth Century, the wheats grown in Spain were surveyed by the Spanish botanists Lagasca and Clemente. Among the collected Triticum species, these authors classified four botanical varieties of einkorn, ten of emmer and seven of spelt (Téllez-Molina and Alonso-Peña 1952). For the Twentieth Century, the percentage of hectares grown with hulled wheats was increased through time with an abrupt decrease during the Spanish Civil War (1936-39). After the 1930s, the popularity of hulled wheats increased until the 1960s when the percentages dropped quickly. Dantín Cereceda (1941) indicated that the crop area in Asturias was of 1050 ha; whereas, at now, this area is approximately of 45 ha (36 of them in ecological system). This corresponds with the rural exodus, which was very important in many Spanish regions during the 60s and 70s, and the generalization of the agricultural mechanisation of agronomic tasks in many areas of Spain, together with the introduction of the semi dwarf wheats from International Center for Improvement of Wheat and Maize (CIMMYT) -México-. The progressive disappearance of these materials was in part stopped by their inclusion in Germplasm Banks. Nowadays, spelt survives in marginal farming areas of Asturias (North of Spain), where the farmers grow it by traditional farming systems for home consumption, mainly. Asturias is a region with a complex orography situated between the Cantabrian Sea and the Cantabrian Chain. The climate is characterized by temperatures medium and abundant precipitations often over 800 mm. These conditions cause an increase in the maturation time and longer cycle of the crops; which in the case of wheat is generally two or three months longer than in the rest of Spain. Administratively, the region is divided in concejos, which represent the local unit or municipality.

Figure 3. Sites or concejos (in shadow) where the culture of spelt wheat was describe in the work of Alvargonzalez (1908) and in the Swiss collecting mission (1930s).

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Figure 4. Sites were carried out the collecting mission in 2004. The numbers indicated the concejos were some populations was found: 1, Aller; 2, Belmonte de Miranda; 3, Cándamo; 4, Lena; 5, Morcin; 6, Oviedo; 7, Proaza; 8, Quiros; 9, Somiedo; 10, Teverga; 11, Villaviciosa; 12, Grado; 13, Pravia; 14, Salas.

In 1908, Calixto Alvargonzalez wrote a work on the origin and the evolution of this crop in Asturias, where he described the cultivation zones of escanda and their annual production that was approximately of 960 Tm. Escanda was cultivated in 37 out of the 78 concejos of this region of Northern Spain (Figure 3). Unfortunately, the areas cultivated with escanda were drastically reduced in the last century. During the 1930s, personnel of the Swiss Federal Research Station for Agroecology and Agriculture collected 50 populations in this region of Spain. This germplasm was stored in the Germplasm Bank of this Swiss Institution in 1939 (Dr. G. Kleijer 2004, pers. commun.). They found clear evidences of the reduction of cultivation zone, given that they found escanda only in 23 concejos (Figure 3). The data of the genetic diversity studies, which will be described after, promoted a collecting mission carried out with the objective to collect hulled wheats in all places of the region where these crops are still cultivated. This was carried out between the end of July and the beginning of August 2004 in Asturias corresponding to the ripening time of escanda. A trip at flowering time (May) was made to select the zones of collection. The explored area was that from 43º 2 27 to 43º 28 49 Latitude North and from 5º 26 25 to 6º 14 22 Longitude West, being the altitude range from 45 meters in Grado (Grado) to 1001 meters in La Bustariega (Somiedo). During the collecting mission, escanda populations were found in 31 localities from 14 concejos (Figure 4). During the 2004 expedition, it was observed the disappearance of the crop in many of the localities indicated by the Swiss expedition of 1930s, only seven out of these 23 concejos were common to both expeditions (Belmonte de Miranda, Grado, Lena, Proaza, Quiros, Salas and Villaviciosa), which indicates a great decline of cultivation of escanda, with respect to those indicated by Alvargonzalez (1908). However, also, there are concejos where the crop has been found now and it was not described in the Swiss collecting mission, possibly because they did not get to visit these zones.

Genetic Diversity of the Spanish Hulled Wheats The variability and genetic diversity for endosperm storage proteins of einkorn (Alvarez et al. 2006), emmer (Pflüger et al. 2001) and spelt (Caballero et al. 2001, 2004a,b,c) present in the old collections of the Germplasm Bank have been studied. These studies carried out on

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623 accessions (31 of einkorn, 102 of emmer and 489 of spelt) of Spanish origin showed a great variability of the protein composition. These materials were obtained from the Centro de Recursos Fitogenéticos (Alcalá de Henares, Spain) and the National Small Grains Collection (Abeerden, Ohio, USA) -Table 1. Table 1. Accessions of Spanish origin obtained from two Germplasm Banks. Species Ploidic level CRF NSGC Einkorn 2 19 13 Emmer 40 62 4 Spelt 117 372 6 Total 176 447 CRF = Centro de Recursos Fitogenéticos (Alcalá de Henares, Collection (Aberdeen, Ohio, USA).

Accessions evaluated 32 102 489 623 Spain); NSGC = National Small Grains

Table 2. Botanical varieties described by Lagasca and Clemente. Species

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Einkorn

Emmer

Botanical variety var. macedonicum Papag. (syn. var. eredvianum Zhuk.) var. vulgare Körn. var. hornemanni Clem. var. inerme Körn. var. tricoccum (Schübl.) Körn. var. lagascae Al.et Tell., nom. nud. var. dicoccon (syn. var. farrum Bayle) var. rufum Schübl. var. pycnurum Alef. var. majus Körn. var. macratherum Körn.

Spelt

var. pseudomacratherum Flaksb. var. atratum (Host) Körn. var. album (Alef.) Körn. var. duhamelianum (Mazz.) Koern. var. arduini (Mazz.) Körn. var. vulpinum (Alef.) Körn. var. albivelutinum Körn. var. rubrivelutinum Körn. var. caeruleum (Alef.) Körn.

Characteristics Glabrous and white glumes, white awns Glabrous and red glumes, red awns. Pubescent and red glumes, red awns Awnless spike, Glabrous and white glumes Short awn, glabrous and white glumes. Short awns, glabrous and black glumes. Long awns, glabrous and white glumes. Long awns, glabrous and red glumes. Long awns, glabrous and red glumes, clavate spike. Long awns, pubescent and white glumes, wide spike. Long awns, pubescent and red glumes, red awns. Long awns, pubescent and red glumes, Black awns. Long awns, pubescent and black glumes. Awnless spike, glabrous and white glumes. Awnless spike, glabrous and red glumes. Glabrous and white glumes. Glabrous and red glumes. Pubescent and white glumes. Pubescent and red glumes. Pubescent and blue-black glumes.

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Between the allelic variants found in these materials (Caballero et al. 2001, 2004a,b,c; Pflüger et al. 2001), some have not been detected in wheat until now, and were included in the Catalogue of Wheat Gene Symbol (McInstosh et al. 1998, Supplement 2003). These novel alleles appeared with low frequency, which suggests the possible loss of allelic variants previously to the 1930s collection. Likewise, this low frequency could suffer an additional danger of loss of these allelic variants, because part of these accessions presents a low germination. The variability for the hulled wheats in Spain was studied in the Nineteenth Century by Lagasca and Clemente in their unpublished ―Ceres Hispanica‖ herbarium (Tellez-Molina and Alonso-Peña 1952). The main interest of this classic work is that permits the comparison of the variability presents in the Nineteenth Century when these crops were still frequent in the Spanish lands as well as with the actual situation. In this herbarium, it was described up four botanical varieties for einkorn, ten for emmer and seven for spelt (Table 2). The lines that we have evaluated for einkorn can be grouped in four botanical varieties; three out of them were not previously described in the ―Ceres Hispanica‖. The most abundant varieties were var. tauricum Drosd. and var. monococcum, being the awn colour the difference between both varieties, black for var. tauricum and white for var. monococcum. In minor frequencies were also found the var. eredvianum Zhuk., f. punctatum Stransk. and the var. nigricultum Flaksb. Both varieties showed glumes shining, being black for the var. nigricultum and white for the var. eredvianum (Guzmán et al. 2009). For emmer, the most representative varieties were dicoccon Körn. and tricoccum (Schübl.) Körn. These varieties, together with the majus Körn. variety, present white glumes. The difference between both varieties (dicoccon and tricoccum) is the awn length, long for dicoccon and short for tricoccum. The macratherum Körn. and majus varieties were less represented, whereas the presence of the three varieties (atratum (Host.) Körn., lagascae Al. et Tell., nom. nud., and pycnurum Alef.) was testimonial (Alvarez et al. 2007). Some of the varieties described by Lagasca and Clemente (Tellez-Molina and Alonso-Peña, 1952) did not appear among the materials analysed here (var. inerme Körn., var. rufum Schübl, and var. pseudomacratherum Flaksb.), which suggests that part of the diversity of this species in Spain could have loosed at first half of the twentieth century. The characterization of the spelt lines derived from the Germplasm Banks indicated that six out of the seven botanical varieties of Lagasca and Clemente were presented in the collection (var. albivelutinum, var. arduini, var. caeruleum, var. duhamelianun, var. rubrivelutinum and var. vulpinum); only the album variety (awnless and white glumes) was not found (Caballero et al. 2007). One part of the spelt collection of 1930s, together with the emmer collection, have been used to develop spelt and emmer lines, which can serve as base for the establishment of core collections of Spanish germplasm for these species. These core collections could be used with the double finality: improvement of the escanda for increasing its culture and introgression of the useful genes in durum or common wheat. When these materials were evaluated for gluten strength measured by the SDS-sedimentation volume (Peña et al. 1990), a wide range of variation was detected; along with certain association with the presence of alleles for HMWor LMW-glutenin subunits not found in the current escanda populations neither in modern durum and common wheats (Caballero et al. 2008). On the other hand, an asymmetric distribution was detected for the HMWGs alleles, since some allelic variants were clearly hegemonic on the rest. Consequently, without an effort for the conservation and the

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evaluation of these rare variants, these could easily disappear, with the consequent loss of variability in the crop. The materials collected in the summer of 2004 were morphologically evaluated and classified according to the botanical varieties indicated by Lagasca and Clemente (TellezMolina and Alonso-Peña 1952). The collected populations were not homogeneous, presenting various botanical varieties; only few populations belonged to only one botanical variety. Awnless spikes were not found in any spelt population, which supposes certain genetic erosion with respect to the Swiss collection. Five of seven botanical varieties described by Lagasca y Clemente (var. albivelutinum, var. arduini, var. caeruleum, var. rubrivelutinum and var. vulpinum) for spelt and two of ten botanical varieties (var. dicoccon and var. rufum) for emmer were detected. This indicates that the actual spelt grown in Asturias presents variability levels similar to the spelt collected in the 1930s; however, the emmer is sharply in recession and seems to be near to extinction because it is considered a weed by most of the farmers. Other spike types not mentioned by previous authors have been also found in the actual materials. In the material collected now, it was frequent to find spelt with yellow spikes (both with glabrous and pubescent glumes). The same occurs with the blue spikes, which had different colour gradations, detecting different tones: bright, dark and black. These spikes can present white awns, black awns or both. The high frequency of these spelt types could be the consequence of the seed material exchange among the farmers of different localities, although the land area has been increased in the last years, the original agrobiodiversity could have suffered an important recession.

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The Present Moment and the Future of the Escanda in Asturias The traditional system of escanda culture in Asturias has been mainly the small orchards for home-consumption. In fact, in many zones of the region, the people named to this crop ―pan‖ (in English, bread), because they only consumed escanda bread. The escanda bread that stays in good conditions during a prolonged time is basic part of the food. Although the most of this flour is used for self-consume, one important part of it is commercialised as bread or other typical products in small local markets or in folk parties where are considered as delicatessen and sold for high prices. Unfortunately, the low level of production of the farmers have made that this bread is hardly known in the rest of the region, although the flour is very appreciated in other parts of Spain, main destiny of the Asturian production. Until recent times, the escanda harvest was carried out manually by all family and neighbours using mesorias, a rudimentary instrument made by two 50 cm long sticks of rounded section joined by a short piece of rope or leather. This instrument permits to cut only the spikes, while the rest of the plant (culms and roots) remain on the field. Now, this process is carried out with scissors. The harvested escanda is stored in spike form until the next spring in the panera, a particular air granary made with chestnut timber and isolated to the floor for avoiding the rodents. In spring, the spikes are breaking into spikelets by flailing with wooden flails named mallos; the result is denominated erga, in reality spikelets. Previously to mill, the awns are burned and the grain separated to the glumes by the rabil, a strange instrument that carried out this process by air. Finally, the grain is milled in a traditional mill name pison (Figure 5).

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Figure 5. A, mesorias (marked with arrow) instrument used for cutting the escanda spikes; B, panera, typical Asturian granary; C, mallo, instrument used for threshing the escanda; D, rabil for hulling the escanda grain; and E, pison for milled the escanda grain.

It is important to emphasise that great part of these farmers were women, many of them elders, in small villages next to the Cantabrian Chain. In other case, we found old coal miners that have recovered this crop as an alternative occupation. Only some of them have this occupation as one economic activity, whereas the most used the escanda for homeconsumption. During the trips carried out for the 2004 collecting mission, we found also that many farmers had begun to neglect the crop, mainly by the hardness of the work and its scarce profit. Two different types of parcels were found during this collecting mission: one dedicated to home-consumption with small dimensions (normally between 200 and 400 m2), and other dedicated to industrial production with up 10 Ha (Figure 6).

Figure 6. Examples of the escanda parcels. Left, small parcel in Bermiego (Quiros); and Right, large parcel in Quinzanas (Pravia). Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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On the other hand, in the materials from the small farmers is possible to find plants of different botanical varieties in the same parcel, and certain heterogeneity for plant height. On the contrary, the great producers generate their material by the collection of few seed quantities from these small farmers. This implies that the materials are one heterogeneous mix of old landraces, which has been selected for some characteristics as the plant height or the spike colour. Likewise, the quality properties of these materials are the consequence of this mixture. Probably due to the selection carried out with these materials, important genetic erosion could have been produced. The principal problem would be that this mix represents approximately 50% of the actual material grown in Asturias, and could indirectly be the cause of the erosion of the rest of the materials, mainly given that the other materials are not optima for the mechanization that is being used with this mixture. In this context, the materials stored in Germplasm Banks could be an useful tool for increasing the genetic pool of escanda grown in Asturias. Nowadays, in collaboration with one escanda producer, we have carried out one experiment for reintroducing autochthon escanda obtained from selected lines derived of Germplasm Bank accessions (Figure 7). These lines obtained by seed single selection are homogeneous for storage proteins composition and could permit the attainment the selected lines with different properties for bread-making quality. These new lines could diversify the escanda culture, together with its use in the breadmaking industry. This must be complementary with the conservation of the minor landraces that have the small farmers. We think that without this diversification, the crop could stop due to the scarce permeability for adapting to new demands of the market. In June 2001, one producers‘ association was founded with the name of ASAPES (Asociación Asturiana de Productores de Escanda, Asturian Association of Escanda Producers). This association has as main goals the improvement and modernization of the escanda crop. Recently, it has applied to Spanish Government the Certified Origin Denomination for the Asturian escanda.

Figure 7. Experiment for reintroducing autochthon escanda. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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On the other hand, one of the greater problems associated to the conservation and maintenance of the genetic resources is indirectly the own improvement of the crops. It is obvious that they are tried to improve aspects of these old crops from the reasonable perspective to try to eliminate those characters that make difficult it handling. The danger is to despise the fact that those that make different from these crops and, in certain way are these characters, which is harnessing its present revival. In the material object of this study, some of the characters that any plant breeder would have the natural tendency to eliminate are: brittle rachis, the highest plant height or tenacious glumes, characters with simple genetics based in one gene. The crossover with modern wheats would harness the elimination of the three characters, having obtained that rachis outside tenacious, the low plant height and dehiscent glumes (Schmid and Winzeler 1990). The problem is that we would have redesigned the current wheat and destroyed the genetic patrimony that represents the hulled wheats. The great danger is try to merge these hulled wheats in the naked wheats, since it is an indirect way to justify why a day they were relegated of our food. They are indeed the particularisations, which make tempting in the context of a new food where the flavours or the textures look for over the nutritional questions, mainly in the developed countries.

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CHESTNUT The genus Castanea, belonging to the family Fagaceae, is widely distributed in the temperate zones of the northern hemisphere and comprises three sections and seven species (Johnson 1988). Section Eucastanon is distributed in eastern and western Asia (Castanea mollissima B.L., C. seguinii Dode., C. crenata Lieb. & Zucc.), eastern north America (C. dentata Marsh. em. Borkh.) and southern Europe (C. sativa Miller). The other two sections are composed by one species each one, Balanocastanon in America (C. pumila Miller) and Hypocastanon in southeast China (C. henryi Skan em. Rehder & Wilson). All members of the genus have a somatic chromosome number of 2 = 24 (Jaynes 1963) and are obligate outcrossers that can hybridise freely (Rutter et al. 1990). The European sweet chestnut (C. sativa) is the only native species in Europe. It can be found from sea level to 1800 m of altitude and need annual rainfall over 500 and 1000 mm. In general, it grows over broad span climatic conditions from wet and cool to hot and dry during the growth periods. It can tolerate many kinds of soils, including stony, gravely and sandy soils, although it is widely accepted that it cannot withstand high levels of active calcium. Chestnut is a tree of remarkable development and exhibits an exceptional longevity, even 1000 years old. There are millenarian exemplars as the ―Cento Cavalli‖ (Sicily, Italy), ―Castaño Viejo‖ de San Román de Sanabria (Zamora, Spain) and ―Castaño Santo‖ de Istán (Malaga, Spain) (Figure 8). The crown is large and spherical and the trunk diameter can reach considerable dimensions, tending to swagger in the centre for the past 100 years of age. It has a high ability to sprout from stumps that is maintained over two centuries. It is a deciduous tree, appearing the first leaves at the beginning of May and falling around November. These are simple, alternate and with dentate-crenate margins.

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Figure 8. ―Castaño Santo‖. An example of a long-lived chestnut located in Istán (Malaga, Spain).

Figure 9. A, example of chestnut inflorescence; B, bisexual catkins; C, male catkins. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Figure 10. Example of burrs with different number of nuts.

This species is monoecious, with female and male flowers spatially separated and borne on the current season growth. It has two types of inflorescences: unisexual, male catkins on the lower part of the shoot; and bisexual catkins towards the tip (Figure 9). Female flowers borne singly or in clusters of two or three at the base of the bisexual catkins and they will become the burrs. Pollination is described as anemophilous, entomophilous, or a combination of both (Crane and Walker 1984). Several studies establish that the species displays gametophytic incompatibility (McKay 1942). Four types of stamen in the male catkins are found: longistaminate, mesostaminate, brachystaminate and astaminate. There is a close relationship between the stamen morphology and the viability of pollen, which displays a graded variation in the fertility of chestnut. At this respect, longistaminate types produce large amount of viable pollen, whereas astaminate types do not produce pollen, and as a consequence, morphologic sterility in male catkins (Breviglieri 1951). The seeds are enclosed in a complex spiny burr dehiscent into four valves at maturity. Nuts are covered with a thin shell. The normal number of nuts per burr is 2-3 in cultivated chestnut and this number can be higher in the case of wild chestnuts (Figure 10). It is thought that chestnut was present in Europe during Palaeocene, around 65 million years ago, being an important component of Tertiary hardwood forests. There are two theories about the origin of the species in Europe. The first establishes that during Würm glaciation (100000-12000 BC) chestnut disappeared from southern Europe and survived only in southwestern Asia, in Turkey and Caucasus region (Zohary and Hopf 1988). Palynological studies support that its diffusion was due to two periods of fast expansions about 5000 years ago and during the Roman Empire about 2000 years ago. This suggests that chestnut did not naturally colonized western Mediterranean regions but that was introduced by man. The second theory supports that the species survived in glacial refuge located in southern Europe. In the Iberian and Italian peninsulas chestnut pollen was found in fossil layers correlated with the Pleistocene. According to this hypothesis, the current chestnut populations might be, therefore, composed by a mixture of the relict populations that survived in the glacial refuge and those that colonized western Mediterranean regions probably introduced by man (Krebs et al. 2004). In relation to its historic evolution, the valuation of the species began with the Greek civilization that increased its cultivation, both for timber and fruit (Adua 1999). The timber was used to make tools and the fruits to obtain flour and making bread. However, there is an evidence of increasing importance of chestnut during the Roman Empire. During this period, chestnut was grafted onto seedling rootstocks for fruit production, different techniques of

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graft were developed and new cultivars were originated through varietal selection (Columela 1979). Moreover, great part of its diffusion was due to the expansion of the association vinechestnut, because its timber was used to produce barrels to transport wines and as poles in the vineyard. During the Middle Age, it was one of the main staple food sources for rural populations in mountain regions, where lands were not suitable for growing other crops. It was considered the ―mountains cereal‖ (Bourgeous 1992). It seems that this was the first important period of development of plantations, in which timber was used with agricultural purposes (stakes, basketry), construction (post, beams) and industry (looms, spinning wheel). However, during Modern Times, chestnut was replaced by other crops as the potato and the corn coming from America, reducing the area devoted to fruit production. Afterwards, in last decades the depopulation of rural areas and the specific pathogen attacks (Cryphonectria parasitica and Phytophthora sp.) have caused an important reduction of the areas devoted to fruit production in many European regions (Bruneton 1984). In spite of this, European chestnut is one of the most economically important multipurpose tree species of the Mediterranean region. It is cultivated both for fruit and for timber and is important not only for its socio-economic and cultural value but for its contribution to the landscape and environment. The current chestnut populations are distributed in all Mediterranean basin countries, spread from Spain and Portugal to Caucasus, through Turkey, Greece, Italy, France and the southern part of Great Britain. It is very probably that both man influence in the management of chestnut populations and fragmentation of their distribution because of pests and changes in land use highlight the complexity involved in chestnut genetic structure. According to the type of management, it may be identified three types of chestnut stands: 1) Naturalised stands, that come from seeds (saplings) and each tree has a different genotype. This type of stands has been used for timber production, although currently they present mainly environmental value. 2) Coppice, exploited for timber production. In this case, the central trees come from seeds but regenerate by stump (coppice shoots). In ancient formations, each of these stumps leads to a different set of feet, arranged in circular form. In any case, the resulting formation has a single genotype. 3) Orchards, grafted chestnut dedicated to fruit production. The clonal varieties are grafted onto seedling rootstocks coming from seeds. In this case, the genetic structure of rootstocks is different to the grafted varieties. Thus, in the grafted part is expected a clone mixture and in the rootstocks is expected that each tree has its own genotype (Figure 11). Moreover, the artificial replacement of trees is carried out with seeds that come from varieties and are used to grafted, acting therefore both natural and artificial selection. All this leads to a particularly complex genetic structure of populations

On-Farm Conservation of Chestnut Genetic Resources In last years, with the progressive revaluation of natural resources according to the principles of sustainable agriculture policies, chestnut ecosystem has increased its ecological and landscape importance becoming a fundamental resource for sustainable development of mountain areas.

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Figure 11. Different types of chestnut stands depending of the management. A, naturalised stands; B, coppice; C, orchards.

In this context, chestnut on-farm conservation plays an important role since it is able to combine the production with the maintenance of biodiversity and using materials in their original zones and by traditional techniques (Maxted et al. 1997). In fact, with changes in food habits of consumers, chestnut has gone from a fruit of everyday use to a product with multiple quality requirements (Bounous, 2002). There is renewed interest in traditional chestnut varieties, due to the increasing market for typical products with a high value and superior quality as attributed by consumers (Negri, 2003). The germplasm of C. sativa is rich of excellent cultivars grown in the main nut areas where a high number of varieties are selected for specific nut qualities and consumer uses as candying, roasting, drying, flour, etc. An example of the large chestnut germplasm resources are the more than 700 cultivars described in France, more than 100 in Spain, Italy and Switzerland and about 30 in Great Britain (Bounous 2002). However, the main problem related with the classification of this germplasm is that these traditional varieties are usually named according to geographic origin, ripening period and type of use, thus making cataloguing very difficult (Fineschi 1988). This absence of standard references, therefore, causes confusion in variety names with cases of homonymies and synonymies (Bounous 2002; Gobbin et al. 2007). Currently, the official methods used to identify and characterise varieties of fruit tree species are based on morphological characterisation and phenological observation according to UPOV (International Union for the Protection of New Varieties of Plants descriptors proposed for chestnut), IPGRI (International Plant Genetic Resources Institute) and FAO (Food and Agriculture Organization). However, molecular markers have been found complementary to these data. In recent years, microsatellite markers (SSRs), are the most used markers for studying genetic diversity; since provide a direct study of genotype that enables identification of chestnut cultivars (Botta et al. 1999; Goulão et al. 2001; Gobbin et al. 2007).

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In last years, it has been carried out a multidisciplinary European project (CASCADE) aimed to integrate different research fields to devise strategies for the conservation of chestnut genetic resources (Villani et al. 2006). The research on the distribution, ecology and management of chestnut has confirmed that the species is adapted to a wide range of environments. Likewise, the study of genetic structure of populations based on molecular markers has indicated the prolonged anthropogenic action on the species, being able to quantify the level of selective pressure depending of the different type of management. In fact, interaction among the species management and environmental factors display a fundamental role on the genetic, eco-physiologic and structural characteristics of the species. Although these results are essential for planning programs for the conservation of the species genetic resources, it is also important to evaluate the socio-economic and environmental impact in those sites where chestnut is still being exploited.

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The Situation of Chestnut in Spain In Spain, chestnut occupies more than 126.000 ha. In northern, it can be found mainly in Galicia, Asturias, Cantabria, País Vasco and Cataluña; in central Spain, in Caceres, Salamanca and Avila, up to the Sierra de Gredos; and in southern, in Andalusia and the Canarias Islands. The two main uses of the species are timber and fruit. Depending on the type of exploitation, chestnut stands can be high forest or coppice forest, where silvicultural treatments play an important role in its management. In the first case, the species forms pure, regular and low density stands dedicated to fruit production. Conversely, stands of coppice forest are generally pure and regular but with higher density and devoted to timber production. In any case, the chestnut groves are managed of traditional form, constituting a valuable element of the landscape and contributing environmental services (Rubio et al. 2002; Gondard et al. 2007). Up to now, 152 cultivars have been identified and characterised, although there is still confusion in varietal identification because the studies have been carried out using morphological and isozymes markers (Ramos-Cabrer and Pereira-Lorenzo 2005; PereiraLorenzo and Fernández-López 1997; Pereira-Lorenzo et al. 2001, 2006; Queijeiro et al. 2006). At this regard, our study in Andalusia, which will be described following is the only one on chestnut traditional varieties in Spain using microsatellites (Martín et al. 2005; Martín et al. 2009), markers that are more suitable for this type of analysis.

Chestnut Orchards in Southern Spain: An Example of on-farm Conservation In Andalusia, the species covers over 9.000 ha and is located mainly in areas of environmental protection. In this region, it plays an important ecologic and socio-economic role, because its maintenance generates incomes (products as fruit and timber; sub-products as honey and mushrooms; and externalities as the rural tourism), which help to maintain the rural population. Nevertheless, the economic viability of many farms is seriously compromised and there are many abandoned chestnut groves.

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In last ten years, our group has carried out the study of chestnut genetic resources in Andalusia (southern Spain) with the aim of establishing the guidelines for its sustainable management. Our purpose was to reach this objective through three aspects: 1. within the approach of ―landscape genetics‖, to highlight the contribution of orchards to the conservation of biological diversity, thus allowing quantifying the environmental services provided by farmers that handle the species; 2. to contribute to the best knowledge of the species as a system to give technical support to farmers, thereby increasing the economic viability of the exploitations; and 3. to characterise the varieties to allow its characterisation and, thus the commercial value of the product.

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Such a work cannot be developed without an active participation of the implied sector. For this reason, we contact both with farmers and public and private organisations involved; reason why we consider this work belongs to the called ―participatory research‖. We carried out several collecting missions in the areas of distribution of the species during 2001-2004 (Martín et al. 2007). It was stated the existence of orchards grafted onto seedling rootstocks with traditional varieties and dedicated to fruit production in the Natural Park of ―Sierra de Aracena y Picos de Aroche‖ in Huelva and the Genal river Valley in Málaga. Furthermore, minor extensions of the species were located in Granada, Sevilla, Córdoba, Jaén, Almería and other points of Malaga where stands come from sexual reproduction (saplings) and chestnuts from mixed stands. We found that in these areas chestnut ecosystem contains a large biodiversity and high cultural heritage created by centuries of human activity and have elements of high aesthetic and landscape value (Alvarez et al. 2005).

Figure 12. Example of geographical location and morphological characterisation of chestnut varieties. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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In the case of orchards, the knowledge about the varietal situation was confuse due to the large number of varietal names and the lack of characterisation of the material. We gathered varietal denominations according to the information given by the farmers. In both regions, 156 trees were identified and catalogued (Figure 12) and up to 43 varietal denominations were compiled, 30 of which had not been previously reported (Martín et al. 2007). We have stated that the situation of the crop is different in each zone. In Malaga, chestnut is a crop in increase with a dominant variety (Pilonga) that represents approximately the 80 percent of the cultivated varieties. In this area, it is possible to find old trees with centuries of antique, orchards established in the last fifty years and young trees planted recently. Conversely, in Huelva there is not a principal variety, the low yield of the crop has taken at a critical situation, and most of the orchards have old trees, being the modern chestnut groves and the young trees repositions very scarce. In general, chestnut stands of sexual nature can be classified as high forest. In these areas, chestnut formed mixed stands integrated with cork oak (Quercus suber L.), holm oak (Q. ilex L.), olive (Olea europaea L.) and walnut (Juglans regia L.). In most cases, it has not been possible to establish with absolute security if these trees are grafted or not. However, the absence of the graft scars, the presence of stumps with numerous sprouts and the low size of the nuts in the most of the evaluated trees, suggest that these trees come from sexual reproduction. Moreover, the chestnut stands located in these extensions were abandoned and showed critical conservation state due to the drought or to effect of some specific diseases as the ink (Phythophthora cinnamomi Rands). Moreover, some coppice stands used for timber production were found in Cordoba and Sevilla provinces. In these zones a tree network consisting on 29 stands was established, that will be used in future studies to characterise its genetic variability. During this time, cotyledon storage proteins were used as a marker of the genetic diversity of the species, providing a fist approach on the diversity of the two main productive zones (Alvarez et al. 2003). In a second stage, the clarification of the varietal situation was approached combining the information provided by farmers and the use of morphological and molecular markers. In this last case, we used microsatellite markers (SSRs), since they are more adapt than cotyledon storage proteins for varietal identification. In this study, we identified up to 38 varieties, 12 in Huelva and 26 in Malaga, detecting cases of homonyms and synonyms in both regions (Martín et al. 2009). This fact can be explained because farmers name these traditional varieties following only morphological and phenological criteria. In this regard, Temprana denomination is an example of homonymy. It is considered an only one variety because of its precocious fruit ripening, although displays different morphological traits in the accessions studied with this name. Conversely, Temprana and Sanmigueleña denominations could be an example of synonymies. The first name derives from the early harvest date of the trees and the second name, San Miguel (Saint Michel) day is celebrated at the end of September, corresponding to the beginning of the chestnut harvest. Another good example of how our work has revealed environmental services rendered by farmers is the case of ―Pilonga‖ denomination. Previous data based on surveys achieved to farmers in Malaga region, concluded that most of chestnuts were grafted with an only variety named ―Pilonga‖. The first field works allowed us to observe that farmers associated such denomination with nuts that peeled well and within this there were derived denominations as ―Pilonga de Jubrique‖, ―Pilonga de Parauta‖, ―Pilonga de Igualeja‖ or ―Bravia Pilonga‖.

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Some trees of each one of these denominations were catalogued and the abovementioned studies revealed that ―Pilonga‖ denomination and its derived constitute up to eight different varieties. Furthermore, the term ―Bravia Pilonga‖ is applied to trees from seeds with nuts that peeled well, and as a result, the trees catalogued under this name showed specific genotypes and some of them are used by farmers to graft other trees, constituting probably a minor variety. The most representative varieties from each region have been characterised using fruit quantitative traits. The results of this study showed significant differences among varieties from Huelva and Malaga (Martín et al. 2008), and established the existence of a group of varieties represented by few individuals, that constitutes an important part of the species genetic diversity in Andalusia, but are in danger of disappearing. Probably, the variability for the radical part or patterns could be higher than the variability for the productive part and due to the old age from some of these patterns is possible that represent a genetic variability missed in the actual varieties. Moreover, during a collecting mission carried in 2007, we have stated the sexual nature of chestnut groves traditionally dedicated to fruit production in Granada province, gathering up to seven more varietal denominations. Twenty percent of the Andalusian chestnut production is based on ―ecological production‖. Results of our study have indicated that, even the fields not included on this productive system, use traditional methods, thus potentially, all the production of chestnut in the region could be ecological production. In addition, preliminary studies conducted on soils have shown high levels of organic matter, both in organic and conventional fields. To sum up, our results have revealed the existence of an autochthonous diversity, associated with areas of high environmental value and with important social and cultural connotations developed by the communities associated with its management. Furthermore, we have also stated that on this system are both internal and external threats. Thus, while it has been stated that chestnut production is based on a high number of varieties that constitute a real on-farm conservation system, and its growers hold a considerable knowledge, many of these varieties are at risk of disappearing in a short time. Varieties used as grafts are landraces that fill ecological, cultural and local socio-economic niches that modern varieties not occupy and show high level of variability. On the other hand, this conservation system presents a high compatibility with the maintenance of other environmental values as the safeguard of ecosystems and notable individuals. In this context, the situation must be corrected, as these production systems have many possibilities to increase their economic viability through improvement of product characterisation, their incorporation to organic farming and the possibility of aid for the conservation of the biodiversity involved in their maintenance. The Ministry of Environment and Agriculture of the Andalusian Government it is currently developing two projects for the establishment of a clonal orchard destined to maintain traditional chestnut varieties in the region. Both projects are based on the results obtained by our group. There are still many outstanding issues to understand the chestnut genetic resources in Andalusia as the identification of ―minor varieties‖ (varieties that correspond to a denomination but there are represented by few trees), the identification of more clonal varieties outside these two cultivation areas, the genetic composition of stands that come from seeds, with the spatial and temporal distribution of its diversity or the contribution to the

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diversity of singular trees and groves. However, we believe that the current state of knowledge has enabled us to move forward in achieving the objectives.

CONCLUSION

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Any agricultural system, as any economic activity, must first be profitable, since this lack of profit forces to the change of the productive system or the abandonment of the activity. In the indigenous communities of the developing countries or the rural communities in the developed ones, this supposes the exodus from the field to the cities, mainly to the fringe areas of the same, becoming a social problem. The main aim of the sustainability must be a feedback mechanism that causes that the farmer does not wish to leave the activity and to migrate to the city. For it, the variability and the diversification are fundamental, especially in a non-extensive agriculture, where the role of the farmer continues being fundamental. It is being solidly established the system of ex-situ and in-situ conservation of the plant genetic resources, a great disproportion between the former (more of six million of accessions conserved in the Germplasm Banks) and the latter, where the scientific information available is very scarce. Our work on hulled wheats and chestnut has allowed us to state that, in both cases, productive systems exist that integrate the conservation, but on such systems looms there are important external and internal threats that make urgent the taking of measures to ensure their continuity. The accomplishment of works of this type is, as well, a form to defend these productive systems, through a double way: (a) its existence and the services that render to the society open the possibility of receiving payment by such services; and (b) the standardisation of traditional products can contribute to improve the economic viability of its corresponding productive systems. On the other hand, the study of the collections conserved in the Germplasm Banks could render good results for: (a) the genetic improvement of modern agriculture; (b) the own conservation; and (c) to reinforce the traditional productive systems. In this chapter, we have valuated the necessity of variation in the crops for guaranteeing the sustainability of the agricultural systems. This is most important when these crops are in traditional systems with great possibilities of depleting. If the plant genetic resources of these crops are missed, it is probably that they began to be vulnerable to the different biotic and abiotic stresses, and consequently the agriculture based in them will be un-sustainable.

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ACKNOWLEDGMENTS We would like to thank to the Asturian farmers and the Andalusian farmers and forest agents for their kindly collaboration during the collecting missions. The hulled wheats research was supported by several grants from the Spanish Ministry of Science and Innovation and the European Regional Development Fund (FEDER) from the European Union (Grants no. AGL2001-2419-C02-02, AGL2004-03361-C02-01 and AGL2007-65685-C02-02). The chestnut research was supported by an agreement (CONV2000-63) between Ministry of Environment from the Regional Government of Andalusia (Spain) and University of Cordoba and grant C03-083 from the Ministry of Agriculture and Fish of the Regional Government of Andalusia (Spain). M.A. Martín is grateful to the «Alfonso Martin Escudero» Foundation for a postdoctoral fellowship and the hosting Institute of the fellowship, Agroenvironmental and Forest Biology Institute from Italian National Research Council.

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REFERENCES Adua, M. (1999). The sweet chestnut throughout history from the Miocene to the third millenium. Acta Horticulturae, 494, 29-36. Alvarez, J. B., Caballero, L., Ureña, P., Vacas, M. & Martín, L. M. (2007). Characterization and variation of morphological traits and storage proteins in Spanish emmer wheat germplasm (Triticum dicoccon). Genetic Resources and Crop Evolution, 54, 241-248. Alvarez, J. B., Moral, A. & Martín, L. M. (2006). Polymorphism and genetic diversity for the seed storage proteins in Spanish cultivated einkorn wheat (Triticum monococcum L. ssp. monococcum). Genetic Resources and Crop Evolution, 53, 1061-1067. Alvarez, J. B., Muñoz-Diez, C., Martín-Cuevas, A., López, S. & Martín, L. M. (2003). Cotyledon storage proteins as markers of the genetic diversity in Castanea sativa Miller. Theoretical and Applied Genetics, 107, 730-735. Alvarez, J. B., Martín, M. A., Muñoz, C., López, S. & Martín, L. M. (2005). Genetic variability of chestnut in Andalucia (Spain). Acta Horticulturae, 693, 471-476. Alvargonzalez, C. (1908). La escanda, su origen y su cultivo. Gijón/Spain. Beccari, I. B. (1745). De frumento. De Boboniensi Scientiarum et Artium Instituto Atque Academia, 2, 122-127. Botta, R., Akkak, A., Marinoni, D., Bounous, G., Kamper, S., Steinkellner, H. & Lexer, C. (1999). Evaluation of microsatellite markers for characterizing chestnut cultivars. Acta Horticulturae, 494, 277-282. Bounous, G. (2002). Il castagno. Coltura, ambiente ed utilizzazioni in Italia e nel mondo. Edagricole. Bologna. Bourgeous, C. (1992). Le chataignier, un arbre, un bois. Institut pour le development Forestier. Paris. Bretting, P. K. & Duvick, D. N. (1997). Dynamic conservation of plant genetic resources. Advances in Agronomy, 61, 1-51. Breviglieri, N. (1951). Ricerche sulla biologia fiorale e di fruttificazione della Castanea sativa e C. crenata nel torritorio di Vallombrosa. Pubbl. Cent. Stud. Sul Castagno, 1, 15-49.

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Jaynes, R. A. (1963). Biparental determination of nut characters in Castanea. Journal of Heredity, 54, 84-88. Johnson, G. P. (1988). Revision of Castanea sect. Balocastanon (Fagaceae). Journal Arnold Arboretum, 69, 25-49. Kato, K., Miura, H., Akiyama, M., Kuroshima, M. & Sawada, S. (1998). RFLP mapping of the three major genes, Vrn1, Q and B1, on the long arm of chromosome 5A of wheat. Euphytica, 101, 91-95. Kemp, B. J. (2005). Ancient Egypt: anatomy of a civilization, 2nd Ed. London, UK: Routledge. Kerber, E. R. & Rowland, G. G. (1974). Origin of the free-threshing character in hexaploid wheat. Canadian Journal of Genetics and Cytology, 16, 145-154. Krebs, P., Conedera, M., Pradella, M., Torriani, D., Felber, M. & Tinner, W. (2004). Quaternary refugia of the sweet chestnut (Castanea sativa Miller): an extended palynological approach. Vegetation History and Archaebotany, 13, 145-160. Luo, M. C., Yang, Z. L. & Dvořák, J. (2000). The Q locus of Iranian and European spelt wheat. Theoretical and Applied Genetics, 100, 602-606. Martín, A. C., Giménez, M. J. & Alvarez, J. B. (2005). Varietal identification of chestnut using microsatellites markers. Acta Horticulturae, 693, 441-446. Martín, M. A., Alvarez, J. B. & Martín, L. M. (2008). Nut characterisation of the main traditional chestnut varieties from Andalusia. Acta Horticulturae, 784, 71-75. Martín, M. A., Alvarez, J. B., Mattioni, C., Cherubini, M., Villani, F. & Martín, L. M. (2009). Identification and characterization of traditional chestnut varieties of Southern Spain using morphological and simple sequence repeat (SSRs) markers. Annals of Applied Biology, 154, 389-398. Martín, M. A., Moral, A., Martín, L. M. & Alvarez, J. B. (2007). The genetic resources of European sweet chestnut (Castanea sativa Miller) in Andalusia, Spain. Genetic Resources and Crop Evolution, 54, 379-387. Mauro, F. & Hardison, P. D. (2000). Traditional knowledge of indigenous and local communities: international debate and policy initiatives. Ecology Applied, 10, 1263-1269. Maxted, N., Ford-Lloyd, B. V. & Hawkes, J. G. (1997). Complementary conservation strategies. In: N., Maxted, B. V. Ford-Lloyd, & J. G. Hawkes, (Eds.), Plant Genetic Conservation. London, UK: Chapman and Hall. 15-39. McFadden, E. S. & Sears, E. R. (1946). The origin of Triticum spelta and its free-theshing hexaploid relatives. Journal of Heredity, 37, 81-87. McIntosh, R. A., Hart, G. E., Devos, K. M., Gale, M. D. & Rogers, W. J. (1998, 2003). Catalogue of gene symbols for wheat. In: Proc. 9th Int. Wheat Genet. Symp., Vol. 5. University Extension Press. University of Saskatchewan. 235 Supplement. McKay, J. W. (1942). Self-sterility in the Chinese chestnut (Castanea mollisima). Proceedings of the American Society of Horticultural Sciences, 41, 156-160. Metakovsky, E. V., Novoselskaya, A. Y., Kopus, M. M., Sobko, T. A. & Sozinov, A. A. (1984). Blocks of gliadin components in winter wheat detected by one-dimensional polyacrylamide gel electrophoresis. Theoretical and Applied Genetics, 67, 559-568. Muramatsu, M. (1963). Dosage effect of the spelta gene q of hexaploid wheat. Genetics, 18, 469-482. National Research Council. (1972). Genetic vulnerability of major crops. Whashington, DC: National Academy of Sciences.

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ISBN: 978-1-60876-269-9 ©2010 Nova Science Publishers, Inc.

Chapter 4

PHYTOTOXINS PRODUCED BY FUNGI RESPONSIBLE  OF FORESTALL PLANT DISEASES Antonio Evidentea,*, Anna Andolfia, Alessio Cimminoa and Mohamed A. Abouzeidb a

Università di Napoli Federico II, Portici, Italy b University of Ain Shams, Cairo Egypt

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ABSTRACT Toxins produced by phytopathogenic fungi have assumed great importance because of their involvement in several plant diseases. These pathogens have seriously damaged plants of agrarian, forestall and environmental interest. Several studies have been carried out to understand the role of bioactive microbial metabolites in pathogenesis and therefore to use them against specific diseases. This manuscript will describe the chemical and biological characterization of the phytotoxins produced by fungus Sphaeropsis sapinea f.sp. cupressi, the causal agent of canker disease of cypress in the Mediterranean basin, and by fungal species belonging to Diplodia, Biscognauxia and Sphaeropsis genera, which are widely spread in the Sardinian oak forests, and are considered one of the main causes of cork oak (Quercus suber L.) and pine (Pinus radiata) decline with important social and economical implications.

1. INTRODUCTION Toxins produced by phytopathogenic fungi have assumed great importance because of their involvement in several plant diseases. These pathogenes are seriously damaging agrarian, forestall and environmental plants. Frequently, the appearance of symptoms and the evolution of the disease, observed at distal parts of the infection sites, suggests the  Dedicated to my friend Frà Luigi Campoli, Monastero di Santa Chiara, Napoli, Italy *Corresponding author. Tel.: +39 081 2539178; Fax: +39 081 2539186; E-mail: [email protected] (A. Evidente).

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involvement of translocable phytotoxins in the disease process development. Considering their social and economical impact, many efforts have been made to avoid losses in the agrarian production and to save the ornamental and forestall plants patrimony. Several studies have been conducted to understand the role of bioactive microbial metabolites in the progress of the pathogenic process and therefore to use them against specific diseases. The chemical nature of these toxins was found to range from low molecular weight compounds, including all classes of natural products as terpenes, chromanones, butenolides, pyrones, macrolides, aromatic derivatives, aminoacids etc., to high molecular compounds such as proteins, glycoproteins and polysaccharides. As a result, many new phytotoxins, pesticides, fungicides, antibiotics, plant growth regulators, and mycotoxins have been reported (Strobel, 1982; Graniti et al., 1989; Ballio and Graniti, 1991; Tabacchi, 1994; Evidente, 1997; Evidente and Motta 2001, 2002). In some cases, toxins have been used to obtain products for plant protection or, by genetic selection, plants resistant to specific disease (Durbin, 1981; Graniti et al., 1989; Ballio and Graniti, 1991). We discuss the isolation, purification and chemical and biological charaterisation of several phytotoxins, produced by fungi pathogenic for plants with forestall interest. Studies on their structure activity relationships and their chemical derivatization are reported. Their role in the pathogenesis have also been hypothesized.

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2. PHYTOTOXINS Studies on the involvement of toxins in plant diseases caused by pathogenic microorganisms date from the second half of the 19th century. Phytotoxins are defined as microbial metabolites that are harmful to plants at very low concentrations. Most of the plant pathogenic fungi produce toxins in culture and in their hosts. Frequently, these compounds play a role in the pathogenesis and produce some or even all of the symptoms of the disease. In many cases, these compounds have low molecular weight and belong to a variety of classes of natural products. They are able to move from the site of their production to the sorrounding tissues or are translocable within the plant vesseles. The virulence of the plant pathogens may depend on their capability to synthesize one or more toxins. Only few phytotoxins are kown to be host-specific toxins since they are more frequently phytotoxic for a broad range of plant species. In some cases, studies on their mode of action and their role as "vivo-toxins" have been also proved to be essential (Strobel, 1982, Graniti et al., 1989; Ballio and Graniti., 1991; Evidente, 1997; Upadhyay and Mukerji, 1997, Evidente Motta 2001, Evidente Motta 2002).

3. FUNGI INVOLVED IN DIFFERENT CANKER FORMS OF CYPRESS The fungi associated with canker disease of the Italian cypress (Cupressus sempervirens L.) and other species of Cupressus in the Mediterranean area are belonging to the genera Diplodia, Pestalotiopsis, Seiridium and Sphaeropsis (Grasso and Raddi, 1979; Graniti, 1985; Graniti and Frisullo 1987; Solel et al., 1987; Madar et al., 1989; Madar et al., 1991; Swart and Wingfield, 1991; Swart et al., 1993; Graniti, 1998).

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They are found to induce similar but different forms of canker with heavy loss of cypress plantation as forestry and ornamental patrimony with consequent alteration of the typical landscape of some regions of Central Italy and other countries of the Mediterranean basin. The consequence of this disease is also very important for the economical point of view considering the noteworthy loss in the nursery industry and all the economy linked with the use of the precious cypress wood (Graniti, 1985). Some important implication regarding also the first correct diagnosis of the disease with the recognition of the pathogen were investigated and discussed. Although similar the canker forms induced by Seiridium is different from that induced by Sphaeropsis and Diplodia species and the metabolites they produce, that proved to have a different chemical nature, could contribute to optimise a rapid, simple and specific method for disease diagnosis as well as to the correct taxonomical classification of the fungi producers (Evidente and Motta 2001).

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3.1. Seiridium Toxins Three species of Seiridium, namely S. cardinale, S. cupressi and S. unicorne, are associated with the canker diseases of cypress (Cupressus sempervirens L.). Since its first introduction in Europe (Barthelet and Vinot, 1944), the canker caused by the imperfect fungus S. cardinale (Wag.) Sutt et Gibbs has become the major disease of the Mediterranean cypress and other species of Cupressaceae. The cypress canker, firstly reported in the U.S.A. (Wagener, 1939), is a destructive disease that kills the trees, causing heavy losses to the nursery industry, to cypress plantations used for afforestation and wind-breaks, and to ornamental cypresses (Grasso and Raddi, 1979; Graniti, 1985). A similar disease caused by strains of S. cupressi (Guba) Boesew. and S. unicorne Cooke et Ellis, although less serious, has spread in Greece (Kos) (Graniti, 1985; Xenopoulos, 1987) and Portugal (Graniti, 1985; Graniti and Frisullo, 1987). However, these fungi and the disease they induce occur in other parts of the world as well. Evaluation of the damage caused by strains of Seiridium to their host plant suggests that necrotic toxins are produced in the infected tissues and are possibly involved in the pathogenesis. The chemical and biological characterization of the phytotoxins produced by the three species of Seiridium was described in a previous review (Evidente and Motta, 2001). The main isolated toxins appeared to be two new disubstituted butenolides, named seirdin and iso-seridin (1 and 2, Fig. 1). (Evidente et al. 1986; Sparapano et al., 1986). Other two minor butenolides were successively isolated from the same fungal culture filtrates and were identified as 7‘-hyroxyseiridin and 7‘-hydroxy-iso-seiridin (3 and 4, Fig. 1) (Evidente et al., 1994). These fungi were found also to produce phytotoxins belonging to other classes of naturally occurring compounds as the three seiricardin A-C (5-7, Fig. 1) (Ballio et al., 1991; Evidente et al.1993), which were are characterized as three new cyclic and bicyclic indene squiterpenoids, respectively. S. cupressi produce two specific toxins identified as a new 14macrolide, and named sericuprolide (8, Fig. 1) (Ballio et al., 1988) as the well known antibiotic cyclopaldic acid (9, Fig. 1), a pentasubstituted benzofuranone produced by different fungal genera (Graniti et al, 1992).

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Antonio Evidente, Anna Andolfi, Alessio Cimmino, et al. 8' CH 3

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Figure 1. Structure of Seridium phytotoxins (1-9).

3.2. Sphaeropsis and Diplodia Toxins Several phytopathogenic fungi belonging to the genus Sphaeropsis and Diplodia are responsible of severe deseases for agrarian and forestal trees. S. sapinea f. sp. cupressi and D. mutila in cypress induce symptoms very similar to those produced by the three phytopathogenic Seiridium species. As previously mentioned, it is well known that phytotoxins may be involved in pathogenesis and that microbial toxins may be used in the biological control of other pathogens which infect the same host plant. The phytotoxins

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produced by S. sapinea f. sp. cupressi and D. mutila that could be used as antimicrobial substances against Seiridium spp. The main toxin, called sphaeropsidin A (10, Fig. 2), was isolated from the in vitro culture of Sphaeropsis sapinea f.s. cupressi (Evidente et al., 1996) This toxin as well as the minor sphaeropsidins B and C (11 and 12, Fig. 2) (Evidente et al., 1997), whose chemical and biological caracterization were extensively reported by Evidente and Motta 2001. All the sphaeropsidins (A-C) belong to the pimarane subgroup of diterpene but differed for the functionalization of the pimarane skeleton as well as their stereochemistry. Sphaeropsidin A and C were also produced by a strain of Diplodia mutila isolated from infected cypress tree (Evidente et al., 1997).

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Me

Me

6

H Me HO

R1

Me

H Me H

O H

19

12

10 R1+R2=O, R3=R4=H 11 R1=R3=R4=H, R2=OH

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13

R1+R2=O, R3=H,

R4=OH

Me

OH

H

Me 11

20

CH2

9

CH3

14

7

Me

H Me H 14

CH2 10

OH

7

OH

6

H H

OH

1

H 6

20

CH3

OH

8

10

H

HO

Me

H Me H

H OH

15

Figure 2. Structure of sphaeropsidins isolated from Sphaeropsis sapinea f. sp. cupressi and Diplodia mutila phytotoxins (10-15).

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Antonio Evidente, Anna Andolfi, Alessio Cimmino, et al. R2

R1

OR1

H H

H3CO

4

H

H3CO

5

3

6

4 5

O

3

1

2

2

OR2

6

R3

1

H R4 O

O

16 R1=H, R2=OH 18 R1=R2=R4=H, R3=Cl

17 R1=OH, R2=H

19 R1=R2=R3=H, R4=Cl 20 R1=R2=Ac, R3=Cl, R4=H 21 R1=R2=R4=H, R3=Br

H3C OAc

CH 3 O H

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H3CO

4

5

O

H3CO

6

4 1

3

5

H

2 Cl

Cl H

OAc O

22

23

Figure 3. Structure of sphaeropsidons (16 and 17), chlorosphaeropsidons (18 and 19) isolated from Sphaeropsis sapinea f. sp. cupressi and their derivatives (20-23).

S. sapinea f. sp. cupressi also found to produce, as Seiridium species, toxins which belong to different classes of natural compounds as sphaeropsidone and epi-sphearopsidone, two new phytotoxic dimedone methyl ethers (16 and 17, Fig. 3) (Evidente et al. 1998). They appeared closely related to other well known fungal metabolites as terremutin and panepoxydon (Miller, 1968; Fex and Wickberg, 1981), chaloxone, epoxydon, (+)epiepoxidon and (+)-deoxyepiepoxidon (Nagasawa et al., 1978). Their chemical and the

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biological properties were also reported in the above cited review by Evidente and Motta, 2001. The isolated sphaeropsidins and sphaeropsidones were toxic to cypress and all the three sphaeropsidins showed antimicrobial activity against some plant pathogenic fungi, particularly against Seiridium cardinale and S. cupressi (Evidente et al., 1996; 1997). Sphaeropsidone and epi-sphaeropsidone showed a lower antifungal activity than that of sphaeropsidins (Evidente et al., 1998). The absolute configuration (AC) assigned to sphaeropsidone and epi-sphaeropsidone (Evidente et al., 1998) was revised using quantum-mechanical calculation of the optical rotatory (OR) power [α]D at the sodium D line [Rosenfeld, 1928; Condon 1937; Buckingam 1967; Polavarapu, 1997a; Polavapu 1997b; Polavarapu and Chakraborty, 1998; Kondru et al., 1997; Kondru et al.,1998; Cheeseman et al., 2000; Stephen, 2000; Stephens et al., 2001; Mennucci, et al., 2002; Stephens et al., 2002; Polavarapu 2002; Pecul and Ruud 2006;]. The last few years have witnessed an increasing interest for the, []D i.e. the most common experimental parameter to label an optically active compound. The reason for such interest is clear, these calculations could provide a practical solution to one of the most important problems of the structural organic chemistry where a possibly reliable (and easy) determination of the molecular absolute configuration, may play a very important role to impart biological acitivity to naturally occurring compounds. The determination of absolute configurations from a comparison of experimental data and theoretical predictions requires that the simulated values are fully reliable in sign and order of magnitude. Since the seminal papers (Polavarapu 1997a; Polavarapu 1997b; Polavarapu and Chakraborty 1998; Kondru et al., 1998) where the very first OR calculations using the Hartree-Fock/small basis set approach were carried out, many studies have been done at different levels of theory to set up methods which couple reliability, accuracy to a reasonable computational effort (Pecul and Ruud 2006; Crawford 2006). From this point of view, the impressive and rigorous investigations of Stephens and coworkers (Stephenes et al., 2001; Stephenes et al., 2002; Stephenes et al., 2003; Stephenes et al., 2004; Stephenes et al., 2005) have demonstrated that appropriate calculation programs gave completely reliable results (with an accetable computational effort) in reproducing experimental optical rotation of at least 100 deg [dm g/cm3]-1. The reliability of this computational approach was used in the determination of the absolute configuration of a series of compounds belonging to a family of highly oxygenated cyclohexane-based metabolites, mainly epoxides, that have been previously isolated from bacteria, fungi, higher plants and molluscs. These compounds possess a variety of biological activities (antifungal, antibacterial, antitumor, phytotoxic and enzyme inhibitory and for this reason they have been object of several structural and synthetic studies (Ichihara 1987; Gautier et al., 1994; Graham et al., 1996; Barros et al., 1997; Miller and Jonson 1997; Graham and Taylor 1997). The optical rotatory power of some natural cyclohexenone oxides has been calculated by means of appropriate calculation program both in the gas phase and in solution by means of the Polarizable Continuum Model. This method was applied to the following cyclohexenone oxides: (+)-chaloxone, firstly isolated from the fungus Chalara microspora; (+)epiepoformine, purified by Nagasawa and coworkers (1978) from the culture filtrate of an unidentified fungus isolated from a diseased leaf and showed marked inhibition activity against the germination of lettuce seeds and which has been an object of several synthetic attempts (Kamikubo and Ogasawara 1995; Takihara and Kitahara 2003; Carreno et al., 2005);

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Antonio Evidente, Anna Andolfi, Alessio Cimmino, et al.

(+)-epoformine, a natural product isolated from the culture broth of Penicillum claviforme, which possesses antibiotic and cytotoxic properties (Barros et al., 1997); (+)-epitheobroxide, which is not a natural product, but is an epimer of the natural (-)-theobroxide, this compound presents a very small rotation, []D -6 in ethanol [13c]; (+)-epoxidone, isolated by Closse and co-workers in 1966 (Closse et al., 1966) as a compound with antimitotic activity. For (+)chaloxone and (+)-epiepoformine, which possess high (about 300 units) optical rotations, gasphase calculations are able to reproduce the experimental values both in sign and order of magnitude and the inclusion of the solvent effects only leads to a better agreement between experiment and prediction: this allows a safe assignment of the absolute configuration. Larger basis sets are required to satisfactorily simulate the OR values of (+)-epoformine and (+)-epitheobroxide, which show smaller (about 100 units or less) rotations. In addition, for these two compounds, when passing from the gas phase to the ethanol solution, a transformation from intra-molecular to inter-molecular hydrogen bonding, may occur i.e. an effect which cannot be accounted for by the present continum solvation model. So it is not unexpected that the final simulations are not satisfactory. By contrast, including solvent effects becomes imperative in the case of the flexible hydrogen bonded system (+)epoxidone; its absolute configuration could not be determined using gas phase calculations. The same method was also applied to revise the absolute configuration (-)sphaeropsidone, 16, and (-)-epi-sphaeropsidone, 17. It is noteworthy that calculations both in the gas phase and in the solvent lead to a positive rotatory power for the laevorotatory natural compound 16 and 17, if the ACs reported in the literature are employed to do the theoretical prediction. This strongly indicates that the ACs previously assigned to these compounds in the literature (Evidente et al., 1998) are not correct, and that the prediction of OR values has become by now a practicable tool for AC assignments. (Mennucci et al., 2007).

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3.3. Sphaeropsis Sapinea (Isolated from Cypress Infected Tree) Toxins The taxonomy of Sphaeropsis sapinea (Fr.:Fr.) Dyko & Sutton (Sphaeropsidales), which is an opportunistic pathogen of more than 30 species of Pinus in 25 different countries (Swart and Wingfield, 1991), has been the subject of considerable confusion and conflicting reports. The pathogen occurs in coniferous forests throughout the world and has been associated with significant economic damage in exotic plantations in New Zealand, Australia and South Africa (Chou, 1976; Zwolinski et al., 1990). S. sapinea also occurs in the Central and Eastern United States causing severe damage on both native and introduced species. In Michigan, Minnesota and Wisconsin, two morphotypes of the pathogen were recognised (Palmer et al., 1987). Isolates of the A morphotype were aggressive on both red and jack pine, but B morphotype isolates caused severe symptoms only on jack pine (Stanosz et al., 1997). More recently, confirmation of two distinct populations of S. sapinea in the North Central United States was obtained by random amplified polymorphic DNA markers (RAPDs) (Smith and Stanosz, 1995). These observations opened a reconsideration of the nature of the hostpathogen interaction. In contribution to understand their physiology, studies on the production and identification of secondary metabolites produced by Sphaeropsis and Diplodia species were conducted. Usually species belonging to the order Sphaeropsidales produce in vivo and in vitro toxic substances (Uspenskaya and Reshetnikova, 1975). Furthermore, on the basis of the

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fungal metabolic behaviour, the metabolites can be used to better biologically characterize S. sapinea f. sp. cupressi from some strains of S. sapinea isolated from infected cypress trees. Recently, morphological, physiological, pathogenic and epidemiological studies on S. sapinea, S. sapinea f. sp. cupressi and Diplodia mutila suggested that a great variability in morphological and physiological characteristics exists among different isolates of the fungal taxa examined (Frisullo et al., 1997a; ibidem 1997b). Moreover, the main toxic metabolites produced by the three strains of S. sapinea, isolated from infected cypress trees proved to be chemically different compared with those produced in vitro by S. sapinea f. s. cupressi and D. mutila isolated from the same host plants. Two 5-substituted dihydrofuranones, named sapinofuranones A and B (24 and 25, Fig. 4), were isolated from liquid cultures of Sphaeropsis sapinea, a fungal strain isolated from Cupressus macrocarpa, at concentrations higher than those produced by the two strains isolated from C. sempervirens (Evidente et al., 1999). 10

H3C

H 9

C

R2

C

C5 7

C H

2

4

8

H

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3

R1

6

1

O

O

H

C H

24 R1=OH, R2=H 25 R1=H, R2=OH Figure 4. Sphaeropsis sapinea isolated from cypress phytotoxins (24 and 25).

The butanolides 24 and 25 is rare as naturally occurring products (Turner and Aldridge, 1983). These compounds are closely related to butenolides and tetronic acids, which are well known as plant, fungal and lichen metabolites, with interesting biological activities (Dean, 1963). Among these, are the 3,4-dialkylbutenolides isolated from culture filtrates of three species of Seiridium that cause canker disease on cypress (Evidente et al., 1986; Sparapano et al., 1986; Evidente and Sparapano 1994). The chemical and biological properties of these two new butenolides were also reported in the review by Evidente and Motta, 2001.

3.4. Other Spheropsidins Isolated from Spheropsis sapinea f. sp. cupressi Oher two pimarane diterpenes structurally related to the sphaeropsidins were isolated from the liquid culture of Sphaeropsis sapinea f. sp. cupressi. These two metabolites were

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characterised by spectroscopic methods (essentially 1D and 2D 1H and 13C NMR and MS techniques) and were called sphaeropsidins D and E (13 and 14, Fig. 2). Sphaeropsidin D had a molecular weight of 362 corresponding to the molecular formula of C20H26O6 and proved to be structurally related to sphaeropsidins A (10). In fact, it almost contains unaltered decahydrophenanthrenone diterpene skeleton as already observed in 10 (Evidente et al., 1996). The molecular formula of 13 differed from that of 10 due to the presence of another oxygen atom, probably present in a further hydroxy group. In fact, the substantial difference, was the presence of a hydroxylated secondary carbon on the cyclohexanol ring. The results of the extensive spectroscopic investigation allowed to locate this hydroxy group at C-11 and therefore, to assign the structure 13 to sphaeropsidin D. (Evidente et al., 2002). The comparison of the 1H and 13C NMR and CD data of 13 with those of 10 (Evidente et al., 1996) showed that the two sphaeropsidins have the same absolute stereochemistry at C-5, C-6, C-9, C-10 and C-13 as reported in their molecular formulae and in agreement with the NOE effects recorded in the NOESY spectrum of 13. The values measured for the coupling of H-11 with both H-12 and H-12‘ in the 1H NMR (Sternhell, 1969) allowed to locate this proton axial with a -configuration and its genimal hydroxy group equatorial with an configuration as depicted for 13 (Fig. 2). The stereochemistry assigned to C-11 was in perfect agreement with the NOE effects observed between H-11 with H-12 and H-12‘ and Me-17, and with the inspection of a Dreiding model of 13, so that Sphaeropsisin D could be formulated as 6α, 6β, 9α, 11-tetrahydroxy-7oxopimara-8(14),15-dien-20-lactone (Evidente et al., 2002). Sphaeropsidin E (14) had a molecular weight of 320 corresponding to a molecular formula of C20H32O3 and by preliminary spectroscopic investigation, it was shown to contain some structural features already observed in sphaeropsidin C (12). As already observed in 12 (Evidente et al., 1997), sphaeropsidin E showed the absence of the system due to the hemiketal lactone and the presence of a further aliphatic methylene group together with that of another methyl group. This new methyl group was probably generated by the reductive opening of the lactone ring and should be linked to the quaternary carbon C-10, as well as the methylene group H2C-6. Moreover, 14 contained more substantial differences when compared to sphaeropsidin C. It showed the absence of the trisubstituted double bond and the quaternary hydroxylated carbons while a tetrasubstituted double bond between C-7 and C-14 and two further hydroxylated secondary carbons (C-7 and C-14), were observed. Furthermore, similar to 13, sphaeropsidin E showed the hydroxylation of C-11. These hypotheses were consistent with the correlations observed in the COSY, TOCSY, HMQC, HMBC, NOESY spectra. On the basis of these results, the structure 14 of a new tricyclic pimarane diterpene was assigned to sphaeropsidin E. (Evidente et al., 2002) The stereochemistry of sphaeropsidin E was assigned using the same techniques used for 13. In fact, the comparison of the 1H and 13C NMR and CD data of 14 with those of 11 and 12 (Evidente et al., 1997; Ellestad et al., 1972) allowed to assign the absolute stereochemistry at C-5, C-10 and C-13 as reported in its structural formula and in agreement with the NOE effects observed in the NOESY spectrum. The constants measured for coupling between H-7 and H-11 with the protons of H2C-6 and H2C-12 (Sternhell, 1969), respectively in the 1H NMR allowed to locate both protons equatorial with an -configuration and their geminal hydroxy group axial with a -configuration as depicted in 14 Fig. 2. The stereochemistry

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assigned to C-7 and C-11 was in agreement with the effects observed in the NOESY spectrum and with the inspection of a Dreiding model of 14. On the basis of these results, sphaeropsidin E could be formulated as 7,11β,14α-trihydroxypimara-8(9),15-diene (Evidente et al., 2002) Sensitivity of various cypress to sphaeropsidins D and E has proved to be different. Sphaeropsidin D, when assayed at concentrations ranging from 0.1 to 0.001 mg ml-1, was toxic to C. macrocarpa and symptoms appeared on the leaves 6 days after absorption of the toxic solution (0.1 mg ml-1), with increased severity during the following week. The leaves first showed chlorosis then turned yellow-brown and finally necrosis. The other two cypress species, C. sempervirens and C. arizonica, were insensitive to sphaeropsidin D. When sphaeropsidin E was assayed at concentrations of 0.2 to 0.02 mg ml-1 on twigs of the same cypress species, no phytotoxicity was recorded. Given the findings of Frisullo et al. (1997b) who demonstrated that the artificial infection induced by the same strain of S. sapinea f. sp. cupressi caused cortical canker and dieback on seedlings of C. macrocarpa, C. sempervirens and C. arizonica, it is possible assume that the susceptibility of all three species tested did not correspond to their sensitivity to all the toxic metabolites produced by the pathogen. (Evidente et al., 2002) The two sphaeropsidins D and E (13 and 14) also appeared to belong to the unrearranged pimaranes, a group of diterpenes already known as metabolites of plants, micro-organisms and marine organisms, some of which show interesting biological activity (McCrindle and Overton, 1969; Manitto, 1981; Turner and Aldridge, 1983; Hanson, 1985). Sphaeropsidin D proved to be structurally related to sphaeropsidin A, the main phytotoxin produced by the same plant pathogenic fungus (Evidente et al., 1996) while sphaeropsidin E represents another fungal metabolite, which notably differs from the other sphaeropsidins (Evidente et al., 1996; ibidem 1997) and from the other known unrearranged pimaranes (McCrindle and Overton, 1969) due to the functionalities of the phenanthrene ring system. Successively from the same fungal culture was isolated another minor sphaeropsidn, named sphaeropsidin F (15, Fig. 2). Sphaeropsidin F (15) had a molecular weight of 336 corresponding to the molecular formula C20H32O4 and differed from sphaeropsidin E (14) due to the presence of another oxygen atom. As already observed for sphaeropsidns C and E inspection of its 1H and 13C NMR spectra revealed the absence of the hemiketal lactone system and, as found in (14), the extra presence of an aliphatic methyl group. Compound 15 differs from 12 and 14 also for an extra secondary hydroxylated carbon present in the B ring. Furthermore, sphaeropsidin F (15) did not show a secondary hydroxyl group at C-11 as already observed in 13 and 14, but the functionalisation of the A ring that is the substantial difference observed for the first time in this sub-group of unrearranged pimarane diterpenes and this was due to the presence of futher secondary hydroxy group at C-1 as ascertained by the correlations observed in the COSY, TOCSY, HSQC, HMBC and NOESY spectra. On the basis of these findings, the structure of a new tricyclic pimarane diterpene, 1,6,79-tetrahydroxypimara-8(14),15-diene, was assigned to sphaeropsidin F (15) (Evidente et al., 2003a). The stereochemistry of sphaeropsidin F was assigned by comparing its NMR and CD data with those of 11, 12 and 14. In agreement also with the coupling observed in the NOESY spectrum, we assigned the absolute stereochemistry at C-5, C-10 and C-13 was assigned as depicted in its structure 15 (Fig. 2). The coupling observed in the 1H NMR, constants between

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H-5 and H-6 and H-6 with H-7, respectively, allowed us to locate H-6 and H-7 in the axial and equatorial positions, respectively, and their geminal hydroxy group in the equatorial and axial positions on B ring, which adopts a pseudo-chair conformation (Sternhell, 1969). Similarly, the coupling constants observed between H-1 and the H-2-2 protons allowed to locate H-1 and its geminal hydroxy group in axial and equatorial positions, respectively, on the A ring, which adopts a chair conformation. The stereochemistry assigned to C-1, C-6 and C-7 was in agreement with the observed NOEs data and with the inspection of a Dreiding model of 15 and therefore, sphaeropsidin F can be formulated as the 1,6,7,9tetrahydroxyprimara-8(14),15-diene (Evidente et al., 2003a). When assayed on test plants, sphaeropsidin F caused less severe symptoms compared with those caused by sphaeropsidin A. A 0.1 mg ml-2 solution of sphaeropsidin F, tested on severed cypress twigs, caused yellowing of the apical leaves of C. sempervirens twigs whereas twigs of the other two species of cypress, C. macrocarpa and C. arizonica, were not affected. This confirms that the three cypress species had different grades of sensitivity towards the action of the toxin. As already demonstrated for rings B and C, the modification of the A ring changed the biological activity of the molecule (Evidente et al., 2003a). Sphaeropsidin F (15) which belongs to the unrearranged pimaranes, proved to be structurally related to sphaeropsidins C and E to some extent. It notably differs from the other sphaeropsidins A, B and D and from the other known unrearranged pimaranes (McCrindle and Overton, 1969) for the functionalities of the phenanthrene ring system. The occurrence of sphaeropsidin D, E and F, whether or not phytotoxic, may contributes to a better understanding if changes in the molecular structure of sphaeropsidin A might affect its biological activity on host and non-host plants and its antifungal activity on plant pathogenic micro-organisms (Evidente et al., 1996 and 1997). The understanding of the secondary metabolism of S. sapinea f. sp. cupressi could help to elucidate the taxonomic relationship between S. sapinea f. sp. cupressi and S. sapinea that has been questioned by Swart et al. (1993). It is also important to point out that the two strains of S. sapinea f. sp. cupressi which are of different origin (strain D3 from Morocco and strain 251.85/CBS from Israel) produced both sphaeropsidins D and E in addition to sphaeropsidins A, B and C and sphaeropsidones.

3.5. Structure-Activity Relationships Studies Among Sphaeropsidins and Some their Deivatives In order to get information on the structure-activity relationship of sphaeropsidins, eight derivatives (26–33, fig 5) were prepared by chemical transformation of the functionalities present in the spaheropsisins A, B and C (10–12). The aim of this work was to identify which structural features are essential for the biological activities of these compounds, in order to better understand their mechanism of action on plants, role in pathogenesis and potential antimycotic activity.

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17

O

11

OH

C 20 1 10

3

18

15

14

16

20

8

O

OH

CO2R3

CH2

CH2

10

6

O Me

OAc

R1

H Me

6

H Me

R2

7

7

5 4

Me

13

9

2

Me

Me

12

19

26

27 R1=R3=H, R2=OH 28 R1+R2=O, R3=Me

Me

O C

14 8

15

OH

C

16

CH3

CH2

9

O

Me

O

O

OAc

OH

7

Me

H Me

O

6

Me

OAc

29

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

H

H Me HO 30

Me 20

OH

CO2Me 10

8

14

21

Me

Me

H Me R1

CH2

9

CH2

10

7 6

14

HO2C

CH2

O

O

7

CHO

6

R2 Me

H Me

O

31 R1+R2=O 33 32 R1=R2=H

Figure 5. Derivatives prepared by sphearopsidin A (26, 29, 30 and 31), B (33) and C (27, 28 and 32).

In this study, the phytotoxic and antifungal activity of eight sphaeropsidin derivatives was evaluated in comparison to the sphaeropsidins A (10), B (11), C (12), D (13) and E (14). Eight key derivatives were obtained by chemical transformations of 10, 11 and 12. The structural features of 10 and those of the other naturally-occurring sphaeropsidins 11, 12, 13 and 14 provide evidence for considering the latter as naturally modified analogues of 10. In fact, spaeropsidin B (11) differs from 10 in the presence of a secondary hydroxyl group at C-7 instead of a ketone group, whereas sphaeropsidn C (12) differs in the presence of a carboxylic

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and a methylene group at C-6 and the absence of an hemiketal lactone ring at C-10. Several structural modifications were observed when sphaeropsidins D and E (13 and 14) were compared to 10. Sphaeropsidin D (13) showed the hydroxylation of C-11 as an only modification which was already observed in 14 too. In fact, 14 showed modifications at the C-ring as the hydroxylation of both C-11 and C-14, the dehydroxylation of C-9 and the double bond shift from C(8)-C(14) to C(8)-C(9). Furthermore, 14 lacked the hemiketal lactone ring, while a methylene and a methyl group were present at C-6 and C-10, respectively, as well as a secondary hydroxyl group at C-7; some of these structural modifications are already observed in 11 and in 12. By acetylation, sphaeropsidin A (10) was converted into the corresponding 6-Oacetylderivative (26, Fig. 5), which showed the modification of the hemiketal hydroxyl group at C-6 of the B-ring. 7,O-dihydrosphaeropsidin C (27, Fig. 5), was obtained by NaBH4 reduction of 12 (Evidente et al., 1996). The methyl ester of sphaeropsidin C (28, Fig. 5), was obtained by reaction of 12 with diazomethane. 6-O-acetyl-14-O-acetyloxy-9-dehydroxy-8,9derivative 29 (Fig. 5), was obtained by reaction of sphaeropsidin A (10) with the Fritz and Schenk reagent (Fritz and Schenk, 1959). This compound showed a modification of the hemiketal hydroxyl group at C-6 of the B-ring, together with the dehydroxylation of C-9 of the C-ring with the consequent shift of the double bond from C(8)-C(14) to C(8)-C(9) and the acetoxylation of the C-14. Furthermore, the catalytic hydrogenation of 10 generated its 7,O,15,16-tetrahydroderivative (30, Fig. 5), which showed the saturation of the vinyl group at C-13 and the expected reduction of the carbonyl group at C-7 into a secondary hydroxyl group. By reaction with diazomethane, 10 was converted in the methyl ester (31, Fig. 5), which showed the opening of the hemiketal lactone producing the carbonyl group at C-6 and the carboxylic group at C-10 with the latter converted into the corresponding methyl ester. Compound 31 also showed, in agreement with literature data (Ellestad et al., 1972) the formation of a cyclopropane ring between C-8 and C-14, due to the addition of the reactive methylene to the double bond previously located there. A cyclopropane ring formation was also observed in the derivative 32, obtained from sphaeropsidin C (12) by reaction with diazomethane (Evidente et al., 1997). This derivative also showed the methyl esterification of the carboxylic group present in sphaeropsidin C (12) at C-10 as already noted in 31. As far as sphaeropsidin C (12) is concerned, the two derivatives 28 and 31 lacked the hemiketal lactone ring and displayed the presence of a methylene and a carboxylic group at C-6 and C-10 (which was converted into the corresponding methyl ester), respectively. Sphaeropsidin B (11), in turn, was converted by sodium periodate oxidation into the derivative 33, which showed marked modification of the B-ring, while the other two rings (A and C) appeared practically unaltered. In particular, the derivative 33 exhibited the opening of hemiketal lactone producing a carboxylic group at C-10, and the cleavage of the C(6)-C(7) bond. The C6 was oxidized into a carboxylic group, which formed a -lactone with the hydroxyl group at C-9, while the carbonyl group at C-7 appeared as a formyl group conjugated with the C(8)C(14) double bond. These noteworthy structural modifications resulted in substantial disruption of the tricyclic pimarane system. The structures of all derivatives (26-33) obtained by chemical modifications of sphaeropsidins A, B and C (10-12) were determined by extensive use of spectroscopic methods (Sparapano et al., 2004).

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The stereochemistry of new stereogenic carbons of derivatives 27, 29, 30, 31 and 32 was deduced from the NMR spectral data (3JH,H), on the basis of mechanistic grounds, and by comparison of their spectral data (IR, UV and 1H NMR) with those already reported for sphaeropsidin B (11) (Evidente et al. 1996). Table 1. Structure of the sphaeropsidins (10-15) and their derivatives (26-33) used in this study Compound Substituents

CH=CH2 H

C(8)-C(14)

CH=CH2 H

C(8)-C(14)

1 at C-7

CH=CH2 H

C(8)-C(14)

2 at C-6 and C-10

CH=CH2 H

C(8)-C(14)

1 at C-11

H CH2

Hemiketal H lactone OH OH Hemiketal H lactone C=O OH COOH at C-H 10 C=O OH Hemiketal OH lactone OH Absent CH3 at C-10 OH

Structural modifications compared to sphaeropsidin A (10) --

CH=CH2 OH

C(8)-C(9)

15

OHOH

OH

OH

CH3 at C-10 H

CH=CH2 H

C(8)-C(14)

26

H OAc

C=O OH

H

CH=CH2 H

C(8)-C(14)

7 at C-6, C-7, C-8, C -9, C-10, C-11 and C14 4 at C-1, C-6, C-7 and C-10 1 at C-6

27

H CH2

OH

C-H

CH=CH2 H

C(8)-C(14)

28

H CH2

C=O

atH

CH=CH2 H

C(8)-C(14)

29

H OAc

C=O

30

H OH

OH

31

H C=O

C=O

32

H CH2

C=O

33

H COOR CHO

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C- C-6 1 10

H OH

11

H OH

12

H CH2

13

H OH

14

C-7

C-9

C(6)-C-10

C-11 C-13

C=O OH

Hemiketal lactone OH COOH at 10 OH COOCH3 C-10 Absent Hemiketal lactone OH Hemiketal lactone OH COOCH3 C-10 OH COOCH3 C-10 COOH at lactone 10

C-14 Double bond

H

CH=CH2 OAc C(8)-C(9)

H

CH2-CH3 H

atH atH C-H

C(8)-C(14)

CH=CH2 -CH2 Cyclopropan e CH=CH2 -CH2 Cyclopropan e CH=CH2 H C(8)-C(14)

3 at C-6, C-7 and C10 2 at C-6 and C-10 4 at C-6, C-8, C-9 and C-14 2 at C-7 and C-13 4 at C-6, C-8, C-10 and C-14 4 at C-6, C-8, C-10 and C-14 4 at C-6, C-7, C-9 and C-10

Biological results were obtained in terms of phytotoxicity of spahaeropsidins A-E (10-14) and their derivatives (26-33) (Tables 1 and 2) against three species of woody plants (cypress) and two herbaceous plants (tomato and mung bean). Sphaeropsidins A, B and C (10-12), absorbed by severed cuttings or injected into the bark of cypress plants, showed the greatest phytotoxic activity both on host and non-host plants. Sphaeropsidin D (13) was only phytotoxic to C. macrocarpa seedlings. Sphaeropsidin E (14) did not have effect on any cypress species. Sphaeropsidins A, B and C (10-12) and sphaeropsidin D (13) also affected the herbaceous plants tested, necrotic spots on leaves and tissue browning appeared on Lycopersicon esculentum and Phaseolus vulgaris. Sphaeropsidin E (14) did not affect any herbaceous plant tested. Compound 26 exhibited a phytotoxic activity similar to that given by

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10. Derivative 27 affected only C. macrocarpa and C. arizonica and was ineffective on the two herbaceous plants. Derivatives 28, 29, 30, 31, 32 and 33 were non-toxic. The four phytotoxins spahaeropsidins A-D (10-14) proved to be non-selective toxins and were able to cause symptoms both on host plants and non-host plants, this finding also proved that the three cypress species had a different tolerance to the toxins. Table 2. Symptoms caused by Sphaeropsidins A-E (10-14) and their derivatives (26-33) on test plantsa

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Compound

Host species Cupressus macrocarpa necr necr necr necr n.s. necr n.s. yel n.s. n.s. n.s. n.s. n.s. n.s.

Cupressus sempervirens brown necr necr n.s. n.s. necr n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s.

Cupressus arizonica necr yel yel n.s. n.s. brown n.s. yel n.s. n.s. n.s. n.s. n.s. n.s.

Non-host species Lycopersicon Phaseolus esculentum vulgaris necr necr necr necr necr necr necr brown n.s. n.s. necr necr n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s.

10 11 12 13 14 26 27 28 29 30 31 22 33 Control (water) a Severed shoots of three cypress species and cuttings of herbaceous test plants were left to take up a 3 ml assay solution (100 g ml-1) for 96 h and 48 h, respectively. Symptoms developed within 2, 4 and 21 days on tomato, mung bean and cypress, respectively: brown = tissue browning; necr = leaf necrosis; yel = yellowing of the whole cutting; n.s. = no symptoms.

The degree of phytotoxicity elicited by each compound permitted us to establish some structure-activity relationships as well as to identify the structural features responsible for the biological activity (Tables 1 and 2). The reduction of the carbonyl group at C-7 to a secondary hydroxyl group (11) and the semi-reductive opening of the hemiketal lactone ring (12), did not reduce the bioactivity of these sphaeropsidins. The hydroxylation of C-11 (13) led to partial loss of activity. The dehydroxylation of C-9, which induces the shift of the double bond from C(8)-C(14) to C(8)-C(9) and the hydroxylation of C-14 of the C-ring (14), caused the loss of bioactivity. The acetylation of the hemiketal group at C-6 of the B-ring in 26 preserved its bioactivity whereas the reduction of the carbonyl group at C-7 into a secondary hydroxyl group (27) caused a complete loss of activity. This my be due to a synergistic effect with the other structural modifications already present in this latter derivative with respect to 10. The dehydroxylation of C-9 of the C-ring, and the acetoxylation of C-14 together with concomitant acetylation of the hemiketal group at C-6 of the B-ring, caused the complete loss of activity for 29. Furthermore, a complete loss of activity was observed for the saturation of the vinyl group at C-13 (30) or for the conversion of the C(8)C(14) double bond into the corresponding cyclopropane ring observed in 31, together with the

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Phytotoxins Produced by Fungi Responsible for Forestall Plant Diseases .

opening of the hemiketal lactone ring and the consequent methyl esterification of the carboxylic group at C-10. The same structural modification was probably responsible for lacking of toxicity in compound 33. Finally, it is interesting to note that modification in the B-ring converted in a -lactone resulting in a substantial disruption of the tricyclic pimarane system (derivative 33) strongly reduced activity, suggesting that the perhydrophenanthrene arrangement of the carbon skeleton is essential for toxicity (Sparapano et al., 2004). Table 3. Sensitivity to sphaeropsidins A-E (10-14) and their derivatives (26-33) assayed at 100 g ml-1 on eight plant pathogenic fungi grown on PDA medium at 25 °C, in the darka. Compound Fungal species Botrytis Fusarium cinerea oxysporum 56.7 28.2 10 (48.85) (32.08) 62.4 30.2 11 (52.18) (33.34) 38.4 27.8 12 (38.29) (31.82) 21.4 18.7 13 (27.56) (25.62) n.i. n.i. 14 26 27 28

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29 30 31 32 33 a

12.5 (20.70) 15.5 (23.19) 10.5 (18.91) 12.5 (20.70) 7.5 (15.89) 10.5 (18.91) 4.5 (12.25) 8.3 (16.74)

20.0 (26.56) 10.0 (18.44) 5.0 (12.92) 3.3 (10.47) 3.5 (10.78) 6.7 (15.00) 8.3 (16.74) 13.3 (21.39)

Penicillium Verticilliu Phomopsis expansum m dahliae amygdali 41.2 28.7 77.0 (39.93) (32.39) (61.34) 38.5 30.2 63.5 (38.35) (33.34) (52.8) 34.2 26.8 41.7 (35.85) (31.18) (40.2) 15.2 12.5 29.7 (22.95) (20.70) (33.02) n.i. n.i. 12.5 (20.70) n.i. 24.6 14.7 (29.73) (22.55) n.i. 26.1 17.6 (30.72) (24.80) n.i. 17.4 21.6 (24.65) (27.69) n.i. 17.4 n.i. (24.75) n.i. 34.8 9.8 (38.53) (18.24) n.i. 24.6 14.7 (29.73) (22.55) n.i. 15.9 15.7 (23.50) (23.34) n.i. 24.6 18.6 (29.73) (25.55)

Seiridium cardinale 54.1 (47.35) 41.3 (39.99) 39.4 (38.88) 3.7 (11.09) 7.4 (15.79) 66.7 (24.76) 29.6 (32.96) 7.4 (15.79) 14.8 (22.63) 11.1 (19.46) 3.7 (11.09) n.i.

Seiridium cupressi 59.9 (50.71) 38.3 (38.23) 42.4 (40.63) n.i.

22.2 (28.11)

30.0 (33.21)

5.0 (12.92) 50.0 (45.00) 25.0 (30.00) n.i. 20.0 (26.56) 30.0 (33.21) 35.0 (36.27) n.i

Seiridium unicorne 52.4 46.38) 40.8 (39.70) 38.7 (38.47) 56.8 (48.91) 18.9 (25.77) 13.5 (21.56) 45.9 (42.65) 24.3 (29.53) 22.5 (28.32) 8.1 (16.54) 29.7 (33.02) 21.6 (27.69) 0.9 (5.44)

L.S.D. (P = 0.05) (9.7) (11.2) (8.6) (12.1) (7.5) (10.5) (9.2) (8.2) (7.2) (7.0) (9.8) (6.7) (8.7)

The antifungal effect of toxins and their derivatives was evaluated by calculating the percentage of linear growth inhibition as 100 (y - x)/y where y = mean colony diameter of toxin-free cultures and x = mean colony diameter of toxin-containing cultures, 1-2 weeks after inoculation. Experiments were repeated twice with five plates per species per toxic solution. The figures are the means of ten replicates. Angular transformations of percentage data are shown in parentheses. L.S.D. = least significative difference; n.i.: no growth inhibition.

The antimycotic activity of sphaeropsidins A-E (10-14) and their derivatives (26–33) was assessed on eight fungal species (Table 3). Phomopsis amygdali proved to be more sensitive to 10 than any other fungi tested, whereas Fusarium oxysporum and Verticillium dahliae appeared to be less sensitive to these toxins. The fungi most sensitive to 11 were P. amygdali and Botrytis cinerea and the least sensitive ones were F. oxysporum and V. dahliae. Sphaeropsidin C (12) appeared to be less active than 11 whereras compound 13 exhibited the highest level of antifungal activity against S. unicorne and a moderate or low fungistatic

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activity against the other seven tested fungal species. Sphaeropsidin E (14) was ineffective on B. cinerea, F. oxysporum, Penicillium expansum and V. dahliae, but it had a moderate effect on P. amygdali and the three species of Seiridium. The antifungal activity of all derivatives referred to all tested fungi was lower than that shown by sphaeropsidins A-D (10-13). P. expansum was not affected by any sphaeropsidin derivative. The acetylation of the hemiketal group at C-6 of the B-ring made for 26 partly preserved its bioactivity; in addition, 26 showed the highest level of antimycotic activity against S. cardinale. The reduction of the carbonyl group at C-7 into a secondary hydroxy group, in 27, caused a remarkable decrease in growth inhibition of the seven fungi except S. unicorne which was more sensitive to this compound. The esterification of sphaeropsidin C into derivative 28 greatly reduced antifungal activity whereas for 29, the dehydroxylation of C-9 and the acetoxylation of C-14 induced a further reduction of bioactivity. Furthermore, the saturation of the vinyl group at C-13 shown by 30 caused a reduction of activity except for V. dahliae whose sensitivity was greater than that shown by sphaeropsidins A-D (10-13) on the same fungus. In 31, the conversion of the C(8)-C(14) double bond into the corresponding cyclopropane ring, elicited low values of growth inhibition vs. S. cardinale, F. oxysporum, B. cinerea, and P. amygdali except those referred to the sensitivity of V. dahliae, S. cupressi and S. unicorne. The same chemical modification present in the compound 32 led either to a partial loss of activity vs. B. cinerea, F. oxysporum, V. dahliae and P. amygdali or even to complete one vs. P. expansum, S. cardinale and S. cupressi. Finally, it is interesting to note that modification in the B-ring converted in a -lactone resulting in a substantial disruption of the tricyclic pimarane system greatly reduced the activity of derivative 33 vs. P. expansum, S. unicorne, and B. cinerea, whereas a moderate reduction of growth inhibition was assessed vs. F. oxysporum, P. amygdali, V. dahliae, S. cardinale and S. cupressi (Sparapano et al., 2004). The antimycotic activity of sphaeropsidins A-E (10-14) may help in the saprophytic survival of sphaeropsidin-producing fungi in their natural habitat, or when they live as parasites within plant tissues. If sphaeropsidins A-E were really produced in planta by the fungus, it is possible postulate that infective growth of S. sapinea f. sp. cupressi along the stem or branches of cypress may prevent the concomitant invasion of the bark by S. cardinale, S. cupressi and S. unicorne. Actually, the fungistatic activity of 10-14 against the Seiridium species infecting cypress can support a possible antagonistic action of S. sapinea f. sp. cupressi and this result could be applied to prevent early infections of Seiridium canker disease of cypress. On the basis of the results of this study, it can be inferred that the toxicity of 10, 11, 12 and 13 was associated with the presence of the double bond between C-8 and C-14 and probably also with that of the tertiary hydroxyl group at C-9. The sphaeropsidins 11, 12 and 13, structurally related to 10, retained these features while sphaeropsidin E (14), which lacks these structural features, did not. Moreover, 14 also differed from the other sphaeropsidins in the reduction of the carboxylic group at C-10 to a methyl group (Me-20). Derivatization of sphaeropsidins produced compounds lacking phytotoxic activity and with reduced antifungal activity. Modifications in the vinyl group at C-13 or in the tricyclic pimarane system, particularly in the C-ring, also reduced bioactivity, suggesting that both C-ring functionalities and spatial conformation are essential for activity(Sparapano et al., 2004). Furthermore, the biological activity described previously of sphaeropsidin F (15), sucessively isolated from the culture filtrates of S. sapinea f. sp. cupressi confirmed these results and also reflected an important role of ring A. When tested on cypress severed twigs, it

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caused yellowing of the apical leaves of C. sempervirens twigs, whereas C. macrocarpa and C. arizonica were not affected. Sphaeropsidin F, which in part structurally related to sphaeropsidins C and E, retained structural features important for the activity. It differed from the other two sphaeropsidins due to the presence of the hydroxy group at C-1 of the A ring, this modification changed the biological acivity of the molecule (Evidente et al., 2003a). Concerning the phytotoxic and antifungal behaviour of sphaeropsidins A-E (10-14)and their derivatives (26–33), it can be speculated that the integrity of the tricyclic pimarane system, the preservation of the double bond from C(8)-C(14), the tertiary hydroxyl group at C-9, the vinyl group at C-13, the carboxylic group at C-10 and integrity of the A ring endow these molecules with phytotoxicity to host and non-host plants and with activity against certain plant pathogenic fungi (Sparapano et al., 2004).

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3.6. Other Sphaeropsisones from Sphaeropsis Sapinea f. sp. cupressi Besides the six sphaeropsidins A-F (10-15), sphaeropsidone and epi-sphaeropsidone (16 and 17) identified in the crude oily residue obtained by extraction of the culture filtrates of S. sapinea f. sp. cupressi, other two more polar metabolites (18 and 19, Fig. 3) were isolated. The preliminary spectroscopic investigation on the last two metabolites 18 and 19, obtained as oily homogeneous compounds, revealed that their structures were closely related to those of the sphaeropsidones. On the basis of the spectroscopic data shown below they were therefore named chlorosphaeropsidone and epi-chlorosphaeropsidone (18 and 19). Chlorosphaeropsidone (18) had a molecular formula of C7H9ClO4 as deduced from the HR FAB and EIMS. Its IR spectrum showed bands characteristic of the hydroxy groups, of a carbonyl group and of the olefinic group of a vinylogous ester. This last structural feature was consistent with the absorption maximum observed in the UV spectrum, which was characteristic of -methoxy--unsaturated cyclohexenone. The 1H and the 13C NMR spectra resembled those of sphaeropsidone (Evidente et al., 1998), but with some marked differences as the absence of signals due to the oxirane ring, while the presence of a glycol system between C-4 and C-5 and a secondary chlorinated carbon (C-6) was noted. This partial structure were confirmed by the analysis of COSY, HSQC and HMBC spectra. Moreover, the glycol system proved to be cis since H-5 and H-6 were both axial-oriented, as indicated by their typical coupling constant and consequently H-4 was equatorial-orientated, based on its coupling with H-5 (Sternhell, 1969; Pretsch et al., 1983). The chlorine atom proved to be trans-oriented with respect to the hydroxy group at C-5, the latter being equatorial-oriented. This structure was confirmed by acetylation carried out under standard conditions with pyridine and acetic anhydride, which yielded the corresponding 4,5-O,O'-diacetyl derivative 20 (Fig. 3) and the aromatized product 22 (Fig. 3). The presence of a cis-glycol system in 18 was confirmed by preparing the corresponding isopropylidene derivative (23, Fig. 3). This later was prepared by acid catalyzed reaction of chlorosphaeropsidone with 2,2dimethoxypropane. These data indicate that compound 18 had a chemical structure of 6-chloro-4,5dihydroxy-3-methoxycyclohex-2-en-1-one (Evidente et al., 2000). The structure and the relative stereochemistry of 18 was confirmed by X-ray analysis, as shown in Fig. 6. The molecular fragment consisted of the atom sequence O(1)-C(1)-C(2)C(3)-C(4) and the methoxy group O(2)-C(7) was planar within 0.04 Å. The six-membered

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ring exhibited a half-chair conformation. The absolute stereochemistry of chlorosphaeropsidone (18) was deduced by circular dichroism measurement. Its CD spectrum showed a clear positive Cotton effect at 248 nm which was also observed with sphaeropsidone (Evidente et al., 1998) and other related 5-hydroxy-7-oxabicyclo[4.1.0]hept3-en-2-ones (Nagasawa et al., 1978), indicating a -configuration for the 4-hydroxy group. This finding, together with and the NMR and X-ray data, made it possible to assign the absolute configuration as depicted in 18 which was designated as 6(S)-chloro-4(S),5(R)dihydroxy-3-methoxycyclohex-2-en-1-one. As deduced from the spectroscopic data (EI-MS and NMR), epi-chlorosphaeropsidone (19) had the same molecular formula of C7H9ClO4, as chlorosphaeropsidone, and gave IR, UV, 1H and 13C NMR and EI-MS data very similar to those of 18, indicating that 18 and 19 were isomers. These two compounds (18 and 19) showed different optical rotations and different chromatographic behaviours in different systems. Therefore, it was possible to hypothesize that 19 was a diastereomer of 18. Comparison of the 1H NMR spectra of 18 and 19 suggested that 19 was the C-6 epimer of 18, and this is in agreement with the CD spectra. Epichlorosphaeropsidone 19 showed the expected positive Cotton effect at 260 nm and different behaviour at a higher wavelength without any definite effect.

Figure 6. Perspective view of chlorosphaeropsidone (18). Relevant bond lengths (Å) and angles (°) are as follows : C(1)-C(2) 1.430(6), C(2)-C(3) 1.340(6), C(3)-C(4) 1.506(5), C(4)-C(5) 1.504(6), C(5)-C(6) 1.515(6), C(6)-C(1) 1.514(5), C(2)-C(1)-C(6) 116.(4), C(1)-C(2)-C(3) 121.9(3), C(2)-C(3)-C(4) 123.2(4), C(3)-C(4)-C(5) 110.7(3), C(4)-C(5)-C(6) 110.1(3), C(5)-C(6)-C(1) 110.8(4).

This structure was further confirmed by converting chlorosphaeropsidone (18) into 19 by enolization in aqueous sodium bicarbonate. The reaction was carried out on 18 in the conditions stated to convert 6(S)-chloro-4(R),5(R)-dihydro-2-hydroxymethylcyclohex-2-en-1one into the corresponding 6-epimer. These are two metabolites structurally related to 18 and 19 and isolated from culture filtrate of Phyllostica sp. (Sakamura et al., 1975). In this reaction, 18 in part remained unchanged and in part converted into 19 and into sphaeropsidone (16). The probable mechanism of these two convertions is shown in Fig. 7.

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Phytotoxins Produced by Fungi Responsible for Forestall Plant Diseases

The formation of sphaeropsidone confirmed the stereostructure of 18 as well as that of 19, which can be designated as 6(R)-chloro-4(S),5(R)-dihydroxy-3-methoxycyclohex-2-en-1-one. The interchange between 18 and 19 was also observed when both metabolites were TLCanalysed and may be due to the acidity of the silica gel and to H2O traces present in the solvent used. Furthermore, a comparison of the 1H NMR data of 18 and 19 with those obtained under the same experimental conditions for trans-bromohydrin (21) (unpublished data), showed very different values for the constant of coupling between H-5 and H-6. The derivative 21 was prepared from sphaeropsidone by nucleophilic substitution with lithium tetrabromonickelate (II), which is a source of ―soft‖ nucleophilic bromide and reacts regioselectively with epoxides to give bromohydrins in high yields (Dawe et al., 1984). In trans-bromohydrin the bromo and the hydroxy residues, attached to the C-6 and the C-5 respectively, assumed an axial-orientation and therefore the value typical for an equatorialequatorial coupling, was observed between H-5 and H-6 (Sternhell, 1969), whereas in 18 and 19 the same coupling yielded values typical for an axial-axial and axial-equatorial orientation respectively (Sternhell, 1969). The relative stereochemistry thus deduced for 18 was in full agreement with that obtained by X-ray analysis as shown in Fig. 6. Moreover, the values observed for the coupling between H-4 and H-5 in 18, 19 and 21, indicated that the latter proton assumed an axial-orientation in 18 and 19 and an equatorial-orientation in bromohydrin (21). Consequently the geminal hydroxy group at C-4 always had a configuration and this was also in agreement with the Cotton effect observed in the CD spectra of 18 and 19. (Evidente et al., 2000). OH

H H3CO 3

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2

OH

5

OH-

OH

H H

H3CO

4

1

OH

H H

OH

OH-

H

H3CO

OH

6

6

Cl

6

1

Cl

H

1

H

Cl

O

OH

O

19

18 OH-

OH

H

H

H3CO 4 3

5 6 2

O

1 H

O

16

Figure 7. Alkaline conversion of chlorosphaeropsidone (18) into epi-chlorosphaeropsidone (19) and sphaeropsidone (16).

When assayed on three species of Cupressus host (C. sempervirens, C. macrocarpa and C. arizonica) and on non-host (tomato), the two chlorosphaeropsidones (18 and 19) showed Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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no singficant phytotoxicity in contrast with the marked symptoms induced by sphaeropsidone and epi-sphaeropsidone (16 and 17) (Fig. 3). The generation of artifacted molecules could easily occur during the extraction, purification and even chemical characterization of metabolites of microbial origin. It has, for example, been observed in the case of some 6-choloro-4,5-dihydroxycyclohex-2-en-1-ones closely related to the compounds that are the subject of this review (Sakamura et al., 1975). The suspicion that 18 and 19 are artefacts generated by sphaeropsidone could therefore not be excluded. However, the data obtained strongly suggested that 18 and/or 19 were fungal metabolites probably generated from sphaeropsidone by an enzymatic opening of the epoxy ring. In that case the other diastereomeric dimedone methyl ether would also be formed by alkaline enolization as depicted in Fig. 7. The natural origin of 18 and 19 was also supported by the fact that the fungal culture filtrate lacked chlorosphaeropsidones which could have been generated from epi-sphaeropsidone (17). As for sphaeropsidone, the dimedone methyl ether nature of these two new fungal metabolites (1 and 2) as well as their absolute stereochemistry thus appear to have been demonstrated. They contain a carbon skeleton also found in other closely related fungal metabolites (Miller, 1968; Sakamura et al., 1975; Nagasawa et al., 1978; Fex and Wickberg, 1981; Turner and Aldridge, 1983; Evidente et al., 1998). The lack of phytotoxic activity by the two metabolites is probably due to the opening of the epoxy ring since it is well known that the epoxy ring is an important structural feature for the biological activity of those fungal metabolites that contain this ring such as some cytochalasins and trichothecens (Cole and Cox, 1981; Vurro et al., 1997). Therefore, an investigation into the structure-activity relationships of the sphaeropsidones and their derivatives, including the two chlorosphaeropsidones (18 and 19) and trans-bromohydrin (21) could be a necessary step supporting the above reported observations. A possible effect of 18 and 19 in synergy with or in addition to phytotoxic sphaeropsidines and sphaeropsidons which are metabolites produced by the same fungal pathogen should also be investigated. S. sapinea f. sp. cupressi appears to be a good example of a phytopathogenic fungus which produces a number of toxins belonging to different families of natural products. This has already been observed for Seiridium spp., which also infect cypress (Evidente and Motta, 2001).

3.7. Sapinopiridione, a New 3, 3, 6-Trisubstituted-2, 4-Pyridione Isolated from Sphaeropsis Sapinea Isolated from Infected Cypress Tree As above cited (paragraph 2.1.3) the production and identification of secondary metabolites produced by three strains of S. sapinea, isolated from infected cypress trees , was studied. The two main metabolites, named sapinofuranones A and B (24 and 25, Fig. 4) were characterised as two epimeric 2(3H)-dihydrofuranones and proved to be phytotoxic on non host plants such as tomato and on host plants as cypress and pine (Evidente et al., 1999). As expected, the two sapinofuranones were chemically different from the phytotoxins (sphaeropsidins A-F and sphaeropsidones) produced in vitro by S. sapinea f. sp. cupressi and D. mutila isolated from the same cypress plants colonized by S. sapinea strains and responsible of a different form of cypress canker (Frisullo et al., 1997; Sparapano et al., 2004).

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The crude organic extract of culture filtrates of all three strains of S. sapinea (D-50, D-54 and D-55) was further purified obtaining another phytotoxic metabolite as white needles. The preliminary spectroscopic investigation (1H and 13C NMR and MS) proved that this latter substantially differed from sapinofuranones and on the basis of the structural characteristics, decribed below, it was named sapinopyridione (34, Fig 8). Sapinopyridione had a molecular formula of C12H15NO4, corresponding to six degrees of unsaturation, and the molecular weight of 237 as measured by HR EI mass spectrometry. The investigation of its 1H NMR spectrum showed a broad singlet a typical chemical shift value of a lactam proton. The extensive 1H and 13C NMR investigation by COSY, TOCSY and HSQC spectra suggested the presence of a 3,3,6-trisubstituted-2,4-pyridione in 34, with the 3side chain including a saturated ketone and an oxgen group. These moiety agreed with the typical bands for saturated ketones and - and -pyridones observed in the IR spectrum (Nakanishi and Solomon, 1977) as well as with the absorption maximum exhibited in the UV spectrum, and in agreement with those reported for 4-hydroxy-2-pyridone derivatives (Scott, 1964). The C-3 is a spiro-carbon that belongs to both the 2,4-pyridione and the oxiran ring, whose second C-atom (C-2) is substituted by a 2-methyl-1-oxobutyl side chain as showed by the signal pattern typical observed in the above cited NMR (COSY, TOCSY and HSQC) spectra (Evidente et al., 2006a). 13

CH3 R2 O

12

10

R1 9

OH

CH3 11

R

2

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7

14

H3C

6

5

4 3

8 3 4

O1

5

N H

6

13

H3C

2 1

O

N H

O 7

8

9

12

10

11

34 R1+R2=O

36 R=OCH2COCH(CH3)CH2CH3

35 R1=H, R2=OH

37 R=CH(OH)COCH(CH3)CH2CH3

Figure 8. Structure of sapinopyridione (34) and its derivatives (35-37).

On the basis of data as above mentioned and fully discussed, the structure of a 3,3,6trisubstituted-2,4-pyridione was assigned to sapinopyridione that can be formulated as the 6methyl-2-(2-methyl-1-oxobutyl)-1-oxa-5-azaspiro[2.5]oct-6-ene-4,8-dione (34, Fig. 8). The structure of the toxin is closely related to the toxin produced by an unidentified species of the genus Macrophoma causing the fruit rot of apple, a disease frequently observed in orchards of northern Japan. This host-selective toxin named FRT-A, whose structure and absolute configuration was first determined by Sassa (1983), was isolated together with the side-chain isomer flavipucine (Sassa and Onuma, 1983). The latter is a well known antibiotic previously isolated from a strain of Aspergillus flaviceps, whose stereo-structural

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characterisation was extensively studied also through the synthesis and analysis by X-ray (Findlay and Radics, 1972; Findlay and Kwan, 1972; Peter et al., 1978; Girotra and Wendler, 1979). However, when the optical rotation of the sapinopyridione was compared with that of FRT-A measured in the same conditions, it appeared quite identical in the value but with opposite sign. This result suggests that the two toxins are enantiomers. This opinion is supported by the fact that other spectroscopic properties are very similar (Sassa, 1983; Sassa and Onuma, 1983). In fact, sapinopyridione showed IR, UV and 1H and 13C NMR data very similar to that of FRT-A as the little observed differences are due to the different solvent and the more high resolution used in recording the UV and 1H NMR spectra, respectively. Also the mass spectral data including the diagnostic fragmentation peaks are very similar. The absolute configuration of FRT-A toxin was determined by chemical degradation and conformational analysis of its partially reduced derivative at C-1 of the 2-methyloxobutyl side chain. The configuration of the heterocyclic ring of this reduced derivative was deduced by NMR data and confirmed by X-ray crystallographic analysis of synthetic (±)-flavipucine (White et al., 1978), while the absolute configuration of the oxiran ring was assigned on the basis of CD data (Sassa, 1983). This stereochemistry is the same in FRT-A, while the absolute configuration of the chiral carbon C-2 of the 2-methyloxobutyl was assigned by chemical degradation (Sassa, 1983). Therefore, the absolute configuration assigned to the FRT-A toxin is 2S,3S,10S (Sassa, 1983). The comparison of the spectroscopic data of the reduced sapinopyridione derivative (35), described below, with those of the analogue FRT-A derivative, which appeared to be similar but not inversely, showed they are two diastereomers. This result confirm the entaiomeric nature of the two original toxins. Consequently, the absolute configuration of sapynopyridione is 2R,3R,10R (Evidente et al., 2006a) The sapinopyridione, the FRT-A toxin and the flavipucine are the only examples of substituted 2,4-pyridione as naturally occurring compounds. In fact, the 2,4-pyridiones more frequently reported are synthetic hypnotic drugs, which are object of several investigations on their action and metabolism in human and animal cells (Rudy and Senkowski, 1973; Baumeler and Dibach, 1976; Borchert et al., 1982) . S. sapinea strains differed in their yield of toxin produced (Table 4). Strain D-50 isolated from C. macrocarpa resulted the greatest producer of sapinofuranones A and B (Evidente et al., 1999) and intermediate producer of sapinopyridione (34). Inversely, D-55, isolated from C. sempervirens,was the greatest producer of 34 and the lowest producer of sapinofuranones A and B. The second strain D-54 isolated from C. sempervirens resulted to be the lowest producer of 34 and intermediate producer of sapinofuranones A and B. These findings suggest that there is a gradient of toxin production among the strains of S. sapinea isolated from both infected cypress species. If we consider the toxins produced and their concentrations as virulence factors of the pathogen, it is also conceivable to assume the existence of virulent (more toxigenic) and hypovirulent (less toxigenic) strains of S. sapinea in the population spread over the host plants. These secondary metabolites produced by S. sapinea may be implicated in pathogenesis and disease susceptibility.

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Table 4. Production of sapinopyridione (34) in liquid cultures of three strains of Sphaeropsis sapinea isolated from Cupressus macrocarpa (D-50) or C. sempervirens (D-54 and D-55) a. Culture Final Mat dry wt Crude extracts Sapinopyridione (1) filtrates (l) pH (g l-1) (mg l-1) production (mg l-1) D-50 6.4 6.1 ( 0.1) 10.9 ( 0.6) 384.4 ( 18.1) 5.4(1.1) D-54 7 6.3 ( 0.1) 12.6 ( 2.8) 267.2 ( 25.11) 1.1(0.5) D-55 14 6.8 ( 0.1) 7.8 ( 0.1) 651.6 ( 12.2) 12.3(5.5) a Each fungal strain was grown as previously reported in detail (Evidente et a., 1999). Figures are the means ± S.D.

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Strain

Furthermore, in order to confirm these findings and to carry out a structure-relationship study on the sapinopyridione, three key derivatives were prepared starting from the original toxin. The goal of this research was to prepare derivatives with modifcation in the side chain and the pyridione ring. By NaBH4 reduction, compound 34 was converted into the 9-hydroxyderivative (35, Fig. 8): 6-methyl-2-(1-hydroxy-2-methylbutyl)-1-oxa-5-azaspiro[2.5]oct-6-ene-4,8-dione. The reaction was carried out as reported by Sassa (1983) for the reduction of FRT-A toxin resulted to be stereoselective and yielded, as the main product, a diastereomer of the dihydroFRT-A toxin. As expected, some spectroscopic properties of the reduced derivative of 34 (35) were very similar (IR, and MS) to those of the analogue dihydroderivative of the FRT-A toxin but quite different for the UV, CD and partially reported 1H-NMR data (Sassa, 1983). The toxin 34 was converted by catalytic hydrogenation into the two corresponding 3substituted 4-hydroxy-6-methyl-2-pyridones (36 and 37, Fig. 8): 3-O-(3-methyl-2-oxo) pentyl-4-hydroxy-6-methyl-2-pyridone and the 3-(1-hydroxy-3-methyl-2-oxo) pentyl-4hydroxy-6-methyl-2-pyridone. The two dihydroderivatives showed the same molecular ion the EIMS spectrum and fragmentation peak deriving from mechanism similar to those observed in 34. When compared to that of 34, the IR spectra of 36 and 37 showed the significant presence of bands due to hydroxy groups, while the UV spectra were quite similar. However, the most significant differences were observed when the 1H and 13C NMR spectra of 36 and 37 were compared to those of 34 which were consistent with the two different reductive opening mechanisms of the oxyran ring. These generated 3-oxo- and 1-hydroxy-2oxo-side chain, respectively attached to C-2. The phytotoxic and antimycotic activity of the three sapinopyridione derivatives (3537), were evaluated in comparison to sapinopyridione (34). Biological results in terms of phytotoxicity of 34 and 3537 against three cypress species are reported in Table 5. The greatest phytotoxic activity was recorded on twigs of C. macrocarpa and C. sempervirens. Dieback was observed testing a solution containing compound 34 at 100 g ml-1; the same compound was moderately toxic to C. arizonica. Derivatives 35, 36 and 37 were practically ineffective. The degree of phytotoxicity elicited by each compound allowed us to ascertain some structure-activity relationships as well as to determine the structural features important for each of the bioactivite compounds. Results of phytotoxicity tests on Cupressus species were dissimilar and it might be possible to

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use sapinofuranones and sapinopyridione for rapid screening of conifer sensitivity/tolerance for relative pathogenicity of Sphaeropsis sapinea. Table 5. Symptoms caused by sapinopyridione (34) and its derivatives (35-37) on test plantsa Cypress species Concentration Cupressus arizonica (g ml-1) 50 None 34 100 Yellowing 50 None 35 100 None 50 None 36 100 None 50 None 37 100 None a Symptoms developed on severed twigs within 14 days Compound

Cupressus macrocarpa Yellowing Dieback None Yellowing None Yellowing None None

Cupressus sempervirens Yellowing Dieback None Yellowing None Yellowing None Yellowing

Table 6. Sensitivity to sapinopyridione (34) and its derivatives (35-37) on three plant pathogenic fungia

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Compound

Concentration (g ml-1)

Fungal species L.S.D. Seiridium Seiridium Seiridium (P0.05) cardinale cupressi unicorne 10 12.0 (20.27) 13.3 (21.39) 15.6 (23.26) (5.4) 34 100 17.3 (24.58) 35.0 (36.27) 40.0 (39.23) (12.7) 10 8.0 (16.43) 8.3 (16.74) n.i. (3.5) 35 100 14.7 (22.55) 16.7 (24.12) n.i. (4.7) 10 13.3 (21.39) 5.0 (12.92) n.i. (5.8) 36 100 16.0 (23.58) n.i. 15.6 (23.26) (7.8) 10 5.3 (13.31) n.i. 6.7 (15.00) (4.2) 37 100 14.7 (22.55) 16.6 (24.04) 42.2 (40.51) (12.3) a The measured values (linear growth inhibition) are the mean of ten replicates. Angular transformation of percentage data and L.S.D. (least significative difference) are shown in parentheses. n.i.: no growth inhibition

The antimycotic activity of sapinopyridione (34) and its derivatives (35-36) was assayed on three fungal species belonging to the genus Seiridium, which are pathogens destructive to cypress (Table 6). Statistical analysis of the data allowed to compare the sensitivity of each fungal species to the toxin and its derivatives. S. unicorne proved to be more sensitive to 34 but S. cardinale was quite tolerant whereas derivative 35 was ineffective against S. unicorne and moderately toxic to S. cardinale and S. cupressi. At at all concentrations, derivative 36 elicited no inhibition when tested against S. cupressi. Only at a 10-fold higher concentration, it caused a moderate reduction of growth of both S. cardinale and S. unicorne. Finally, derivative 37 was either not effective vs. S. cupressi or weakly active vs. S. cardinale and S. unicorne when assayed at low concentration. When it was assayed at a 10-fold higher concentration, a remarkable increase of growth inhibition of S. unicorne was observed whereas S. cardinale and S. cupressi were less affected. Among the three Seiridium species,

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S. unicorne proved to be the most sensitive. The sensitivity of S. unicorne to all toxic compounds tested may be explained in terms of its pathogenicity and virulence characteristics which are weaker than those elicited by S. cupressi and S. cardinale on cypress trees. (Evidente et al., 2006a) Sapinopyridione contains a 2,4-pyridione and an epoxy ring. Pyrones, related to pyridiones, and epoxy group are structural features which play an important role in the biological activity of some classes of naturaly-occurring compounds as some substituted pyrones (Evidente et al., 2003b; Altomare et. al. 2004,) sequiterpenes eremophilanes (Capasso et al., 1984), trichothecenes, verrucarins and cytochalasins (Cole and Cox, 1981; Vurro et al., 1997; Andolfi et al., 2005) and sphaeropsidones (Evidente et al., 1998). Therefore, the marked reduction or the total loss of both phytotoxic and antifungal activities of two isomeric 4-hydroxy-6-methyl-2-pyridones (36 and 37) in respect to those of 34 was not surprising that these two latter lacked the epoxy group. In derivatives 36 and 37, the epoxy group is open and converted into an ether and a secondary hydroxy group, respectively. Furhermore, in these two derivatives, the pyridione ring is converted into a 2-pyridone ring, which could be isomerized to the 2-hydroxypyridine tautomer and therefore may further contribute to the observed loss or marked decrease of activities. Finally, the reduced phytotoxic and antifungal activities showed by derivative 35, in respect to those of sapipyridione, also showed a role to impart activity of the carbonyl group present in the side chain attached at C-3 of the pyridione ring. The antimycotic activity of sapinofuranones and sapinopyridione may help the saprophytic survival of S. sapinea in its natural habitat, or it can preserve the fungus from the frequent attacks by other colonising microorganisms, pathogens or saprobes. Therefore, the production of sapinofuranones and sapinopyridione during the infection process of S. sapinea in the bark or shoots, may prevent via an antagonistic reaction, the concomitant invasion of the same host tissues by pathogens as the three Seiridium species. In addition, the compounds that act as major determinants of pathogenicity and virulence in plant pathogenic fungi, are candidate targets when specific antifungal compounds are designed because their roles are essential during the infection process and disease development. There is a great potential reservoir of biologically active substances, which are particularly suitable for interactions with biological systems.

4. FUNGI INVOLVED IN THE PINE DECLINE Pinus (the true pines) is the largest and most widespread genus, characteristic of many north temperate regions (except the plains), especially at lower altitudes, and in a few tropical regions, notably on mountain slopes. Pine decline is a disease complex resulting from the interactions of both biotic and abiotic stressors. More common than previously thought, this disease is often misdiagnosed as either little leaf disease or annosus root rot. Shortleaf pine, however, is also quite susceptible to this disease, while longleaf pine and other conifer species are less susceptible. Thus far, evidence shows that slash pine is not susceptible to the factors that result in pine decline. Affected pines expressing declining symptoms can succumb within two to three years. Pine decline usually exists with trees that are over 35 years of age, but can exist in trees as young as 12 years old. Pines will have bark beetles and Leptographium fungi

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present in deteriorating roots. Saprogenic fungi are distinguished in part by their inability to cause disease in healthy hosts, and relatively high ability to kill or accelerate the decline of stressed hosts (Langstrom et al., 2001). Infected primary roots will have blue-stain and resinsoaked lesions caused by the Leptographium fungi (L. truncatum, L. procerum, L. terebrantis, L. serpens, and L. huntii). This group of fungi is present in the roots because of their association with the various root-feeding bark beetles (Hylastes salebrosus, H. tenuis, H. porculus, H. opacus, Pachylobius picivorus, Hylobius pales, and Dendroctonus terebrans). Just like their above-ground counterparts, these root-feeding insects will act as vector of the Leptographium fungi or create wounds in the roots that will allow the fungi to enter. Beyond the lesions, the fine roots are either damaged or significantly reduced in number (Langstrom et al., 2001).

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4.1. Phytotoxins Produced by Sphaeropsis Sapinea Involved in Pine Decline In 1998 and 1999 Sphaeropsis sapinea was repeatedly isolated in Sardinia from symptomatic samples taken in the upper part of declining Pinus radiata plants. Observed symptoms mainly consisted of foliage chlorosis, drying of needles and cankers on branches. Following these observations, a monitoring program for Pinus spp. plantations in Sardinia, was started. Fungi in the genus Sphaeropsis Sacc. are well-known for the in vitro production of different biologically active metabolites. As above reported, several studies were carried out to investigate the phytopathogenic properties of S. sapinea f. sp. cupressi in many Cupressus L. species as well as those of different strains of S. sapinea isolated from infected cypress tree in Italy. The phytotoxic metabolites characterised belonged to various chemical families as sphaeropsidins and sphaeropsidones. Previous papers confirmed that there are great differences in the morphological characteristics (Swart et al., 1993), pathogenic behaviour (Swart et al., 1993; Linde and Kemp, 1997; Xenopoulos and Tsopelas, 2000), isoenzyme profile (Swart et al., 1993) and RAPD profile markers (Stanoz et al., 1998) between S. sapinea and S. sapinea f. sp. cupressi. Few reports on phytotoxin production by S. sapinea (Fr.:Fr.) Dyco et Sutton are present in literature. Evidente et al. (1999) described the isolation and chemical characterisation of two 5-substituted dihydrofuranones, named sapinofuranones A and B, from liquid cultures of S. sapinea isolated from Cupressus macrocarpa. This pathogen has been associated with severe diseases on a wide range of forest hosts throughout the world. It would be interesting to study the metabolites produced by an isolate of S. sapinea from Pinus radiata previously characterised using morphological, physiological and molecular technique (unpublished data). Extraction of culture filtrate with ethyl acetate gave a brown oily residue with high phytotoxic activity which when was fractionated through silica gel column chromatography, as described above, gave homogeneous fraction groups. Further purification of the active fractions produced a homogeneous amorphous compound, which was identified as (R)-(-)mellein (38, Fig. 9) by its spectroscopic and optical properties. In fact its spectral and physical data were very similar to those reported for this fungal metabolite in literature (Cole and Cox, 1981). A mixture of two compounds in 6.5:1 ratio, was also obtained, further purification of this mixture (named fraction T4) gave two further amorphous homogeneous compounds which were identified as (3R,4R)-(-) and (3R,4S)-(-)-4-hydroxymellein (39 and 40, Fig. 9) (Cabras et al., 2006), respectively, by examining their spectroscopic and optical properties.

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Their spectral and physical data were very similar to those reported in literature (Aldridge et al., 1971; Cole and Cox, 1981, and Devys and Barbier, 1992, respectively).

R1

R2 5 4

6

3

4a

2

7 8a

1

O

8

OH

O

38 R1=R2=H 39 R1=H, R2=OH 40 R1=OH,

R2=H

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Figure 9. Structure of (R)-(-)-mellein, (3R,4R)-(-)- and (3R,4S)-(-)-4-hydroxy-mellein (38, 39 and 40, respectively).

When assayed on P. radiata cuttings, the mellein solution (0.05 mg ml-1), induced symptoms on the needles 1 week after treatment, and their severity increased during the following days. The needles first showed chlorosis, then browning and finally necrosis. When a mellein solution from 0.1 to 0.01 mg ml-1 was assayed on tomato cuttings, it first induced collapse of leaves, and then wilting of the cuttings within 48 h and 4 days after treatment. The positive response in the tomato cuttings test confirms that mellein is a non- host specific phytotoxin.

Figure 10. Symptoms of subcortical injection of fraction T4, [mixture of (3R,4R)-(-) and (3R,4S)-(-)-4hydroxy-mellein in 6.5:1 ratio]: (a) longitudinal section of stem tissues showing alterations in texture; (b) Control. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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When assayed on P. radiata cuttings, fraction T4 caused chlorosis and necrosis on the needles and the symptoms appeared 12 days after treatment with 0.1 mg ml-1. On tomato cuttings, fraction T4 at 0.05 mgml-1 induced brown discoloration at the leaf margins. Eventually the affected leaves dried and the entire cutting wilted, the latter occurring from 48 h to 3 days after treatment. When injected into cortical tissues of pine seedlings, this fraction produced a brown discoloration on the bark and on the corresponding internal tissues together with a loss of texture (Fig. 10) (Cabras et al., 2006). During the assay for antifungal activity of fraction T4, the most sensitive fungal species were Colletotrichum acutatum, Sclerotium rolfsii and Botrytis cynerea with a moderate inhibition effect of the mycelial growth (up to 42%). The least sensitive species were Fusarium oxysporum. f.sp. radicis lycopersici, S. sclerotiorum, and Verticillium dahliae(Cabras et al., 2006). Mellein and 4-hydroxymellein are 3,4-dihydroisocoumarins belonging to the family of pentaketide as well as related compounds with different substitution patterns on the phenyl moiety (Garson et al., 1984). Considering their relation with the ochratoxins group, potent mycotoxins reported for the first time from Apergillus ochraceus but also produced from other fungi genus including Penicillium, they are named ochracins (Cole and Cox, 1981). Mellein is a widely distributed dihydroisocoumarin derivative in fungi (Turner and Aldridge, 1983). Its production by Aspergillus melleus (Garson et al., 1984), Cercospora taiwanensis (Camarda et al., 1976), Septoria nodorum (Devys et al, 1980), Hypoxylon spp. (Anderson and Edwards, 1983), Botryosphaeria obtuse (Venkatasubbaiah and Chilton, 1990 ; Venkatasubbaiah et al., 1991), Phoma tracheiphila (Parisi et al., 1993), Pezicula livida, Plectophomella sp., Cryptosporiopsis malicicorticis and Cryptosporiopsis sp. (Krohn et al, 1997), Microsphaeropsis sp. (Hoeller et al., 1999) and Xylaria longiana (Edwards et al., 1999) has been reported. The biological properties of mellein include: phytotoxic activity on tomato cuttings at 0.1 mg ml-1, zootoxic activity on brine shrimp (Artemia salina) at 0.2 mg ml-1 (Parisi et al, 1993), moderate antifungal activity in agar diffusion assays against Eurotium repens at the 50 g level (Hoeller et al., 1999) and weak bioactivity in agar diffusion tests against Eurotium repens, Fusarium oxysporum and Ustilago violacea at 18 mg ml-1 (Krohn et al., 1997). (3R,4R)-(-) and (3R,4S)-(-)-4-hydroxymellein (39 and 40) were contained in fraction T4 in a ratio of 6.5:1. (3R,4S)-(-)-4-hydroxymellein was previously isolated from A. ochraceus (Cole et al., 1971), C. taiwanensis (Camarda et al., 1976), Microsphaeropsis spp. (Hoeller et al., 1999) and X. longiana (Edwards et al., 1999). A moderate antifungal activity in agar diffusion assay against Ustilago violacea at the 50 g level was reported (Hoeller et al., 1999). Moreover, (3R,4R)-4-hydroxymellein has been produced by Lasiodiplodia theobromae (Aldrige et al., 1971), S. nodorum (Devys et al., 1980), A. melleus (Bartlett et al., 1981), B. obtuse (Parisi et al., 1993; Venkatasubbaiah, et al., 1991), Microsphaeropsis sp. (Krohn et al., 1997), X. longiana (Edwards et al., 1999) and Apiospora montagnei (Alfatafta et al. 1994). This hydroxymellein was active in toxicity bioassays on apple and weed leaves (Parisi et al., 1993). It also showed a moderate antifungal activity in agar diffusion assays against Eurotium repens and U. violacea at the 50 g level (Hoeller et al., 1999). Tomato cuttings and pine seedlings, treated with 0.1 mgml-1 solutions of pure (3R,4R)-(-) and (3R,4S)-(-)-4hydroxymellein, presented no symptoms. The results of bioassays showed that the phytotoxic activity of fraction T4 could be due to a synergism between the two metabolites. The assays of

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antifungal activity also confirmed that the pathogenic fungi tested were sensitive only to the mixture of the two 4-hydroxymelleins. The most sensitive fungal species were C. acutatum, S. rolfsii and B. cinerea whereas the least sensitive ones were F. ox. f.sp. radicis lycopersici, S. sclerotiorum, and V. dahliae with a no significant growth inhibition (Cabras et al., 2006). Synergistic interactions between secondary metabolites were already observed (Creppy et al., 2004; Carpinella et al., 2005), although little is known about the mechanisms underlying the synergistic or antagonistic interactions. This is the case of the phytotoxic lipodepsipeptides produced by Pseudomonas fuscovaginea in modulation of plant plasma membrane H+-ATPase. (Batoko et al., 1997). Also the two phytotoxins produced by Fusarium avenaceum act in synergistic manner to cause necrotic lesions on detached knapweed (Centurea maculosa) leaves (Hershernhorn et al., 1992) as well as the phytotoxins produced by Bursaphelenchus xylophilus, when tested in combination for their toxicity on pine seedlings (Hachiro, 1988). (3R,4R) and (3R,4S)-4-hydroxymellein, from S. sapinea, in the above described tests, were not toxic if assayed separately, while they showed phytotoxic and moderate antifungal activity when tested in a mixture resembling that produced by the fungus (6.5:1 ratio).

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5. FUNGI INVOLVED IN THE DECLINE OF CORK OAK One of the most destructive of all tree root pathogens, the oomycete fungus Phytophthora cinnamomi, is associated with mortality and decline of cork and holm oaks in the Mediterranean region (Brasier 1996). The symptoms and distribution of this decline are described. P cinnamomi is a primary pathogen on a very wide range of trees and woody ornamentals worldwide, but is probably a native of the Papua New Guinea region. It is soil borne and requires warm, wet soils to infect roots. Since 1900 it has caused major epidemics on native chestnuts in the United States and Europe, and now threatens the stability of entire forest and heath communities ecosystems in some parts of Australia. Together with drought, it may be a major predisposing factor in the Iberian oak decline (Brasier et al., 1993). The potential influence of climate warming on the activity of P cinnamomi is also considered. A model based on the CLIMEX program suggests that warming would significantly enhance the activity of the pathogen at its existing disease locations (such as the western Mediterranean and coastal northwest Europe), but that it would not greatly extend its activity into areas with cold winters such as central and eastern Europe (Brasier et al., 1993). Also Botryosphaeria stevensii Shoemaker (anamorph: Diplodia mutila Fr. apud Mont.) is reported as, the cause of canker and dieback of cork oak (Quercus suber L.) in Catalonia (NE Spain). It also causes wilting of trees after cork is removed for industrial purposes.

5.1. Phytotoxins Produced by Diplodia Corticola Diplodia mutila (Fr.) apud Mont., anamorph of Botryosphaeria stevensii Shoem., is an endophytic fungus, widespread in Sardinian oak forests, and considered one of the main causes of cork oak (Quercus suber L.) decline (Franceschini et al., 1999). The fungus can affect plants of different age, inducing symptoms very similar to those produced by

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tracheomycotic disease. When inoculated on stems of young cork oak plants, D. mutila induced a slight collapse and dark brown discoloration of the cortical tissues around the inoculation site, a sudden wilting of the plant above it and subsequently a sprouting of the secondary shoots below it (Franceschini et al., 2002). These symptoms suggested that this fungus produced phytotoxic metabolites, as also observed for isolates of D. mutila from cypress and other oak species (Evidente et al., 1997). The organic extract obtained from culture filtrates of D. mutila was purified using a combinataion of column and preparative TLC chromatography to obtain the main phytotoxic metabolite named diplopyrone (41, Fig. 11). This latter had a molecular weight of 196 corresponding to a molecular formula of C10H12O4, consistent with five unsaturations. Absorption bands were typical of ,-unsaturated carbonyl groups and hydroxy groups were observed in its IR spectrum. The structure of diplopyrone was essentially determined by NMR (COSY, TOCSY and HSQC spectra) and EIMS methods, which allowed its formulation as a 6-(1-hydroxyethyl)2,4a,6,8a-tetrahydropyran[3,2-b]pyran-2-one (41) (Evidente et al., 2003c). This structure was supported by the 1H,13C long range correlations recorded for 41 in the HMBC spectrum and the typical fragmemntation peaks observed in of its HR EIMS spectrum. 10

H R

CH3 O 9

5

4

6

4a 3

7

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2

8a 8

1

O

O

41 R=OH 42 R=S-MTPA* 43 R=R-MTPA*

CF3 MTPA= Ph

COO OCH3

Figure 11. Structure of diplopyrone (41) and its derivatives obatined with Mosher‘s reagent (42 and 43).

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The stereochemistry of the bicyclic moiety of 41 was deduced from the J3H,H coupling constants. In fact, a cis-configuration for the junction between the two dihydro-2H-pyran rings, both of which probably adopt a half-chair conformation, was deduced by comparing the coupling value between H-4a and H-8a with those reported for model compounds (Pretsch et al., 1983; Sternhell 1969). The lacking of coupling between H-7 and H-6 located the latter proton in the axial position and consequently the 1-hydroxyethyl group equatorially. Therefore, in agreement with the NOESY data and after inspection of a Dreiding model of 41, a relative stereochemistry with the bridgehead hydrogens (H-4a and H-8a) on the same side of molecule and opposite to H-6 is suggested for diplopyrone. The stereochemistry of the secondary hydroxylated carbon of the 1-hydroxyethyl side chain at C-6 was determined applying the Mosher‘s method (Dale et al., 1969; Dale and Mosher 1973). Diplopyrone, by reaction with the R-(-)--methoxy--trifluorophenylacetate (MTPA) and S-(+)MTPA chlorides, was converted into the corresponding diastereomeric S-MTPA (42, Fig. 11) and RMTPA (43, Fig. 11) esters, whose spectroscopic data were consistent with the structure assigned to 41. In particular, the comparison between the 1H NMR data (Table 3) of the RMTPA ester (43) and those of the S-MTPA ester (42) showed a downfield shift of Me-10, along with and an upfield shift of H-6. These results, in agreement with literature data (Dale et al., 1969; Dale and Mosher 1973), allowed the assignment of an S-configuration at C-9. Therefore diplopyrone (41) can be definitely formulated as 6-[(1S)-1-hydroxyethyl]2,4a,6,8a-tetrahydropyran[3,2-b]pyran-2-one. Diplopyrone, assayed at concentrations ranging from 0.01 to 0.1 mg ml-1, was toxic to Q. suber. Necrotic lesions appeared on the leaves within 4 days after absorption of the toxic solutions (0.1-0.01 mg ml-1). Cork oak cuttings wilted within 8 days. When 41 was assayed on tomato cuttings, phytotoxicity was evident at 0.2 and 0.1 mg ml-1, inducing internal tissue collapse on stem. No phytotoxicity was detected at 0.05 and 0.02 mg ml-1 (Evidente et al., 2003c). Pyran-2-ones (-pyrones), are a group of naturally occurring compounds which are broadly distributed in nature as plant, animal, marine organism and microbial metabolites, most with interesting biological activity (Dean 1963; Thomson 1985; Moreno-Monas and Pleixats 1992) and the total synthesis of some of them has been achieved. Other secondary metabolites containing the pyran-2-one moiety are produced by fungi belonging to several genera including Alternaria, Aspergillus, Fusarium and Trichoderma, and exhibit antibiotic, antifungal, cytotoxic, neurotoxic, and phytotoxic activities (Dickinson 1993).

5.2. Absolute Stereochemistry of Diplopyrone The spectroscopic data above reported for diplopyrone (41) established that: i) the two rings are connected by a cis-junction; ii) the H-4a and H-8a hydrogen atoms lie on the same side and are opposite to the H-6 hydrogen; iii) the absolute configuration at C9 is (S). As a consequence, for (+)-41 only two stereoisomers are possible: 4a(R),8a(R),6(S),9(S), structure I, or 4a(S),8a(S),6(R),9(S), structure II. To establish the real stereostucture of (+)-41 from the analysis of its chiroptical properties study of the Cotton effects, present in its circular dichroism (CD) spectrum were performed and allied to electrically allowed transitions, by means of the coupled-oscillator model due to DeVoe (DeVoe, 1964; ibidem, 1965; Rosini et

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al., 1993; Superchi et al., 2004). In addition the assignment reached above was confirmed by means of an approach very recently proposed (Polavarapu 1997a; ibidem 1997b; Kondru et al., 1998; Stephens et al., 2001; Polavarapu 2002; Takeshi et al., 2003; Vogensen et al., 2004) and also reported in paragraph 3.2: the ab initio calculation of the []D. In this way it will possible not only making a safe absolute configuration assignment of this interesting natural compound but it will be also possible to make a comparison of scope and limitations of these two different approaches. The absorption and CD spectra of (+)-41, measured in trifluoroethanol between 400 and 185 nm, are collected in Fig.12. 30

15

 x 10

-3



12,5

25

10

CD

7,5

CDx10

20

5 2,5

15

0 -2,5

UV 10

-5 -7,5

UVx10 5

-10 -12,5

0

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200

220

240

260

280

300

320

340

360

380

-15 400

 (nm)

Figure 12. Absorption (UV) and circular dichroism (CD) spectra of (+)-41in trifluoroethanol.

Conformer (b) Conformer (a) Figure 13. Structure of the (a) and (b) conformers of 4a(S),8a(S),6(R),9(S)-diplopyrone (41), as found by the MM2 calculations.

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211

15 12.5 10

Experimental CD spectrum

7.5 5 2.5 0 -2.5 -5 -7.5 -10

Predicted CD spectrum

-12.5 -15 185

195

205

215

225

235

245

255

(nm)

15

 x 10

-3

14 13 12 11 10 Predicted absorption spectrum

9 8

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7 6

Experimental absorption spectrum

5 4 3 2 1 0 185

195

205

215

225

235

245

255 (nm)

Figure 14. Lower curves: predicted (for 4a(S),8a(S),6(R),9(S)-diplopyrone) and experimental absorption spectra of (+)-41. Upper curves: predicted (for 4a(S),8a(S),6(R),9(S)-diplopyrone) and experimental CD spectra of (+)-41.

The UV spectrum showed two main regions of absorption: a first, weak band is present at 260 nm (200 ca.), followed by a more intense band at 200 nm ( 12000 ca.). Taking onto account position and intensity, the first absorption band could be related to a n* transition involving the unsaturated ester chromophore (Murrel 1963), whilst the short-wavelength region of absorption can result from transition involving both the -unsaturated ester chromophore (Harada and Nakanishi 1983) as well as the olefinic group (Drake and Mason,1977). In the CD spectrum at least four different Cotton effects can be noticed: the

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lowest energy one is at about 275 nm ( +0.25), followed by a second positive ( +5) CD band at 225 nm and by a succession of two oppositely signed Cotton effects at 225 nm ( 8) and 215 nm ( +10). Considering that these two CD bands have the same intensity, with opposite signs and correspond to a region of intense absorption, they clearly constitute a CD ―couplet‖ (Haas et al., 1973), derived from the coupling of the electrically allowed transition on the above-quoted -unsaturated ester chromophore and olefinic chromophore. As it is nowadays generally accepted, the presence in a CD spectrum of the so called ―exciton couplet‖ can be exploited (Mason 1967; Gottarelli et al., 1971; Charney 1979; Mason 1982; Harada and Nakanishi 1983; Nakanishi and Berova 1994; Nakanishi and Berova 2000) to carry out a non empirical assignment of the molecular absolute configuration. In fact, the exciton (coupled oscillator) method constitutes nowadays a relatively simple, reliable and powerful tool to assign the absolute AC of organic molecules. In particular, by means of the DeVoe coupled oscillator (or polarizability) model (DeVoe 1964), it is possible to calculate  as a frequency function, i.e. the CD spectrum in the range of the electrically allowed transitions can be quantitatively predicted, assuming arbitrarily the molecular AC, so from the comparison between predicted and experimental CD a safe AC assignment can be achieved. The possess all the necessary geometrical and spectroscopic parameters allowed to carry out the DeVoe calculations and produce a theoretical CD spectrum in the range 220-185 to be compared with the experimental one. It is interesting to note that the exocyclic alcoholic group bearing the C9 atom does not absorb significantly in the region of interest being a saturated alcohol, so its presence can be safely disregarded. This makes enantiomeric structure I and structure II, quoted above. Therefore it will be sufficient to carry out the calculations for only one of them, say 4a(S), 8a(S), 6(R), considering the existence of two different conformers: (a) and (b) in Fig. 13. Interestingly, both for conformer (a) and conformer (b) a negative couplet is predicted by our DeVoe calculations, the only difference being the intensity -10; +10 for conformer (a); -2.3; +2.3 for conformer (b). So in Fig. 14 the predicted (as a weighted average, using a Boltzmann statistics, of the CD spectra calculated for the single conformers) and the experimental absorption/CD spectra are reported. The excellent agreement (also from a quantitative point of view) clearly shows that (+)diplopyrone possesses 4a(S),8a(S),6(R),9(S) absolute configuration (Giorgio et al., 2005). The ab initio calculation (Polavarapu 1997; Kondru et al., 1998; Stephens et al., 2001; Polavarapu 2002; Takeshi et al., 2003; Vogensen et al., 2004) of the optical rotary power, for instance at the sodium D line, i.e. []D, has become possible only very recently, mainly thanks to the extraordinary progresses of computational techniques. In this way one now can, at least in principle, assign the molecular AC by a comparison between the experimental rotation and the value predicted ab initio, assuming arbitrarily a certain AC, by means of some commercially available packages (Rosenfeld 1928; Helgakar et al., 2001; Ahlrichs et al., 2002). The assignment can be made if the theoretical result is fully reliable. From this point of view Stephens et al. established (Stephens et al., 2001) that a reliable ab initio calculation of the optical rotation requires the Time Dependent Density Functional Theory (TDDFT) method with the hybrid B3LYP functional and the use of large basis sets, containing diffuse functions. We decided to follow this protocol, reasoning that since (+)-41 is a molecule with a reduced size the high level calculation of []D suggested by Stephens et al., 2001, does not require a high computational effort. It was noticed also that the exocyclic alcoholic group bearing the C9 atom which, reasonably, is almost freely rotating so several

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different relative dispositions of the external tail with respect to the bicyclic part are easily accessible and therefore a correct prediction of the optical rotation requires an averaging over multiple orientations of the tail with respect to the rest of the molecule, making all the calculation procedure quite complex. We reasoned that the C9 carbon atom does not carry any strong chromophoric group whilst, by contrast, all of them are inserted in the bicyclic moiety of (+)-41, so the main contributions to the optical rotatory power must come from this molecular fragment. Therefore we carried the calculations of []D substituting the hydroxymethyl group linked to C6 with a methyl group, leaving C6 with the same absolute configuration. This approximation is useful not only in avoiding conformational problems but also because it makes enantiomeric the above described structure I and structure II. Therefore it will be sufficient to carry out the calculations for only one of them, say 4a(S), 8a(S), 6(R), as we did before for the DeVoe prediction of the CD spectrum. This model compound exists as a mixture of two conformers with populations 78% and 22%, respectively. In the most populated conformer the methyl group is equatorial whilst in the other it is axial, as shown in Fig.15.

Equatorial conformer (78%).

Axial conformer (22%)

Figure 15. Structure of the equatorial and axial conformers of the 4a(S),8a(S),6(R)-model compound as obtained by means of DFT/B3LYP/6-31G* calculations.

The calculation of optical rotation at 589 nm has been carried out at TDFT/B3LYP level, using the Sadlej basis set (199199 i.e. a basis set which has a size similar to the aug-cc-pVDZ basis set suggested by Stephens et al. (2001) but being purposely designed to correctly reproduce electric properties, should be particularly useful in calculating optical rotatory powers (Stephens at al., 2004). As a matter of fact it provide excellent results in the calculation of the OR of (S)-propylene oxide (Giorgio et al., 2003). The predicted [D value for the equatorial conformer is +35 of diplopyrone, whilst for the axial one we have +298. The average value, taking into account the relative populations of the two conformers, is +93, in good agreement with the experimental one. This result confirms that the absolute configuration of (+)-41 is 4a(S),8a(S),6(R),9(S). (Giorcio et al., 2005)

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5.3. Other Phytotoxic Metabolites Isolated from Diplopia Corticola 5.3.1. Diplobifuranylones A and B The organic extract obtained from culture filtrates of D. corticola was further purified to isolate, beside diplopyrone (41), other minor metabolites. In fact, also sphaeropsidins A-C and sapinofuranone B were successively isolated (Evidente et al., 1999). These metabolites, as above reported, were already described as fungal phytotoxins produced by Spheropsis sapinea f.s. cupressi and S. sapinea phytopathogenic to cypress (Cupressus sempervirens L.) and conifers, respectively. Furthermore, from the same organic extract the same the (S,S)enantiomer of sapinofuranone B, which was isolated previously from Acremonium strictum, a saprophytic fungus commonly found in soil and plant surfaces (Clough et al., 2000), and (3S,4R)-trans- and (3R,4R)-cis-hydroxymelleins (Cole and Cox 1981; Aldridge et al., 1971; Devys and Barbier 1992) were isolated.

4'

3'

H3C

H

2'

5'

R

5

2

1'

H

4

3

H

O

O

1

O 44 R=OH 46 R=S-MTPA

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48 R=R-MTPA

H

H3C

H

O

2'

5'

R

O O

H

45 R=OH 47 R=S-MTPA 49 R=R-MTPA Figure 16. Structure of diplobifuranylones A and B (44 and 45) and their Mosher‘ esters (46 and 48 and 47 and 49).

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Further investigation among the most polar fungal metabolites allowed to isolate other two new metabolites obtained as homogeneous oils resistant to crystallization, which were named diplobifuranylones A and B (42 and 43, Fig. 16) on the basis of the structural features shown below. Diplobifuranylone A (44) was assigned a molecular formula of C10H14O4, corresponding to four degrees of unsaturation, as deduced from the molecular weight of 198, measured by HRESIMS for its adduct with sodium. Absorption bands typical of -lactone carbonyl groups and hydroxy groups were observed in the IR spectrum (Nakanishi and Solomon 1977). Preliminary NMR spectroscopic observation showed that three out of four of unsaturations in 44 were consistent with a -lactone carbonyl group and a cis-simmetrically disubstituted double bond. Analysis of the 1H and 13C NMR spectra confirmed these structural features. The 1H NMR spectrum showed systems typical for a cis-disubstituted olefinic group and those of two protons of a methylene group (H2C-4) α-positioned in respect to a lactone carbonyl group. The coupling observed in the COSY spectrum showed the presence of another methylene group and oxygenated methyne which were in good agreement with those reported for protons positioned - and -with respect to the carbonyl group of a -lactone ring (Pretsch et al., 1983). In the same spectrum, the methyne proton coupled with a broad singlet of another oxygenated methyne group which on the basis of other coupled systems appeared to be αpositioned in 2,5-disubstituted 2,5-dihydrofurane ring (Pretsch et al., 1983). The same spectrum also showed that at C-5 of this latter ring is bonded a 1-hydroxyethyl side chain. The presence of the -lactone and the 2,5-dihydrofuran rings in 44 as well as the side chain attached to C-5' were confirmed by correlations observed in the HSQC spectrum. The diplobifuranylone A (44) is constituted by a 2-monosubstituted -lactone ring and a 2,5disubstituted dihydrofuran ring joined through a C-2-C-2' bond, with the side chain linked at Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

C-5' of the dihydrofuran ring. Therefore, 44 could be formulated as 5'-(1-hydroxyethyl)3,4,2',5'-tetrahydro-2H-[2,2']bifuranyl-5-one (Evidente et al., 2006b). This structure was supported by the long-range correlations recorded for 44 in the HMBC spectrum and by its ESIMS data which showed, in addition to the pseudomolecular, fragmentation peaks typical of the -lactone and -alkyl substituted furan ring. Diplobifuranylone B (45) showed the same molecular formula of C10H14O4, as deduced from its adduct with sodium in its ESIMS, and its spectroscopic properties (UV, IR, NMR and MS spectra) were very similar to those described for 41, but the optical rotation power was different. These preliminary data suggested that 44 could be a diastereomer of 45.This was confirmed by analyzing the 1H and 13C NMR, whose complete assignments were made from the COSY and HSQC NMR spectra. In particular, both the 1H and 13C NMR spectra differed from those of 44 only for the chemical shifts and multiplicity of the protons and carbons of C2' and C-5', the carbons of the 2,5-dihydrofuran ring linked to the -lactone ring and to the hydroxyl ethyl side chain, which also showed significant changes in the chemical shifts of both carbons and protons. These results suggest a different stereochemistry essentially for the carbon of 2,5-dihydrofuran ring bearing the two substituents, namely, the -lactone ring and the hydroxyl ethyl side chain, and a different stereochemistry of the chiral carbon (MeCHOH) of this latter residue.

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This was confirmed by comparing the NOESY spectra of 44 and 45 which allowed to assign a relative cis-stereochemistry between C-2' and C-5' in 45. This result was also confirmed by a ROESY experiment carried out on the same metabolite 45 but was not observed in diplobifuranylone A (44), which consequently should have a transstereochemistry between C-2' and C-5'. These results, agreed with a Dreiding model inspection of both diplobifuranylones A and B and were confirmed by the results of a series of double decoupling experiments carried out on 44 and 45. The experiments allow to recorded the coupling constants between H-2 and H2', but essentially the homoallylic coupling between H-2' and H-5' in 44 and 45, respectively, whose values are in agreement with the values reported in the literature for the trans- and the cis-coupling between H-2 and H-5 in a 2,5-dihydrofuran ring (Pretsch et al., 1983; Sternhell 1969). The absolute stereochemistry of the secondary hydroxylated carbon of the 1-

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hydroxyethyl side chain at C-5' was determined applying the Mosher‘s method (Dale et al., 1969; Dale and Mosher, 1973; Ohtani et al., 1991). Diplobifuranylones A and B by reaction with the R-(-)--methoxy--trifluorophenylacetate (MTPA) and S-(+)MTPA chlorides, was converted in the corresponding diastereomeric S-MTPA and R-MTPA esters (46 and 48 and 47 and 49, respectively, Fig. 16), which spectroscopic data were consistent with the structure assigned to 44 and 45. The comparison between the 1H NMR data of the S-MTPA ester (47) and those of the R-MTPA ester (49) of 44 and as well as those of S-MTPA ester (47) and those of the R-MTPA ester (49) of 45 allowed to assign a S- and R-configuration at MeCH of the side chain in 44 and 45, respectively. Therefore, diplobifuranylones A and B (42 and 43) can be formulated as 5'-[(1S)-1-hydroxyethyl)-3,4,2',5'-tetrahydro-2H-[2,2‘]bifuranyl-5-one and its R-epimer at the chiral carbon of the side chain, respectively (Evidente et al., 2006b). Diplobifuranylones A and B, assayed at 0.05-0.1 mg ml-1 on non-host plants (tomato), showed no signs of phytotoxicity. Lethality tests for compound 44 and 45 on larvae of brine shrimp (Artemia salina ) were run in order to detect potential citotoxicity on cancer cell line. This simple and preliminary bioassay allowed to test minute amount of toxins, to compare the toxicity of different compounds, and also to quantify the effects. Both compounds were inactive against A. salina even when being sampled at the highest concentration tested (300 g/ml) (Evidente et al., 2006b). The lack of phytotoxicity observed testing diplobifuranylones A (44) and B (45) on nonhost tomato plants compared with to the strong activity recorded for the structurally related sapinofuranones A and B on host (cypress and pine) and non-host plants, can be explained by the structural modification of the 1-hydroxy-2,4-hexadienyl side chain at C-4, which in 44 and 45 is converted into a trans-and cis-2,5-disubstituted 2,5-dihydrofuran ring, while the lactone residues remain unaltered. A hypothesized mechanism for biosynthetic conversion of sapinofuranone into diplobifuranylones is reported in Fig. 17. The first step of this mechanism could be the eletrophilic addition of a proton to C-9 doube bond of of sapinofuranone. At the resulting cation at C-8 was attached the hydroxy group at C-5 of the same chain generating the dihydrofuranoxonium ion. This step is not stereospecific so that the addition could generated a cis- or a trans-junction between the two rings as it was present in diplofuranylenes, A and B. Finally, the stereospecific hydroxylation of the ethyl side chain at C-5 generated the two diplobifuranylones.

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Bisfuranoids are a polyketide group of naturally occurring compounds that are broadly distributed in nature essentially as microbial metabolites produced by different fungal species such as Aspergillus, Bipolaris, Cercospora, Chaetomium, Dothistroma, Farrowia and Monocillium. Most of these substances showed important biological activities such as aflatoxins (Turner and Aldridge 1999). These natural compounds have two furan rings joined through one side while bisfuranyls, as 44 and 45 in which the furan rings are joined through a bond are only known as synthetic compounds (Brown et al., 2002; Langer et al., 2002; Chiusoli et al., 2003; Behr et al., 2004). Diplobifuranylones A (50) and B (51) represent the first example of monosubstituted natural bifuranyls joined through a bond.

H

+

H

10

H 3C

4

5

8 7

6

2

3

OH

9

1

O

O

H

sapinofuranones

4' 5'

H 3C

4

3 2

+

H

H

3' H 2' H

5'

5 1

O

O

H 3C

H

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H H

O H

O

O

O

2'

H H

+

HO

-

HO

+

-

H OH H

4'

3' 2'

5'

3

H

4

H

H

H 3C

O

1

O Diplobifuranylone A

O

2'

5'

O

5

2

H

OH

O

H H 3C

O

H

Diplobifuranylone B

Figure 17. Hypothesized mechanism of conversion of sapinofuranones into diplobifuranylones.

5.3.2. Diplofuranones A and B From the purification of the organic extract obtained from D. corticola culture filtrates as reported above and from the most polar fraction, were isolated diplopyrone (Evidente et al., Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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2003), diplobifuranylones A and B (Evidente et al., 2006) sphaeropsidins A-C (Evidente et al., 1997) and the sapinofuranone B already described together to sapinofuranone A (Evidente et al., 1999) as phytotoxic metabolites produced by Sphaeropsis sapinea f.s. cupressi and S. sapinea phytopathogenic to cypress (Cupressus sempervirens L.) and conifers, respectively, and (3S,4R)-trans- and (3R,4R)-cis-hydroxymellein (Aldridge et al., 1971; Cole and Cox 1981; Devys and Barbier 1992). Further purification of the same organic extract yielded two metabolites as homogeneous oils resistant to crystallization, named diplofuranones A and B (50 and 51, Fig. 18) Diplofuranone A has a molecular formula of C10H14O3, corresponding to four degrees of unsaturations, as deduced from the molecular weight of 182, measured by HR EIMS spectrometry. Absorption bands typical of -lactone carbonyl groups and hydroxy groups were observed in the IR spectrum (Nakanishi and Solomon 1977), while the UV spectra showed the absorption maximum of a dienyl residue at 230 nm (Pretsch et al., 2000). R 9 10

8

7

H3C

6

5

H

O H

O

50 R=OH 52 R=S-MTPA*

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53 R=R-MTPA*

HO 10

7

9

6

8

5

H3C 51

H

O O CF3

*MTPA =Ph

COO OCH3

Figure 18. Structure of diplofuranones A and B (50 and 51) and diplofuranylones A Mosher‘ esters (52 and 53).

Preliminary 1H- and 13C-NMR spectra, compared to those of sapinofuranone A and B, showed a similar pattern for the -lactone residue while those of the side chain at C-4 appeared strongly modified.

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In particular, the 1H-NMR spectrum of diplofuranone A showed systems typical of a hydroxyhexadienyl side chain in addition to those of a butan-4-olide residue, the latter already observed in the spectra of sapinofuranones A and B. The presence of these systems was confirmed by the investigation of its 13C NMR spectrum (Breitmaier and Voelter, 1987). The COSY and HSQC spectral data. On these bases, diplofuranone A (50) can be formulated as 4-[(1E,3E)-5hydroxyhexadienyl]butan-4-olide. This structure was supported by the 1H,13C long-range correlations recorded for 50 in the HMBC spectrum and by data of its EI MS spectra. The latter, in addition to the molecular ion, showed the peaks generated from fragmentation typical of the -lactone and -alkadienoyl substituted furan ring (Pretsch et al., 2000; Porter 1985). The ESIMS(+) spectrum showed the potassium and the sodium clusters, respectively (Evidente et al., 2007). Diplofuranone B (51) had a molecular formula of C10H16O3 as deduced its HR EIMS spectrum and spectroscopic properties (IR, NMR and MS spectra) similar to those described for 50. Therefore, it differed from 50 for the lack of unsaturation which was localized in the side chain. In fact, the UV spectrum of 51 lacked the typical absorption maximum of a dienyl system observed in the same spectrum of 50. Therefore, 51 showed a different side chain in respect to 50 as compared by investigation of its 1H- and 13C-NMR spectra. In fact, these latter differed from those of 50 only for the signal system of the side chain residue while those of the -lactone ring remained substantially unaltered. The signal observed were consistent with a 5-hydroxy-1-hexenyl side chain which was positioned on the same carbon of the lactone ring as in 50 in agreement with the couplings in the HMBC spectrum. On the basis of these results diplofuranone B differed from 50 for the side chain and in particular for the lacking of the double bond between C-7 and C-8. Therefore, it can be formulated as 4[(1E)-5-hydroxy-1-hexenyl]butan-4-olide (51) (Evidente et al., 2007). This structure was supported by the 1H,13C long-range correlations recorded for 51 in the HMBC spectrum and by its ESIMS data spectrum, which showed the potassium and the sodium cluster ions, respectively. The stereochemistry of the double bonds of the side chain at C-4 of both 50 and 51 was deduced from the 3JH,H coupling constants that are consistent for all with a transstereochemistry (Pretsch et al., 2000). The stereochemistry of the secondary hydroxylated carbon at C-9 of diplofuranone A was determined applying the Mosher‘s method (Dale et al., 1969; Dale and Mosher 1973). Diplofuranone A by reaction with the R-(-)--methoxy-trifluorophenylacetate (MTPA) and S-(+)MTPA chlorides, was converted in the corresponding diastereomeric S-MTPA and R-MTPA esters (51 and 52, Fig. 18), whose spectroscopic data were consistent with the structure assigned to 1. The comparison between the 1H-NMR data of the S-MTPA ester (52) and those of the R-MTPA ester (53) of 50 allowed to assign, in agreement to the Mosher‘s method (Dale and Mosher 1973) and its further improvement (Ohtani et al., 1991), a R configuration at C-9 of the side chain of 1. Diplofuranone A can be formulated as 4-[(5R,1E,3E)-5-hydroxyhexadienyl]-3,4-dihydro-2Hfuranone (48, Fig. 18). (Evidente et al., 2007) Considering the structures of sapinofuranones it is also possible to hypothesize a biosynthetic pathway, which starting from this fungal metabolites, leads to diplofuranones A and B as reported in Fig. 19. The first step could be the protonation of the hydroxyl group at C-5 of the side chain attached at C-4 of the -lactone ring, followed by the elimination of a

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H2O molecule and the consequent shift of the double bond between C(6)-C(7) to C(5)-C(6) and that between C(8)-C(9) to C(7)-C(8) with the stereoselective attach of a H2O molecule at C-9. Finally, the deprotonation of the intermediate protonated alcohol generate the diplofuranone A (50). The successive reduction of the double bond between C(7)-C(8) yielded the diplofuranone B. This hypothesized biosynthetic mechanism is in full agreement with the stereostructural features of (50) and (51) and allowed to rule out the possibility that these two metabolites could be formed by sapinofuranones as an artefact of the work-up of the fungal culture filtrates. This biosynthetic mechanism was supported by the stereochemistry of C-9 and C(5)-C(6) and C(7)-C(8) double bonds, which have Econfiguration in both (50) and consequently also in (51), and by the absence of other possible stereoisomers in the fungal culture filtrates (Evidente et al., 2007). H+ H

10

H3C

4

5

8 7

6

2

3

OH

9

H3C 1

O

+

H 5

8

O

H

OH2 9

7

H2O

6

O H

O

sapinofuranones

HO HO H3C

8

7 6

H3C

5

O H

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Diplofuranone A

O

7 8

Reduction O H

O

Diplofuranone B

Figure 19. Biosynthetic pathway of sapinofuranones conversion into diplofuranones A and B.

Diplofuranone A, when assayed at 0.2 mg ml-1 on non host tomato plants, did not show phytotoxic activity whereas the phytotoxicity of diplofuranone B was not assessed due to the lacking of sufficient amount of this fungal metabolite. This inactivity was not surprising as 51, in respect to the phytotoxic sapinofuranones A and B (24 and 25, Fig. 4), had a marked modification of the 1-hydro-2,4-hexadienyl side chain at C-4, which reveals its importance in phytotoxicity. Diplofuranones are strictly related to the sapinofuranones A and B isolated for the first time from Sphaeropsis sapinea infecting cypress tree (Evidente et al., 1997) and the S,Senantiomer of sapinofuranone B which was previously isolated from Acremonium strictum, a saprophytic fungus commonly found in soil and plant surfaces (Clough et al., 2000). Butanolides are rare as naturally occurring compounds but they are closely related to butenolides, which are well known as plant, fungal and lichen metabolites that also exhibit interesting biological activity (Dean 1963). Among these there are the seiridins, which are 3,4-dialkylbutenolides isolated from the culture filtrates of three species of Seiridium associated with the canker diseases of cypress (Sparapano et al., 1986; Evidente and Sparapano 1994).

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5.3.3. Chemotaxonomic Significance Independently from the phytotoxic activity, the occurrence of diplofuranones A (1) and B (2) may help to understand whether changes in the molecular structure of sapinofuranones affect its biological activity on host and non-host plants (Evidente et al., 1999). Furthermore, understanding of the secondary metabolism of D. corticola could help to elucidate the taxonomic relationship between D. corticola and D. mutila, the fungus most frequently isolated from branches and twigs of declining oaks (Kolwaski 1991). S. sapinea f. sp. cupressi [syn: Diplodia pinea (Desm) Kickx, Petrax et Sydow f. sp. cupressi] and S. sapinea (Fr.:Fr.) Dyko & Sutton is an opportunistic pathogen of more than 30 species of Pinus in 25 countries (Swart and Wingfield 1991). In fact, it is important to point out that D. corticola produces diplopyrone, diplofuranones, diplobifuranylones, sphaeropsidins A-C, sapinofuranones and 4-hydroxymelleins while D. mutila produces sphaeropsidins A and C (Sparapano et al., 2004), S. sapinea f. sp. cupressi produces sphaeropsidins A-F and sphaeropsidones (Evidente et al., 1997), while S. sapinea, isolated from cypress, only produces sapinofuranones A and B and sapinopyridione (Evidente et al., 1999), while S. sapinea isolated from pine produced mellein and 4-hydroxymellein. Therefore, D. corticola produces toxins in part similar to those (sphaeropsidins) produced by D. mutila and S. sapinea f. sp. cupressi, and those (sapinofuranones) of S. sapinea, but differ for the original biosynthesis of diplopyrone, the main phytotoxin, diplobifuranilones, diplofuranones, and the 4-hydroxymelleins. S. sapinea from cypress produced in part toxin similar to those (sapinofuranones) D. corticola but specifically produced sapinopyridione. S. sapinea from pine produced toxin similar to those (4-hydroxymelleins) of D. corticola but specifically produced mellein.

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5. 4. Phytotoxins Produced by Biscognauxia Mediterranea Biscogniauxia mediterranea (De Not.) O. Kuntze, is an endophytic fungus, widespread in Sardinian oak forests, and considered one of the main causes of cork oak (Quercus suber L.) decline (Franceschini et al., 2002) This fungus can survive as an endophyte in all of the aerial organs of the oak plants, as well as being able to act as an opportunistic pathogen when the oaks suffer from prolonged periods of stress. The fungus induces discoloration of the woody tissues, dieback and stem and branch cankers, progressing to the appearance of characteristic black carbonaceous stromata on dead organs (Marras et al., 1995). These symptoms suggested that the fungus produced phytotoxic metabolites, as also observed for isolates of Hypoxylon mammatum (Wahlenberg) Miller, the causal agent of the poplar canker disease (Pinon and Manion 1991). Indeed, the role of 5-methylmellein, a well known metabolite produced by Xylariaceae ascomycetes such as B. mediterranea (Anderson and Edwards, 1983; Whalley and Edwards, 1995) has been extensively studied in relation to its role in disease induced on the host plant (Maddau et al., 2002). From the crude oily residue obtained by extraction of the culture filtrates of B. mediterranea three phytotoxic metabolites were isolated by this process: the previously described 5-methylmellein (52, Fig. 20) (Maddau et al., 2002), and two other metabolites, the most polar of which was identified by means of its spectroscopic properties as phenylacetic acid (53, Fig. 20), a low molecular weight acid, isolated for the first time as toxic metabolite from this fungus. The third metabolite which is the main toxin was called biscopyran (54, Fig.

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20) on the basis of its structural features described below. The latter (54) was obtained as white needles by crystallization from ethyl acetate and many attempts to determine its structure by X-ray analysis failed. Biscopyran has a molecular weight of 388, corresponding to a molecular formula of C22H28O6, which is consistent with the presence of nine unsaturations. These results together with the signal pattern observed in both the 1H and 13C NMR spectra as well as in the EI and ESI mass spectra suggested a symmetrical structure for this toxin. In particular, the 1H NMR spectrum showed a signal typical of a pentasubstituted 2H-pyran ring and those of a 2methoxy-but-2-enoyl side chain and two vinyl methyl groups. 2

OH

1

CH 2COOH

O

O

6'

1' 2'

CH 3

3'

5' 4'

H Me

53

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52

OMe

H

O

Me

1

H

O

H

O 8a

Me

8

2

7

3

6 4

Me

4a

Me

MeO

5

O Me

H

Me 54

Figure 20. Structures of 5-methylmellein, phenylacetic acid and biscopyran (52, 53 and 54) isolated from Biscogniauxia mediterranea.

The presence of these partial structures in 54 was confirmed by the correlations observed in the HSQC spectrum. Furthermore, the 13C NMR spectrum showed the presence of six quaternary carbons, which were also attributed on the basis of the correlations observed in the HMBC spectrum. These structural features were also consistent with the typical absorption

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band observed for conjugated carbonyl and triene systems in the IR (Nakanishi and Solomon 1977) and UV (Scott 1964) spectra. Finally, in base of that each proton and carbon signal, except those of the headbridged carbons, is double and giving all the correlations described above and observed in the COSY, HSQC, HMBC and TOCSY spectra On this basis, the structure of 2-methoxy-1-[7-(2-methoxy-but-2-enoyl)-3,4,5,6tetramethyl-2H,7H-pyrano[2,3-b]pyran-2-yl]-but-2-en-1-one was assigned to biscopyran (54) (Evidente et al., 2005). The symmetrical structure 54 assigned to the toxin was supported by the 1H,13C longrange correlations recorded in its HMBC spectrum and by data of its EI and ESI MS spectra. Indeed, the HREIMS spectrum showed the molecular ion and peaks generated by fragmentation mechanisms typical of 2H-pyran and ether Pretsch et al., 2000; Porter 1985). The ESIMS spectrum showed the potassium and the sodium clustered and the pseudomolecular ions, respectively, as well as the same adducts corresponding to the half molecule. Considering the effect observed in the NOESY spectrum the bicyclic 2H-pyran moiety of 54 should be assumed a conformation of two fused half-chairs with H-2 located pseudoequatorial and consequently the 2-methoxy-but-2-enoyl side chain pseudoaxial, in one of the possible conformation in a continuous equilibrium with other preferred conformations. This side chain has a Z-stereochemistry as showed by the significant effect observed in the NOESY spectrum between its methyl and the methoxy groups. Furthermore, in agreement with the NOESY data and an inspection of a Dreiding model, and considering the optical inactivity of biscopyran, the relative stereochemistry of 2R,7S (equal to 2S,7R) could be assigned to the toxin (54). When assayed on test plants, 53 and 54 showed phytotoxic activity. Both substances were shown to be non-selective toxins. Phenylacetic acid, assayed at concentrations ranging from 0.01 to 0.1 mg ml-1, was toxic to Q. suber. Necrotic lesions appeared on the leaves within 5 days after absorption of the toxic solutions. Cork oak cutting wilted within 10 days at 0.1 mg ml-1. When 53 was assayed on tomato cuttings, phytotoxicity was observed at 0.1-0.05 mg ml-1, inducing internal tissue collapse on the stem. When biscopyran was assayed at concentrations ranging from 0.1 to 0.01 mg ml-1 on cork oak cuttings, epinasty was observed. On non-host plants (tomato), biscopyran caused wilting at a concentration of 0.05 and 0.1 mg ml-1 (Evidente et al., 2005). Further studies on the antifungal activity of 53 and 54 are now in progress in order to understand the competition between B. mediterranea and other fungal endophytes within the host. The biscopyran belongs to the family of pyranopyrans, which are well known as synthetic intermediate compounds, but few are known as natural compounds (Kozikowski and Jaemoon 1990; Leeuwenburgh et al., 1997; Grotenbreg et al., 2004). The latter include the brevetoxins (Mori et al., 1997) and dactomelynes (Aydogmus et al., 2004) a new phytotoxin recently isolated from Diplodia mutila, another causal agent of a canker disease of cork oak (Evidente et al., 2003). Isolation of phenylacetic acid as a phytotoxin was not surprising since it was previously reported as a fungal phytotoxic metabolite produced by Rhizoctonia spp. (Turner and Aldridge 1983). Furthermore, low molecular weight acids like namely -nitropropionic (Evidente et al., 1992), oxalic (Noyes and Hancock 1981), fumaric (Mirocha 1961) and 3-

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methylthiopropionic (Scala et al., 1996) acids, were previously described as toxins that produced by both phytopathogenic fungi and bacteria. The previous isolation of 5-methylmellein from B. mediterranea was also no surprise, as this is the most frequent dihydroisocoumarin isolated from Ascomycetes belonging to different genera (see Entonaema, Hypoxylon, Xylaria, Resillinia, Poronia, Podosodaria, Hycocopra, Daldinia, Nummularia, Kretzschmaria, Camillea and Penzigia) of the Xylariaceae family, which have also been shown to produce toxic metabolites with different chemical structures such as cytochalasins, naphthelene derivatives, butyrolactones, succinic acid derivatives, chromanones and diketopiperazines. Several studies have been carried out to use the distribution of such secondary metabolites in conjunction with traditional taxonomic characters in an attempt to develop a better understanding of natural relationships within the family (Anderson and Edwards 1983; Whalley and Edwards 1995; Stadler et al., 2001). Chemical data indicate that there are at least two major divisions within the family and on the basis of production of 5-methylmellein B. mediterranea was grouped together with Hypoxylon, Daldinia, Camillea, Entonaema genera (Whalley and Edwards 1995). Furthermore, the phenylacetic acid and biscopyran are specifically biosynthesized by B. mediterranea, and although a polyketide origin could be hypothesized for biscopyran as for dihydroisocoumarins (Turner and Aldridge 1983), they could be used as exclusive metabolite profiles to recognize the fungus producer.

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Uspenskaya, GA; Reshetnikova, IA. On toxins produced by sphaeropsidal fungi. Mikologjia i Fitopatologia, 1975 9, 355-357. Vurro, M; Bottalico, A; Capasso, R; Evidente, A. Cytocalasins from phytopathogenic Ascochita and Phoma species. In: Upahyay RK, Mukerji KG editors. Toxins in Plants Disease Development and Evolving Biotechnology., New Delhi: Oxford & IBH publishing Co. Pvt. Ltd.; 1997; pp. 127-147. Venkatasubbaiah, P; Chilton, WS. Phytotoxins of Botryosphaeria obtuse. J. Nat. Prod., 1990 53, 1628-1630. Venkatasubbaiah, P; Sutton, TB; Chilton, WS. Effect of phytotoxins produced by Botryosphaeria obtusa, the cause of black rot of apple fruit and frogeye leaf spot. Phytopathology, 1991 81, 243-247. Vogensen, SB; Greenwood, J R; Varmin, AR; Brehm, L; Pickering, DS; Nielsen, B; Liljefors, T; Clausen, RP; Johansen, TN; Krogsgaard-Larsen, P. Stereochemical anomaly: the cyclised (R)-AMPA analogue (R)-3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine5-carboxylic acid [(R)-5-HPCA] resembles (S)-AMPA at glutamate receptors. Org. Biomol. Chem., 2004 2, 206-213. Wagener, WW. The canker of Cupressus induced by Coryneum cardinale n. sp. J. Agric. Res., 1939 58, 1-46. Wang, CG; Blanchette, RA; Palmer, MA. Differences in conidial morphology among South African isolates of Sphaeropsis sapinea. Plant Dis., 1985 69, 838-841. Whalley, AJS; Edwards, RL. Secondary metabolites and systematic arrangement within the Xylariaceae. Can J. Bot., 1995 73, 5802-5810 White, PS; Findalay, JA; Wah Hung, J. The X-ray crystal structure of (±)-flavipucine. Can. J. Chem., 1978 56, 1904-1906. Xenopoulos, S. A new for Greece pathogen causing the cypress canker disease. Dasike Eurena, 1987 2, 85-94. Xenopoulos, S; Tsopelas, P. Sphaeropsis canker, a new disease of cypress in Greece. Forest Pathol., 2000 30, 121-126. Zwolinski, JB; Swart, WJ; Wingfield, M. Economic impact of a post-hail outbreak of dieback induced by Sphaeropsis sapinea. Eu. J. Forestry and Pathol., 1990 20, 405-411

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Chapter 5

RETHINKING THE NOTION OF „MULTIFUNCTIONAL AGRICULTURE‟ Geoff A. Wilson* University of Plymouth, Plymouth, UK

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ABSTRACT The debate surrounding the notion of ‗multifunctional agriculture‘ is gathering speed. This has assumed greater importance as global agriculture is facing renewed pressures for intensification based on rising demand for agricultural commodities and biofuel production. European and American debates on agricultural change intertwine, especially with regard to calls for a more environmentally sustainable agriculture, highlighting similarities in changing nature-society interactions across cultural and geographical divides. This article addresses the issue of agricultural change from a conceptual perspective. It suggests that agricultural change can be understood as occurring along a spectrum of decision-making bounded by the ‗extreme‘ spaces of ‗productivism‘ and ‗non-productivism‘, and anchors the notion of ‗multifunctional agriculture‘ within this spectrum of decision-making. The article suggests that this enables a normative view of multifunctionality based on strong, moderate and weak multifunctional agricultural pathways. Building on work by human geographers and other social scientists, this normative view challenges often simplistic policy-based and economistic conceptualisations of multifunctionality. The article argues that the multifunctionality spectrum provides a robust framework with which to understand agricultural change in any location, and suggests that ‗strong‘ multifunctionality should be the type of multifunctionality that agricultural stakeholders and policy-makers should be striving for. The article concludes by cautioning that many research challenges lie ahead, in particular as future methodologies for assessing multifunctional quality need to move away from absolute and ‗measurable‘ indicators and, instead, adopt more qualitative approaches to assess subtle attitudinal and identity-related shifts that form crucial components of the multifunctionality spectrum.

* Correspondence: School of Geography, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK; e-mail: [email protected]

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1. INTRODUCTION: THE NEED FOR A RECONCEPTUALIZATION OF „MULTIFUNCTIONAL AGRICULTURE‟ The debate surrounding the notion of ‗multifunctional agriculture‘ is gathering speed in many agricultural regions of the world (Potter and Tilzey, 2005; McCarthy, 2005; Ramniceanu and Ackrill, 2007; Wilson, 2007, 2008a, 2008b). In recent years, this has assumed ever greater importance as global agriculture is facing renewed pressures for intensification based on rising demand for agricultural commodities in emerging markets (especially China and India) and associated rises in commodity prices (e.g. doubling of wheat price in 2007), and because the planting of crops for biofuel production (e.g. oil seed rape) is increasingly jeopardising global food production spaces (Lang and Heasman, 2004). This is also beginning to have repercussions for farm trajectories in the United States of America (U.S.), where farms that had begun a process of disconnection from the agri-industrial regime are re-intensifying production (Bell, 2004; McCarthy, 2005). As a result, European and American debates on agricultural change intertwine, especially with regard to calls for a more environmentally sustainable agriculture (Hassanein, 1999; Pretty, 2002; Jackson and Jackson, 2002; Marsden, 2003). This highlights similarities in changing nature-society interactions across diverse geographical spaces, in particular with regard to the way society views agricultural pathways. As McCarthy (2005) emphasised, although the terminology for these changes in agricultural trajectories may vary between regions of the developed world, the globalised processes underlying these changes are increasingly converging. Echoing notions of complexity (O‘Sullivan, 2004; Pavlovskaya, 2004) and hybridity (Whatmore, 2002), emergent farm transitional pathways in developed countries emphasise a kaleidoscope of different approaches ranging from often environmentally malign globalised agri-businesses to more environmentally benign small-scale family farming. It is this wide spectrum of opportunities open to farmers that is increasingly referred to as the ‗multifunctional‘ spectrum of decision-making (Hollander, 2004; Holmes, 2006; Wilson, 2007, 2008a). Indeed, the last twenty years or so have seen the use of the notion of ‗multifunctional agriculture‘ in a wide variety of contexts. Multifunctionality has been approached from various vantage points including economic approaches that focus on commodity and non-commodity production of goods generated by modern agriculture with associated ‗externality problems‘ (e.g. Vatn, 2002; Van Huylenbroek and Durand, 2003), policy-based approaches that see the policy environment as a key driver for multifunctionality (e.g. Potter and Burney, 2002; Potter and Tilzey, 2005), and ‗holistic‘ approaches that also incorporate the strengthening of social, economic and environmental capital and changing societal perceptions of farming as key components of multifunctionality (e.g. Marsden, 2003; Clark, 2005). As a result, in the Anglo-American context, the last twenty years have seen the emergence of some of the most interesting and challenging theoretical debates about the nature and future trajectories of modern agricultural and rural systems from a variety of economic, social, political and environmental stances. Some European and American commentators argue, for example, that we are facing the end of a conventional agriculture that had, as its sole purpose, the production of food and fibre, and that a new ‗post-agrarian‘ agricultural regime may be emerging that has much wider purposes, including the

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‗production‘ of nature and new spaces for leisure (Blank, 1998; Marsden, 1999; see also Salamon, 2002, for the American Midwest). Yet, although multifunctionality has been much debated in the literature, it is remarkably poorly researched in terms of decisions, behaviour and intentions of farmers and those stakeholders who influence farming decisions at the grassroots level (Wilson, 2007, 2008a). This is particularly surprising as it is at the farm level that the most direct expression of multifunctional action and thought, and the most important level for mediation of multifunctional influences exerted by other scales in the hierarchies of multifunctionality can be found (Clark, 2005). Buller (2005, ii), therefore, suggested that ―what is missing is a more holistic evaluative framework for assessing the broader multifunctional contribution of agriculture‖. This critique is also reflected in recent calls for a more normative evaluation of multifunctionality that should be applicable in various geographical contexts (e.g. Van Huylenbroek and Durand, 2003, for the EU; Losch, 2004, and Wilson, 2008b, for global multifunctionality pathways). This article has particularly emerged out of the growing dissatisfaction with the uncritical and weakly theorised use of the notion of ‗multifunctionality‘ in contemporary debates on agricultural change. Current understandings of multifunctionality are relatively reductionist and based on relatively narrow economic and policy-based approaches predicated on structuralist interpretations of agricultural and rural change (Garzon, 2005). Nonetheless, recently a more holistic view of multifunctionality has emerged that places more emphasis on the interlinkages of the concept with rural development, culture, the consumption countryside, societal needs, agency-led patterns and processes of agricultural and rural change, as well as environmental issues (e.g. Freshwater, 2002; Holmes, 2006). Yet, the predominant structuralist interpretations of multifunctionality have suffered from discursive insularity that has confused rather than clarified what multifunctionality could be about (Clark, 2005, 2006). As a result, the notion of multifunctional agriculture is still largely understood as a policy-led process describing current agricultural trends in Europe, rather than as a normative concept explaining global agricultural change. This Euro-centricity of multifunctionality, interpreted by many as a ‗smokescreen‘ to defend the continuing productivist subsidy culture of European agriculture, has emerged as a particularly problematic issue (Potter and Burney, 2002). Many have questioned the applicability of the term beyond Europe, because multifunctionality is perceived by many non-European scientists and policy-makers as a ‗European policy project‘ with little relevance to countries such as the U.S. or Australia for example (McCarthy, 2005; Cocklin et al., 2006). Problems surrounding multifunctionality are, therefore, linked to the early (mis)appropriation of the term by European policy-makers eager to use it as a tool for shallow policy decision-making to further productivist subsidy-oriented Common Agricultural Policy (CAP) goals in light of mounting World Trade Organisation (WTO) pressures (Potter and Tilzey, 2005). In my view, this gave early ‗legitimacy‘ to the notion of multifunctionality before it had been thoroughly conceptualised at an academic level, and also explains why in the U.S. – outside the framework of the CAP – the notion of multifunctional agriculture has not (yet) been widely incorporated in agricultural and rural policy discourses. Many authors have also suggested that agricultural multifunctionality is a new process, i.e. something that did not exist before popularisation of the term by policy-makers. The result has been a notion of multifunctionality largely predicated on its relevance for policybased decision-making (Freshwater, 2002; McCarthy, 2005), characterised largely by short-

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termism, weak theorisation and pragmatism. Ironically, this may have, in turn, lessened the need for conceptual and theoretical investigations of what multifunctional agriculture could mean, as the term was already part of an established ‗mainstream‘ political and economic discourse by the early 1990s1. The result of this anachronistic process has been an understanding of multifunctionality that has not yet gelled into a coherent workable framework for fully understanding contemporary agricultural change. Thus, none of the debates on multifunctionality have shed sufficient light on what the notion of multifunctionality implies, who the beneficiaries should be and how it ought to be put into practice – in other words, multifunctionality has remained poorly linked to wider debates in the social sciences (Wilson, 2007). We, therefore, urgently need a new concept of multifunctionality that is conceptually better anchored in current debates on agricultural change, and a model that draws on existing holistic debates of multifunctionality that goes beyond economic and policy-based understandings and that is applicable globally. This article, therefore, aims at providing a new understanding of ‗multifunctional agriculture‘. It conceptually anchors the notion of multifunctional agriculture within what I term the productivism/non-productivism spectrum of decision-making, and suggests that this enables a normative view of multifunctionality based on strong, moderate and weak multifunctional agricultural pathways. The article will particularly argue that academic and scientific debates need to re-appropriate the notion of multifunctionality from policy-makers who have used the term in a rather cavalier fashion, expose it to thorough conceptual analysis, and reconceptualise it into a normative concept that can be used to explain agricultural change in any region of the world. Building on emerging work by human geographers and other social scientists (e.g. Evans et al., 2002; Holmes, 2002, 2006; Marsden, 2003; Mather et al., 2006), the article will argue that this normative view enables the challenge of policy-based and economistic conceptualisations of multifunctionality. My background as a human geographer will be vital, as the discipline of geography – possibly more than any other social science discipline – enables insight into a variety of dimensions that form key building blocks of conceptualisations of multifunctional agriculture. The article suggests that the ‗multifunctionality spectrum‘ suggested here provides a robust framework with which to understand agricultural change. In particular, and echoing Bell‘s (1994, 2004) call for a more ‗moral‘ agriculture in the U.S., the article argues that the normative view enables identification of strong multifunctionality as the morally, economically and environmentally ‗best‘ pathway. The article concludes by arguing that many research challenges lie ahead of human geographers and other social scientists, in particular as future methodologies for assessing multifunctional quality need to move away from absolute and ‗measurable‘ indicators and, instead, adopt more qualitative approaches to assess subtle attitudinal and identity-related shifts that form crucial components of the multifunctionality spectrum.

1

Contrast this with the comparable notion of ‗sustainability‘, first theorised at academic level during the 1980s and then gradually appropriated by policy-makers from the 1990s onwards after it had been exposed to thorough academic debate.

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2. THE PRODUCTIVISM/NON-PRODUCTIVISM SPECTRUM OF AGRICULTURAL DECISION-MAKING In order to situate current debates on multifunctionality, we need to briefly review some of the key conceptual debates that have recently shaped research on agricultural and rural change. Over the past two decades, European researchers in particular have suggested that agricultural and rural change can best be conceptualised as a shift from ‗productivist‘ to ‗postproductivist‘ agriculture (the p/pp transition) (Marsden et al., 1993; Ward, 1993). In its simplest form, and largely based on the U.K. agricultural and rural experience, the productivist era has been described as lasting from the end of the Second World War to about 1985. It has been broadly characterised as a period when the main preoccupation of agriculture was maximum food production to ensure self-sufficiency, as a time when agriculture held a central ‗hegemonic‘ position in society, and as an era characterised by a small but powerful and tight-knit agricultural policy community. Productivism has also been associated with a ‗strong‘ state model with predominantly top-down policy-making structures, and with farming techniques that have often relied on the application of high external inputs and the use of heavy machinery that have caused severe environmental degradation (Evans et al., 2002; Mather et al., 2006). It has then been argued that the transition to a post-productivist era began in the 1980s and has lasted to the present day (Ilbery and Bowler, 1998). Post-productivism has generally been seen as the ‗mirror-image‘ of productivism, i.e. as an agriculture characterised by a reduction in the intensity of farming through extensification, diversification and dispersion of agricultural production; an associated move away from agricultural production towards ‗consumption‘ of the countryside; the loss of the central position of agriculture in society characterised by ‗contested‘ countrysides; a widening of the agricultural community to include formerly marginal actors at the core of the policy-making process; and a weakening of the state role in policy-making powers with a more inclusive model of governance that also includes grassroots actors (Marsden et al., 1993; Mather et al., 2006). Simultaneously, farming techniques in the post-productivist era are seen to be more in tune with environmental protection through reduced application (or total abandonment) of external inputs (e.g. organic farming). During the post-productivist era the main threats to the countryside are generally perceived to be agriculture itself rather than urban or industrial development (Marsden, 2003). However, recently critics have argued that the notion of a full temporally linear transition towards post-productivism can not be substantiated empirically (Wilson, 2001, 2007; Evans et al., 2002). It has also been argued that the notion of the p/pp transition has suffered from discursive insularity focused largely on the experience of the U.K. (and to a lesser extent a few other Western European countries). As a result, commentators from other global regions have argued that the notion of ‗post-productivism‘ finds little resonance with agricultural and rural processes in their territories (e.g. Argent, 2002, and Holmes, 2002, for Australia; Wilson and Rigg, 2003, for developing countries). Indeed, in the U.S. context, for example, little reference is made to notions of a p/pp transition in discussions of agricultural and rural change (McCarthy, 2005). This suggests that the p/pp model may not be robust enough to explain agricultural change and that it may be a gross oversimplification of complex transitional processes. Critical studies that have dissected the notion of ‗post-productivism‘ as

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yet another ‗post-ism‘ with little tangible substance have argued that the so-called ‗transition‘ towards post-productivism is instead characterised by temporal non-linearity (productivist and post-productivist processes occur simultaneously), spatial heterogeneity (there are a multitude of productivist and ‗post-productivist‘ spaces often occurring side-by-side) and structure-agency inconsistency (i.e. structural processes, such as policies and regulation, and agency-related processes, such as farmer action and thought, have not moved at the same pace through the postulated ‗post-productivist‘ transition) (Holmes, 2002; Wilson, 2007). Potter and Tilzey (2005, 13; emphasis added), therefore, suggested that primary production should be seen as ―an increasingly bifurcated agricultural industry, comprising both productivist and post-productivist sectors‖, where ―productivist and post-productivist functions are delivered side by side‖. Clark (2003, 28-29) also emphasised that ―productivism and post-productivism [should] be seen as a ‗spectrum‘ rather than a duality, with post-productivist forms of agriculture often coexisting in rural regions alongside productivist patterns of farming‖. That such productivist and post-productivist action and thought occur in multidimensional coexistence leads one to question the implied directionality of the productivist/postproductivist debate. Post-productivism has, therefore, not replaced productivism. Both processes co-exist temporally, spatially and structurally (Goodman, 2004), and postproductivist agriculture runs concurrent with (rather than ‗counter‘ to) productivism (Halfacree, 1999). These critiques make the notion of a shift towards post-productivism difficult to substantiate (Evans et al., 2002; Holmes, 2006). Yet, the main conceptual problem rests less with the notion of ‗productivism‘, but rather with the concept of ‗post-productivism‘ (especially with the prefix ‗post‘) and the suggestion of a transition from one organisational state to another. As novelist Margaret Atwood (1988, 86) succinctly argued, ―post this, post that … everything is post these days, as if we‘re all just a footnote to something earlier that was real enough to have a name of its own‖. Elsewhere I, therefore, suggested that a reconceptualization of the p/pp transition model is necessary if this model (or parts thereof) is to have wider scientific credibility in the future (Wilson, 2007). The failure of the reductionist p/pp transition model to explain contemporary agricultural change means that the continued use of the term ‗post-productivist‘ is untenable. In my view, ‗post‘ implies something following after something else, and the evidence does not support the suggestion that a coherent and conceptually well defined era has ‗followed on‘ from the productivist era. This is not to say that the p/pp transition debate has been futile. On the contrary, as with many theoretical propositions it has usefully forced social scientists (including many human geographers) to re-evaluate conceptions of agricultural change. As both Evans et al. (2002) and Mather et al. (2006) argued, the p/pp model has had real heuristic value as a descriptor of agricultural change. I, therefore, do not wish to do away entirely with useful terms and terminologies that have evolved from these debates. In line with Marsden (2003), I wish to argue that the term ‗productivism‘ continues to be relatively robust, as all indications are that productivist tendencies can be identified in contemporary action and thought affecting agriculture and rural areas – especially if shorn of the assumption that productivism represents an agricultural ‗epoch‘. This is particularly the case as the indicators of ‗productivism‘ have, to some extent at least, withstood the test of time, and are based on tangible, at times measurable, evidence (Mather et al., 2006). This has also been confirmed for advanced economies outside of Europe where the utility of the concept of ‗productivism‘

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has been much less questioned than ‗post-productivism‘ (Holmes, 2002, 2006; Wilson and Memon, 2005). My main criticism is, therefore, with the implied transition towards a so-called postproductivist era. Instead, agricultural action and thought should be viewed as occurring along a temporally non-linear and spatially heterogeneous spectrum of decision-making possibilities. This acknowledges the fluidity and flexibility of agricultural action and thought. If we acknowledge that such a spectrum exists that continues to include productivist elements at one end, we, therefore, need to find a term that better encapsulates the ‗opposite end‘ of productivism than the current term ‗post-productivism‘. I suggest that we should use nonproductivism as the opposite of productivist action and thought, arguing that this is a true opposite (which ‗post-productivism‘ never was) that allows for the juxtaposition of temporal, spatial and structure/agency-related pathways of agricultural decision-making2. I will refer to this as the revised productivism/non-productivism model (the p/np model). The substitution of ‗post-productivism‘ with ‗non-productivism‘ is more than a semantic or syntactic change: while there is an implicit notion of temporal linearity in conceptualisations of ‗postproductivism‘ (i.e. something following after something else), ‗non-productivism‘ is a neutral term that simply denotes action and thought that is ‗not productivist‘. Thus, while nonproductivism will contain many ‗indicators‘ used to conceptualise post-productivism in the past, it does so without the underlying assumption that there is necessarily a temporally linear movement towards such action and thought over time.

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3. THE MULTIFUNCTIONALITY SPECTRUM In this section I wish to link the discussion on productivism and non-productivism with the notion of multifunctionality. I suggest that the conceptual territory of multifunctionality occupies the (conceptual and real) space between the extreme pathways of productivism and non-productivism (Figure 1). I will refer to this as the multifunctionality spectrum (the MF spectrum). In line with Knickel and Renting (2000), multifunctionality is seen here as the antithesis of monofunctionality which is closely associated with the extreme productivist end of the MF spectrum in which agriculture serves relatively ‗narrow‘ functions of food and fibre production (see also Wilson, 2001; Potter, 2004). Multifunctionality is, thus, about multiple functions of agricultural land use, practices and thoughts, as well as about how such agricultural processes influence rural areas and communities and societal conceptions of farming and agriculture (Van der Ploeg, 2003; Bell, 2004). Contrary to most conceptualisations of multifunctionality as a static state, this new view of multifunctionality sees it at a dynamic transitional process (see also Holmes, 2006). Echoing work by Sayer (1991), Murdoch (1997) and Gerber (1997), I argue that the MF spectrum emphasises the non-dualistic but symmetrical perspective on agricultural change that is increasingly gaining ground in agricultural and rural research (see in particular Evans et al., 2002, and Marsden, 2003, for Europe, and Hassanein, 1999, and Bell, 2004, for the U.S.). Multifunctional 2

The notion of ‗non-productivism‘ has been used by others in the past: e.g. Tovey, 2000, in the context of Irish agri-environmental policy; Potter and Tilzey, 2005, with reference to non-productivist forms of agrarianism; Gallardo et al., 2003, with reference to ‗non-productive‘ functions of agriculture not valued by the market (see also Rapey et al., 2004; Buller, 2005; Mather et al., 2006).

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agriculture is, therefore, characterised by manifold and at times highly complex development pathways bounded by productivism and non-productivism. Figure 1 shows such pathways that vary over time for specific actors/actor groups (e.g. farm development pathways ‗a‘-‗h‘), depending on the ‗mix‘ of productivist and non-productivist drivers. This illustrates the value of the p/np spectrum for situating agricultural actors/processes with a sense of directional impetus towards strong multifunctionality (see below for a definition of ‗weak‘ and ‗strong‘ multifunctionality).

Figure 1. Farm development pathways and the multifunctionality spectrum. (Source: Wilson, 2007, 284)

Several conceptual issues emerge from this. First, this means that there will be few actors whose actions and thoughts will be exclusively productivist or non-productivist. Any agricultural action will almost always contain some productivist and non-productivist elements. We, therefore, witness the multidimensional coexistence of productivist and nonproductivist tendencies, albeit with a multitude of different, and highly individual, expressions of such coexistence of what can be, at times, highly contradictory pressures (Wilson, 2008a)3. Second, opportunities for multifunctional action and thought will always be highly dynamic over time, with some actors moving towards non-productivist action and thought, and some moving towards the productivist end of the spectrum. Others may, indeed, move beyond non-productivism and leave farming altogether. As with any model attempting to understand complex processes, the MF spectrum can be seen as yet another reductionist attempt at conceptualising complexity. Yet, as Holmes (2006, 157) succinctly argued in the context of Australian multifunctionality, ―although incomplete 3

A stakeholder situated exactly at the non-productivist end of the spectrum or ‗beyond agriculture‘ is likely to be no longer involved in farming or agricultural activities and may, therefore, be ‗outside‘ the multifunctional agricultural regime (see Wilson, 2008a).

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and capable of encompassing only one dimension in multidimensional contexts, the spectrum analogy, applied to the relative power or importance of two contending interests [i.e. productivism and non-productivism], can at times provide a useful, partial appraisal of appropriate (or probable) outcomes‖ (see also discussions of the ‗hybridity‘ of societal transitions by Whatmore, 2002, and Nederveen Pieterse, 2004). Contrary to the binary unilinear notions of productivism and post-productivism, the notion of a spectrum enables us to situate and understand multiple actions and processes simultaneously in a non-linear and spatially heterogeneous way. In particular, it brings agriculture ‗back in‘ as a significant shaper of the countryside and rural areas, both for productivist and non-productivist purposes. Thus, almost any agricultural/rural action and thought will contain elements of both productivism and non-productivism (territorialisation) (Walford, 2003; Knickel et al., 2004). The MF spectrum shows parallels with Marsden‘s (2003) spatiality of the p/pp transition (which he termed the agro-industrial, post-productivist and rural development dynamics). The MF spectrum enables us to bring together Marsden‘s three dynamics within one unifying concept that is both spatially and conceptually robust. In this context, the MF spectrum highlights that complexity does not necessarily trump simplification, especially as it helps in seeking the greatest explained variance in agricultural decision-making while suggesting the fewest possible number of ‗variables/indicators‘ to understand agricultural change. In addition, the MF spectrum also fits with Marsden‘s (2003) acknowledgement of the coexistence of ‗neo-productivist‘ and multifunctional pathways, while also drawing on debates on ‗alternative rural development‘ (Goodman, 2004) as well as Clark‘s (2005, 2006) useful conceptualisation of multifunctionality into different conceptual ‗levels‘ including multifunctional policy goals, outputs and territorial functions4. Yet, the MF spectrum suggested here goes well beyond mere issues of processes and production. Multifunctionality should mean that elements of both productivism and nonproductivism will at any time and in any space influence action on the ground that will result in multiple development pathways. The spectrum particularly acknowledges that highly productivist action and thought can still be ‗multifunctional‘ (see discussion below on ‗weak‘ multifunctionality) (Goodman, 2004; Holmes, 2006). While the notion of post-productivism implied a directionality of action and thought towards a specific goal, the MF spectrum allows for multidimensional coexistence of both productivist and non-productivist spaces. The spectrum, thus, enables us to conceptualise productivist and non-productivist action and thought at any scale and in any territorial and temporal context, and across various stakeholder group interests (see also Winter, 2005), and allows an understanding of the synchronous coexistence of pressures to maintain productivist competitiveness of agriculture on the one hand, and the consolidation of an agricultural model based more on nonproductivist principles on the other. It also builds on the OECD (2001) definition of multifunctional agriculture that argued that the term should be interpreted as a characteristic of agriculture that produces multiple and interconnected effects. 4

For Europe, see also Ward‘s (1993) notion of the ‗two-track countryside‘, the ‗production-consumption spectrum‘ by Marsden (1999), or Marsden‘s (2003) notion of the ‗bifurcation‘ of farmer roles between production and consumption spaces. Similarly, there are overlaps with Lowe et al.‘s (1997) notion of multifunctionality as the ‗third way‘, and with Van der Ploeg‘s (2003) concept of the three-dimensional farm in which the arenas of the ‗rural area‘, the ‗mobilisation of resources‘ and the ‗agro-food supply chain‘ lead to a complex positioning and repositioning of agricultural and rural actors along a spectrum of decision-making opportunities. For the U.S., see, in particular, Bell‘s (2004) critical analysis of the increasingly bifurcated sociology of US farming, and Salamon‘s (2002) notion of agrarian/post-agrarian change in the American Midwest.

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Most importantly, the MF spectrum suggests that agriculture has always been multifunctional in some way or another (see also Larsen, 2005, on multifunctional forests) and that multifunctionality has been present since the emergence of the first agricultural societies, albeit with a highly differentiated spectrum of multifunctional ‗quality‘ (see Section 4). As a result, I disagree with Mather et al. (2006, 452) who argued that multifunctionality ―is not an obvious [conceptual] improvement on post-productivism‖, or with Vandermeulen et al. (2006) who suggested that ‗conventional‘ farming systems should be transformed into ‗multifunctional‘ ones. I also disagree with those who suggest that multifunctionality exemplifies a new process and a shift away from productivism (e.g. Walford, 2003; Potter, 2004) or a shift from post-productivism to multifunctionality (e.g. McCarthy, 2005; Clark, 2006). In my view, both productivism and non-productivism form inherent components of multifunctional agricultural processes, and the artificial division made between ‗conventional‘ and ‗multifunctional‘ agricultural businesses by some authors (e.g. Hollander, 2004; Clark, 2006) should, therefore, be questioned. The MF spectrum differs markedly from economistic and policy-based conceptualisations of multifunctionality, in particular economistic interpretations that only associate multifunctionality with non-commodity or non-competitive forms of agriculture (e.g. Gallardo et al., 2003). Similarly, conceptualisations of multifunctionality predicated on policy-based approaches that place heavy emphasis on the policy environment as a driver for guiding multifunctionality action (e.g. Potter and Burney, 2002) only provide partial answers. In particular, the MF spectrum goes well beyond conceptualisations that place emphasis on neo-liberal agricultural trade discourses and the WTO as global policy drivers for the seemingly new emergence of multifunctional agriculture (e.g. Hollander, 2004; Potter and Tilzey, 2005). In this sense, the MF spectrum challenges the Euro-centric paradigm that claims that European farming landscapes are more multifunctional than others (see also Hollander, 2004, and McCarthy, 2005, for similar critiques from a U.S. perspective). Indeed, the new multifunctionality concept can be applied in any location around the world as it sees policy change as only one of many components of multifunctionality and is, therefore, largely independent of the history of policy-making trajectories specific to a given territory (e.g. the EU) – a problem that has marred the exporting of the ‗European multifunctionality concept‘ to non-European geographical contexts (Cocklin et al., 2006). Most importantly, and contrary to the proposition that we may witness different types of ‗multifunctionality‘ in the developed and developing world (e.g. Bresciani et al., 2004), multifunctionality conceptualised as a decision-making spectrum no longer needs to be associated with a Euro- or Northern-centric policy discourse restricted by anti-development rhetoric (Wilson, 2008b).

4. TOWARDS A NORMATIVE VIEW OF MULTIFUNCTIONALITY The key advantage of the MF spectrum is that it enables a normative view of multifunctionality. The notion of a spectrum inevitably implies normative judgements about the ‗value‘ and ‗direction‘ of transitional pathways. In other words, multifunctionality can and should not be a neutral term. Thus redefining multifunctionality is about accepting that priorities need to be set for specific actions and processes influencing agricultural (and rural) development pathways.

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Conceptualising Weak, Moderate and Strong Multifunctionality I propose that the MF spectrum comprises three conceptual levels: ‗weak‘, ‗moderate‘ and ‗strong‘ multifunctionality (Figure 2; see also Figure 1 above). The use of these valueladen terms is deliberate. Weak multifunctionality is seen here the ‗worst‘ type of multifunctionality close to the productivist decision-making pathway of decision-making, while strong multifunctionality is the ‗ideal‘ model that all societies should be striving for. Strong multifunctionality will be conceptualised as engendering synergistic mutual benefits between individual actions and processes and, therefore, as good for the environment, good for farmers, good for socio-rural relationships and governance structures and good for food quality (see also Knickel et al., 2004). Strong multifunctionality is, therefore, predicated on strong natural, social, moral and cultural capital (Bourdieu, 1983; Bryant, 2005; see also Bell, 1994, 2004, for the U.S.). Adopting such a quality-based approach is not new. Potter and Tilzey (2005), for example, also referred to ‗weak‘ and ‗strong‘ versions of multifunctionality, albeit in the context of a policy-based conceptualisation, while both Hollander (2004) and Guillaumin et al. (2004) suggested that the notion of multifunctionality requires a multi-faceted and variable conceptualisation5. Agricultural systems characterised by weak multifunctionality have weak environmental sustainability, in particular through external-chemical-input-heavy ‗neotechnic‘ farming practices predicated on high farming intensity6 and productivity often characterised by relative uniformity of crops or animals (monofunctionality) (cf. Harris, 1978). These systems also display locally disembedded and vertically integrated rural/farming communities that show little internal socio-political cohesion, long food chains (i.e. little redistribution of knowledge and locally produced food within the immediate locality), and tendencies of disempowerment of local actors and stakeholder groups linked to the rising power of corporate retailers (Goodman, 2004). Pretty (1995) referred to such processes as the ‗suffocation of local institutions‘, while Bell (2004, 39), using the example of Iowa in the U.S., associated this with the experience of a ―disappearing rural culture‖. The weak multifunctionality regime will, therefore, also often show tendencies of strong integration into the global capitalist market, with a strong agricultural export orientation that allows/forces agricultural actors to bypass their immediate rural neighbourhood for sale of agricultural commodities (Marsden, 2003; Lang and Heasman, 2004). This regime is also associated with the globalised production of standardised products, highlighting the increasing role of ‗downstream‘ sectors in shaping at distance the farm sector. Most crucially, globalisation leads to a progressive lack of self-reliance and the loss of local social embeddedness of farmers (Goodman, 2004). From an occupational identity perspective, landholders on weakly multifunctional farms would see production of food and fibre as their foremost goal as a ‗farmer‘ (Burton and Wilson, 2006).

5

For debates on ‗sustainable development‘ many commentators have suggested an equally value-laden spectrum, ranging from weak to strong sustainability, where strong sustainability is (often implicitly) expressed as the ultimate societal goal (e.g. Millington and Williams, 2004). 6 ‗Intensive‘ farming is seen here as a type of farming that attempts to maximise food and fibre production to the very limit of the productive capacity of the agro-ecosystem (the opposite of ‗extensive‘ farming) (Pretty, 1995, 2002; Jackson and Jackson, 2002; Bell, 2004).

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Figure 2. Indicators of weak, moderate and strong multifunctionality. (Source: Wilson, 2007, 229) Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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It is useful to link the depth of diversification activities with Bowler‘s (1992) model showing different ‗degrees‘ of diversification (Figure 3). Thus, weakly multifunctional farm holdings are likely not to diversify at all or, if diversification is taking place, to diversify into diversification pathways described by Bowler (1992) as ‗maintaining a viable enterprise‘ by either following a productivist industrial model pathway or by embarking on agricultural diversification. In a similar vein, pluriactivity is only weakly developed (Clark, 2005). In addition, weak multifunctionality may also be encouraged by action and thought beyond the farm gate, as farming/rural populations will see ‗farming‘ and ‗agriculture‘ as almost exclusively concerned with productivist food and fibre production (hegemonic role of agriculture is not questioned) (Pretty, 2002; Guillaumin et al., 2004).

Figure 3. Multifunctional quality and farm diversification pathways. (Source: author, adapted from Bowler, 1992)

Moderate multifunctionality, meanwhile, combines elements of both productivist and non-productivist action and thought that, in their entirety, more or less balance each other out. It, therefore, occupies the ‗middle ground‘ of the MF spectrum. These farming systems have higher levels of environmental sustainability than weak multifunctionality systems, but are

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still often characterised by environmental degradation caused by agriculture. Actors in moderately multifunctional systems have higher levels of local embeddedness, and show some evidence of horizontally integrated rural/farming communities with close(r) interaction between local rural communities and their farming populations. Yet, in these systems, many farmers continue to operate ‗outside‘ of the rural community and may not necessarily operate within short food chains. Marsden (2003) highlighted that the increasingly complex interlinkages between retailers and processors are producing interesting ‗mutations‘ in supply chains that can be seen to combine both weak and strong multifunctionality characteristics. Similarly, Holmes (2006) highlighted how many rural communities in Australia currently straddle the line between strong and weak multifunctional quality (which he terms ‗complex multifunctionality‘) where there is, yet often untapped, potential of integration of productivist and non-productivist processes. Moderately multifunctional farmers generally show tendencies for lower farming intensity and productivity than their weakly multifunctional counterparts, but they still farm in relatively intensive ways. Diversification activities are more likely to fall into Bowler‘s (1992) pathway of ‗non-farm income diversification‘ (see Figure 3 above) that involves both structural diversification (redeployment of farm resources into new non-agricultural products or services; e.g. farm gate sales, farm tourism) and income diversification through more elaborate forms of pluriactivity (use of non-specific farm household assets for nonagricultural activities unconnected to the farm) (Clark, 2005). Further, on moderately multifunctional farms integration into the global capitalist market will be less pronounced than in weakly multifunctionality systems, but most farmers will produce for a market that lies well outside their immediate rural community. In addition, in moderately multifunctional agricultural regimes some mental changes through more open-minded farming and rural populations will have taken place, although few stakeholders will see ‗farming‘ and ‗agriculture‘ as processes that go entirely beyond productivist food and fibre production, mass production and profit maximisation. Finally, wider society in the moderately multifunctional regime will have partly accepted that the nature of ‗farming‘ and ‗agriculture‘ is in the process of change, but will still accord a relatively important role to agriculture and agricultural production as key pillars of economic and social development. Strong multifunctionality is characterised by action and thought located close to the nonproductivist pathway boundary of the MF spectrum, with strong social, economic, cultural, moral and environmental capital (Bourdieu, 1983; see Logsdon, 1994, Hassanein, 1999, Jackson and Jackson, 2002, and Bell, 2004, for the U.S.). This notion of strong multifunctionality, therefore, differs from Hollander‘s (2004) policy-oriented notion of strong multifunctionality, but shows parallels with Bryden‘s (2005) ‗broad definition‘ of multifunctionality based on a more holistic interpretation that also includes social and cultural capital. High environmental sustainability plays a key role in strongly multifunctional systems, based on often highly diverse assemblages of crops and livestock often akin to ‗palaeotechnic‘ types of agricultural production (Harris, 1978; Belletti et al., 2003). Strongly multifunctional systems also include activities with a low carbon footprint and are predicated on agro-food chains that reduce the need for long-distance food transport. Actors in the strongly multifunctional agricultural regime, meanwhile, show strong tendencies for local and regional embeddedness, in particular through horizontally integrated rural/farming communities with very close interaction between local communities through reciprocal ruralagricultural relationships characterised by strong lateral actor linkages and newly empowered

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stakeholder groups (Goodman, 2004; see also Buller‘s, 2005, notion of ‗transversal linkages and networks‘ that permit social and economic capital to be retained within rural communities). Bryden (2005) referred to the important linkage between strong multifunctionality and ‗quality of life‘ in rural areas, also highlighted by French researchers through preservation of the ‗social and cultural tissue‘ of rural areas and through facilitation of processes of ‗cohabitation‘ of agricultural/non-agricultural actors (Guillaumin et al., 2004). In line with similar conceptualisations of multifunctional forestry (e.g. Freshwater, 2002; Larsen, 2005), social and cultural capital are particularly well developed in strongly multifunctional agricultural systems. Such embedded social networks include activities that will help provide new income and employment opportunities for the agricultural sector (i.e. new or strengthened relationships between the agricultural sector and rural society), as well as so-called ‗associational interfaces‘ that are both informal but highly significant in establishing trust, common understandings, working patterns, and different forms of cooperation between stakeholder groups in the food supply chain (Pretty, 2002; Marsden, 2003; Clark, 2005). Thus, partnerships and close interpersonal linkages of farmers with other grassroots actors in the locality will be particularly well developed (Meert et al., 2005), and strong governance structures will be evident (Wilson, 2004). In countries with ethnic minorities in rural areas (e.g. U.S., Australia, New Zealand, Canada) local embeddedness will also mean empowerment and inclusion of ethnic groups (e.g. American Indian communities in the U.S.; Aborigines in Australia) in agricultural/rural decision-making processes (Argent, 2002; Holmes, 2006; McCarthy, 2006). Strongly multifunctional systems will also be characterised by short food chains and high(er) food quality associated with more differentiated food demand by consumers (the ‗quality turn‘; Goodman, 2004), the capacity to re-socialise or re-spatialise food, a demand for food products with high (often regionally based) symbolic characteristics, the creation of additional value for rural regions, and enlightened visions about food and health (Lang and Heasman, 2004). Venn et al. (2006) emphasised that ‗alternative‘ and ‗conventional‘ food networks cover a wide (and at times overlapping) spectrum of multifunctional possibilities, with alternative food networks often showing strongly multifunctional tendencies. As a result, strongly multifunctional food consumption habits can be interpreted as a countervailing force to Popkin‘s (1998) notion of the ‗nutrition transition‘ (rapidly declining dietary quality that is a particular problem in the U.S. and many other developed countries). Strongly multifunctional systems will also display low farming intensity and productivity (Evans et al., 2002), in most cases characterised by a reluctance to use Green Revolution or genetically modified crops (Pretty, 2002; Wilson, 2008b), and will also emphasise carbon neutral food production and transport. There will also be a revaluation of existing farm household knowledge (e.g. of women and young people) and the need to develop new skills and professional abilities (see Belletti et al., 2003, for Italy, or Bell, 2004 for the U.S.). Thus, strongly multifunctional farming systems are likely to embark on Bowler‘s (1992) diversification pathways that lead to reduced farm activity (see Figure 3 above), or, as Knickel et al. (2004) suggested, through the ‗deepening‘ of diversification activities (Meert et al., 2005). More controversially, some have argued that strongly multifunctional farms are more likely to be weakly integrated into the global capitalist market, as only partial or complete disengagement from global capitalist (productivist) networks and agriculture liberalisation processes will enable on-farm implementation of above dimensions of strong

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multifunctionality (e.g. Goodman and Watts, 1997; Wilson, 2007). This was echoed by McCarthy (2005) who emphasised that strongly multifunctional systems are most threatened by trade liberalisation and globalisation, and by Hollander (2004) who argued that strong multifunctionality may be a form of resistance against global neoliberalism. As a result, strong multifunctionality will also imply that substantial mental changes have taken place among various stakeholder groups, in particular through open-minded farming and rural populations who see ‗farming‘ and ‗agriculture‘ as processes that go well beyond productivist food and fibre production. Strongly multifunctional agriculture, therefore, can be seen to act as a bridge between agricultural practices and the wider community (Clark, 2006). The ‗strongest‘ level of multifunctionality can be achieved if all of the above processes and activities occur simultaneously, based on what Knickel and Renting (2000) called selfreinforcing multiplier effects of multifunctional activity, or what Van der Ploeg (2003) called clusters of compatible and mutually reinforcing multifunctional activities. The multifunctionality spectrum implies that certain farm systems will show tendencies for stronger multifunctionality than others, based on their more favourable positioning with regard to the multifunctionality drivers highlighted in Figure 2 above. Most agri-businesses, for example, will show tendencies of weak to moderate multifunctionality as they are often large, vertically integrated (i.e. well embedded into national or global agro-commodity chains), and well capitalised (Barlett, 1993; Walford, 2003; Adams, 2003; Wilson, 2007, 2008a). In a developing countries context, this would also include large plantation farms with their often high capitalisation and export-oriented nature (Wilson, 2008b). As Marsden (2003) highlighted, many of these farms have been placed on a technologically driven cost-price squeeze which has led them to race towards reduced prices in the increasingly intensified ‗standard‘ agricultural product sector often predicated on ‗disembedded‘ agro-commodity chains (see also Bell, 2004, for agri-industrial farms in Iowa). This is not to say, however, that agri-businesses may not also embark on moderate or even strong multifunctionality pathways (‗smart farming‘) with some of their farm management decisions (e.g. niche market pathways or set-aside of land for conservation) (Jackson and Jackson, 2002; Van der Ploeg, 2003). Farms in peri-urban fringe areas, meanwhile, often have potential for strongly multifunctional pathways involving various multifunctional diversification activities (e.g. golf courses, farm zoos, etc.) that exploit the farm location near large centres of population (Vandermeulen et al., 2006; Wilson, 2008a). Thus, Luttik and Van der Ploeg (2004, 210) argued that ―in the mosaic of agricultural land in near-urban agriculture, there is a special role for multifunctionality‖. There is also a tendency in the literature to suggest that farms with mixed food and fibre production may show tendencies for more moderate/strong multifunctionality pathways than their monocultural counterparts, especially if they are located in areas with good tourism and diversification potential (Hassanein, 1999; Jackson and Jackson, 2002; Walford, 2003; Clark, 2005). Mixed farms are often characterised by less intensive agricultural production practices, higher levels of diversification, better horizontal integration into the local rural community (due to more complex product and workforce differentiation), and may have owners who see the role of agriculture in more moderately or strongly multifunctional ways than their more specialised neighbours. As Swagemakers (2003, 198) argued, ―the multifunctional farm is, in essence, a mixed farm‖ (see also Logsdon, 1994, and Jackson and Jackson, 2002, for the U.S.). This is also true for subsistence farms in developing countries that are often characterised by mixed production and weak integration into the global capitalist agro-food market (Pretty, 1995; Losch, 2004), although I

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recently suggested that these farms may be rapidly losing multifunctional ‗quality‘ due to their increasing embeddedness into globalised agro-commodity chains (Wilson, 2008b). Throughout the world, farm specialisation, therefore, may have an important bearing on the position of farms along the multifunctionality spectrum. Discussions on the positionality of organic farming in the multifunctionality spectrum are also illuminating, as organic farming has been the subject of heated debates concerning its contribution towards environmental conservation and sustainability (Tovey, 1997; Dabbert et al., 2004). On the one hand, there are clear arguments for conceptualising organic farming as embedded in the strong multifunctionality model. Swagemakers (2003, 202), for example, argued that ―using some form of organic farming is an obvious choice for multifunctional farms‖, while Marsden (2003, 232) suggested that ―organic production does emphasise the multifunctionality of farming systems‖. As Twyne (2005) and Hopkins (2005) argued, there is relatively undisputed evidence that organic farming contributes towards increased biodiversity due to lack of application of biochemical inputs on farms. The environmental sustainability dimension of organic farming as part of the strong multifunctional model is, therefore, not greatly disputed. There is also an argument that organic farming systems can contribute towards safeguarding local embeddedness of organic farmers, with close interaction between local communities through reciprocal rural-agricultural relationships engendered by local sale of organic products (e.g. in farm shops) and by better ‗control‘ of organic farmers over their crops (i.e. no dependency on large agro-chemical companies). Thus, short food chains often characterise organic farming systems. Yet, arguments for organic farming fitting the weak multifunctionality model can also be found (Evans et al., 2002; Lang and Heasman, 2004). Organic farmers are not necessarily more likely than ‗conventional‘ farmers to diversify activities away from food and fibre production, and they are not necessarily more weakly integrated into the global capitalist market than their conventional counterparts. Indeed, some argue that organic farming can be as intensive as other forms of farming and can, therefore, be a highly productivist system geared towards profit maximisation (Gregory, 2005). Recent evidence from the EU that farmers converting towards organic farming are increasingly doing so largely for financial reasons (organic conversion subsidies and higher product prices) suggests that ideological and ‗green‘ factors are not always the overriding reason for organic conversion (Twyne, 2005). Some organic farmers are, therefore, more firmly embedded in the global capitalist system than many highly productivist ‗agri-businesses‘ (Barrett et al., 1999; Gregory, 2005) and may, therefore, not be as firmly embedded locally as some authors suggest. Lifestyle or hobby farms – i.e. farmers who adopt farming as a hobby and who do not rely on the sale of food and fibre for economic survival – provide another interesting example with regard to farm system positionality on the multifunctionality spectrum. Hobby farms can be seen to be most closely linked with the non-productivist end of the multifunctionality spectrum (Holloway, 2002; Mather et al., 2006). Indeed, often hobby farmers (in the developed world) have purchased a farm (usually small) to farm in the most strongly multifunctional way – a decision-making pathway made possible as they usually do not need to maximise profits to ensure survival of the farm, enabling them to focus on agricultural land as a consumption good rather than as a production asset (Wilson, 2008a). As Bohnet et al. (2003, 349) emphasised for the U.K., we need to start distinguishing ―between holdings that are still seen primarily as sites of production by their farming family occupiers and those that are coming to be regarded chiefly as spaces for living by a new category of lifestyle

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occupiers‖. Hobby farming is assuming ever greater importance, not only in the gentrified countryside of Western Europe (see Holloway, 2002, for the U.K.; Cayre et al., 2004, for France), but also in farming areas near large urban centres in Australia and in states such as New Hampshire in the U.S. (Holmes, 2006; Gulbrandsen, T.C., pers. comm., Director of Centre for Rural Partnerships, Plymouth State University, Plymouth, New Hampshire, U.S.; interview held 31st March 2008 at University of Plymouth, U.K.). Yet, hobby farming should not be over-romanticised as the ‗most‘ strongly multifunctional farm type, as they may also straddle moderate multifunctionality pathways (Wilson, 2008a). These farmers are often wealthy urbanites who have not been brought up in the region where they bought their farm and, as a result, the strong multifunctionality dimension of ‗local embeddedness‘ may be relatively weak. This brief discussion of farm type examples and the MF spectrum highlights that the concept of weak, moderate and strong multifunctionality pathways allows a relatively nuanced approach for conceptualising agricultural change. In particular, it emphasises that there will be virtually no agricultural area in the world where productivist action and thought exclusively predominates. Indeed, even in the ‗worst‘ agricultural landscapes (in environmental and social terms in particular), some evidence of non-productivism can be found. As Bell (2004) emphasised for the highly multifunctional agricultural and rural landscape of Iowa in the U.S. or Gulbrandsen (2008) for the complex farming landscapes of New Hampshire, it is, therefore, dangerous to paint all agricultural/rural actors in a given region with the same brush. Thus, the neighbour of a highly productivist agro-business in Iowa, for example, may be a farmer whose practices can best be described as close to the nonproductivist pathway of decision-making. Similarly, while many Australian intensive cotton farmers may have exhausted their fragile soils through over-intensive productivist agricultural practices, some farmers in the same area may be heavily engaged in local Landcare groups attempting to mitigate desertification and soil degradation processes on their farms (Wilson, 2004; Cocklin et al., 2006). This means that analysing the quality of multifunctionality in an agricultural region needs a research methodology that allows each farm to be investigated on a case-by-case basis, including analysis of relative changes in multifunctional quality over time. The larger the scale of investigation, the less likely it will be that we can ‗accurately‘ position a given area along the MF spectrum.

A Normative View of Multifunctionality: Conceptual Implications Four points emerge from this normative conceptualisation of multifunctionality. First, if we accept that conceptualising multifunctionality along a spectrum is linked to value judgements, strong multifunctionality should be seen as the ‗best‘ type of multifunctionality – or, indeed, the type of multifunctionality with the best quality. As both Lowe et al. (1997) and Bell (1994) have highlighted for the U.K. and U.S. respectively, such an agricultural system is not only predicated on ensuring the protection of the environment and on healthy farming and rural communities, but it can also be seen as the most ‗moral‘ type of multifunctionality. Intuitively, there is something ‗good‘ about strong multifunctionality, as most of its dimensions resonate positively with what producers, rural stakeholders and wider society would see as the ‗optimum‘ type of agricultural regime in any region of the world. This means that the ultimate aim of any agricultural system should be to ‗move‘ towards the strong

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multifunctionality model. Strong multifunctionality may enable both diversity and sustainability in human and natural systems without undermining economic efficiency (Pretty, 2002; Farley, 2007). In the long term, economic efficiency and survival of farming systems may be predicated on strong multifunctionality pathways. Indeed, I would argue that social systems over time have always attempted (not always successfully) to either maintain strong multifunctional agriculture regimes or to move away from weak or moderate multifunctionality towards strong multifunctionality. Strong multifunctionality is, therefore, the model policy-makers and agricultural/rural stakeholders should strive for. Yet, we need to be careful not to fall into the trap of romanticising one multifunctionality model over another. Historically, it would be wrong to argue that for most of the time since inception of farming agricultural systems operated on the basis of strong multifunctionality. Virtually every place on the globe has historically seen different phases of weak, moderate and strong multifunctionality, and it is debatable whether the strong multifunctionality model has been the dominant model over time (Wilson, 2008b). One also needs to ask whether the strong multifunctionality model in one area may be predicated on the co-existence (temporally and spatially) of moderate and weak multifunctional agricultural regimes in other areas (i.e. win-win situation or ‗zero-sum-game‘)? In other words, could global agriculture be based solely on a strong multifunctionality model? Second, we have seen that environmental sustainability forms an important component of conceptualisations of strong multifunctionality7 (Potter and Burney, 2002; Marsden, 2003). However, it is important to reiterate that environmental sustainability is only one of several key components of the strong multifunctionality model. As Buller (2005, 2) emphasised, ―multifunctionality is distinct from nature conservation or biodiversity management per se, because it explicitly links these to processes of agricultural production‖. While weak multifunctionality shares many similarities with the notion of ‗sustainable economic development‘, strong multifunctionality is more closely associated with the original Brundtland Commission definition of sustainability that also takes into account intergenerational equity and, indirectly, criticises the productivist global capitalist model. Third, the discussion has highlighted that there are close associations between the concept of weak, moderate and strong multifunctionality and Bowler‘s (1992) spectrum of ‗shallow‘ or ‗deep‘ diversification pathways (see Figure 3 above). Yet, contrary to debates in the current literature that often equate multifunctionality with diversification/pluriactivity, farm diversification – just like environmentally sustainable farming – only forms one component of what multifunctional agriculture is about. Finally, we need to be cautious not to oversimplify categorisations. The new multifunctionality model highlights that weak, moderate and strong multifunctionality are in themselves highly complex categories that include many diverse farming systems and agricultural areas. As Figure 1 (above) highlighted, the ‗mix‘ of productivist and nonproductivist action and thought will vary greatly between individual case studies. Weak, moderate and strong multifunctionality should, therefore, not be seen as agricultural regimes with clearly delineated boundaries, but as relatively fuzzy conceptual entities that show ‗clusters of dimensions‘ associated with one of the three multifunctionality regimes, but that also, simultaneously, will often include dimensions from one or both of the ‗other‘ 7

In many ways, this echoes arguments long held by agro-ecologists who have emphasised the importance of environmental sustainability in conceptualisations of agricultural ‗best practice‘ (cf. Altieri, 1987).

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multifunctionality regimes (see also Marsden, 2003, and Holmes, 2006). Thus, monocultural farming associated with the weak multifunctionality model will often go hand-in-hand with weak environmental sustainability and long food chains, but some elements of moderate multifunctionality, such as evidence of farm diversification, may also be present (however, it is unlikely that many dimensions characteristic of the strong multifunctionality model would be found in these systems) (14). In addition, all three types of multifunctionality should be seen as flexible and relatively permeable entities. As I have argued for the developing world, some agricultural areas may be moving from strong or moderate multifunctionality towards weak multifunctionality, while others may have just gone beyond the weak multifunctionality model by placing greater emphasis on non-productivist agricultural development pathways (Wilson, 2008b).

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5. CONCLUSIONS: EMERGING RESEARCH AGENDAS FOR LAND USE POLICY This article began by arguing that the debate surrounding the notion of ‗multifunctional agriculture‘ is gathering speed in many agricultural regions of the world. I also suggested that European and American debates on agricultural change intertwine. Although terminology varies (indeed the notion of ‗multifunctionality‘ has not yet been widely applied in a North American context), many commentators have argued that the underlying processes of agricultural change increasingly converge (McCarthy, 2005; Potter and Tilzey, 2005; Holmes, 2006; Wilson, 2007). This is particularly true with regard to calls for a more environmentally sustainable agriculture, suggesting similarities in changing nature-society interactions and how society views agricultural change in most of the developed world (e.g. Logsdon, 1994; Hassanein, 1999; Jackson and Jackson, 2002; Bell, 2004, for the U.S.). Building on recent debates about agricultural change, the article suggested that agricultural change can be understood as occurring along a spectrum of decision-making bounded by the ‗extreme‘ spaces of ‗productivism‘ and ‗non-productivism‘. I then anchored the hotly debated notion of ‗multifunctional agriculture‘ within this spectrum of decision-making, and suggested that this enables a normative view of multifunctionality based on strong, moderate and weak multifunctional agricultural pathways, whereby strong multifunctionality can be seen as the ‗ideal‘ model that all societies should be striving for. Based on emerging work by human geographers and other social scientists, I argued that this normative view enables the challenge of often simplistic policy-based and economistic conceptualisations of multifunctionality. This conceptualisation leaves many opportunities for future researchers who may want to use arguments made here as a platform for future research. What still needs to be done is to find additional empirical evidence to further substantiate (or, indeed, refute) the MF spectrum suggested here. As both Holmes (2006) and Wilson (2008a) argued, researchers from different disciplinary vantage points (including human geographers) now need to ‗swarm out‘; get their ‗boots dirty‘; talk to farmers, rural citizens, policy-makers and other agricultural and non-agricultural decision-makers about multifunctionality-related issues; establish case studies investigating different agricultural regions specifically investigating the nature, pace and processes of agricultural multifunctional transitions; and analyse if, and to

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what extent, the normative MF spectrum suggested here provides a robust framework with which to analyse, and understand, agricultural change in any part of the world. As McCarthy (2005, 780) highlighted, ―we are in urgent need of ethnographies of multifunctional rural areas‖, not only within specific country settings but also between different countries and world regions. What is particularly needed in my view are studies that focus on four key aspects of future multifunctional agricultural trajectories. First, as a human geographer I advocate that more work is needed to investigate spatial issues of the new multifunctionality concept. Future work should focus on the interrelationships between different spatial scales and on the complex question of global-level multifunctionality (e.g. is strong multifunctionality at the global level based on a win-win situation or a zero-sum-game?). Would strongly multifunctional farming systems be capable of feeding the world in ways that are much more environmentally, socially and culturally benign than the currently predominant weakly/moderately multifunctional agricultural systems (see also Pretty, 1995, 2002; Losch, 2004; Wilson, 2008b)? There are, therefore, many fruitful arenas of investigation for those interested in the geography of multifunctionality. Particularly challenging questions await not only researchers in the U.S. where the notion of multifunctionality has not yet been incorporated into mainstream agricultural, environmental and political discourses, but also researchers in developing countries where, so far, little work exists on the nature and pace of multifunctional agricultural transitions (Potter and Tilzey, 2005; Wilson, 2008b). Second, we also need to investigate whether farming areas that currently have relatively well developed strong multifunctionality pathways may be at risk of losing multifunctional quality, as global agriculture is facing increasing pressures for intensification based on rising demand for agricultural commodities, rises in commodity prices, and because the planting of crops for biofuel production is jeopardising global food production spaces. Many have suggested that this is beginning to have repercussions for farm trajectories in many regions of the developed (and developing) world, where farms that had begun a process of disconnection from the agri-industrial regime (e.g. via agri-environmental schemes or set-aside) have reintensified production to meet food market needs. Third, the various dimensions of weak, moderate and strong multifunctionality outlined here are based on current transitional processes. However, we may be at an important crossroads for multifunctional transitional processes in both the developed and developing world, with some uncertainty about the precise future shape of transitional corridors. As the multifunctional transition proceeds over the next few decades influenced by climate change and rapidly shifting global food consumption markets and trends, new dimensions of multifunctionality may need to be considered, especially at the interface between strong multifunctionality and non-productivist pathways of decision-making (e.g. farming for ‗carbon offsetting‘). An important question, therefore, is whether the boundary of nonproductivist action and thought should be seen as relatively clearly defined, or whether we need even more flexible indicators about what ‗agriculture‘ is? It is likely that discussions about the boundaries of agriculture will assume ever greater importance in future, as strongly multifunctional processes of deagrarianisation, diversification and rural gentrification assume greater importance in some regions of the world. Fourth, commentators are also calling for a new research focus on food chains as opposed to considering agriculture as a purely land-based occupation in isolation (Marsden, 2003). Winter (2005), in particular, highlighted the importance of reconnecting research on food,

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agriculture and nature. Although we can conceive of eating as an ‗agricultural act‘, I admit that the focus on multifunctional agriculture may lead to a shift of emphasis away from debates on food networks – debates that, as Goodman (2004) amply illustrated, also have the potential to lead to further refinements of the MF spectrum. Is it, for example, possible to conceptualise food chains along notions of weak, moderate or strong multifunctionality? Can Goodman‘s (2004) assertion about the possible emergence of a new ‗multi-tiered food system‘ in the developed world be seen as an emerging expression of differing multifunctional pathways along p/np consumption decision-making trajectories? I, therefore, also hope that this article will spark a debate in Europe, the U.S. and beyond about the dimensions, or constituents, of the MF spectrum beyond the question of agricultural pathways. As I highlighted elsewhere (Wilson, 2007, 2008a), this will also need to be associated with a new approach towards methodologies how to assess multifunctional ‗quality‘. This is particularly important as multifunctionality, as conceptualised here, does not describe an absolute state but a flexible transitional process. This highlights that using absolute indicators – often advocated by policy-makers in the European Commission for ease of data collection (Wilson and Buller, 2001) – is not the right approach. As McCarthy (2005, 778) rightly emphasised from a North American perspective, ―there are tensions inherent in the fact that indicators simplify, standardize, and quantify complex information and relationships … when much of the point of multifunctionality is to emphasize the heterogeneous and synergistic aspects of [agricultural and rural processes]‖. Thus, I disagree with Bryden‘s (2005, 9; emphasis added) assertion that ―the degree of co-production [multifunctionality] involved in the production of different commodities by different farm types and farming styles must be capable of measurement‖. Some attempts have been made at developing such methodologies (e.g. Holmes‘, 2006, suggestion of an ‗index of multifunctionality‘ based on production, consumption and protection processes of rural areas), but Knickel and Renting (2000) rightly cautioned that most of the data on agricultural activities and change is still in the form of relatively productivist and positivist statistics relating to agricultural commodity production, with little information available on less tangible qualitative multifunctionality indicators such as changes in the globalised position of agricultural spaces or mental changes of rural actors. I, therefore, suggested that ―most information on multifunctionality is at present almost exclusively related to agricultural activities, highlighting that most data currently available do not directly measure multifunctionality, but only provide proxy indicators of the influence of agricultural activities on the physical, economic and socio-cultural environment‖ (Wilson, 2008a; emphasis in original). In addition, regional averages or the use of aggregate data may hide significant individual multifunctional transitional pathways (Knickel et al., 2004). Randall (2002, 305) attempted to develop a comprehensive methodology, but recognised that researchers ―have seldom if ever attempted a task so demanding as valuing the outputs of multifunctional agriculture … Consistency as we move from single to multiple components of multifunctionality, and from local to continental spatial scales, is a substantial conceptual and empirical challenge‖. Assessment of multifunctional quality may, therefore, only be possible through the use of more qualitative and ethnographic methods that will enable researchers to engage more closely with life histories, transitions and development pathways as a basis for developing a multifunctional farm/rural area typology based on the MF spectrum (Pretty, 1995; Holmes,

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2006; Wilson, 2008a). In this context, some attempts have been made at refining methodologies how to assess multifunction quality with specific emphasis on less tangible qualitative multifunctionality indicators. Bohnet et al. (2003), for example, assessed multifunctional trajectories of family farms in the U.K. using in-depth ethnographic methods. French researchers Cayre et al. (2004), meanwhile, used photographs and ethnographic approaches through an in-depth qualitative survey to identify farmers‘ attitudes about multifunctional quality of rural landscapes. Hollander (2004) also used a complex quantitative/qualitative methodology to analyse multifunctional pathways of sugar cane farmers in Florida (U.S.), while Rapey et al. (2004) suggested field-based assessment of existing, desired and potential multifunctionality functions on French farms. Clark‘s (2005) study of localised multifunctionality networks in a case study in the U.K. also offers useful guidance, in particular for how multifunctional ‗networks‘ and associated power relations can be identified, as does Pretty et al.‘s (2001) analysis of how the ‗positive externalities‘ linked to strong multifunctionality can be assessed methodologically (see also Knickel and Renting, 2000; Knickel et al., 2004; Wilson, 2008a, 2008b). While many of these approaches have been developed in a European context, they can also usefully inform assessment of multifunctional agricultural pathways in the U.S.. Finally, and possibly most importantly, the MF spectrum also has implications for our construction of knowledge, in particular related to agricultural sciences, rural studies and cognate sub-disciplines such as human geography. Indeed, approaching multifunctionality from a mono-dimensional and mono-causal perspective (e.g. economic or policy-based perspective) is likely to generate simplistic evaluations of, and solutions for, the challenge of multifunctionality (Wilson, 2008a). Only through a multi-disciplinary approach will we be able to fully understand multifunctional agriculture and put forward suggestions for a constructive research agenda for the future. As a strong multifunctional agricultural regime means a relative withdrawal of productivist agriculture, it is evident that ‗classical‘ – often technocentric – agricultural science approaches towards understanding agricultural change may become less relevant in the future. Other disciplinary approaches rooted, for example, in rural studies, sociology, psychology, environmental sciences or human geography will take on a more important role in the investigation of future ‗agricultural‘ development pathways that straddle the non-productivist end of the MF spectrum than has hitherto been the case (see also Bell, 2004, for the U.S.). Indeed, I argued in this article that human geographers – through their spatial and interdisciplinary approaches – are particularly well placed to investigate issues surrounding multifunctional agriculture, especially as most of the indicators of multifunctionality overlap with current research agendas and priorities of human geography (e.g. globalisation, embeddedness, environmental sustainability, etc.). In addition, the use of so-called ‗expert knowledges‘ to assess multifunctionality may need to be questioned, and – echoing Bell‘s (2004) in-depth analysis of farming trajectories in Iowa (U.S.) – evaluations of change at the local scale may need to involve both ‗experts‘ and ‗nonexperts‘ (see also Winter, 2005). The recent closure of many agricultural colleges (e.g. in the U.K. and Germany) can be interpreted as an indication that there is currently less need for institutions that are largely embedded in the productivist paradigm and based on outdated productivist teaching structures geared only towards training farmers to intensify agricultural production (Wilson, 2008a). Just as the notion of strong multifunctional agriculture leads to a blurring of what has hitherto been associated with ‗agriculture‘ and ‗food and fibre production‘, the transition towards strong multifunctionality concurrently necessitates a

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readjustment in the way academics and scientists will research agricultural and rural issues in the future.

ACKNOWLEDGMENTS I wish to acknowledge very valuable critical comments on ideas expressed in this article from Clive Potter (Imperial College London, U.K.), Jonathan Rigg (University of Durham, U.K.), Karlheinz Knickel (University of Frankfurt, Germany), James Sidaway (University of Plymouth, U.K.), Jacqui Dibden and Chris Cocklin (Monash University, Australia), John Holmes (University of Brisbane, Australia), James McCarthy (Pennsylvania State University, U.S.), Olivia Wilson (University of Plymouth, U.K.), Rob Burton (Agresearch Dunedin, New Zealand) and from all delegates who attended our session on ‗Multifunctional agricultural and rural spaces‘ at the 2007 RGS/IBG Conference in London.

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In: Sustainable Agriculture Editors: A. Salazar, I. Rios, pp. 265-289

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Chapter 6

THE SUSTAINABILITY OF COTTON PRODUCTION IN CHINA AND IN AUSTRALIA: COMPARATIVE ECONOMIC AND ENVIRONMENTAL ISSUES Xufu Zhao1 and Clem Tisdell2 1

Agricultural Economics, Wuhan University of Science and Engineering, Wuhan, Peoples Republic of China 2 School of Economics, The University of Queensland, Brisbane, Australia.

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ABSTRACT After providing some background about the importance of cotton as a fibre, this article provides information about the global relevance of China‘s and Australia‘s cotton industries and compares the structure and other significant features of their cotton industries. Attention is given to trends in overall cotton yields and the volume of production of cotton globally, in Australia, and in China as indicators of the sustainability of cotton supplies. Some simple economic theory is applied to indicate the relationship between market conditions and the sustainability of global cotton supplies. Then the environmental and economic factors that challenge the sustainability of Australian cotton production are outlined and analysed and this is done subsequently for China‘s cotton production. Geographical and regional features that affect the sustainability of cotton supplies in Australia and China are given particular attention. Some new economic theory is proposed to model hysteresis in Australia‘s supplies of cotton. Ways of coping with the sustainability difficulties that are being encountered by both these nations are compared. Many of the sustainability challenges facing these two countries are found to differ but some of their environmental obstacles to sustainable cotton production are similar.

1. INTRODUCTION Despite its reduced share of the textile fibre market, cotton still remains the major natural fibre used in textiles. The prime reason for cotton‘s reduced share of the textile fibre market has been increased competition from man-made fibres (Tisdell and McDonald, 1979, Ch.1).

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In 2007, cotton accounted for 38% of the global market by weight based on the data available from the Japan Chemical Fiber Association (2008) whereas in 1960-61 it accounted for 68% of world fibre production (Tisdell and McDonald, 1979, p.23). Nevertheless, the global volume of cotton production has continued to show a strong upward trend. Whereas just over 10 million tonnes of cotton were produced globally in 1960-61, by 2007, this had risen to 25.7 million tonnes, that is to about 2.5 times its volume in 1960-61. This can be attributed in part to technical progress in the production of cotton and improvements in the management of cotton cultivation as well as valuable attributes of cotton which sustain demand for its use in blends with chemical fibres. Whether or not growth in the global supply of cotton will continue to be maintained is not clear. Changing economic and environmental factors will constrain future changes in cotton global supply. Other writers have also emphasised the importance of cotton for the textile industry. It represents over 90 percent of the global consumption of natural fibres by weight (Oerlikon, 2008). Plastina (2008) mentions that: over the last 5 decades, although the market share of cotton decreased from an average of 62.4% in the 1960s to 39.8% in the 2000s, cotton consumption increased one-and-a-half times during that period to reach 26.4 million tons in 2007. World textile fiber consumption more than tripled over the last 5 decades. Other fibers (wool, chemical and non-chemical synthetic fibers) increased eight times to reach 45.7 million tons in 2007. In addition to its use in the textile industry, cotton is used in many other fields. For example, the cottonseed which remains after the cotton is ginned is used to produce cottonseed oil, which after refining can be consumed by humans like any other vegetable oil. The cottonseed meal that is left is generally fed to livestock. Nevertheless, the most valuable use of cotton is in the cotton textile industry. Cotton has also served as an engine of economic growth and provides income to millions of farmers in both industrial and developing countries worldwide (Wang and Chidmi, 2009). In Australia, in a non-drought year, the cotton industry generates in excess of $1 billion per year in export revenue, is one of Australia‘s largest rural export earners and helps underpin the viability of many rural communities (Cotton Australia, 2008a). It employs 10,000 Australians and directly supports 4,000 businesses that are reliant on cotton (Cotton Australia, 2008b). In China, the value of its output accounts for 7% – 8% of the value of gross agricultural output. In 2002, China‘s export of cotton and cotton textile garments was $26 billion, and accounted for 35% of its total textile and garment exports by value (Mao, 2006). According to Wang and Chidmi (2009): ―Cotton also does play an important part in the US, the United States has produced about 20 percent of the world's cotton supply and consumed 10 percent of world cotton. It provides about 0.1 percent of the U.S. Gross Domestic Product‖. The purpose of this article is to focus on the sustainability of the supply of cotton by China and Australia and examine the constraints they have experienced in recent years in producing cotton, how they have fared in this regard, and the challenges they face for maintaining or increasing the level of cotton production. These two countries are of interest as cases because of differences in the socioeconomic conditions influencing their cotton industries as well as contrasts in their approaches to cultivating cotton. China is the world‘s major producer of cotton (ahead of the USA and India) and Australia is one of the main cotton exporting nations (noted for its export of fine cotton) and is the nation with the highest yields of cotton per ha (Zhao and Tisdell, 2009). Australia has only become a significant global producer of cotton in recent decades whereas China has been a major producer for

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several centuries. China regards cotton as a strategic material and this gives it particular (but not overriding) importance in relation to its agricultural policy. By way of background, some general information is provided about the global relevance of China‘s and Australia‘s cotton industries and then sustainability issues are addressed. At a general level, the sustainability of global cotton production depends on possible shifts in the market demand and supply curves for cotton. This is discussed briefly. The features of the geographical locations of Australia‘s and China‘s production of cotton are outlined and discussed. These locations have important implications for the sustainability of cotton production in both these countries. Cotton production in Australia occurs in a different type of economic environment to that in China and there are also differences in their farming systems and size of farms, all of which have consequences for maintaining cotton production. After discussing this, the experiences of Australia and China in sustaining cotton production are outlined and their economic and environmental challenges for future sustainability of cotton production are discussed.

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2. THE GLOBAL RELEVANCE OF CHINA‟S AND AUSTRALIA‟S COTTON INDUSTRIES The cotton industry is a significant contributor to China‘s and Australia‘s agricultural sector. Australia is the major cotton-producing country in the Southern Hemisphere, and has been an important cotton exporter. Table 1 provides information on the level of Australian production and export of cotton in the period 1980-2007. These levels peaked in 2000 and have declined since then due to water shortages as a result of prolonged drought, possibly a consequence of climate change. However, some rebound is expected for 2009 due to the drought easing. At its peak in 2000, Australian cotton production amounted to 819 kilotonnes (hereinafter referred to as KT), and made up 4.16% of the world total production; Australia exported 850 KT, of cotton which accounted to 14.90% of the world‘s cotton export trade (see Table 1). China is not only the major global producer of cotton, it is its major consumer as well. In the five years from 2003 to 2007, the average output of Chinese cotton was 6,750 KT per year, which was 27% of the world total, on average. On average, China also imported annually 2,466 KT of cotton and this accounted for 30% of the world‘s exports of cotton. In the corresponding period, China‘s textile industry consumed 9,499 KT of cotton annually, accounting for 38% of the total quantity of cotton consumed in the world. Table 2 provides data on China‘s cotton production and its imports of cotton for the period 1980-2007. Australia and China are among the 10 major cotton-producing countries in the world, Table 3 shows the basic situation of the 10 major cotton-producing countries in the world in terms of their level of production, area planted, and yield for a recent 5 year period (2002/032006/07). From Table 3, we find that China is the major global cotton producer, Australia has the highest yield of cotton per ha (hereafter referred to simply as yield) and India has the largest planted area of cotton. In this group of the 10 major cotton producers, the planted area of cotton in China ranks second and its yield ranks fifth. The combined effect of these two factors makes the level of gross cotton production of China the highest in the world.

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Table 1. The volume of Australia’s cotton output and exports (1980-2007) in ‘000 tonnes and the global share of these

Year 1980 1985 1990

World 13799 17450 18975

1995 2000 2001 2002 2003 2004

20439 19400 21491 19809 21067 26441

Production Australia 99 259 434 429 819 728 366 371 654

% 0.73 1.49 2.29

World 5719 6114 6437

Export Australia 53 248 299

2.10 4.16 3.39 1.85 1.77 2.48

5958 5705 6347 6632 7229 7624

319 850 682 579 470 436

% 0.93 4.06 4.65 5.36 14.90 10.75 8.74 6.51 5.72

2005 25383 610 2.41 9708 628 6.47 2006 26561 294 1.11 8077 464 5.75 2007 26245 133 0.52 8370 266 3.18 Sources: (1) United States Department of Agriculture (USDA), Foreign Agricultural Service (FAS), 2009; (2) Australian Bureau of Agricultural and Resource Economics (ABARE)，2009. Notes: year: Aug. 1 - July 31.

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Table 2. The volume of China’s cotton production and imports (1980-2007) in ‘000 tonnes and the global share of these

1980

Production World China % 13799 2700 19.57

Import World China 5934 773

% 13.03

1985 1990 1995 2000 2001 2002

17450 18975 20439 19400 21491 19809

6310 6658 5879 5711 6381 6573

0.02 7.23 10.79 0.9 1.54 10.37

Year

4137 4507 4769 4420 5313 5487

23.71 23.76 23.34 22.79 24.73 27.7

1 481 634 51 98 681

2003 21067 5182 24.6 7406 1923 25.97 2004 26441 6598 24.96 7283 1391 19.1 2005 25383 6184 24.37 9686 4199 43.36 2006 26561 7730 29.11 8150 2306 28.3 2007 26245 8056 30.7 8283 2511 30.32 Sources: (1) United States Department of Agriculture, Foreign Agricultural Service, 2009; (2) The National Cotton Council, 2009. Notes: year: Aug. 1 - July 31..

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Table 3. Ranking of the 10 major cotton producing countries in terms of their level of cotton production, area planted and yield. Production

Area

KT rank 1000 ha rank China 6235.73 1 5409.98 2 USA 4537.15 2 5181.00 3 India 3677.43 3 8424.27 1 Pakistan 2047.51 4 3065.28 4 Brazil 1197.72 5 990.11 6 Uzbekistan 1079.93 6 1421.03 5 Turkey 861.29 7 668.06 7 Australia 458.54 8 242.17 9 Greece 366.65 9 355.56 8 Syria 280.69 10 215.78 10 Source:The National Cotton Council of America (NCC), 2009. Note: quantitative data are on a 5-year average for 2002/03-2006/07.

Yield Kg/ha 1150.91 872.48 430.98 665.50 1206.24 758.91 1288.45 1893.47 1029.50 1298.30

rank 5 7 10 9 4 8 3 1 6 2

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3. MARKETS AND THE SUSTAINABILITY OF COTTON PRODUCTION The economic theory of market operations can be used to provide background on the forces affecting the sustainability of global cotton production. The theory asserts that market demand and supply conditions determine the volume of production of a commodity and the direction of change in this. Other things held equal, a rise in the demand for a product will normally increase its market supply, as will a fall in the cost of its supply. The latter increases the willingness of producers to supply the good to the market. In the case of cotton, the global demand for it appears to have increased with the passage of time as has the willingness of farmers to supply cotton. At the same time, there has been a long-term tendency for the real price obtained by growers for cotton (that is its price adjusted for price inflation) to decline. This long-term pattern of change can be analysed by means of market demand and supply relationships. Consider the illustration in Figure 1 which is based on the assumption that the market for cotton is a purely competitive one. This implies that neither individual buyers nor sellers of cotton have any market power, they are price-takers. In an initial period, it is assumed that the market demand for cotton as a function of its price is as shown by line D1D1 and that its market supply (also as a function of its prices) is as indicated by line S1S1. The result is that market equilibrium is established at point E1 with the equilibrium supply of cotton being X1 and its real price being P1. However, with the passing of time, the market demand curve for cotton shifts upwards and the supply curve moves to the right. In Figure 1, this results in a shift from D1D1 to D2D2 and from S1S1 to S2S2 respectively with the equilibrium of the market altering from E1 to E2. The volume of cotton production rises but its real price falls. As long as it is possible to sustain shifts in the cotton supply and demand curves in this way, cotton production will not only be sustained but will increase in volume.

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Xufu Zhao and Clem Tisdell P S1

Real price of cotton

D1

D2

S2 E1

P1

E2

P2 D2 S1 S2 O

D1

X1

X2

X

Quantity of cotton per period

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Figure 1. Globally the volume of cotton supply has shown a long-term upward trend. This is consistent with the market change illustrated above as is discussed in the text. Cotton production has not only been maintained but has grown. Whether or not this trend will be sustained is not clear.

Although chemical fibres are a substitute for cotton, they are not a perfect substitute. The qualities of many chemical fibres are improved when they are blended with cotton. Rising global population and the presence of more people with higher income have helped to raise the demand for textiles, including cotton. Hence, the demand curve for cotton has moved upwards but because there is now scope for the substitution with chemical fibres, the market demand curve (shown by D2D2 in Figure 1) has become flatter, that is more price elastic. The global supply curve of cotton appears to have moved to the right more quickly than the demand curve has shifted upward. This is to a large extent due to lower real costs of producing cotton as a result of new techniques and improved management of its cultivation. The global yield of cotton per hectare has, for example, shown an upward trend since 1980 and the area planted with cotton has also risen (see Zhao and Tisdell, 2009). Cotton production has both intensified and become more extensive. Improved varieties of cotton and the introduction of genetically modified cotton seem to have played a positive role in reducing the per unit costs of producing cotton. Whether or not past trends will continue is uncertain. Increased demand for land to supply food and for organic material to produce biofuels could, in the long-term, result in less land being available for growing cotton. Furthermore, reduced availability of water for growing cotton may occur due to climate change and increased competition for use of water for other crops and purposes. The world‘s population is expected to increase by 30 per cent in the next two decades and this will place increased economic pressure on agriculture (Mann, 2008). In addition, cotton production (particularly in higher income countries, and increasingly so in less developed countries) depends to a large extent on the availability of non-renewable resources such as mineral oil. These resources are predicted to become scarcer in the future.

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Another factor that could result in cotton supplies not being sustained is a reduction in its ecological fitness. For example, due to natural selection, genetically modified cotton may no longer be able to perform the functions for which it was originally intended. For instance, some types of caterpillar pests may no long be deterred by Bt cotton and new pests may emerge that are not affected by the Bt cotton. So far, however, the industry has been successful in staving off challenges to its sustainability

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4. TRENDS IN OVERALL COTTON YIELDS AND SUPPLIES AS INDICATORS OF THE SUSTAINABILITY OF COTTON PRODUCTION The yield of cotton per hectare and the area planted with cotton determines its aggregate level of production. As pointed out in the previous section, global yields of cotton have shown an upward trend in the period 1980-2007 and the total volume of cotton production rose. In China‘s case, both its yield of cotton and its total land area planted with cotton displayed a fairly steady upward trend. In Australia, cotton yields have shown a strong tendency to grow, but the volume of Australia‘s production of cotton has not been sustained. In the period 1980-2007, the volume of Australia‘s cotton production peaked in 2000 and then declined due to lack of availability of water caused by drought. Drought reduced the land area planted with cotton in Australia after 2000. Trends and factors influencing levels of China‘s and Australia‘s cotton production are outlined in Zhao and Tisdell (2009). Zhao and Tisdell (2009) using linear regression analysis found a close statistical fit between cotton yields per ha as a function of time for the world, China, and Australia on the basis of data for the period 1980-2007. According to the relevant regression analysis (Zhao and Tisdell, 2009), world cotton yields per ha tended to increase by 9.77kg per year, China‘s yields rose by 22.27kg per year and Australia‘s cotton yields increased by 29.93kgs per year. There is no hint from this historical data that yields per ha are going to decline nor that their absolute rate of increase is about to decline. However, projection of the historical record is risky. It is merely a mechanical exercise. A more rewarding approach is to analyse the underlying relationships that influence yields. Amongst other things, this requires that consideration be given to the geographical location of cotton production and any changes in this as well as the nature of the farming systems used and their ecological consequences. Globally (and within some countries), there have been alterations in the location of cotton production as well as in systems for producing cotton, for example, replacement of traditional cotton varieties with genetically modified varieties. Although globally China has retained its position as the major producer of cotton, India has edged out the United States as the second largest producer of cotton, and in recent decades Australia progressed from being of negligible importance as a global cotton supplier to being a significant supplier. Although the general location of cotton production in Australia has not changed much since 1980, the location of China‘s cotton production has tended to shift towards its west, particularly Xinjiang. This shift has had a positive impact on aggregate yields of cotton in China because growing conditions for cotton tend to be more favourable there than in eastern China, especially compared to areas in the Yellow River region. Improvements in farming systems have, of course, also played a role in increasing cotton

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yields in China and elsewhere. In considering the sustainability of cotton yields and production, it is important to take into account economic factors, the geographical location of cotton growing and the farming systems involved. This will now be done for Australia and China in order to better appreciate the challenges faced by both those countries in sustaining their cotton supplies.

5. THE GEOGRAPHICAL LOCATIONS OF COTTON PRODUCTION IN AUSTRALIA AND CHINA AND THE SUSTAINABILITY OF SUPPLY

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The cotton production of Australia is located in New South Wales (NSW) and Queensland (QLD), in the river valleys along rivers, between 23ºS and 33ºS (Tennakoon and Milroy, 2003). The major production area in NSW stretches south from the Macintyre River on the Queensland-NSW border and covers the Gwydir, Namoi and Macquarie valleys. In NSW, cotton is also grown along the Barwon and Darling Rivers in the west and the Lachlan and Murrumbidgee rivers in the south. In Queensland, cotton is grown mostly in the south in the Darling Downs, St George, Dirranbandi and Macintyre Valley regions. The remainder is grown near Emerald, Theodore and Biloela in Central Queensland (Figure 2). Except for this cotton (which is grown in the Fitzroy River Basin), all Australian cotton is grown in the Murray-Darling Basin. Whereas the Fitzroy River flows into the Pacific Ocean, the water from the Darling and Murray rivers and their tributaries flow through inland Australia to reach the Southern Ocean.

Figure 2. Map showing the general location of cotton production in Australia and potential cotton region.

The Murray-Darling River System has been subject to severe drought since 2000 (Draper, 2009) and this has adversely affected the supply of Australian cotton. It is estimated Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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that approximately 20% of water used for irrigation in the Murray-Darling system is used to irrigate cotton (Draper, 2009, p.47). Apart from drought conditions, state governments have tended to issue rights to use water in the Murray-Darling basin in excess of its sustainable capacity to supply water. This over allocation has reduced water flows in the Murray River to such an extent that it no longer reaches the sea. This is a similar situation to that for the Yellow River in China.

Heilongj iang J ilin

Xinjia

Liao

ng

Ga nsu

Qinghai

Bei ning

Inner Mongolia Nin gxia

Tibet i Sichuan

jing Tia He njin bei Shan Sh dong anxi H Shaanx Jiang su enan Sha H A nghai ubei nhui Zhejia

Jia

N one

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little

A

Northwestern Inland Yellow River Watershed Yangtze River Watershed

Y unnan

H ngxi

Guiz hou

unan

Gua ngxi

Guang dong

ng

F ujian

T aiwan

H ainan

Figure 3. Map showing the general location of cotton production in China by province.

Because water shortages in the Murray-Darling Basin are a major constraint on the sustainability of Australian cotton supplies, consideration has been given to promoting the planting of cotton in new areas in tropical northern Australia (see Figure 2). Rainfall in these areas depends on the annual monsoon. At the present time, however, Australia‘s cotton fields are concentrated in its southwest in inland locations, and water availability is the main constraint on Australia‘s supply of cotton. Approximately two-thirds of Australia‘s cotton is grown in NSW with the remainder produced in Queensland (Cotton Australia, 2008a). In 2006/07, the planted area in NSW and QLD occupied respectively 73% and 27% of the total planted area of cotton in Australia and the percentages of their production were respectively 76% and 24% (ABARE, 2009). The geographical location of cotton growing in China is much more dispersed than in Australia. In China, the planting of cotton spreads over 25 provinces and regions. Only 6 provinces and regions do not grow cotton (Zhao, 2006). Nevertheless, China‘s cotton production is comparatively centralized in the three major regions (Figure 3): the

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Xufu Zhao and Clem Tisdell

Northwestern Inland Cotton Region (Xinjiang), Yellow River Watershed Cotton Region (Huang-Huai-Hai Plain) and Yangtze River Watershed Cotton Region (Middle and Lower Reaches). Significant constraints on the supply of cotton vary according to the region considered. Farming systems for producing cotton also differ between China‘s major cottonproducing regions. Xinjiang is the only cotton region with large-area plantations and with a high-level mechanization. In the Yangtze River Watershed and Yellow River Watershed, the cotton fields are small and very dispersed with low yield, high production costs and low comparative benefits. Furthermore, these two regions are China‘s main grain-producing areas. There is intense competition in favour of using land to grow grain and other food crops and as a result that available for cotton fluctuates considerably. (Zhao and Ding, 2008). In 2006, according to NBSC (2007), the Yangtze River Watershed, Yellow River Watershed and the Northwest accounted respectively for 26.38%, 47.12% and 25% of the area planted with cotton in China. Moreover, 24.06%, 39.82% and 34.35% of China‘s total production of cotton by weight in 2006 was supplied respectively by these regions. Xinjiang (located in the Northwest area) alone produces 32.4% of China‘s cotton, almost one-third of it. These statistics have some interesting implications. They imply that in 2006, the three major cotton-producing regions of China accounted for 98.5% of the area planted with cotton in China and 98.23% of its production of cotton by weight. Furthermore, it can be deduced that significant difference exists in cotton yields per ha in the various regions. Yields are highest in the Northwest region, significantly lower in the Yangtze Basin and lowest in the Yellow River Watershed. In 2006, yields of cotton per ha in the Northwest were 50% higher than those in the Yangtze River region and 62.26% higher than in the Yellow River region. Therefore, as stated in the previous section, the geographical movement of China‘s production towards it northwest has been a major factor in increasing its overall yield of cotton since 1980. There are great differences in climate, soil, quality, ecological conditions and the incidence of plant diseases and insect pests in the three main cotton-growing regions of China. The Yangtze River Watershed cotton region has suitable temperatures and soil fertility for growing cotton but experiences frequent summer drought; the Yellow River Watershed cotton region has abundant sunshine in the spring and fall but drought often occurs in the winter and the spring, its soil is poor and its ecological conditions are fragile. The Xinjiang cotton region has abundant sunlight in summer, a dry climate and big differences occur between day and night temperatures. These environmental conditions are favourable for the growth of cotton. Because this region has little rainfall in normal years, its cotton production depends completely on irrigation (Zhang, 2001). Due to irrigation works and its utilization of both surface water and groundwater, the irrigated area of Xinjiang expanded from 1,450 ha in the early 1950s to over 4,000 ha in 2007. About 2,000 ha can be irrigated even in drought years. The area planted with cotton in Xinjiang in 2007 was 1,782.6 ha (Guan, 2008). This means that about half the irrigated area in Xinjiang is planted with cotton and probably an even larger proportion of the area for which irrigated water supplies are assured. The construction of irrigation works and the adoption of water-saving irrigation technology make Xinjiang an important cotton producing region. Nevertheless, water availability is a constraint on the expansion of cotton production in Xinjiang.

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6. THE STRUCTURE AND THE NATURE OF AUSTRALIA‟S AND CHINA‟S COTTON FARMING SYSTEMS AND THE SIZE OF FARMS – SUSTAINABILITY ISSUES

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Australian cotton is produced on farms of very large size (usually 500-2000 ha in size) and individual fields of cotton also tend to be very large (see Figure 4). Australian methods of cotton production are also very capital-intensive and depend heavily on purchased material imports. On the other hand, cotton production on three-quarters of the land used for cotton in China depends on labour-intensive methods with farm sizes being extremely small. Cotton production in Xinjiang is exceptional in China because it is much more capital-intensive than cotton production in the rest of China. However, even here cotton farms employ temporary migrant labour to pick cotton and to weed the cotton crop. The difference in the culture of cotton in Australia and China is a consequence of China being a country in which agricultural labour is relatively plentiful whereas agricultural labour is relatively scarce in Australia. There are about 1,100 farms in Australia producing cotton and most are family operated (Cotton Australia, 2008a). Apart from growing cotton, most cotton growers also produce other broadacre crops such as sorghum, maize and sunflower and some graze cattle and sheep (Cotton Australia, 2008a; Morris and Stogdon, 1995). The whole process of cotton production in Australia is mechanized. This includes land preparation, planting, irrigation, weeding and pest control, cotton defoliation prior to harvesting, harvesting (see Figure 5), transport to the cotton gin, (see Figure 6) and processing and packaging.

Figure 4. Photo of an Australian cotton field with one of the authors in the foreground). Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Figure 5. Machinery harvesting cotton on the Darling Downs in Australia.

Figure 6. Transport of cotton to the gin in Australia is completely mechanized. This shows cotton being compacted on a farm for transport to the gin.

A huge number of families in China produce cotton and each on average cultivates only a small amount of land for this purpose. According to Lei (2004), about 45 million Chinese Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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families are engaged in the planting of cotton with an average area of 0.13 ha of cotton being planted by each family growing cotton. For most of the families who plant cotton, especially the ones in the non-major cotton regions, their cotton plots are scattered and are unsuitable for planting food crops. They plant cotton just as a supplement to their principal crops (mostly food crops). In these regions, the planted varieties and acreage of cotton vary greatly between years (Du, 2005). Most cotton is tended and picked by hand because it is impractical to use machines of even moderate size on small scattered cotton plots. Australian production of cotton involves a high level of yield but also a high level of nonlabour input per unit of output. In fact, Australian cotton yields per ha exceed that of other countries. By contrast most Chinese cotton growers depend much less on purchased imports for their production but their cotton yield per ha is lower than in Australia. Because of the high intensity of Australian cotton production, Australian cotton growers have to give considerable attention to the best practice to sustain and increase their yields. The problems which they have in sustaining yields differ in many respects for those experienced by farmers who have small plots of cotton in China. In Australia‘s case, there is a risk of soil compacting due to use of heavy machinery in cotton cultivation and deterioration in soil quality due to substantial use of chemicals applied in cultivating cotton. These problems appear to be less acute in China because of most of its production does not depend on the use of heavy machinery and in most cases less use is made of chemical fertilizers and pesticides. However, some problems involved in sustaining levels of cotton production and cotton yields are the same in China and Australia. Let us further consider the challenges facing each country in sustaining their levels of cotton production. In doing this we concentrate on economic and ecological challenges but to some extent the economic challenges reflect sociological challenges. The sustainability of agricultural supplies has been claimed to depend on economic ecological (including environmental) and sociological factors (Tisdell, 1999; see also Conway, 1985, 1987).

7. CHALLENGES BEING FACED IN SUSTAINING AUSTRALIA‟S COTTON PRODUCTION 7.1 Economic Challenges and Economic Phenomena Affecting the Sustainability of Australia‟s Cotton Supply The nature of cotton production in Australia has important economic consequences for Australia‘s supply of cotton and its sustainability. As in the United States, cotton is a high input crop requiring sustained careful management. It requires high levels of fixed investment as well as a high level of investment in each crop sown. In the Australian case, fixed capital investment is needed in machinery (much of which is specific to cotton) and irrigation infrastructure, such as dams (See Figure 7). However, some of the investment in machinery specific to cotton can be avoided by individual cotton growers by hiring equipment or contractors to undertake some of the processes involved in cultivating cotton. Nevertheless, this also involves market risks because it depends on the availability of such contractors. In addition, for these farmers who have not previously grown cotton, they have to learn a great deal about how to optimally cultivate the crop. These factors tend to reduce the elasticity of

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the supply curve for cotton in Australia and result in a degree of lock-in to the growing of cotton by farmers who have begun to grow it successfully. The latter means that, to some extent, path-dependence exists in cotton supplies in the Australian industry.

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Figure 7. A large earthen dam on a cotton farm in Southwest Queensland, Australia. $ S1

E1

P1

D1

E0

P0

E3

D0

A B O

X0

X1

X2

X

Quantity of Australian cotton supplied

Figure 8. An illustration of hysteresis in the Australian supply of cotton. In this case, there is a lock-in effect on supply of X1 − X0 due to the historical occurrence of an equilibrium at E1, as is explained in the text. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Theoretically, this phenomena means that the supply curve of Australian cotton exhibits hysteresis which implies that it lacks perfect reversibility. This is illustrated in Figure 8. There, the line AS1 represents the aggregate supply of Australian cotton in response to a sustained level of its price, other things (such as water availability) held constant. If the price of cotton should rise from P0 to P1 in a way that appears as though it will be sustained the supply of cotton expands from X0 to X2. Suppose, however that after remaining at P1 for some considerable time the price of cotton falls back to P1. The supply of cotton does not return to X0 but may only fall back to X1 because market equilibrium has been at E1 and many investments specific to cotton supply have been made. The effective supply curve after such investments may then be the kinked line BE1S1. The lock-in effect due to pathdependence is, therefore, equivalent to X1 − X0. This means that because of past economic decisions, cotton production is sustained at a higher level than would otherwise occur. Of course in the very long run, this lock-in effect will diminish. However, it results in supply being reduced at a slower rate with the efflux of time when the price of the product is reduced than occurs for a comparable increase in its price. Because of differences in the nature of cotton production in more developed countries (such as Australia and the United States) one expects the lock-in phenomenon in supply to be more important in such countries than in less developed countries, such as China, because the latter have lower levels of specific investment in cotton production. However, in China‘s case this phenomenon has more relevance to its production of cotton in Xinjiang than in its other provinces.

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7.2 Environmental Factors Affecting the Sustainability of Australian Cotton Production Given the above-mentioned considerations, the elasticity of supply of Australian cotton in relation to its price can be expected to be relatively inelastic, more so than in the case of alternative summer crops such as sorghum, sunflower and maize. These crops (especially sorghum) require less investment than cotton and less intensive management. Sorghum is also more drought-tolerant. As Commins (2008) points out, growing cotton in Australia is risky because of the considerable sunk investment involved. Financial losses are high if there is crop failure or a partial crop failure or if prices are low. Therefore, many farmers will not risk growing cotton, especially if they have no previous experience with growing it. Furthermore, in Australia cotton must be grown on a large-scale and intensively if it is to be profitable (economic) unlike in China. The prices received by Australian farmers for cotton can vary considerably because they are world prices (Carpio, 2002). There is no government intervention to help stabilize prices paid to Australian farmers for their cotton and no subsidies for Australian cotton. This contrasts with the situation in the United States where the government guarantees cotton growers a minimum price for their cotton. Also, the Chinese government attempts to moderate fluctuations in prices paid to Chinese farmers for cotton. When global cotton prices are depressed, the Chinese government reduces the amount of cotton that can enter China duty free and also it increases its level of tariffs on cotton imports. This helps maintain the price paid for domestic cotton. Furthermore, the Chinese import system often requires that Chinese cotton importers buy a specified amount of cotton from Xinjiang to qualify for their

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import quotas. This is a way of giving financial preference to Xinjiang cotton-growers who are financially much more dependent on cotton than most growers of cotton elsewhere in China. Despite these interventions, the prices paid to Chinese growers of cotton still fluctuate considerably. Given that most Australian producers of cotton are relatively efficient (compare Chan and Zepeda, 2001) and are relatively well informed about price trends, economic factors are not the major constraint on Australian cotton supplies. The availability of water has become the major challenge in recent times to sustaining supplies of Australian cotton. Due to drought in the Murray-Darling Basin, there was a major decline in the quantity of cotton produced in Australia in the period 2000-20007. In 2000, Australian production of cotton peaked at 819 kilotonnes and declined to 133 kilotonnes in 2007. This was mainly due to the reduced area planted with cotton. This fell from 527 thousand ha in 2000 to 63 thousand ha in 2007; a reduction of about 88 per cent in the area planted with cotton. Nevertheless, yields continued to show an upward trend in this period. There are fears that due to climate change water availability is likely to become more variable and lessen in Australia‘s regions that now grow most of its cotton crop. While water availability increased to some extent in 07/08 and in 08/09, Commins (2008) reports that some cotton farmers are wary about increasing their exposure to cotton. They continue to be worried about the availability of water and think it will become more valuable in the future. There is a possibility that government restrictions on the use of water for agriculture will increase in Australia.

Figure 9. Baled ginned cotton at a cotton gin near Dalby Queensland, awaiting export to China.

A consequence of the sharp reduction in Australian production of cotton has been that many cotton gins have excess capacity. Instead of working three shifts per day, most now Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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only work a single shift and operate for fewer months of the year. Given the considerable fixed costs incurred by gins, their costs per unit of cotton ginned have tended to rise because Australian cotton production has not been maintained. Their continuing economic viability depends on Australian farmers supplying more raw cotton than in recent years. Lack of sustainability of primary cotton production has flow-on consequences (see Figure 9). A continuing challenge for Australian cotton production has been managing the pressure of diseases, weeds and insect pests in cotton in order to maintain the profitability of growing cotton. This is, however, not a problem peculiar to the Australian cotton industry – it is a global challenge. The problem is that biological systems adapt to control measures and evolve so that particular pest control measures usually only have a limited effective life and repeatedly new measures need to be developed. While transgenic varieties of cotton have boosted the effectiveness of pest control in Australia, it is too optimistic to think that particular genetic variations will be fit for their purpose forever because nature is very adaptable. Despite all such challenges, yields per ha of Australian cotton have displayed a strong upward trend, even though the volume of Australian cotton production fell sharply between 2000 and 2007. Reduced yields were not the reason for the slump in production of Australian cotton. Its main cause was lack of water availability due to drought which resulted in a severe reduction in the area planted with cotton in Australia. Once water supplies in the Murray-Darling Basin increase again, the area planted with cotton will increase but the indications are that the response will be damped given recent experiences of farmers with drought and long-term prognosis about water availability.

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8. CHALLENGES BEING FACED IN SUSTAINING CHINA‟S COTTON PRODUCTION 8.1 Economic Factors Affecting the Sustainability of China‟s Cotton Supply In its agricultural policy, China gives top priority to the production of food. Consequently, the allocation of land for growing non-food crops (such as cotton) is limited to some extent (Guan, 2008). Nevertheless, there are fewer limitations on agricultural land-use in China than in the pre-reform period, even though market and related government interventions are still of importance. Farmers now have the right to decide which crops to plant, but the State can regulate this indirectly according to need, by such means as altering the price between cotton and grain, granting different subsidies for different crops and so on. A new issue that is affecting the economics of China‘s agricultural production is a relative shortage of agricultural labour. This contrasts with the earlier situation in China when China had surplus of agricultural labour (Cao and Tisdell, 1992; Cao, 2005). Because many young and middle-aged people leave rural areas and agricultural industry for jobs in urban areas, all agricultural production, including cotton production, faces new challenges. According to the survey made in 2006 in 17 provinces (municipalities and autonomous regions) (Zhang, 2009), 74.3% of villages responded that nearly all young and middle-aged people went out to work and more than 80% of young and middle-aged labour force in approximately one third of the investigated villages had transferred to cities. On average, 48 young and middle-aged people per village stayed at home; the proportion was 17.82% (Xia,

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2009). The aged rural labour force without much education and with little enthusiasm for farming not only influences the input of farmers, but is also unfavourable to the adoption of modern agricultural technologies. Returns from growing cotton are very unstable in China these days and economic returns tend to be low. Economic returns fluctuate because the cotton price fluctuates all the time and production costs, due to variations in the prices of pesticides and chemical fertilizers, change constantly (Zhang, Wang, and Tuo, 2008). Furthermore, labour costs have risen, so the gains from cotton production are unstable and have declined sharply in recent years, thereby lowering farmers‘ willingness to plant cotton. Because of the very small scale of most Chinese farms growing cotton, mechanization and capital-intensive methods of cotton production tend to be uneconomic in China. In fact, most techniques used for cotton production on a large scale in Australia and in the United States are uneconomic in China, except (to a certain extent) in Xinjiang Autonomous Region. The most frequent situation is that all processes involved in cotton production are done manually (see Figure 10). The undersupply of cotton pickers in Xinjiang becomes a pressing problem when the picking season comes and these workers must be introduced from the inland on a large scale. Picking cotton by hand is of low efficiency with a long-time required to complete the harvest, and a large amount of labour is used at a high cost. This hinders the expansion of cotton production in China.

Figure 10. Cotton seed being planted by hand on a small plot in Hubei Province, China. All operators involved in growing cotton on this farm are done by hand.

Given the rapid economic development of China in the last three decades, and the major movement of rural labour to off-farm work and its drift to cities for work, it has become more difficult for China to sustain its level of agricultural production using traditional labourintensive methods. This, together with China‘s preference for agricultural production of food, is making it more difficult for China to sustain increases in its level of cotton production. Nevertheless, China‘s trend in total cotton production has remained an upward one (see Table 2). However, further economic growth in China‘s economy can be expected to add to the difficulty of sustaining growth in China‘s cotton production and may increase pressures for the amalgamation of farms. Larger sized farms could make the use of more capital-intensive

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techniques more economic. However, much institutional change would be needed to make farm amalgamations possible in China and the reform process may be slow. The general pattern of economic development in Western economies has been for farm sizes to become larger and for farms to become more specialized in their production but this adjustment problem is more difficult in transitional economies, such as China and Vietnam (see Tisdell, 2010 in this volume).

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8.2. Environmental Factors Influencing the Sustainability of China‟s Cotton Production The main regions in which cotton is grown in China experience different agro-climatic conditions. While some environmental problems are common to all of China‘s cotton growing areas, there are also regional differences in the nature and severity of these problems. These differences are much greater than in Australia‘s case. In Australia, there is less dispersion of the areas in which cotton is grown and greater similarity of environmental conditions experienced in these areas than in China, even though the land in which cotton is grown in Australia is from north to south over a 1000 kms in length. Water availability exerts a major influence on the sustainability of China‘s cotton supplies and the issues involved varying according to the region in China where cotton is grown. Drought, floods and the unsustainable use of available water supplies (especially groundwater) are of concern. The Yangtze River Watershed Cotton Region has a relatively sufficient water supply but experiences floods and droughts (Xu, 2007). In the Yellow River Watershed Cotton Region drought prevails, and Xinjiang Cotton Region is characterized by ―drought in spring, flood in summer, water shortage in fall and low water in winter‖ (Ouyang, 2008). Almost all the surface water resource of Xinjiang have been used for irrigation. Although only 20% of water resources of Ertix River and Ili River are developed and utilized, nearly 85% of water in most middle and small rivers is diverted (Ouyang, 2008). According to research by Chen, Chen, and Wang (2007) and Zhang (2004), groundwater is the main water source for northern China. Taking Hebei, Shanxi and Henan in the Yellow River Basin Cotton Region for example, in 2004, the proportions of groundwater use to the total water use were respectively 74.3%, 66.8% and 55% for the three provinces. The percentages of groundwater used for agricultural production were 75% in Hebei province and over 50% in Shanxi and Henan. The groundwater exploitation rates are 128%, 78.1% and 83.2% respectively. This means that in Hebei province the rate of withdrawal of underground water exceeds its rate of replacement and therefore the watertables are falling. Such a situation is unsustainable. Even in other provinces, this is a problem in some areas. Falling underground watertables add to the cost of extracting water and lower the availability of surface water. The overuse of groundwater (as well as surface water) can have many adverse ecological consequences. In addition, while China has many irrigation works (reservoirs and canals etc.), most of these were built in 1950s and 1960s with low standards of construction. Most have not been maintained, renovated and transformed for a long time and are ageing. According to the statistics (Yu, Zhang, and Fang, 2008), 10% of irrigation projects fail to function and 60% are damaged to some degree. From 1999 to 2008, 20 reservoirs in China collapsed because of

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defects or other quality problems. In 2009, there are estimated still to be 37,000 dangerous reservoirs, 43.3% of all reservoirs in China (Chen, 2009). Cotton cultivation methods used in many places in China are reducing soil quality. First, the practice of continuous cropping with cotton is a problem. Generally speaking, cotton plots are continuously cropped with cotton for more than 10 years, and even some are continuously cropped for up to 20 years (Bai, 2008). Secondly, plastic film is used to mulch many cotton crops and suppress weeds but its use leaves plastic residues in the soil (Ma, 2008). As is indicated by an investigation completed by Wan and Wang (2006), one year of plastic mulching leaves 46.2% of plastic residues in the soil; if plastic mulching occurs for five consecutive years, the cotton yield is reduced by 10% to 23%. Third, increasing application of chemical fertilizers and a relative decrease in the use of organic fertilizers has reduced the organic matter (humus) in some cultivated land and the soil structure has deteriorated. Diseases in cotton plants, insect pests and weeds, make it difficult to maintain cotton yields. While the broadacre planting of cotton (as in Xinjiang) can yield economies of scale, it provides favourable ecological conditions for the spread of plant diseases and insect pests. For example, in the Xinjiang Cotton Region, commonly 20% to 30% of plants in cotton plots are diseased and the proportion is over 80% for a few plots (Bai, 2008). Furthermore, continuous cropping adversely affects the balance of soil nutrients and provides suitable conditions for the multiplication of insect pests (Ma, 2008). China finds it to be difficult to achieve and maintain a high uniform quality in its supply of cotton because of the lack of uniformity in the varieties of cotton sown. Even in the same plot of land, multiple varieties of cotton are often sown. When multiple varieties are planted in the same plot, they cross pollinate, leading to variety variation and lower cotton quality and fibre strength, dull lustre, big differences between the quality of bales and poor spinnability. By contrast, the quality of cotton in each Australian bale is virtually uniform. Nevertheless, despite all these difficulties, the yield and supply of Chinese cotton has displayed an upward trend since 1980. In part, however, this can be attributed to the shift in cotton production towards China‘s Northwest Region. It seems likely that China will face greater difficulties in sustaining its production of cotton in the future than in the past.

9. DISCUSSION OF SOME MEASURES TO COUNTER LACK OF SUSTAINABILITY OF COTTON SUPPLIES IN AUSTRALIA AND CHINA China and Australia are both aware of the sustainability challenges facing their supply of cotton. Several initiatives have been adopted in Australia‘s cotton industry to help secure the sustainability of its cotton supplies. These include the following: (1) The Best Management Practices (BMP) program has been adopted. This is designed to help cotton growers identify and manage the risks associated with their use of pesticides and petrochemicals, and to improve the management of their soil, water and vegetation (Williams, 2008). As a result of the BMP Program, it is claimed that Australia‘s cotton industry is at the forefront of sustainable practices, thereby fostering a positive future for the industry and the natural systems that support it (Cotton Australia, 2008c).

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(2) Progress in agricultural technology development, especially in transgenic technology and its application in cotton production, many contribute to the sustainability of yields. In 2006, 95 per cent of Australia‘s cotton growers planted transgenic varieties, and these account for 80 per cent of the total area planted with cotton (Cotton Australia, 2008a). (3) Fallow and rotation of cotton plots are recommended so that the soil fertility can be maintained. (4) There is increased emphasis on the more efficient use of water in cultivating cotton. These measures are of great importance for the future sustainability of cotton production in Australia and they need to be adhered to for a long period and to be continuously perfected. In the long run, Australia may have an opportunity to increase its area planted with cotton. Although yield may be approaching its maximum, Australia still has land resources that are suitable for planting cotton. It may be possible to expand the planted area:

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(1) by replanting areas previously planted in NSW and QLD with cotton in 2000/01; and (2) as mentioned by the Office of the Gene Technology Operator (OGTR, 2008), several regions in the north of QLD might be developed for cotton production and the cropping area could even be extended to other states. However, unless water availability increases considerably and reliably in the MurrayDarling Basin or new types of cotton requiring much less water are developed, the recovery mentioned in (1) seems unlikely. A study by the Australian Cotton Cooperative Research Centre (ACCRC), based on average temperatures during the growing season, timing of rainfall, and the suitability of the soil for cotton cultivation, indicates considerable potential for expansion into northern Australia in particular areas of WA, the NT and QLD. The ACCRC study examined potential regions for cotton growing in northern Australia and suggested at least 200,000 ha of potential irrigation-areas that could be developed over the next ten years (OGTR, 2008). China has also been giving consideration to how it can sustain its supply of cotton given current demands on the use of its agricultural land, particularly to grow food. One strategy has been to increasingly locate its cotton production in its northwest, especially Xinjiang (Zhao and Tisdell, 2009). However, there appears to be little scope for increasing the area planted with cotton in the northwest, unless new varieties of cotton that are less water dependent are developed or significant increases in the efficiency of water use can be achieved. A second strategy has been to adopt transgenic technologies to raise yields and to maintain these for longer than otherwise. In 2007, 67% of the area under cotton in China was said to be planted with transgenic cotton (ISAAA, 2007). If the Chinese economy continues to grow and develop at a fast pace, this is likely to result in significant structural change in Chinese agriculture as rural-to-urban migration continues. In turn, this may result in changes that favour the merging of farms and greater mechanization in agriculture, that is a trend towards more industrial-type specialized farms. The long-term implications of such changes for China‘s cotton industry are unclear but they may result in a decline in cotton production in all regions of China, except in its northwest. Nevertheless, it is theoretically possible for China to increase its cotton yields which on average are much lower than those in Australia.

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10. CONCLUSION Global supplies of cotton have shown a persistent upward trend despite the increasing share of the market for textile fibres occupied by chemical fibres. In addition, yields of cotton globally have tended to rise partly as a result of new techniques for the cultivation of cotton (such as the introduction of transgenic cotton) and because new areas have been opened up for growing cotton some of which are more suitable for its growth than areas where cotton was previously established as a crop. The latter has happened in China as a result of an increasing proportion of its cotton being grown in its northwest, mostly Xinjiang. Whether or not these past trends in cotton supply will continue is unclear but it was argued that projecting past trends is risky and that disaggregation of the statistics on cotton supply is needed to obtain a better picture of the sustainability issues faced by the cotton industry. In order to progress with this aspect, Australia and China were selected for case studies. Both countries are globally important producers of cotton. While the volume of China‘s cotton production far exceeds that of Australia, Australian cotton is much superior in quality and is mainly exported. Both economic and environmental factors were shown to have important implications for the sustainability of China‘s and Australia‘s cotton supplies. In recent times, lack of water has been the main constraint on Australian cotton production. This has resulted in a dramatic reduction in the area planted with cotton in Australia and a large fall in its volume of production, even though Australian cotton yields per hectare have continued to rise strongly due to improved techniques and methods of production. On the other hand, China‘s supply of cotton has continued increasing despite the economic and environmental difficulties which its cotton-growers face. The depth and nature of these difficulties vary between the major cotton-producing regions of China. Water is in short supply in the Yellow River Region and almost all the available water resources have been utilized in China‘s Northwest Region. Increasing production in these regions (as in Australia) may depend on the development of varieties of cotton that need less water to flourish and on the more efficient use of water. In the Yangtze River Region and the Yellow River Region, government policies favouring the growing of grain and other food crops are edging out cotton production. Furthermore, some cultivation methods, such as the use of plastic sheeting for mulching cotton, are reducing yields. Labour availability is emerging as another problem for China‘s agricultural production. As a result of China‘s economic growth, rural-to-urban migration and increased off-farm work rose in importance thereby creating an agricultural labour shortage compared to the past. Consequently, it is no longer possible to maintain many of the labour-intensive techniques used in the past for cultivating crops, including cotton. As discussed, the bulk of China‘s cotton supply is obtained by the use of labour-intensive methods. If China continues on the path of economic development which it has experienced in the last thirty years (see Tisdell, 2009) structural change in the nature of its agricultural sector is likely to be unavoidable. With less agricultural labour available in China, there are likely to be economic pressures to increasingly mechanize and adopt more capital-intensive techniques for agricultural production, raise the size of farms and import more agricultural produce rather than rely as heavily as in the past on domestic production. These complex economic changes

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may make it very difficult for China to sustain the level of its cotton production in the long term.

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11. REFERENCES ABARE. (2009). Australian crop report. The Australian Bureau of Agricultural and Resource Economics, Report, No.149, February, 17, 2009. Bai, Y. (2008). Research on the sustainable development of cotton planting by the Xinjiang Production and Construction Corps(XPCC). Xinjiang State Farms Economy, (5), 27-36. [In Chinese] Cao, Yang, (2005). Rural-urban labour mobility and income inequality in China against the background of globalisation. 354-373 in C. Tisdell (ed.) Globalisation and World Economic Policies. Serials Publications, New Delhi. Cao, Yang, & Tisdell, C. (1992). China‘s surplus agricultural labour force: its size, transfer, prospects for absorption and effects of the double-track economic system. Asian Economic Journal, 6, 149-182. Carpio, C. E. (2002). Production Response of Cotton in India, Pakistan and Australia. Submitted to the Graduate Faculty of Texas Tech University for the Degree of Master of Science. Accepted in May, 2002. Chang, H. S. & Zepeda, L. (2001). Agricultural productivity for sustainable food security in Asia and the Pacific: The role of investment. In: Lydia Zepeda: (ed). Agricultural Investment and Productivity in Developing Countries. FAO, Viale Delle, Rome. Chen, L. (2009). Giving an alarm: still relying on beating gongs and setting off firecrackers in China if reservoirs were to suffer major problems. http://politics.people.com.cn /GB/index.html. [In Chinese] Chen, X, Chen, D. H. & Wang, Z. (2007). Some opinions about the groundwater exploitation for agricultural production in Northern China. Acta Geoscientica Sinica, 28(3), 309-314. [In Chinese] Commins, R. (2008). Responding to drought - Industry growth regions: expansion in Southern NSW and a move north in the Burdekin. 14th Australian Cotton Conference, Gold Coast, Queensland. August, 12-14 2008. Conway, G. (1985). Agrosystem analysis. Agricultural Administration, 20, 31-55. Conway, G. (1987). The properties of agrosystems. Agricultural Systems, 24, 95-117. Cotton Australia. (2008a). Facts and Figures/ General. From http://www.cottonaustralia.com. au/facts/factsandfigures.aspx?id=18. Accessed December, 1, 2008. Cotton Australia. (2008b). Facts and Figures/ Natural Resource Management Issues. from http://www.cottonaustralia.com.au/facts/factsandfigures.aspx?id=17. Accessed December, 1, 2008. Cotton Australia. (2008c). Growers’ Toolkit / Best Management Practices. http://www. cottonaustralia.com.au/toolkit/bmp/ Draper, R. (2009). Australia‘s dry run. National Geographic, 215(4), 34-59. Du, M. (2005). Analysis on the present situation and countermeasures of cotton production supply and demand in China. China State Farms, 7, 26-29. [In Chinese]

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Fitt, G., Mares, C. & Constable, G.(2002). Enhancing host plant resistance of Australian cotton varieties. Australian Cotton CRC, Narrabri. Guan, R. J. (2008). Xinjiang and National Cotton Industry Security. China Agricultural Press, Beijing, China. [In Chinese] ISAAA. (2007). Global Status of Commercialized Biotech/GM Crops: 2007. The International Service for the Acquisition of Agri-biotech Applications. No. 37. Japan Chemical Fiber Association (2008). http://www.textileinfo.com/en/news/ 2008_01/ 0127_03.html Lei, J. X. (2004). The influence of China‘s development of cotton industry on the international cotton market. The Marketing of Cotton and Jute of China, (4), 7-9. [In Chinese] Ma, H. X. (2008). Predicaments for the sustainable development of Xinjiang‘s cotton industry – a research based on the household economy. Finance and Economics of Xinjiang, (6) 24-29. [In Chinese] Mann, C. C. (2008). Our good earth. National Geographic, 214(8), 80-107. Mao, S. C. (2006). Report on Prosperity of China’s Cotton Production 2005. China Agricultural Press, Beijing, China. [In Chinese] Morris, D. & Stogdon, A. (1995). World markets for cotton: forecasts to 2000. Textiles Intelligence Limited and the Economist Intelligence Unit, Special Report, No. 2640. NBSC, National Bureau of Statistics of China. (2007). China Statistical Yearbook, 2007, China Statistics Press, Beijing. Oerlikon. (2008). The fiber year 2007/08---A world survey on textile and nonwovens industry. Oerlikon textile Gm.bH and KG. Remscheid Germany, http://www. Oerlikontextile.com. 72-73. OGTR. (2008). The Biology of Gossypium hirsutum and G. barbadense, (Cotton), Ver. 2.Office of the Gene Technology Regulator, Australian Government Department of Health and Ageing, Canberra. 11. Ouyang, J. Q. (2008). Analysis and countermeasure of the supply and need of water resources in Xinjiang. Economic Tribune, (24), 40-42. [In Chinese] Plastina, A. (2008). Cotton‘s share of world textile fiber use to decline in 2008 and 2009. Presented at the IFCP Session on Cotton Promotion: A Call to Action, 67th ICAC Plenary Meetings, November, 19, 2008. Tennakoon, S. B. & Milroy, S. P. (2003). Crop water use and water use efficiency on irrigated cotton farms in Australia. Agricultural Water Management, 61(03), 179-194. Tisdell, C. A. (1979). Economics of Fibre Markets. Pergamon Press, Oxford and New York. Tisdell, C. A. (1999). Economic aspects of ecology and sustainable agricultural production. 37-56 in A.K. Dragun and C.Tisdell (eds.), Sustainable Agriculture and Environment. Edward Elgar, Cheltenham, UK and Northampton, MA, USA. Tisdell, C. A. (2009). Economic reform and openness in China: China‘s development policies in the last 30 years. Economic Analysis and Policy, (in press). Tisdell, C. A. (2010). The survival of small-scale agricultural producers in Asia, particularly Vietnam: General issues illustrated by Vietnam‘s agricultural sector, especially its pig production. In this volume, Sustainable Agriculture: Technology, Planning and Management, Nova Science Publishers, New York.

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Wan, S. M. & Wang, L. X. (2006). Give full play to regional resources superiority for promoting the sustainable development of cotton production in Xinjiang. Journal of Tarim University, (1), 98-101. [In Chinese] Wang, Q. Z. & Chidmi, B. (2009). Cotton price risk management across different countries. Presented at the Southern Agricultural Economics Association Annual Meeting, Atlanta, Georgia, January 31-February 3, 2009. Williams, A. (2008). Managing the environmental impacts of cotton growing – An Australian perspective. Cotton Research and Development Corporation(CRDC). http://www.crdc.com.au/uploaded/File/E-Library/EENVIRO/Mging_Envir_Impacts_Cotton_Growing.pdf. Xia, L. Y. (2009). Negative effects of labor force drain on rural economy. Journal of Nanjing Agricultural University, (1), 14-19. [In Chinese] Xu, L. H. (2007). Status quo and development ideas for sustainable development of cotton production in Jiangsu Province. China Cotton, (4), 4-7. [In Chinese] Yu, Q., Zhang, H. X. & Fang, J. (2008). Discussion on sustainable utilization of agricultural water resource in China. Journal of Hebei Agricultural Sciences, 12(10), 87-89. [In Chinese] Zhang, Z. H. & Li, L. R. (2004). Ground Water Resources in China.: Sino-Map Press, Beijing. 206-214. [In Chinese] Zhang, C. X. (2001). Cotton Disaster and Disaster Prevention and Reduction Techniques. China Agricultural Scientech Press, Beijing. [In Chinese] Zhang, P. Z., Wang, X. J. & Tuo, H.T. (2008). Status quo, existing problems and countermeasures of the development of Xinjiang‘s cotton industry. Xinjiang Agricultural Sciences, 45 (S2), 174-176. [In Chinese] Zhang, Z. Z. (2009). Agricultural labor shortage – A new challenge for the new socialist countryside construction. Agricultural Outlook, (1), 36-40. [In Chinese] Zhao, X. F. (2006). Development of China’s Agricultural Textile Materials in Relation to Industrial Chains. Wuhan University Press, Wuhan. [In Chinese] Zhao, C. H. & Ding, J. G. (2008). ―Soft cotton‖ in Xinjiang with increasing ―hard strength‖. Economic Information Daily, Feb. 19, [In Chinese] Zhao, X. F. & Tisdell, C. (2009). A comparative economic study of China‘s and Australia‘s cotton production. Economic Theory, Applications and Issues, Working Paper, No. 53, School of Economics, The University of Queensland, Brisbane 4072.

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In: Sustainable Agriculture Editors: A. Salazar, I. Rios, pp. 291-313

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Chapter 7

ROLE OF PLANT RHIZOSPHERE-ASSOCIATED FLUORESCENT PSEUDOMONADS IN SUSTAINABLE AGRICULTURE P. Ravindra Naik, G. Raman and N. Sakthivel1* 1

Department of Biotechnology, School of Life Sciences, Pondicherry University, India

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ABSTRACT Fluorescent pseudomonad group of bacteria are often predominant among bacterial species associated with the plant rhizosphere. This group of bacteria has innate traits of bacterial fitness in soil such as the ability to adhere to soil particles and to the rhizoplane, motility and prototrophy, synthesis of antibiotics, production of hydrolytic enzymes, and synthesis of hormones. Fluorescent pseudomonad bacteria have the capability to suppress disease severities and enhance growth of crop plants. In addition, fluorescent pseudomonads play a vital role in inducing systemic resistance in crop plants against pathogens and also known for their participation in bioremediation of soil pollutants. This chapter describes the role of fluorescent pseudomonads in soil fertility, biodegradation of agricultural pollutants, plant growth-promotion, biocontrol of weeds, phytopathogens and nematodes.

1. INTRODUCTION Fluorescent pseudomonads are Gram-negative, motile, rod-shaped bacteria with predominant habitat in the vicinity of rhizosphere. The aggressive colonization of plant root and rhizosphere soil is due to their ability to utilize a variety of substrates such as organic acids, sugars and amino acids exudated by plant roots (Lugtenburg and Dekkers, 1999). This group of bacteria is considered to be the most promising group among the rhizobacteria involved in biocontrol of plant diseases, maintain soil health and influence plant growth directly or indirectly (Kloepper et al. 1980; Cattelan et al. 1999). Direct promotion of plant *

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growth is through the production of siderophore (Baker et al. 1986; Mavrodi et al. 2001) and phosphatase enzyme (Katznelson and Bose, 1959) that can solubilize iron and phosphorus respectively from the soil and make them accessible to plants. Fluorescent pseudomonads are also known to produce phytohormone, indole-3-acetic acid (IAA) (Patten and Glick, 2002) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase enzyme that sequesters the ethylene precursor ACC (Belimov et al. 2001; Penrose and Glick, 2002). Indirect promotion of plant growth by fluorescent pseudomonads occurs due to the prevention of the deleterious effects of phytopathogens. Suppression of plant pathogens by fluorescent pseudomonad bacteria is mainly due to the production of an array of antibiotics (Gurusiddaiah et al. 1986; Shanahan et al. 1992; Keel et al. 1990; de Souza and Raaijmakers, 2003; Pfender et al. 1993; Kraus and Loper, 1995; Nielsen et al. 1998, 2000; Sorensen et al. 2001; de Bruijn et al. 2008; Blumer and Haas, 2000) and fungal cell wall degrading enzymes (O‘Sullivan and O‘Gara, 1992). Specific metabolites by fluorescent pseudomonads may elicit defense reactions and induce systemic resistance of the host plants (Van Loon et al. 1998; Ramamoorthy et al. 2001). The study on the role of fluorescent pseudomonads in agriculture and environment has been a matter of interest because of their potential to suppress pathogens, enhance plant growth, and participate in carbon, nitrogen and phosphorous cycling in nature (O‘Sullivan and O‘Gara, 1992; Ahn et al. 2007). This chapter describes the diversity, plant-growth promoting traits, herbicidal potential, antagonistic properties and biodegradation potential of plant rhizosphere-associated fluorescent pseudomonads and exploitation of their plant beneficial traits for sustainable agriculture.

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2. TAXONOMY AND DIVERSITY OF FLUORESCENT PSEUDOMONADS Members of ―Pseudomonas‖ (-Proteobacteria subclass, Pseudomonadales order, Pseudomonadaceae family) are Gram-negative, aerobic, non-spore forming, straight or slightly curved rods. They are typically motile by means of one or more polar flagella, oxidase-positive, catalase positive and chemo-organotrophic, with a strict respiratory metabolism (using oxygen and in some cases nitrate as terminal electron acceptor). The term pseudomonad (Pseudomonas-like bacteria) is often used to describe strains that have not been established in detail for their taxonomic affiliation. A distinction was made in between Pseudomonas sensu stricto (in the -subclass of Proteobacteria) and the genera Burkholderia, Ralstonia, Acidovorax and Comamonas that were formerly grouped as Pseudomonas but belong to the -subclass. Fluorescent pseudomonads that produce the fluorescent pigment (psedobactin) mainly comprise P. aeruginosa, P. putida, P. fluorescens and P. syringae. Fluorescent pseudomonads are heterogeneous bacteria and fall into one of the five different ‗rRNA homology groups‘ on the basis of rRNA-DNA hybridization. The G+C content typically ranges from 58 to 68%. These bacteria have the ability to grow in simple minimal media at the expense of a large variety of low molecular weight organic compounds without organic growth factors. Among the plant growth promoting rhizobacteria, fluorescent pseudomonads are predominant and are well documented for their role in biocontrol of phytopathogens and soil health (Antoun et al. 1998). The advantage of this group of bacteria over other biocontrol and biofertilizing bacteria is microbial diversity and multiple beneficial

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roles in iron and phosphate mobilization, suppression of phytopathogens, control of weeds and degradation of soil pollutants. Several strains representing different species of fluorescent pseudomonads such as P. fluorescens D7 (Gurusiddaiah and Gealy, 1994), Pf1 (keel et al. 1996), Pf-5 (Loper et al. 2007) , F113 (Moenne-Loccoz et al. 1998; Martinez-Granero et al. 2005), CHAO (Hass and Defago, 2005), DR54 (Sanguin et al. 2008), PFM2 (Levy et al. 1992), Hv37a (James and Gutterson, 1986), 96.578 (Nielsen et al. 2000) , 2-79 (Gurusiddaiah et al. 1986), WCS365 (Tziros et al. 2007), WCS373 (Mercado-Blanco et al. 2001), WCS417r (Duijff et al. 1997), B5 (Wiyono et al. 2008), Q8r1-96 (Mavrodi et al. 2006), GL20 (Lim et al. 2002) and 2P24 (Wei and Zang, 2006), P. chlororaphis 30-84 (Pierson and Thomashow, 1992), PCL1391 (Chin-A-Woeng et al. 1998; 2000; Tziros et al. 2007; Bardas et al. 2009), GP72 (Liu et al. 2007), 06 (Han et al. 2006), 54/96 (Timms-Wilson et al. 2000) and 7NSK2 (Audenaert et al. 2002), P. cepacia 5.5B (Cartwright et al. 1995), P. putida WCS358 (Lemanceau et al. 1992) and P. aeruginosa PNA1 and PUPa3 (Sunish Kumar et al. 2005) have been reported as efficient strains as biocontrol agents in sustainable agriculture. A high degree of genetic diversity among fluorescent pseudomonad strains have been reported on the basis of their phenotypic and genetic traits (Ayyadurai et al. 2007). Polymorphism among phenazine (Liu et al. 2006), pyoluteorin (de Souza and Raaijmakers, 2003; Liu et al. 2006), 2, 4-diacetylpholoroglucinol (DAPG) (Ramette et al. 2001), cyclic lipopeptide (Raaijmakers et al. 2006) and hydrogen cyanide (HCN) (Ramette et al. 2003) producing strains of fluorescent pseudomonads has been reported. In a recent study from our laboratory, it has been reported that a total of 41% of strains phosphate solubilizing fluorescent pseudomonads associated with banana rhizosphere were found antagonistic against phytopathogens (Ravindra Naik et al. 2008).

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3. PLANT GROWTH-PROMOTION Beneficial effects of plant rhizosphere-associated fluorescent pseudomonads have been studied well. Plant and soil health management take advantage of multiple plant-growth promoting rhizobacterial traits such as siderophores, phosphate-solubilizing enzymes and phytohormones along with other bacterial determinants that are responsible for plant growth and induced resistance.

3.1 Solubilization of Iron Fluorescent pseudomonads produce a range of iron-complexing agents, the siderophores under iron-limiting conditions. Siderophores have a very high affinity for ferric iron. Fe3+ binding sites of siderophores (eg. pyoverdin) are present in the quinoline chromophore and the peptide chain (Budzikiewicz, 1993). Strains of fluorescent pseudomonads utilize heterologous pyoverdins and pseudobactins for iron acquisition. The spectrum of ferrisiderophores used by fluorescent pseudomonads forms the basis of strain identification through siderotyping (Meyer, 2000; Meyer et al. 2002; Lamont and Martin, 2003). Ironregulated salicylic acid synthesis by pseudomonads has been reported (Visca et al. 1993). Pyochelines frequently accompany pyoverdins and seems to be involved for second iron-

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transport system. Pyochelines are implicated to have similar antifungal activities to that of pyoverdins through minimizing availability of iron to deleterious microorganisms of plants. The abundant production of pyochelines was reported in P. aeruginosa (Cox et al. 1981). P. fluorescens ATCC 17400 was shown to produce quinolobactin siderophore in addition to pyoverdine, which itself results from the hydrolysis of the unstable molecule thioquinolobactin. P. fluorescens ATCC 17400 was identified as antagonist against the oomycete, Pythium sp., which is repressed by iron, suggesting the involvement of siderophores in disease suppression. A new class of lipopeptidic siderophore, ornicorrugatin was reported to be produced by a pyoverdin-negative mutant of P. fluorescens AF76 (Matthijs et al. 2008).

3.2 Phytohormone and Enzyme

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3.2.1 Indole-3-acetic acid Indole-3-acetic acid (IAA), a phytohormone is known to be involved in root initiation, cell division and cell enlargement (Salisbury, 1994). This hormone are commonly produced by specific strains of plant rhizsosphere-associated fluorescent pseudomonads (Barazani and Friedman, 1999; Sunish Kumar et al. 2005). IAA-producing fluorescent pseudomonads are known to increase root growth and root length, resulting in greater root surface area, which enables the plant to access, more nutrients from soil. Patten and Glick (2002) reported the role of IAA producing P. putida in development of the host plant root system. 3.2.2 Cytokinin Cytokinins are a class of phytohormones, which are known to promote cell divisions, cell enlargement and tissue expansion (Salisbury, 1994). Cytokinins are believed to be the signals involved in mediating environmental stress from roots to shoots (Jackson, 1993). P. fluorescens strains of soybean have been reported for the production of cytokinins and enhancement of plant growth (de Salmone et al. 2001). 3.2.3 1-Aminocyclopropane-1-carboxylate deaminase Ethylene is the only gaseous phytohormone. It is also known as the ‗wounding hormone‘ because its production in the plant can be induced by physical or chemical perturbation of plant tissues (Salisbury, 1994). Among its myriad of effects on plant growth and development, ethylene production can cause an inhibition of root growth. Glick et al. (1998) put forward the theory that the mode of action of some plant growth-promoting rhizobacteria was the production of aminocyclopropane carboxylate (ACC) deaminase, an enzyme that could cleave ACC, the immediate precursor to ethylene in the biosynthetic pathway for ethylene in plants. ACC deaminase activity would decrease ethylene production in the roots of host plants and result in root lengthening (Glick et al. 1994). Transforming Pseudomonas sp. strains with a cloned ACC deaminase gene enabled the bacteria to grow on ACC as a sole source of nitrogen and promoted the elongation of seedling roots when used as inoculants (Shah et al. 1998). The growth promotion effects are also expressed in stressful situations such as flooded (Grichko and Glick, 2001) or heavy metal-contaminated soils (Burd et al. 1998; Belimov et al. 2001).

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3.2.4 Phosphatase Phosphate solubilizing fluorescent pseudomonad bacteria is common in the plant rhizosphere. Secretion of organic acids and phosphatase enzyme are common methods of facilitating the conversion of insoluble forms of phosphorus to plant-available forms (Kim et al. 1998; Richardson, 2001). Fluorescent pseudomonad species such as P. fluorescens (Gulati et al. 2008), P. chlororaphis, P. putida (Pandey et al. 2006) and P. aeruginosa (Bano and Musarrat, 2003; Sunish Kumar et al. 2005; Jha et al. 2009), P. plecoglossicida (Jha et al. 2009), P. mosselii (Jha et al. 2009), P. trivialis and P. poae (Gulati et al. 2008) have been identified as phosphate solubilizing rhizobacteria.

3.2.5 Promotion of rhizobia-legume symbiosis Strains of Pseudomonas sp. (Raverkar and Konde, 1988; Li and Alexander, 1988) and P. fluorescens were reported for their ability to stimulate rhizobia-legume symbiosis in pea (Andrade et al. 1998), red clover (Marek-Kozaczuk and Skorupska, 2001) and soybean (Li and Alexander, 1988). Efficient fixation of nitrogen and subsequent enhancement of growth and yield requires effective rhizobia-legume symbiosis.

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4. BIOLOGICAL CONTROL OF PHYTOPATHOGENS Fluorescent pseudomonads are considered as biologically important components of agricultural soils due to their antagonistic to their antagonistic potential. These bacteria suppress disease severities caused by plant pathogens and enhance growth of a variety of crops like rice (Mew and Rosales, 1986; Sakthivel and Gnanamanickam, 1987), wheat (Weller and Cook, 1983), potato (Burr et al. 1978; Kloepper et al. 1980) sugar beet (Suslow and Schroth, 1982), radish (Kloepper and Schroth 1978), cotton (Howell and Stipanovic, 1980) and cassava (Hernandez et al. 1986). A number of different fluorescent pseudomonad species such as P. putida (Scher and Baker, 1982), P. aeruginosa (Bano and Musarrat, 2003; Sunish Kumar et al. 2005), P. chlororaphis (Chin-A-Woeng et al. 1998) and P. cepacia (Cattelan et al. 1999) have been reported as growth-promoting rhizobacteria as well as biocontrol strains against phytopathogenic fungi (de Salmone et al. 2001).

4.1 Polysaccharide and Flagellin Beneficial fluorescent pseudomonads are the trigger of plant immune responses. It was reported that the fluorescent pseudomonad cell surface components such as flagellin and lipopolysaccharides (LPS) are potent inducers of host immune response. Biocontrol strains such as P. putida WCS358 and P. fluorescens WCS417 and WCS374 have shown differential resistance-inducing activities on Arabidopsis, tomato and bean (Bakker et al. 2007). Role of LPS by P. fluorescens WCS374 in inducing systemic resistance against Fusarium wilt diseases of radish (Leeman et al. 1995) and in enhancing colonization in tomato (Dekkers et al. 1998) was reported. The O-antigen of LPS has been shown to be involved in induced

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systemic resistance of plants and thereby enhancing defense activities against pathogen attack (Van Peer and Schippers, 1992).

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4.2 Siderophore, Salicylic Acid and N-Alkylated Benzylamine Derivative Siderophores are the low-molecular weight iron-chelating ligands that sequester the limited iron supply available in the rhizosphere and making it unavailable to harmful pathogenic fungi and thereby, suppressing their growth (Campbell et al. 1986; Keel et al. 1992). Siderophores such as pyoverdin and pyochelin are reported to play in the suppression of Pythium-induced damping-off disease of tomato (Buysens et al. 1996). Production of siderophores sustains the survival and growth of bacterial cells under iron-limiting conditions because certain strains of pseudomonads are capable of utilizing siderophores for their iron supply (Bakker et al. 1988; Jurkevitch et al. 1992; Mirleau et al. 2000). The yellow green water soluble chromopeptide type of siderophore, pyoverdines (pseudobactins) are prevalent class of siderophores. Salicilic acid (SA; 2-hydroxybenzoic acid) which is also the precursor or intermediate in the biosynthesis of siderophores, such as pyochelin and dihydroaeruginoic acid in P. aeruginosa (Cox et al. 1981; Serino et al. 1995, 1997) or pseudomonine in P. fluorescens (Anthoni et al. 1995; Mercado-Blanco et al. 2001) also produced in iron-limiting conditions. Role of iron- regulated salicylic acid, pyochelin and pyocyanin in inducing systemic resistance has been demonstrated (Audenaert et al. 2002). The SA biosynthetic genes, pmsB and pmsC have been identified in P. fluorescens WCS374 (Geels and Schippers, 1983; Mercado-Blanco et al. 2001). Expression of these SA biosynthetic genes enhanced the accumulation of SA and SA glucosidase and constitutive expression of acidic pathogenesisrelated (PR) proteins in plants and enhanced their disease resistance (Verberne et al. 2000). Pyoverdin and salicilate by fluorescent pseudomonads also act as elicitors for inducing systemic resistance against pathogens as reported in tobacco (Bakker et al. 2003; Maurhofer et al. 1998; Van Loon et al. 1998). The role of siderophores has been demonstrated against Fusarium wilt of radish (Raaijmakers et al. 1995), Pythium damping-off (Buysens et al. 1996) and Botrytis cinerea (Audenaert et al. 2002) in tomato. Besides their role in disease suppression, siderophores also reported to promote roots in cucumber seedlings (De Bellis and Ercolani, 2001). Another bacterial determinant, N-alkylated benzylamine derivative of P. putida acts as elicitor of induced systemic resistance in bean (Ongena et al. 2005).

4.3 Antibiotic Fluorescent pseudomonads are known to produce an array of antimicrobial compounds that play a vital role in their antagonistic potential. Production of antimicrobial compounds by specific strains of fluorescent pseudomonads has been demonstrated using antibiotic-deficient mutants (Colyer and Mount, 1984; Carruthers et al. 1995; Chatterjee et al. 1996; Velusamy et al. 2004). Concerted efforts have been made to study the biosynthesis and production of antimicrobial compounds such as phenazines (Gurusiddaiah et al. 1986; Thomashow and Weller, 1988; Pierson and Thomashow, 1992; Chin-A-Woeng et al. 1998), phenolics (Keel et al. 1990, 1992; Vincent et al. 1991; Shanahan et al. 1992), pyrrole-type compounds (Homma and Suzui, 1989; Pfender et al. 1993), polyketides (Nowak-Thompson et al. 1994; Kraus and

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Loper, 1995) and peptides (Nielsen et al. 1999, 2000; Sorensen et al. 2001; de Bruijn et al. 2008; Loper et al. 2008). The role of DAPG (Raaijmakers and Weller, 1998) phenazine-1carboxylic acid (PCA) (Thomashow et al. 1990; Thomashow and Weller, 1988) in suppression of take-all disease of wheat has been demonstrated. Similarly, the involvement of phenazine-1-carboxamide (Sunish Kumar et al. 2005), pyocyanin (Watson et al. 1986), 2acetamidophenol (Slininger et al. 2000), pyrrolnitrin (Arima et al. 1964), pyoluteorin (Howell and Stipanovic, 1980), viscosinamide (Nielsen et al. 1999), tensin (Nielsen et al. 2000) and hydrogen cyanide (Voisard et al. 1989) in plant disease suppression has been documented.

4.4. Fungal Cell Wall-Degrading Enzyme

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Productions of fungal cell wall-degrading enzymes by microorganism are frequently known to be involved in the suppression of phytopathogenic fungi (Martin and Loper, 1999; Nielsen and Sorensen, 1999; Picard et al. 2000). Chitinase, β-1,3 glucanase and cellulase are especially important fungus-suppressing enzymes due to the ability to degrade the fungal cell wall components such as chitin, β-1,3 glucan and glucosidic bonds (Potgieter and Alexander, 1966; Schroth and Hancock, 1981; Chet, 1987; Lorito et al. 1996). Chitinase excreting microorganisms have been reported as efficient biocontrol agents (Sneh, 1981; Ordentlich et al. 1988; Inbar and Chet, 1991). Role of chitinase in biological control as well as in plant defense mechanisms has been documented well (Shapira et al. 1989). Nielsen et al. (1998) reported that in the sugar beet rhizosphere associated fluorescent pseudomonads inhibit R. solani by production of cell wall-degrading endochitinase. Biological control of F. solani, mainly via laminarinase and chitinase activities of P. stutzeri YPL-1 has been reported. It was also reported that β-1,3-glucanase producing P. cepacia decreased the incidence of root diseases caused by R. solani, Sclerotium rolfsii and P. ultimum (Lim et al. 1991).

5. HERBICIDAL POTENTIAL Weeds cause significant economic loss in agricultural lands. Currently, herbicides have been widely used to control weeds (Kremer and Kennedy, 1996). Excess use of chemicals often leads to pollution and therefore, biological methods are appropriate. The occurrence of weed associated bacteria that exhibit weed suppression property has been reported (Suslow and Schroth, 1982; Schippers et al. 1987; Kremer et al. 1990; Kremer and Kennedy, 1996). Several studies described the use of agricultural weed associated fluorescent rhizobacteria as bio-herbicides against dicotyledonous weeds (Charudattan, 1991; Cattelan et al. 1999) and grassy weeds in cereal crop fields (Gurusiddaiah and Gealy, 1994). This group of bacteria has the ability to reduce seed germination and delay development of weeds such as velvet leaf, lamb‘s quarters, pigweed, cocklebur, downy brome, wild oats and green foxtail (Kremer et al. 1990). Strains of rhizobacteria that selectively inhibits giant foxtail weed but non-toxic to soybean have been reported. Several recent reports have indicated that filtrates of fluorescent pseudomonads are found to be phytotoxic against weeds (Alstrom et al. 1993; Alstrom and Burns, 1989). Selective strains belonging to P. fluorescens and P. putida species of fluorescent pseudomonads have been reported to reduce green foxtail seedling growth by

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50% in agar plate bioassays (Li and Kremer, 2000). P. fluorescens strain D7 has been successfully demonstrated to suppress the growth of downy brome weed (Johnson et al. 1993). A reduction in emergence of downy brome (Bromus techtorum L.) up to 35% by P. fluorescens was reported (Kremer and Souissi, 2001). Begonia et al. (1994) proved that the pseudomonads isolated from velvetleaf (abutilon theophrasti) roots were able to reduce the viability and emergence of velvetleaf weed significantly.

5.1. Herbicidal Metabolites Gurusiddaih and Gealy (1994) have attempted to purify the antimetabolite from P. fluorescens D7, which was inhibitory to downy brome (Bromus tectorum). The metabolite showed two polypeptides, a chromophore, fatty acid esters, and a lipopolysaccharide matrix. Further purification of this compound resulted in near complete loss of phytotoxin because purification procedures may damage the phytotoxin (Gurusiddaih and Gealy, 1994). A secondary metabolite produced commonly by rhizosphere pseudomonads is hydrogen cyanide, a gas known to negatively affect root metabolism and root growth (Schippers et al. 1990). Hydrogen cyanide produced in the rhizospheres of seedlings by selected fluorescent pseudomonads is a potential and environmentally compatible mechanism for biological control of weeds. Growth inhibition of lettuce and barnyard grass by volatile metabolites of these cyanogenic rhizobacteria confirmed that HCN was the major growth inhibitory compound (Alstrom and Burns, 1989; Kremer and Souissi, 2001).

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6. NEMATODE CONTROL Fluorescent pseudomonads have the ability to control nematode infestation and nematode causing yield loss. Strains of P. putida caused reduction in galling and multiplication of Meloidogyne incognita in chick pea (Akhtar and Siddique, 2009). Potential of P. putida, P. alcaligenes strains and a Pseudomonas isolate Ps28 on the hatching and penetration of M. incognita in chickpea (Cicer arietinum) roots were studied. P. putida had the greatest inhibitory effect on hatching and root penetration of M. incognita followed by P. alcaligenes and Ps28, respectively. Similarly, P. putida colonised roots more effectively than P. alcaligenes or Ps28 (Akhtar and Siddique 2009). These recent reports indicated the use of fluorescent pseudomonad for nematode management.

7. BIODEGRADATION POTENTIAL Chlorinated aromatic compounds used as herbicides, pesticides, preservatives, solvents and lubricants constitute a major class of environmental pollutants (Keith and Telliard, 1979). Selective strains of rhizosphere associated fluorescent pseudomonad bacteria have been reported for biodegradation of agricultural pollutants and hydrocarbons. The use of plant rhizosphere associated bacteria for the bioremediation of pollutants in soils has been proposed as an efficient way to spread degrading bacteria in contaminated soils (Andersen et al. 2001).

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7.1. Pesticide Malathion is an organophosphate pesticide used non-systemic broad spectrum insecticide for the control of mosquito, aphid and turf insects. A Pseudomonas strain capable of degrading malathion has been identified and the degradation potential was confirmed with HPLC (Irman et al. 2004). Selective strains of Pseudomonas strains isolated from agricultural soil have been reported for the biodegradation of γ-hexachlorocyclohexane (γ -HCH) or phorate and their degrading ability was determined by the gas chromatography (Akbar et al. 2003).

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7.2. Herbicide A commonly used herbicide, 2,4-Dichlorophenoxyacetic acid (2,4-D) has been found to be actively degraded by several strains of fluorescent pseudomonad bacteria. The recombinant strain P. cepacia DBO1 (pRO101) was successfully used as a model system for degradation of chlorinated aromatics to degrade 2,4-D in soil (Daugherty and Karel, 1994). The rhizosphere colonizing Pseudomonas that degrades herbicide has been reported (Crowley et al. 1996; Jacobsen, 1997). The biological degradation of 2,4-Dichlorophenol (DCP) by P. putida CP1 was investigated in batch shake-flask cultures. DCP is a chlorinated derivative of phenol with the molecular formula C6H4Cl2O. DCP is used primarily as intermediate in the preparation of the herbicide 2,4-D. The 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T) is a herbicide that has been used extensively for the last several decades not only for brush and weed control on rangelands, pastures and rights-of-way, but also as a growth regulator to delay coloration of lemons, increase the size of citrus fruits and reduce deciduous fruit drop (Grant, 1979). A pure culture of Pseudomonas cepacia AC1100, capable of degrading 2,4,5-T as its sole source of carbon and energy and determined to degrade more than 97% of 2,4,5-T within 6 days as determined by chloride release, gas chromatographic and spectrophotometric analyses (Kilbane et al. 1982).

7.3. Insecticide The insecticide 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) was used extensively in agriculture and public health. DDT is the most persistent environmental pollutant on the U.S. Environmental Protection Agency (EPA) National Priority List because of its toxicity, hydrophobicity and bioaccumulation (Kannan et al. 1994; Kelce et al. 1995). Pseudomonas sp. strain capable of degrading DDT was isolated from insecticidecontaminated soil by biphenyl enrichment culture and identified as a Pseudomonas species. A detailed study of the pathway for DDT degradation by P. aeruginosa 640x isolated from DDT-polluted soils was reported (Golovleva and Skryabin, 1981). P. aeruginosa 640x degraded DDT through the intermediate formation of 2,3-dihydroxy-DDT, which undergoes meta-ring cleavage, ultimately yielding 4-chlorobenzoic acid as a stable metabolite. A strain P. aeruginosa BS 827 which has an enhanced capability of degrading DDT was generated by genetic engineering (Golovleva et al. 1982). Pseudomonas sp. isolate NJ-101 capable of biodegradation of insecticide, carbofuran was also reported (Bano and Musarrat, 2004). A

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strain of P. putida isolated from rice field soil was to be hydrolyzed methyl parathion effectively (Lakshmi Rani and Lalithakumari, 1995).

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7.4. Hydrocarbon The successful bioremediation of oil in the open environment by the naturally adapted strain of P. putida isolated from oil-contaminated site was reported (Raghavan and Vivekanandan, 1999). Polycyclic aromatic hydrocarbons (PAH) are common pollutants in contaminated soils and usually occur as a complex mixture of low- and high-molecular weight compounds. These compounds are of concern due to their acute toxicity, mutagenicity, or carcinogenicity (Shiaris, 1989; Wilson and Jones, 1993). Pseudomonas saccharophila P15 strain isolated from soil contaminated with PAH grows on phenanthrene. Preincubation with phenanthrene and downstream intermediates through salicylate stimulated PAH dioxygenase activity and initial rates of phenanthrene removal, suggesting that salicilate is the inducer of these activities. Salicylate also greatly enhanced initial rates of removal of fluoranthene, pyrene, benz[a]anthracene, chrysene and benzo[a]pyrene and high-molecular weight substrates (Chen and Aitken, 1999). Degradation of petroleum hydrocarbons (PHCs) of n-alkane members that include short-chain (n-dodecane), medium-chain(n-hexadecane and n-octadecane) and long-chain (n-octacosane) hydrocarbons, petroleum fractions such as crude oil and lubrication oil containing components of higher carbons (C > 29) by Pseudomonas sp. strain PUP6 (Ravindra Naik and Sakthivel, 2006). Chlorpyrifos, a pesticide that can easily enter the human food chain has more victims to its credit than carcinogenic air pollutants such as polycyclic aromatic hydrocarbons (PAHS). Chlorpyrifos is used both for agricultural pest control and in households as a termiticide (Ansaruddin and Vijayalakshmi 2003). Singh et al. (2003) have reported a total of 6 chlorpyrifos degrading bacteria from an Australian field soil. The Pseudomonas strain PN-1, which aerobically metabolize p-hydroxybenzoate through protocatechuate using the meta pathway of ring cleavage has been reported (Taylor, 1970). A novel bacterium strain, P. aeruginosa T1 capable of degrading different types of fats and oils, including edible oil waste has been reported (Hassanuzzaman et al. 2004). The molecular diversity of strains of pseudomonads capable of degrading tannic acid and gallic acid were grouped on the basis of 16S rRNA sequence and found P. citronellolis and P. plecoglossicida were abundant among the strains in tannic acid and gallic acid degradation, respectively (Chowdhury et al. 2004).

8. CONCLUSION After the introduction of high yielding crop cultivars, due to the selection pressure in the natural ecosystem, many races of devastating phytopathogens have proliferated and became severe production constraints. Agricultural weed infestations also cause significant economic loss. Chemical fungicides, by and large, has been used in routine to control phytopathogens and weeds. Overuse of chemicals reported to affect plant nutrition (Osborne and Robson, 1992) and increase root diseases caused by fungi (Rovira and McDonald, 1986). Besides the high cost of chemicals, the prospect of their inflowing into the food chain when applied

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continuously over a long period of the time has necessitated the search for environmentfriendly control strategies. Fluorescent pseudomonads are considered to be the most promising group among rhizobacteria involved in biocontrol of plant diseases due to their ability to maintain soil health, promote plant growth and suppress phytopathogens (Kloepper et al. 1980). The predominant nature of fluorescent pseudomonad bacteria in the vicinity of rhizosphere is due to their ability to utilize a variety of substrates such as organic acids, sugars and amino acids exudated by plant roots (Lugtenburg and Dekkers, 1999). Ability to produce an array of antimicrobial compounds such as phenazines, phenolics, pyrrole-type compounds, polyketides and peptides made fluorescent pseudomonad bacteria as potent candidates in biological control of crop diseases and weeds. Rhizosphere colonizing pseudomonad bacteria have also have the ability to degrade agricultural pollutants (Crowley et al. 1996; Jacobsen, 1997) and the use of such plant rhizosphere inhabiting bacteria has been proposed as an efficient way to spread degrading bacteria in contaminated soils for bioremediation (Andersen et al. 2001). As modern agricultural practices require eco-friendly and sustainable technologies for biological control of disease, bioremediation of pollutants and promotion of plants growth, fluorescent pseudomonads with multiple beneficial traits could be used as prospective candidates for sustainable agriculture. Fluorescent pseudomonads have already been accepted as versatile members of the microbial community for their use as biological control and biofertilizing agents. Since biological control along with bioremediation of chemical pollutants, induction of systemic resistance against pathogens and plant growth promotion is the logical corridor in sustainable ecosystem, the fluorescent pseudomonads could be widely used as soil inoculants for sustainable agriculture.

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ACKNOWLEDGMENT We thank the University Grants Commission, New Delhi, for financial support through a special assistance programme (SAP).

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Slininger, P. J., Burkhead, K. D., Schisler, D. A. & Bothast, R. J. (2000). Isolation, identification and accumulation of 2-acetamidophenol in liquid cultures of the wheat take-all biocontrol agent Pseudomonas fluorescens 2-79. Appl Microbiol Biotechnol, 54, 376-381. Sneh, B. (1981). Use of rhizosphere chitinolytic bacteria for biological control of Fusarium oxysporum f. sp. diunthi in carnation. Phytopathology, 100, 251-256. Sorensen, D., Nielsen, T. H., Christophersen, C., Sorensen, J. & Gajhede. M. (2001). Cyclic lipoundecapeptide Amphisin from Pseudomonas sp. strain DSS73. Acta Crystallogr Sect. Cryst Struct Commun, 57, 1123-1124. de Souza, J. T. & Raaijmakers, J. M. (2003). Polymorphisms within the PrnD and PltC genes from pyrrolnitrin and pyoluteorin-producing Pseudomonas and Burkholderia spp. FEMS Microbiol Ecol, 43, 21-34. Sunish Kumar, R., Ayyadurai, N., Pandiaraja, P., Reddy, A. V., Venkateswarlu, Y., Prakash, O. & Sakthivel, N. (2005). Characterization of antifungal metabolite produced by a new strain Pseudomonas aeruginosa PUPa3 that exhibits broad-spectrum antifungal activity and biofertilizing traits. J Appl Microbiol, 98, 145-154. Suslow, T. V. & Schroth, M. N. (1982). Rhizobacteria of sugar beets: Effects of seed application and root colonization on yield. Phytopathology, 72, 199-206. Taylor, B. F. (1970). Anaerobic degradation of the benzene ring by a pseudomonad. Bact. Proc. GP, 92. Thomashow, L. S. & Weller, D. M. (1988). Role of a phenazine antibiotic from Pseudomonas fluorescens in biological control of Gaeumannomyces graminis var. tritici. J Bacteriol, 170, 3499-3508. Thomashow, L. S., Weller, D. M., Bonsall, R. F. & Pierson, L. S. III (1990). Production of the antibiotic phenazine-1-carboxylic acid by fluorescent Pseudomonas species in the rhizosphere of wheat. Appl Environ Microbiol, 56, 908-912. Timms-Wilson, T. M., Ellis, R. J., Renwick, A., Rhodes, D. J., Weller, D. M., Mavrodi, D. V., Thomashow, L. S. & Bailey, M. J. (2000). Chromosomal insertion of the phenazine biosynthetic pathway (phzABCDEFG) enhances the efficacy of damping off disease control by Pseudomonas fluorescens 54/96. Mol Plant-Microbe Interact, 13, 1293-1300. Tziros, G., Lagopodi A. L. & Tzavella-Klonari, K. (2007). Reduction of fusarium wilt in watermelon by Pseudomonas chlororaphis PCL1391 and Pseudomonas fluorescens WCS365. Phytopathologia Mediterranea, 46, 320-323. Van Loon, L. C., Bakker, P. A. H. M. & Pieterse, C. M. J. (1998). Systemic resistance induced by rhizosphere bacteria. Annu Rev Phytopathol, 36, 453-483. Van Peer, R. & Schippers, B. (1992). Lipopolysaccharides of plant-growth promoting Pseudomonas sp. strain WCS417r induce resistance in carnation to fusarium wilt. Neth J Plant Pathol, 98, 129-139. Velusamy, P., Defago, G., Thomashow, L. S. & Gnanamanickam, S. S. (2004). Role of 2,4diacetylphloroglucinol (DAPG) for plant disease control: its importance to rice bacterial blight suppression in India. pp. 182-191. In: Biotechnological approaches to the integrated management of crop diseases. Mayee, C. D., Manoharachary, C., Tilak, K. V. B. R., Mukandam, D. S. & Jayashree, D. (ed.). 8-14, Daya Publishing House, New

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In: Sustainable Agriculture Editors: A. Salazar, I. Rios, pp. 315-328

ISBN: 978-1-60876-269-9 ©2010 Nova Science Publishers, Inc.

Chapter 8

THE SURVIVAL OF SMALL-SCALE AGRICULTURAL PRODUCERS IN ASIA, PARTICULARLY VIETNAM: GENERAL ISSUES ILLUSTRATED BY VIETNAM‟S AGRICULTURAL SECTOR, ESPECIALLY ITS PIG PRODUCTION Clem Tisdell School of Economics, The University of Queensland, Brisbane, Australia

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ABSTRACT Economic growth in more developed countries has resulted in farms increasing their scale of production and becoming more specialized in their production. The sizes of farms have tended to increase, agricultural production has become more capital-intensive, and the percentage of the workforce employed in agriculture has shown a falling trend. This process has been brought about by the operation of market systems and has reduced the number of small-scale agricultural producers. Asia still has a huge number of smallscale agricultural producers. As Asian countries experience economic growth and as market systems become more established in Asia, the survival of Asia‘s small-scale agricultural producers is likely to be threatened. Since these producers are poor, this is of concern to several international aid agencies. On the other hand, some Asian governments (such as Vietnam‘s) want to encourage larger scale agricultural production units. This article presents arguments for and against government strategies to promote large-scale agricultural units in emerging economies and presents an economic theory that models agricultural supply in emerging economics as being dualistic in nature. It provides information about the predominance of small-scale units in agricultural production in Vietnam, particularly in pig production, and assesses policies proposed for by Vietnam‘s Government for increasing the size of units producing pigs.

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1. INTRODUCTION In developing countries, including emerging economies in Asia, farm sizes are very small compared to those in more developed countries, especially compared to those in Australia, Canada and the United States and New Zealand. The scale of farms in developed countries has tended to increase. The tendency towards larger-scale farms in developed countries is underlined by a recent case study of the growth in farm-sizes and diversifications in Washington State in the USA by Skolrud et al. (2009). They find a trend towards larger scale farms in this state in the period 1992-2002. Furthermore, economies of specialization in agricultural production rather than economies of diversification (sometimes called economies of scope) appear to be the dominant attribute on this growth. Larger farms and more specialized farms tend to be more profitable than smaller sized and diversified farms. Therefore, the trend towards consolidation of farms (evident in most developed countries for at least two centuries) continues. Vietnam provides a useful case study of the sustainability of small-scale agricultural units in less developed nations in Asia. As a result of its economic reforms, doi moi, this socialist republic has given an increased role to market systems as a means to manage its economy and, like China, it has increasingly opened up to the outside world. For example, it is now a member of the World Trade Organization (WTO). Agriculture makes a major contribution to employment in Vietnam‘s economy and is dominated by very small-scale farming units. Given the current market situation of Vietnam‘s economy and its increasing openness, Vietnamese policy-makers have several concerns. They are concerned about whether or not small-scale units are able to be economically efficient, and about whether they can withstand increased market competition, particularly from imports of agricultural produce. A related issue is whether small agricultural producing units are able to maintain ‗adequate‘ hygiene and quality standards and satisfactorily control agricultural pests and diseases as well as improve their performance in these areas as economic development occurs. Hygiene and quality of agricultural products have increased as a priority as urbanisation and levels of income have increased in Asia. Some policy-makers (including some in Vietnam) are of the view that larger scale industrial commercial-type agricultural units are likely to have lower costs of production compared to small-scale household units and also are likely to display superior performance in meeting hygiene and quality standards, as well as in controlling agricultural diseases. It is, therefore, believed that by increasing the scale of production of agricultural units, this will benefit domestic consumers and help to meet potential competition from imports. The purpose of this article is to assess generally whether government strategies to promote larger-scale commercial agricultural units are likely to be economically beneficial to developing countries, particularly Vietnam. First, arguments for and against the adoption in developing countries of government strategies that favour farm enterprises of larger scale are advanced and a relevant economic theory is developed. Secondly, the scale and nature of Vietnam‘s agricultural production units are outlined paying particular attention to its pig sector. Thirdly, the long-term strategies of the Government of Vietnam for the development of its livestock sector, especially its pig sector, are given attention and several relevant economic implications of this strategy (which is intended to favour larger scale producing units) are highlighted by applying the theory developed earlier in this paper.

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2. ARGUMENTS FOR AND AGAINST GOVERNMENT STRATEGIES IN EMERGING ECONOMIES INTENDED TO PROMOTE LARGE-SCALE AGRICULTURAL UNITS AND A RELEVANT ECONOMIC THEORY As countries experience economic growth, it is normal for the level of employment in their agricultural sector to decline as rural to urban drift of their population occurs and a greater population of the workforce is employed in secondary and tertiary industry (Clark, 1957). Nevertheless, there is a limited speed at which labour which would otherwise be employed in primary industry can be absorbed into other sectors of the economy. If technological and structural change occurs at a rate greater than the rate at which displaced agricultural labour can be employed elsewhere, this is likely to result in growing unemployment, or under employment of the displaced population. Such underemployment or unemployment is a risk if governments in emerging economies promote larger-sized agricultural production units that replace smaller-scale ones. Government policies may directly or indirectly drive small-scale agricultural units out of business. Larger-scale units are usually more capital-intrusive and less labour-intensive than smallscale economic units. In developing countries where labour is relatively abundant, labourintensive technologies are usually preferable to capital-intensive ones from an economic efficiency point of view (Eckhaus, 1955; Tisdell, 1972, pp 312-319). This needs to be kept in mind by policy-makers. As more labour is absorbed in sectors outside of primary industry and labour becomes scarcer in agriculture, less labour-intensive technologies can be expected to become more economic in agriculture. However, the optimal pace at which this occurs may be slow. Certainly, in the early stages of the economic growth of developing economies, it is unlikely that capital-intensive agricultural technologies will be appropriate. Technologies that are appropriate in developed countries are unlikely to be economically appropriate for emerging economies in their early stages of development. This is because for some time to come, labour in agriculture is likely to be comparatively more abundant in emerging economies than in more developed ones. A further consideration in developing economies is that agricultural households provide some economic security for family members who have migrated to the urban sector to find employment. These migrants are usually younger family members of agricultural households. In difficult economic times (such as that now being experienced by many Asian developing countries as a result of the global recession), family members can return to their agricultural household if they become unemployed in their urban setting. These rural households provide a security blanket for many rural to urban migrants in emerging Asian economies when macroeconomic conditions are unfavourable to their employment. This is important because few government schemes exist to assist such migrants in emerging Asian economies. By sustaining rural households, governments in developing countries provide an economic security back-up that otherwise would not exist or be of limited help. The problem is that development of the urban sector in less developed countries can be subject to major macroeconomic fluctuations which change the economic fortunes of rural-to-urban migrants. An argument sometimes put forward for favouring an increase in the scale of production by individual productive units in agriculture is that this will improve hygiene in agricultural production and the quality of agricultural products. Furthermore, traceability is less costly

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when there are large-scale producers and products become more standardised. Most supermarkets consider this to be an advantage. The development of supermarkets as retailers, therefore, tends to favour large-scale agricultural producers. Furthermore, market exchange with large-scale producers tends to reduce market transaction costs in the whole production chain. Apart from reduced market transaction costs for buyers of agricultural produce (for example, supermarkets and processors), suppliers of agricultural inputs may also incur lower transaction costs in supplying these inputs to large agricultural units. This applies, for example, to suppliers of agricultural fertilizers, chemicals, and sellers of commercial food for livestock. Despite this, standardisation of products, improvement in their quality and extra safeguards to ensure their purity, usually involve extra costs. When incomes are low (as they still are in many emerging Asian economies), a significant proportion of the population may not wish to pay for these product improvements. Therefore, a conflict of interest can emerge when a portion of a country‘s population is urbanised and has a high income but this is not so for the bulk of its population. LRSH D2 Unit of Currency

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Figure 1. An illustration of the theory outlined in the text that at an intermediate stage of economic development of a country, a dual structure of suppliers of agricultural products is likely to be economically efficient.

A further argument sometimes advanced by officials in favour of large-scale agricultural units is that they are likely to be more effective in reducing the occurrence of diseases in agricultural crops and livestock. For example, there seems to be a view in some circles that large-scale agricultural units would be more effective in preventing the occurrence of bird flu, various diseases of pigs and the spread of these. The extent to which this is so needs further study. Considerable economic costs are experienced as a result of the occurrence of such diseases in developing countries. Another relevant issue is the control of pollution associated with agricultural production. Excrement and odours from livestock in and near urban areas can be a major pollution

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problem. The problem is usually greater for livestock units of a large size, such as piggeries. In rural areas, much of the manure and the wastes generated by livestock are used to fertilize crops. Relatively scattered livestock in rural areas probably creates fewer pollution problems than livestock concentrated in or close to urban areas. It seems likely that the supply of agricultural products by small-scale agricultural units is relatively inelastic compared to large units engaged in industrial-type commercial agriculture. This is assuming that small-scale agricultural units utilize traditional techniques and rely heavily on inputs supplied by the household and its farming area. Larger-scale agricultural units rely heavily on inputs produced in the market, many of which may be imported. This means that the supply curve of agricultural products supplied by large commercial agricultural units is comparatively elastic. This implies that large-scale units have a greater capacity to meet increased demand for agricultural products in economies where that demand is growing considerably. Hence, in many developing economies experiencing significant economic growth, a dual agricultural structure can be expected to develop. Agricultural supplies are likely to be obtained from suppliers that mainly use traditional methods of agricultural production to produce their product and a second set of producers that supply this product by adopting industrial-type commercial methods. The former are usually small-scale household suppliers whereas the latter consist of larger commercial units that are normally not based on households. The theory of such a dual structure and its consequences can be illustrated by Figure 1. There the curve ABC represents the long-run supply curve of an agricultural product (e.g. pigs) by small-scale household units. Costs are relatively low when each householder has a low-level of production of the product because the household can use household and farm ‗wastes‘, family labour (with low opportunity costs) and so forth to produce low levels of output. But as demand expands and the level of production by households increases, their marginal costs of greater supply rises sharply as they become more dependent on purchased inputs and their opportunity cost of labour rises. For commercial-type units, their long-run supply curve might be as represented by curve FGJ. This supply curve is relatively elastic. However, households can supply the product more cheaply than commercial producers if there is limited demand for the product. For example, if in Figure 1, the demand for the agricultural product X, is as represented by the line D1D1, market equilibrium would be established at B. Supply of the agricultural product is then obtained at minimum cost if it is supplied only by households. X1 of the product is produced and sold at a price per cost of P1. However, if the demand for the agricultural product rises to D2D2, there is scope for both larger-sized industrial-type agricultural and households to contribute to its supplier. The new market equilibrium would be established at J with X3 of the agricultural product being supplied and sold at a market equilibrium price of P2. Small-scale producers would supply X2 of the product and X3 – X2 of it would be supplied by larger-scale commercial units. This dual system of supply is efficient from an economic point of view. The industry supply curve is the kinked one, AGJ, in Figure 1 and is identified by the heavy line. With the passage of time the supply curve of the agricultural product of households may move upwards as the economy become more integrated and household members find superior economic employment opportunities outside of agriculture, and the supply curve of commercial producers may fall as technological change occurs. Eventually, this process could result in the replacement of households by commercial enterprises as suppliers of the product.

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The speed at which this process occurs depends on the rate of economic growth of the economy and in most cases, is probably a slow process. In any case, the above theory implies that at an intermediate stage of economic development, a dual structure for supply of agricultural products can be expected to be efficient from an economic point of view. Taking into account transport costs, dual structures (combinations of commercial and household suppliers) are more likely to be observed near large urban centres than in remote rural regions in emerging economies, and the proportion of commercial units in relation to household units is likely to be higher near large urban centres than further away. There is supporting evidence for this in the case of Vietnam‘s pig industry (Tisdell, 2008, 2009). Table 1 summarises the comparative socioeconomic attributes of large-scale and smallscale productive units in agriculture and indicates whether or not, they are likely to be an advantage or disadvantage in developing countries experiencing significant economic growth. The list is not necessarily exhaustive. From Table 1, it can be seen that large-scale agricultural production units are not superior in developing countries to smaller ones in terms of several socioeconomic attributes. The fact that large-scale commercial units are characteristic of more developed economies and appear to be modern does not mean that they are an optimal choice for less developed countries. It is highly unlikely that the skew in favour of large-scale commercial units observed in more developed countries is likely to be economically optimal in less developed nations. Nevertheless, as Figure 1 demonstrates a mixture of a small household units and large commercial ones is likely to be appropriate for nations at an intermediate stage of economic development.

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3. THE PREDOMINANCE OF SMALL-SCALE UNITS IN AGRICULTURAL PRODUCTION IN VIETNAM, PARTICULARLY IN PIG PRODUCTION The number of persons employed in agriculture in Vietnam continues to decline but in 2006, 21.26 million persons were still employed in agriculture in Vietnam, and agriculture employs a greater portion of Vietnam‘s workforce than any other sector of its economy. In 2006, agricultural units were dominated by households (9.74 million, 99.92% of all agricultural units) followed by co-operatives (6,971,0.07%), registered enterprises (608, less than 0.01%) and agricultural subsidiary organizations (343, less than 0.01%) according to General Statistics Office of Vietnam (2007, Vol.3. p.41). Between 2001 and 2006, the numbers within all categories of agricultural units declined except for the number of enterprises which showed a slight increase. The largest percentage reduction was in the number of cooperatives. Nearly a million Vietnamese households abandoned agriculture between 2001 and 2006. One expects that the rate of exodus would now be slower due to the global recession which is reducing employment opportunities in the urban sector in Vietnam and all Asian economies. Table 2 provides a summary of the amount of land used by individual agricultural production units in Vietnam in 2006. It shows that the majority of agricultural households had less than half a hectare of agricultural land and that only 5.87% of agricultural households had 2 hectares or more of land.

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Table 1. A comparison of the socioeconomic attributes of large-scale and small-scale agricultural units and their likely advantages and disadvantages in developing economies Attributes Capital intensity Labour intensity Import dependence Traceability of product Environmental pollution Disease control Control of quality of product Ability to meet increasing demand Costs per unit of production Long-term prognosis

Alienation

Large-scale Units High (−) Low (−) Usually high (−) Easier (+) Often major (−) Possibly easier (+) Easier (+) Easier to do (+)

Small-scale Units Low (+) High (+) Low (+) More difficult (−) Usually minor (+) More difficult (−) Difficult (−) Limited (−)

Lower for large volumes of supply Increase in relative importance with development

Lower for small volumes of supply Decrease as a source of supply with economic development Not a problem (−)

Can occur (−)

Note: + Likely to be an advantage in a developing country − Likely to be a disadvantage in a developing country

Table 2. The distribution of agricultural households in Vietnam in 2006 by the size of their holding of land.

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Size of Holding

Number of Percentage of Agricultural Households households Less than 0.2 ha 3,753,454 32.21 0.2 ha but < 0.5 ha 4,259,744 36.55 0.5 ha but < 2 ha 2,956,742 25.37 2 ha and over 683,538 5.88 11,653,478 100.00a (a) Does not add exactly to 100 due to rounding Source: Based on General Statistics Office (2007) Vol 3, Table 6, p.51.

An examination of the distribution of land used for annual crops, paddy and even perennial crops in Vietnam in 2006 reveals that most households involved used less than a half hectare of land for these individual crops (General Statistics Office, 2007, Vol.3). Again agricultural households having livestock operated on a very small scale. In 2006, 80.11% of Vietnamese agricultural households had chickens, 65% had pigs and 27.8% held cattle. The majority of Vietnamese agricultural households keep chickens and pigs. The size distribution of their holdings of chickens, pigs and cattle are shown in Table 3. For all these types of livestock, small holdings predominate. Between 2001 and 2006, the number of agricultural households keeping pigs in Vietnam declined by just over 1 million, that is by slightly more than the total decrease in the number of agricultural households in this period. Although most rural households keeping pigs in

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2006 still had 1 or 2 pigs, holdings with 1-2 pigs and with 3-5 pigs declined in number whereas those households with a greater number of pigs rose in number (see Table 2). Consequently, the scale of pig holdings by households increased, even though their scale still remained low by comparison with the size of piggeries in more developed countries. Table 3. The percentage distribution of agricultural households in Vietnam by size of their holdings of cattle, chickens and pigs in 2006. CATTLE Size of Holding No of Head 1-2 3-6 6-10 11 and over TOTAL % of total 71.42 22.39 5.06 1.14 100 CHICKENS Size of Holding No of Head 1-19 20-99 900-999 1000 and over TOTAL % of total 66.4 32.06 1.24 0.06 100 PIGS Size of Holding No of Head 1-2 3-5 6-20 21 and over TOTAL % of total 56.73 27.64 12.09 1.78 100 Source: Based on General Statistics Office (2007). Tables 90, 92 and 94, Volume 3.

Table 4. The distribution of households raising pigs in Vietnam in 2001 and 2006 by the size of their pig holding.

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Size

Number of Percentage Households No of head 2001 2006 2001 2006 1-2 4,937,352 3,528,297 66.8 56.73 3-5 1,887,448 1,749,844 25.54 27.64 6-20 443,597 942,000 7.35 14.89 21 and over 22,518 111,000 0.3 1.75 TOTAL 7,290,875 6,331,941 100(a) 100(a) (a) May not add to 100 due to rounding Source: Based on result of the rural agricultural and fishery census of 2001 and 2006 as reprinted by the General Statistics Office, Vietnam

From Table 4, it is seen that the scale of pig production by pig producing units in Vietnam shows an upward trend and that very small production units are becoming less common, even though they still predominate in Vietnam‘s pig industry. This is a trend favoured by the Government of Vietnam. For example, the General Statistics Office (2007, Vol 3, p.26) states that household production scale has expanded and that this is positive for economic development. The General Statistics Office (2007, Vol 3, p.26) continues ―in 1994, there were only 17.4% households with more than 3 pigs, in 2001, it was 33.4% and is 44.3% in 2006. Especially in 2006, there were 17,844 households with more than 50 pigs, more than 5.5 times in comparison with the year 2001. There is also the same trend in cattle and poultry

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rearing [and it claims that] large-scale animal husbandry, together with processing and consumptions, should be encouraged.‖ The Vietnamese Government intends to adopt strategies to increase the scale of production by units producing livestock, including those supplying pigs.

B: A typical industrial-type producer

A: A typical household producer MCH

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Figure 2. Theoretical differences in the type of per unit cost of production relationships facing household producers of pigs and those confronting industrial-type producers of pigs.

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4. POLICIES PROPOSED BY VIETNAM‟S GOVERNMENT TO INCREASE THE SCALE OF UNITS PRODUCING PIGS AND OTHER LIVESTOCK As pointed out in Section 2, a normal pattern in the economic development of nations is for small-scale agricultural units to decline in relative importance and for larger scale production units to increase in relative importance. This trend has been observed in Vietnam‘s case. However, the Government of Vietnam wants to accelerate this trend as far as livestock production is concerned to an even greater extent than in the past. (Ministry of Agriculture and Rural Development, MARD, 2007). Drucker et al.(2006) argue that the Government of Vietnam has in recent years adopted policies that effectively have encouraged larger-scale pig-producing units and the substitution of imported breeds of pigs for local ones. The increased presence of imported breeds and their crosses in Vietnam favours larger-scales of pig production based on the use of commercially processed food, much of which is imported to Vietnam, as are many other products used in intensive pig-production. Drucker et al. (2006) estimate that government subsidies paid to pig producers for the adoption of imported breeds to be substantial. Be that as it may be, livestock development policy in Vietnam is expected to begin a new phase in which explicit subsidies are to be given to units of larger scale. The government believes that this will accelerate Vietnam‘s economic development, reduce the cost of pork production, and improve the quality of pork. Indirectly, this discriminatory policy is likely to reduce the number of household suppliers of pigs operating on a small scale. There are, however, some reasons for being wary of such an approach.

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First, the fact that industrial-type commercial pig units experience economies of scale whereas household units may not, does not mean that industrial units have the lowest costs for pig production. Households may have the lowest costs for production on a low-scale, and even when industrial units fully realize their economics of scale, their per-unit cost of production may be higher than for small-scale households. This possibility is illustrated in Figure 2 where diagram A represents the assumed per unit cost of producing pigs of a typical household producer and diagram B represents that of a typical industrial-type producer. For a level of small-scale production (possibly production involving 3 pigs or less) per unit costs of production by the household is low and shown by the line AF. It is low because household and farm wastes can be fed to the pigs and the opportunity costs of labour is also likely to be low. However, once the scale of household production exceeds a low threshold (x1 in the case illustrated) per unit cots rise rapidly, as shown by line marked MCH. The exact nature of the per unit cost of industrial pig production in Vietnam does not seem to have been specified empirically by the Government. In Figure 2, it is assumed to be U-shaped. Increased economies of scale occur until a scale of production of x3 is obtained and after that diseconomies begin to emerge. The curve identified by ACI represents the average cost of production of the industrial unit and the curve market MCI indicates its marginal cost of production. It can be noted that minimum per unit cost of production of the industrial unit is OB and is higher than that of the household unit, OA. In this static case, even when industrial units all operate at maximum efficient scale (minimum per unit cost), some contribution to production by household units is less costly. However, as pointed out in Section 2, household units can only make a limited contribution to aggregate production because they are constrained in their available resources. Therefore, the type of kinked aggregate supply curve shown in Figure 1 applies. The type of relationship illustrated in Figure 1 can be developed further to explore the potential economic consequences of policies that favour large-scale agricultural producers. Assume that the relationships illustrated in Figure 2 are long run ones and that, for simplicity, all household suppliers have the same cost relationship as shown in inset A in Figure 2 and that all industrial producers have the same U-shaped cost curves as shown in inset B in Figure 2. Then the industry supply curve for households is like that shown in Figure 3 by ACSH. This indicates that the maximum quantity of pigs per unit of time that can be supplied by households at minimum cost is X0. For a greater quantity of supplies, their extra cost of supply rises sharply. On the other hand, the supply curve of industrial units is an elastic straight line shown by BG. Supply is elastic because greater production can be obtained by replicating industrial units operating at minimum efficient scale (x3 in Figure 2) and consequently, the cost of supply can be kept constant at OB per unit, assuming that the scale of industrial units is relatively low relative to the size of the market. Unlike household units, commercial units do not have significant supply constraints – they can import pig food and draw on a large labour pool. The supply curve for the whole industry is then as specified by the kinked relationship ACEFG. Given that DD is the demand for pigs, market equilibrium is established at F. This results is X2 pigs being supplied by households and X3 − X2 being supplied by industrial units with the price per pig being P2. Suppose that the government provides a subsidy of BJ per pig exclusively to large-scale producers of pigs which in this dualistic model are industrial-type producers of pigs. In Figure 3, this reduces the supply curve of industrial-type producers of pigs from BG to JK because their marginal cost of production falls by the full amount of the subsidy, unless suppliers of

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industrial inputs, such as produce (feed) merchants, have enough market power to raise the price of their supplies to piggeries and therefore, capture some of the economic gains from the subsidy. For the time being, let us assume that produce merchants lack market power. Then the following economic impacts can be observed: 1. After the subsidy, the market supply curve becomes the kinked one ACMK and the market equilibrium shifts to F from K. The supply of pigs from (small-scale) households declines from X2 to X1 and the supply from industrial type units rises by X2 − X1 plus X4 − X3. The former term is the displacement effect of the subsidy and the latter term is its impact on expanding the quantity of pigs traded. 2. The surplus income of households involved in raising pigs falls. Before the intervention this surplus equals the area of quadrilateral ACEB but after the intervention, it equals the area of the marbled quadrilateral ACMJ. The economic surplus of household producers falls by an amount equivalent to the area of quadrilateral JMEB. These mostly poor households are even poorer as a result of this intervention. 3. In the long-term, the surplus of industrial piggeries is unaltered because their supply curve is perfectly elastic. They only make normal profit. If their long-run supply curve were upward sloping some increase in the surplus of industrial piggeries would occur, the amount being greater the steeper their supply curve. In the short-run, industrial piggeries would most likely have an increased surplus because supply is less responsive in the short-run than it is in the long-run. 4. There is a net social loss from the subsidy if the potential Paretian improvement (also known as the Kaldor-Hicks criterion) is applied because the total economic costs of the policy outweigh its total economic benefits (see, for example, Tisdell and Hartley, 2008, Ch.2 or Tisdell, 2009c, Ch.3). The overall economic costs of this policy consists of two components. First, there is the increased cost of obtaining the displaced supplies (X2 − X1) of households when these supplies are produced by industrial piggeries. This additional cost is shown in the area of the hatched triangle in Figure 3. Secondly, there is another misallocation cost corresponding to the excessive supply equal to X4 − X3 to the market. The additional value that buyers place on this extra supply is less than the extra cost of producing it. This loss is shown by the dotted area of triangle FKG in Figure 3. 5. Furthermore, the subsidy increases the tax burden on taxpayers. Extra tax revenue equivalent to P2 − P1 times X4 − X1 must be found in order to pay the subsidy. It is possible that the main beneficiaries of the subsidy could be produce merchants if they have some market power. In Vietnam, there are few major suppliers of produce for livestock (Drucker et al. 2006), so this is a possibility. This is especially likely to be the case if in local areas there are fewer produce suppliers than exist nationally.

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Figure 3. An illustration designed to highlight some of the economic consequences of subsidies that favour units that produce pigs on a large rather than on a smaller scale.

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If it could be shown that industrial-type piggeries have reduced environmental externalities compared to small-scale household producers, this might provide an economic case for favouring the former. However, subsidisation of large-scale piggeries might not be the best way to address this matter.

5. CONCLUDING COMMENTS As economic growth proceeds, small-scale production units in agriculture tend to become uneconomic and the scale of such units increases. This process tends to occur naturally in market systems so that in the very long-term, small-scale agricultural producers fail to survive if substantial economic development occurs. Institutional factors may impede or accelerate the trend. For example, in communist countries in Asia, such as Vietnam and China, restrictions on land transfers have slowed this trend; property rights in land are still in flux in these transitional economies but land transfers are restricted. This could change, however. For example, the Central Committee of the Chinese Communist Party announced in October, 2008 that it is to develop new policies for greater property rights in agricultural land, including the right to transfer such land (World Bank, 2008, p.19). The World Bank (2008, p.19) states: ―The [China‘s] new land policy encourages an orderly evolution of agriculture from household-based towards larger-scale operations, promotes the development of a rural land rental market by improving tenure security and strengthens farmers‘ bargaining position in land transactions and acquisitions‖. Whether Vietnam will follow suit eventually remains to be seen. Vietnam has adopted a strategy for the long-term development of its livestock sector that encourages units that adopt a larger scale of production. It is not, however, apparent that this

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is a wise economic decision given that Vietnam is a developing economy still in economic transition. Reasons for being cautious about such a policy have been outlined in this article. There do not seem to be strong arguments for subsidising large-scale agricultural producers thereby reducing the economic sustainability of small-scale agricultural producers in Vietnam at this stage of its development. This seems to be so in many developing Asian economies. Consideration needs to be given to the removal of limitations on property rights which, amongst other things, limits the transferability of land. These limitations impede the operation of market forces likely to favour an increase in the scale of units involved in agricultural production. Reforming systems of property rights could be more efficient from an economic point of view than subsidisation to ensure that the scale of agricultural units is such as to minimize the overall costs of agricultural production. However, promoting economic efficiency is not the sole purpose of economic policy (Tisdell, 2009b)

6. ACKNOWLEDGMENTS I wish to thank Dr. Lucy Lapar of ILRI for bringing some relevant references to my attention and the Center for Economic Policy, Vietnam, for help with data. This paper is a contribution to the research project ―Improving the competitiveness of pig producers in an adjusting Vietnam market‖ managed by the International Livestock Research Institute (ILRI) and funded by the Australian Centre for International Agricultural Research (ACIAR).

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7. REFERENCES Clark, Colin. (1957). The Conditions of Economic Progress 3rd Edn. Macmillan, London. Drucker, A. G., Bergeren, E., Lenke, U., Thury, L. T. & Zàrate, A. V. (2006). Identification and quantification of subsidies relevant to the production of local and imported breeds in Vietnam. Tropical Animal Health Production, 38, 305-322. Eckhaus, R. S. (1955). The factor-proportions problem in underdeveloped areas. American Economic Review, 45, 539-568. Government Statistics Office, Vietnam. (2007). Results of the 2006 Rural, Agricultural and Fishery Census. Statistical Publishing House, Hanoi. Skolrud, T. D., O‘Donaghue, E. O., Shumway, C. R. & Melhim, A. (2009). Identifying growth and diversification relationships in Washington agriculture, Choices: The Magazine of Food, Farm and Resource Issues, 24(1), 45-48. Tisdell, C. A. (1972). Microeconomics: The Theory of Economic Allocation. John Wiley, Sydney, New York and London. Tisdell, C. A. (2008). Structural Transformation in the Pig Sector in an Adjusting Vietnam Market: A Preliminary Investigation of Supply-side Changes. Economic Theory, Applications and Issues, Working Paper No. 50, School of Economics, The University of Queensland, Brisbane, 4072. Tisdell, C. A. (2009a). Trends in Vietnam‘s Pork Supply and the Structure of its Pig Sector. Economic Theory Applications and Issues, Working Paper no. 54, School of Economics, The University of Queensland, Brisbane, 4072.

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Tisdell, C. A. (2009b). Complex policy choices regarding agricultural externalities: efficiency, equity and acceptability. 83-106 in V. Beckmann and M. Padmanabhan (eds) Institutions and Sustainability: Political Economy of Agriculture and the Environment. Springer Science and Business Media, Dordrecht, The Netherlands. Tisdell, C. A. (2009c). Resource and Environmental Economics: Modern Issues. World Scientific, Singapore, London, New Jersey. (In Press). Tisdell, C. A. & Hartley, K. (2008). Microeconomic Policy: A New Perspective. Edward Elgar, Cheltenham, UK and Northampton, MA, USA. World Bank, (2008). China Quarterly Update – December 2008. World Bank Office, Beijing.

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Chapter 9

THE BIOCHAR APPROACH: A COMPLEMENTARY USE OF WASTE BIOMASS FOR RENEWABLE ENERGY PRODUCTION, CARBON SEQUESTRATION AND SOIL FERTILITY ENHANCEMENT Christoph Steiner* The University of Georgia, Biorefining and Carbon Cycling Program, Drifmier Engineering Center, Athens, GA 30602, U.S.A.

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Extraordinary demands are being placed on agricultural systems to produce food, fiber and energy. Biomass burning and the removal of crop residues reduce carbon in soil and vegetation, which has implications for soil fertility and the global carbon cycle. Pyrolysis of waste biomass generates fuels and biochar (charcoal) recalcitrant against decomposition. The process of pyrolysis or carbonization is known globally. It can be implemented on a small scale (e.g., cooking stove) as well as a large scale (e.g., biorefinery) and in most agricultural systems. Biochar offers unique options to address issues emerging from the conflicts and complementarities between cultivating crops for different purposes, such as for energy or for CO2 sequestration or for food and the impacts on food security, soil degradation, water, and biodiversity. Biochar is proposed as a soil amendment in environments with low carbon sequestration capacity and previously carbon-depleted soils (especially in the Tropics). From recent studies it is known that biochar amendments to soil increase and maintain fertility and the human-made Terra Preta soils in the Amazon prove that infertile soils can be transformed into fertile soils and long-term SOC enrichment is feasible even in environments with low carbon sequestration capacity. The prospects are to increase the sustainability of land use, establish a large carbon sink, reducing the rate of deforestation and competition between different land use purposes through waste biomass utilization. *

E-mail: [email protected]

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Christoph Steiner This chapter reviews the potential of waste biomass utilizations, the importance of the soil organic carbon pool for climate and explains our options to manage this carbon pool by biochar carbon sequestration.

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THE VALUES OF SOIL ORGANIC CARBON (SOC) Before the invention of mineral fertilizers, management of SOC was the only way to restore or maintain soil fertility. Sedentary farmers either depleted their SOC stocks for nutrients, facing nutrient depletion, or found ways to maintain SOC. Over decades, smallscale African farmers have removed large quantities of nutrients from their soils without using sufficient quantities of manure or fertilizer to replenish the soil. As a result, Africa south of the Sahara is the only remaining region of the world where per capita food production has not increased over the past 40 years (Sanchez, 2002). Migration is the solution to nutrient depletion for an estimated 300 to 500 million people affecting almost one third of the planet‘s 1500 million ha of arable land (Goldammer, 1993; Giardina, et al., 2000). This agricultural system is termed ―shifting cultivation‖, indicating moving from one spot to another as soil fertility declines. Decreasing SOC contents correlates with soil nutrient depletion (Zech, et al., 1990; Goldammer, 1993; Silva-Forsberg and Fearnside, 1995; Hölscher, et al., 1997). Soil infertility and inability to buy fertilizers force these poor farmers to clear a new piece of land (tropical Rainforest) every 3 years when SOC reaches critical levels (Tiessen, et al., 1994). The critical limit of SOC concentration for most soils of the tropics is 1.1% (Aune and Lal, 1997). Traditional shifting ―slash and burn‖ agriculture is considered to be sustainable if adequate fallow periods (up to 20 years) allow regeneration of the SOC pool (Kleinman, et al., 1995). The relationship between soil fertility and SOC was well known in the first half of the 19th century as the German agronomist Albrecht Thaer published his ―Humus Theory‖. Thaer‘s approach, and quantitative assessment of agro-ecological and economic sustainability of farming systems was used with success during half a century, until 1849 when Sprengel and Liebig published on the mineral nutrition of plants (Feller, et al., 2003). From then on, the ―minimal nutrition theory‖ progressively abandoned recycling of nutrients from settlements to agricultural fields (Manlay, et al., 2007). But it took more than 60 years until the German chemist Fritz Haber found a way to synthesize ammonia. This was the basis of all subsequent nitrogenous fertilizer. Since 1950 (after the world wars and Great Depression) the problem of nutrient depletion was addressed by mineral fertilization (McNeill and Winiwarter, 2004). This boosted crop production and replenished nutrient stocks but did not treat soil degradation accompanied by accelerated loss of SOC. Most soils have lost 30 to 75% of their antecedent SOC pool or 30 to 40 t C ha-1 (Lal, et al., 2007). The observed loss of SOC is associated with yield decreases (Grace, et al., 1995), reduced nutrient cycling and reduced nutrient-use efficiency of applied fertilizer (Yamoah, et al., 2002). Throughout the world, intensive agricultural land use often has resulted in soil physical and chemical degradation, erosion, and higher losses than input rates of nutrients and organic materials. In contrast, the intentional and unintentional deposition of nutrient-rich materials within human habitation sites and field areas has in many cases produced conditions of heightened fertility status (Woods, 2003). An anthropogenically-enriched dark soil found throughout the lowland portion of the Amazon Basin and termed Terra Preta de Índio is one

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such example. Its fertility is the secondary result of the transport of natural and produced foods, building materials, and fuel to prehistoric dwelling places (Woods, 1995). These materials and their byproducts were then transformed and differentially distributed within the zone of habitation and associated garden areas. The resulting soil contains high concentrations of charcoal (Glaser, et al., 2001a) and significantly more plant available nutrients than in the surrounding Oxisols (Lima, et al., 2002). This is in contrast to today‘s urban wastes in the region which are deposited as contaminated toxic material far away from settlements or into the rivers. The existence of Terra Preta proves that infertile Ferralsols and Acrisols can be transformed into permanently fertile soils in spite of rates of weathering 100 times greater than those found in the mid-latitudes. Such a transformation cannot be achieved solely by replenishing the mineral nutrient supply, however; SOC is also of prime importance for insuring the retention of soil nutrients (Zech, et al., 1990). According to Duxbury, et al. (1989) and Sombroek, et al. (1993), it is important to separate effects due to organic matter per se (maintenance and improvement of water infiltration, water holding capacity, structure stability, cation exchange capacity (CEC), healthy soil biological activity) from those due to decomposition (source of nutrients). The SOC pool is an important indicator of soil quality, and has numerous direct and indirect impacts on it such as, improved structure and tilth, reduced erosion, increased plant-available water capacity, water purification, increased soil biodiversity, improved yields, and climate moderation (Lal, 2007a). This is essential to sustain the quality and productivity of soils around the globe, particularly in the tropics where there is a greater proportion of nutrient poor soils with a greater susceptibility to SOC loss (Feller and Beare, 1997).

Figure 1. shows the values of soil organic carbon (SOC) and its implications on the environment, agronomy, and quality of life. Redrawn and lightly modified from (Lal, 2004).

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GREENHOUSE GAS (GHG) EMISSIONS FROM AGRICULTURE Measurable anomalous emissions of GHG began already 8000 years ago. These early anthropogenic CO2 emissions were caused by forest clearing in Eurasia for agricultural purposes, and methane (CH4) emission rose from widespread rice irrigation about 5000 years ago (Ruddiman, 2003). After 1750 the increase in atmospheric CO2 was mainly caused by fossil fuel combustion but emissions from land use change contributed about 30%, from which more than half is estimated from depletion of SOC. This depletion is exacerbated by further soil degradation and desertification (Lal, 2003). These losses from the earth‘s native biomass and from soil due to cultivation amount approximately 170 Pg (x 1015) carbon, most of it as CO2 in the atmosphere (Sauerbeck, 2001a). The global SOC pool in the upper 1 m for the world‘s soils contains 1220 Pg carbon, 1.5 times the total for the standing biomass (Sombroek, et al., 1993). As most agricultural soils have lost 50 to 70% of their original SOC pool (Lal, 2003) they represent a considerable carbon sink if efforts are made to restore SOC, but also a huge source of GHG if soil management and deforestation rates are not reduced. There is high agreement and much evidence that with current climate change mitigation policies and related sustainable development practices, global GHG emissions will continue to grow over the next few decades (25–90% between 2000 and 2030) (IPCC, 2007).

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REPLENISHING SOC POOLS AND THE GLOBAL POTENTIAL OF CHARCOAL CARBON SEQUESTRATION Increasing SOC with conventional means, e.g., conservation tillage, use of manures, and compost, conversion of monoculture to complex diverse cropping systems, meadow-based rotations and winter cover crops, and establishing perennial vegetation on contours and steep slopes can sequester carbon from 100 to 1,000 kg ha-1 year-1. The sequestration potential depends on climate, soil type, and site specific management. The global potential of SOC sequestration is estimated at 0.6 to 1.2 Pg carbon per year (Lal, et al., 2007). Climate, particularly rainfall and temperature, is an important factor for SOC formation from decomposing biomass residues. Therefore the SOC pool is in dynamic equilibrium with climate and soil management. West and Post (2002) used a global database to investigate 67 long-term agricultural experiments for their potential to sequester carbon. They found that a change from conventional tillage to no-till can sequester 570 ± 140 kg carbon ha-2 yr-1 and enhancing rotation complexity can sequester on average of 200 ± 120 kg carbon ha-2 yr-1. Carbon sequestration rates will peak in 5 to 10 yr with SOC reaching a new equilibrium in 10 to 15 yr and 40 to 60 yr if rotation complexity is enhanced. West and Six (2007) estimate that changing from conventional tillage to no-till can increase soil C by 16 ± 3 %, within 21 years. The drawback of SOC enrichment with conventional methods is that this carbon-sink option is of limited duration. Humus enrichment follows a saturation curve, approaching a new equilibrium level after some 50 to 100 years. The new SOC level drops rapidly again, as soon as the required careful management is no longer sustained. SOC of cropland increases only if either SOC additions are enhanced or decomposition rates reduced (Sauerbeck, 2001a). Roots contribute more C to SOC than aboveground residue. Only one-third of the

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aboveground residues remain in the soil after 1 year and only 10–20% remains after 2 years. Furthermore the addition of degradable crop residues and reduced tillage systems can increase N2O and CH4 emissions substantially. Baker, et al. (2007) reviewed literature on conventional plowing and conservation tillage and did not find consistent accrual of SOC due to conservation tillage. He assumes that root growth and distribution might be affected by conservation tillage leading to increased SOC in surface horizons but SOC depletion in subsoil horizons. Reduced decomposition is an advantage of charcoal soil amendment (biochar). Seiler and Crutzen (1980) were the first to point out the potential importance of charcoal formation to the global carbon cycle. In natural and agroecosystems residual charcoal is produced by incomplete burning. As the SOC pool declines due to cultivation, the more resistant charcoal fraction increases as a portion of the total carbon pool (Zech and Guggenberger, 1996; Skjemstad, 2001; Skjemstad, et al., 2002) and may constitute up to 35% of the total SOC pool in ecosystems (Skjemstad, et al., 2002). Therefore, biomass burning has important negative and positive impacts on C dynamics. Carbon dating of charcoal has shown some to be over 1500 years old, fairly stable, and a permanent form of carbon sequestration (Lal, 2003). The storage of carbon in charcoal was proposed in 1993 (Seifritz, 1993). Seifritz proposed to produce charcoal (biochar) and dispose it in landfills. This proposal did not receive much attention, until recent research on Terra Preta revealed the importance of charcoal to maintain soil fertility particularly in the humid tropics (Glaser, et al., 2001b; Steiner, 2007). Inspired by recreation of Terra Preta, Slash and Char was described as an alternative to slash and burn (Lehmann, et al., 2002), and Steiner, et al. (2004b) observed that charcoal is currently used by Amazonian settlers to improve soil fertility. If a forest is burned, only around 2–3% of the above-ground carbon is converted into charcoal (Fearnside, et al., 2001), but charcoal production can capture 50% of the above-ground carbon. If re-growing resources (fallow vegetation or crop residues) are used, slash and char could become a significant carbon sink and an important step towards sustainability and SOC conservation. The global potential of biochar (non fuel use charcoal) reaches far beyond slash and char. Increasing interest in renewable energy raised the prospect to supply biochar from pyrolysis of waste biomass. Pyrolysis would facilitate bio-energy production and carbon sequestration if the biochar is redistributed to agricultural fields. Thus the uses of crop residues as potential energy source or to sequester C and improve soil quality can be complementary, not competing uses. Lenton and Vaughan (2009) rated biochar as the best geo-engineering option to reduce CO2 levels. The United Nations Convention to Combat Desertification (UNCCD) started an initiative to include biochar in the post-2012 agreement on climate change mitigation and acknowledgement as carbon sink by the UNFCCC. This would facilitate CDM projects based on biochar carbon. A review by Johannes Lehmann (2006) and the article ―Black is the new green‖ (Marris, 2006) emphasize the potential of biochar on a global scale. A global analysis by Lehmann, et al. (2006) revealed that up to 12% of the total anthropogenic carbon emissions by land use change (0.21 Pg carbon) can be off-set annually in soil, if slash and burn is replaced by slash and char. Agricultural and forestry wastes add a conservatively estimated 0.16 Pg carbon yr-1. If the demand for renewable fuels by the year 2100 was met through pyrolysis, bio-char sequestration could exceed current emissions from fossil fuels (5.4 Pg carbon yr-1).

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Figure 2. This demonstrates the historical knowledge about the recalcitrance of charcoal. Wooden poles were (are) blackened (carbonized) on the outside to increase their persistence in soil (Austria, Foto: C. Steiner).

BIOCHAR AND SOIL FERTILITY The recalcitrant nature of charcoal makes biochar a rather exceptional SOC constituent. Whether biochar can improve soil quality to the same extent as decomposable organic materials is a valid question. Recent studies showed that soil charcoal amendments are indeed capable of increasing soil fertility (Iswaran, et al., 1979; Ogawa, 1994; Glaser, et al., 2002; Topoliantz, et al., 2005). Charcoal significantly increased plant growth and nutrition in a pot experiment by Lehmann, et al. (2003) and a field experiment by (Steiner, et al., 2007). The authors proposed that charcoal can improve soil chemical, biological, and physical properties. Lehmann, et al. (2003) found significantly reduced leaching of applied fertilizer N in charcoal containing pots. This was corroborated in the field experiment by Steiner, et al., (2008). Soil respiration and the microbial population growth rates were significantly altered by charcoal amendments. Steiner, et al., (2004a) found increased microbial activity on charcoal amended plots. Terra Preta soils were marked by very low soil respiration but very high population growth after glucose additions. Unmanaged forest soils (Ferralsol) had a higher respiration rate but a very low population growth potential. These results reflect the relatively high biodegradable SOC content of primary forest topsoil but low available nutrients (requirement for microbial population growth), in contrast to refractory Terra Preta SOC with high available soil nutrient contents. This indicates that nutrient availability in Terra Preta is

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independent from SOC decomposition. The effects on soil biology seem to be essential as charcoal has the potential to alter the microbial biomass (Steiner, et al., 2004a) and composition (Birk, 2005) and the microbes are able to change the charcoal‘s properties (Glaser, et al., 2001a). The majority of experiments conducted show that biochar soil amendments result in enhanced colonization rates my mycorrhizal fungi (Warnock, et al., 2007). Rondon, et al. (2007) found increased biological N fixation by common beans through charcoal additions and Gehring (2003) increased occurrence of nitrogen-fixing nodules in plants in forests on Terra Preta compared to adjacent soils. Lehmann and Rondon (2006) reviewed 24 studies with soil charcoal additions and found improved productivity in all of them ranging from 20 to 220% at application rates of 0.4 to 8 Mg (x 106) carbon ha-1.

ADVANTAGES OF BIOCHAR CARBON SEQUESTRATION

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No Competition between SOC Restoration, Bio-Fuels and Food Production Numerous researchers warn of deleterious effects on soil fertility if crop residues are removed for bio-energy production (Sauerbeck, 2001b, Lal, 2005, Blanco-Canqui and Lal, 2007, Lal, 2007a, Lal, 2007b, Lal and Pimentel, 2007). Blanco-Canqui and Lal (2007) found that an annual corn stover removal rate of > 25% reduces SOC and soil productivity. Pyrolysis with charcoal carbon sequestration provides a tool to combine SOC management (carbon sequestration), and renewable energy production. While producing renewable energy from biomass, SOC sequestration, agricultural productivity, and environmental quality can be sustained and improved if the biomass is transferred to an inactive carbon pool and redistributed to agricultural fields. The uses of crop residues as potential energy source or to sequester carbon and improve soil quality can be complementary, not competing uses. The global amount of crop residue produced is estimated at 2.802 Pg yr-1 for cereal crops and 3.758 Pg yr-1 for 27 food crops. The energy value of crop residues (without forestry residues) produced in the US is 976 x 106 barrels of diesel or 9.1 x 1018 J of energy. The corresponding global values are 7,516 x 106 barrels of diesel or 69.9 x 1018 J of energy (Lal, 2005). Sauerbeck (2001a) estimates potential savings of fossil energy use by 10-25%, while providing the same amount of energy without enriching the atmosphere with additional CO2. An enormous amount of biomass is burned each year without any use. Frequently biomass (forests, fallow vegetation, grassland, crop residues) is burned to get rid of it, adding CO2 to the atmosphere for only marginal and short term increases in soil fertility. Kim and Dale (2004) evaluated the amount of wasted biomass globally. They estimated that 0.667 Pg of rice straw is wasted In Asia annually. Before the introduction of mineral fertilizers, rice residues were a valued resource and mostly returned to the soil as organic fertilizer. Since then, the importance of organic soil amendments has declined continuously and they are likely to play a minor role in the management of nutrients in favorable rain-fed environments. This is the result of the availability of cheap inorganic fertilizer and the increasing opportunity costs of organic fertilizer use (Pingali, et al., 1998). Simultaneously, increasing yields lead to ever greater quantities of rice residues available and intensification of land use results in insufficient time for decomposition. As a consequence residues

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accumulate in the field and can cause considerable crop management problems. Increasing residue incorporation in flooded rice paddies causes higher methane emission, a very potent GHG. Many Asian farmers find it more expedient to burn crop residues than to incorporate them into the soil (Haefele, IRRI, personal communication). Kim and Dale (2004), estimate that globally 1,549 Pg of stover and straw (from the 7 most important crops) are wasted per year. Worldwide, the total carbon release from fire is of the order of 4-7 Pg of carbon per year. This flux is almost as large as the rate of fossil fuel consumption (about 6 Pg per year in 1990) (Goudriaan, 1995). Tropical forest conversion is estimated to contribute globally as much as 25 % of the net CO2 emissions (Palm, et al., 2004). These numbers emphasize the potential for biochar carbon management if only the biomass is utilized that is burnt with no use except for getting rid of it.

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Pyrolysis or Gasification with Biochar Carbon Sequestration Carbon capture and sequestration usually assumes geo-sequestration (CO2 capture in depleted oil and gas fields, saline aquifers etc.) as the sequestering tool. To capture carbon as CO2 is very cost-intensive (Ho, et al., 2005). These technologies require vast capital inputs and large scale projects. Using this technology for coal power plants can at best reduce its CO2 emissions, while using re-growing biomass would establish a carbon sink. Bio-energy with biochar carbon sequestration would only capture a maximum of 50% of the carbon stored in the biomass but offers several advantages. Biochar producing gasifiers can have a broad range in size and in technological complexity. Biochar can be produced as a byproduct from cooking (biochar producing kitchen stoves). Decentralized small scale projects are feasible and large capital investments are not necessary. As biochar is a byproduct of gasification, no carbon capture technology is necessary. There is no risk of harmful CO2 leakage from biochar. Most scientists agree that the half life of charcoal is in the range of centuries or millennia.

Fast SOC Buildup Beyond the Maximum Sequestration Capacity From biomass to humus a considerable fraction of carbon is lost by respiratory processes, and also from humus to resistant soil carbon. Only 2-20% of the C added as above ground residues and root biomass enters the SOC pool by humification. The rest is converted to CO2 due to oxidation, and furthermore the SOC pool is not inert to oxidation (Lal, 2004). Soils can only sequester additional C until the maximum soil C capacity, or soil C saturation, is achieved, which requires a steady input of biomass and careful management practices. 8090% of the carbon from crop residues in the field is lost due to decomposition in the first 5 to 10 years. In contrast, about 50% of the carbon can be captured if biomass is converted to biochar (Lehmann, et al., 2006). The existence of Terra Preta proves that SOC enrichment beyond the maximum capacity is possible if done with a recalcitrant form of carbon such as biochar. These soils still contain large amounts of biochar derived SOC in a climate favorable for decomposition, hundreds and thousands of years after they were abandoned.

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Reduced Deforestation The carbon trading market holds the prospect to reduce or eliminate deforestation of primary forest, because cutting intact primary forest would reduce the farmer‘s carbon credits. Fearnside, (1997) estimated the above-ground biomass of unlogged forests to be 434 Mg (x 106) ha-1, about half of which is carbon. This carbon is lost if burned in a slash-and-burn scenario and lost to a high percentage (> 50%) if used for charcoal production. Only regrowing plant biomass can establish a carbon sink. The carbon trade could provide an incentive to cease further deforestation; instead reforestation and recuperation of degraded land for fuel and food crops would gain magnitude. As tropical forests account for between 20 and 25% of the world terrestrial carbon reservoir (Bernoux, et al., 2001), this would reduce emissions from tropical forest conversion which is estimated to contribute globally as much as 25 % of net CO2 emissions and up to 10 % of N2O emissions to the atmosphere (Palm, et al., 2004).

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CURRENT OBSTACLES FOR BIOCHAR CDM PROJECTS A prerequisite for the above-mentioned management practices is access to the global carbon trade. According to Lal, (2007b) the global C market has a potential to grow to $1 trillion by 2020 or before. This market must be made accessible to land managers, especially in the tropics where sustaining SOC and soil fertility is most challenging and CO2 emissions due to land use change are highest. One Mg of charcoal is roughly the equivalent of 3Mg CO2. Biochar-based carbon sequestration is incompatible with the current international Framework Convention on Climate Change (UNFCCC, Kyoto Protocol) in several ways. Current CDM projects dealing with charcoal aim either at reduction of methane emissions during charcoal production or substitution of fossil fuels by burning charcoal. In both cases the charcoal does not reduce GHG in the atmosphere. Biochar as a soil amendment would provide a large permanent carbon sink but is, as other soil management practices, not acknowledged by the UNFCCC as a carbon sink. Potential drawbacks such as difficulty in estimating greenhouse gas removals and emissions resulting from land use, land use change and forestry (LULUCF), or destruction of sinks through forest fire or disease do not apply for biochar soil amendments even though the charcoal carbon sink is easily quantifiable. Biochar production transforms carbon from the active (crop residues or trees) to the inactive C pool. The definition of a carbon sink should be revised to include the difference between a sink to the inactive carbon pool, such as biochar, and a sink that remains in the active carbon pool, such as reforestation. In terms of additionality, there are significant differences between activities that reduce emissions and activities that transfer carbon from the active to the inactive carbon pool. Such a transformation should be seen as additional. The use of biochar as soil amendment needs to be recognized as a carbon sink under the LULUCF and the additionality tests revised. There is growing consensus that biochar sequestration should be eligible as a carbon sink type under the UNFCCC, and interest in biochar from the agricultural community is expanding worldwide. Biochar carbon sequestration could be a strong link between the three

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Rio conventions as it simultaneously addresses climate change, desertification and biodiversity.

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Steiner, C., Glaser, B., Teixeira, W. G., Lehmann, J., Blum, W. E. H. & Zech, W. (2008). Journal of Plant Nutrition and Soil Science. Steiner, C., Teixeira, W. G., Lehmann, J., Nehls, T., Macêdo, J. L. V. D., Blum, W. E. H. & Zech, W. (2007). Plant and Soil, 291, 1-2, 275-290. Steiner, C., Teixeira, W. G., Lehmann, J. & Zech, W. (2004a). In: Amazonian Dark Earths: Explorations in Space and Time; Glaser, B. & Woods, W. I., Ed., Springer Verlag: Heidelberg, 195-212. Steiner, C., Teixeira, W. G. & Zech, W. (2004b). In: Amazonian Dark Earths: Explorations in Space and Time; Glaser, B. & Woods, W. I., Ed., Springer Verlag: Heidelberg, 183193. Tiessen, H., Cuevas, E. & Chacon, P. (1994). Nature, 371, 6500, 783-785. Topoliantz, S., Ponge, J. F. & Ballof, S. (2005). Biology and Fertility of Soils, 41, 15-21. Warnock, D. D., Lehmann, J., Kuyper, T. W. & Rillig, M. C. (2007). Plant and Soil, 300, 920. West, T. O. & Post, W. M. (2002). Soil Sci Soc Am J, 66, 1930-1946. West, T. O. & Six, J. (2007). Climatic Change, 80, 25-41. Woods, W. I. (1995). In Papers and Proceedings of the Applied Geography Conferences; Schoolmaster, F. A., Ed., Applied Geography Conferences: Denton, Texas, 158-165. Woods, W. I. (2003). In: Amazonian Dark Earth: Origin, Properties, Management; Lehmann, J., Kern, D., Glaser, B. & Woods, W., Ed., Kluwer Academic Publishers: Dordrecht, The Netherlands, 3-14. Yamoah, C. F., Bationo, A., Shapiro, B. & Koala, S. (2002). Field Crops Research, 75, 5362. Zech, W. & Guggenberger, G. (1996). In: Humic substances in terrestrial ecosystems; Piccolo, A., Ed., Elsevier. Zech, W., Haumaier, L. & Hempfling, R. (1990). In: Humic substances in soil and crop sciences; selected readings; McCarthy, P., Clapp, C. E., Malcolm, R. L. & Bloom, P. R., Ed., American Society of Agronomy and Soil Science Society of America: Madison, 187-202.

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In: Sustainable Agriculture Editors: A. Salazar, I. Rios, pp. 341-352

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Chapter 10

CONTROL METHODS FOR REDUCING NITRATE ACCUMULATION IN VEGETABLES CULTIVATED SOILLESS UNDER PROTECTED CONDITIONS: A REVIEW Wenke Liu* and Qichang Yang Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural sciences, Key Lab. for Agro-Environment & Climate Change, Ministry of Agriculture, Beijing, 100081, China

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ABSTRACT Vegetables, particularly leafy vegetables, are dominant sources of nitrate intake through dietary pathway for human due to high level nitrate accumulation and large consumption. Today, off-season vegetable production in winter and spring, are usually cultivated under protected conditions worldwide. As a result, more nitrate would be accumulated in vegetables when they were cultured under protected conditions for the weaker inner light intensity. Excessive intake of nitrate will pose potential hazards on human health. Therefore, to develop efficient measures to decrease nitrate content in vegetables before harvest is a hot research issue worldwide in the past more than thirty years. Nowadays, based on our knowledge, it has been realized that nitrate content in vegetables cultivated soilless can be successfully controlled through nutrient solution regulation and environmental factor control. In this paper, the regulation measures through nutrient solution regulation and environmental control on nitrate accumulation in vegetables were summarized, highlighting the control strategy.

*

:

Corresponding author E-mail address: [email protected]

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INTRODUCTION In China, people are traditionally like to consume more vegetables than other countries in dietary each day (See table 1). Thus, Chinese people are more easily to be jeopardized caused by nitrate intake through vegetables due to high accumulated level, especially during offseason time. Nowadays, Off-season supply of vegetables during winter or spring in China were mainly cultivated under protected conditions, such as solar greenhouse, multi-span greenhouse, glass greenhouse, plastic tents and even plant factory etc. Low light intensity inside the facilities aggravates nitrate accumulation level[4]. In the past two decades, in order to meet the increasing requirements on off-season vegetables, more and more cultivation facilities were constructed with an ever developmental rate. China owns over 3.0 million hectares of protected vegetables in 2007, ranking the first globally l[5]. Vegetables, in particular leafy vegetables, are nitrophilous plants, which absorb luxuriously nitrate from substrates. Subsequently, more and more nitrate will accumulate in vacuoles since they are not reduced in time for future use in case of nitrogen deficiency. The petioles are the most sensitive part to N application. In addition, the nitrate accumulation in petiole was over the half of that in the whole plant, ranged from 55% to 75%[6]. Nitrate form nitrogen is necessarily added in nutrient solution or inevitable appearance in soil solution for vegetable production. For soil cultivation, organic manure, urea and ammoniacal nitrogen will transform into nitrate nitrogen after processing by soil microorganisms. For soillesss cultivation, nitrogen in nutrient solution can not presented solely by ammoniacal nitrogen for ammonia toxicity and imbalance of solution pH. In conclusion, nitrate accumulation in vegetables is inevitable without adopting special control measures both in the open and under protected conditions. There is weaker light intensity for vegetable growth inner the greenhouses after the sunlight being absorption, reflection, shading or interception by cover materials, such as plastic films, glasses, and truss structure. Furthermore, light quality has also been changed inner the greenhouses after transmission of mulch. It had been well documented that low light intensity would lead to nitrate accumulation in vegetables by suppressing photosynthesis. Many investigations around the world have found that nitrate accumulation in vegetables was serious [7、8、9、10]. Just in China, more than fifty pieces of articles have given describing the nitrate pollution situation in vegetables cross the country. It had been reported that approximately 80% nitrate intake of human body was from vegetables eaten [11]. Excessive intake of nitrate will pose potential hazard to human health, especially for infants. The toxic effects of nitrate are due to its endogenous conversion to nitrite, which is implicated in the occurrence of methaemoglobinaemia, gastric cancer and many other diseases [12]. Incidence of methaemoglobinaemia, earlier believed to have been confined to infants only, has been reported in all age groups with high nitrate ingestion, with infants and above 45 years age groups being most susceptible to nitrate toxicity [13]. It has been widely accepted that a reduction in dietary nitrate is a desirable preventive measure [14], which is a more urgent issue for Chinese people for high vegetable intake. Therefore, developing measures to reduce nitrate concentration in vegetables are effective method to lower dietary nitrate instead of changing consumption, as well as working out the compulsive policy. Today, many countries had issued the limits for nitrate concentration of vegetables (Table 2).

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Table 1. Comparison of the intake of nitrate and nitrite in north China with other countries (mg person-1•day-1) Country China Denmarka Englandb Egyptc

Vegetable consumption (g• day-1) 510 142 322 159

Nitrate intake (g• day-1) 486.0 38.9 108.5 296.0

Nitrite intake (g• day-1) 0.78 0.09 2.20 -

a

Petersen and Stoltze(1999)[1], bYsart et al. (1999) [2], cSaleh et al. (1998) [3]

Table 2. Guide and maximum tolerated nitrate concentrations of vegetables (mg NO3 kg-1 in fresh weight) Germany Netherland Switerland Austrilia Russia EC (guide) (Maximum) (Guide) (Maximum) (Maximum) (Maximum) 3500(4-10) 3000(S) 3000(S) 2000(O) Lettuce 3000 3500 4500(11-3) 4500(W) 4000(W) 3000(G) 2500(O,5-8) 3500(S) 2500(4-10) 2000(7) 3000(G) 2500(1995) 2000(P) Red 4000(4-6) 3500(S) 3000 3000 beet 3500(7-3) 4500(W) 3500(S) Radish 3000 4500(W) Endive 2500 900(S) 3000(S) 875 cabbage 1500 500(W) 400(S) Carrot 1500 250(W)

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Species

Note: S:summer. W:winter. O:outdoor. G:greenhouse. P:processed product (preserved/frozen). 7:harvest from July. 1995: from 1995. 4-10:1 April to 31 October. 11-3:1 November to 31 March. 5-8:1 May to 31 August. Data from Sohn and Yoneyama (1996)[15] and MAFF UK (1999)[16].

Table 3. Nitrate pollution and hygienic evaluation

1

Nitrate concentration (mg/kg) ≤432

2

≤785

Medium

3

≤1440

High

4

≤3100

Serious

Classification

Pollution degree Slight

Hygienic evaluation Fresh-eating permission Fresh-eating permission is not permitted, pickling and cookingeating permission Fresh-eating and pickling is not wed permitted; cooking-eating permission Eating is not permitted

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To sum up, seasonality (summer and winter) and cultivation patterns (outdoor and greenhouse) were considered in drawing up the limits of nitrate content of vegetables. In general, limits for vegetables grown in greenhouse are higher than those in the open field. In addition, vegetables grown in summer contain lower nitrate content. As early as in 1973, WHO and FAO put forward an acceptable daily intake (ADI) maximum for nitrate intake, 3.65mg/kg fresh weight. According to the ADI value, if a person with 60kg weight ingests 0.5kg fresh vegetable per day, the nitrate content can not exceed 438 mg/kg fresh weight. Based on above data and the discount ratio of nitrate content after pickling (45%) and cooking (60%-70%) treatments, Shen et al. (1982) [17] gave an evaluation criteria listed in table 3. Additionally, National standard (GB18406-2001) of China described the criteria for non-pollution vegetables on nitrate content. Nitrate in melon and fruit should be lower 600mg/kg, root and stalk vegetables should not exceed 1200mg/kg, and leafy vegetables should be less 3000mg/kg. Furthermore, nitrite content of all kinds of vegetables should not surpass 4 mg/kg. In view of nitrate limits issued, measures should be developed to decrease nitrate content in vegetables before harvest, not exceed the limits. In the past three decades, how to control nitrate content in vegetables has been a hot international research topic. Currently, compared with field, vegetables grown in protected conditions are easily to accumulate more nitrates in tissues for low light intensity and sufficient water and nutrient supply. It has been evidenced that nitrate accumulation is in proportion to growth rate and water content, therefore, higher water and nitrogen supply will lead to heavy accumulation and out of limits. For vegetable growers, in order to obtain high yield, larger fertilizer and irrigation were carried out to get more economic income. To conclude, over-limit of nitrate occurs frequently for vegetables grown under protected conditions attributed to a result of combined effects of heavy water and fertilizer input, biological property of nitrate accumulation and adverse lighting. Up to date, previous studies mainly focused on nutrient supply regulation and environmental control to lower nitrate content in vegetables. In fact, in protected conditions, environmental controlling such as temperature, lighting, CO2 concentration, and nutrient solution constitutes are readily realized. For soilless cultivation of vegetables, controllable environmental factors facilitate nitrate content reduction during cultivation. Therefore, most previous studies are aimed at soilless cultivation, especially on the regulation of environmental factors and constitutes of nutrient solution. In this review, previous studies were summarized with highlight on environmental control and nutrient solution control measure, also control strategy was discussed at last.

1. CONTROL ENVIRONMENTAL FACTORS TO LOWER NITRATE CONTENT 1.1. Light Light is the unique energy source of plants, which control the growth, development and nutritional quality. Plants are empowered with an array of photoreceptors controlling diverse responses to light parameters, such as spectrum, intensity, direction, duration etc. These photoreceptors include the red and far-red-absorbing phytochromes, the blue and UV-A light absorbing cryptochromes, phototropins, and other implied photoreceptors, absorbing in UV-A

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and green regions. Spectral changes of illumination evoke different morphogenetic and photosynthetic responses, which can vary among different plant species[18, 19]. This photoresponse is important in agrotechnology, since feasibility of tailoring illumination spectra enables one to control plant growth, development, and nutritional quality. There are true changes of light intensity and light spectrum into greenhouse, which may affect the productivity and quality of vegetables. Therefore, it is necessary to optimize the light supplementary system in greenhouses, especially in phytotron or plant factory to yield higher biomass and quality. Furthermore, light source is the main energy consumption equipment in artificial light plant factory, thus novel energy-saving light source is more feasible based on the benefits.

1.1.1. Light intensity Light intensity is a key environmental factor that affects nitrate accumulation in vegetables[4] by determining carbohydrate content, reducing substances and energy supply for nitrate assimilation. Previous investigations had found that nitrate content in vegetables presented obviously seasonality and diurnal fluctuation. Usually, vegetables have higher nitrate content in winter and night than summer and daylight [20, 21, 22, 23, 25].. Somebody found that crops grown in north Europe contain higher nitrate content than those in south Europe[26], which attribute to the growth rate differences under various light intensity conditions[27]. However, Byrne et al.(2004）[25] and Hardgrave（1994）[28] found no temporal differences in nitrate content of lettuce during the daylight. Based on the roles of light intensity in nitrate accumulation, increase in light intensity is a effective method to decrease nitrate content in vegetables. Demšar et al. (2004)[29] developed a set of lightdependent aeroponics system controlled by computer, by which the supplied nitrate level could be regulated in terms of light intensity. Controlled nutrition resulted in efficient reduction in leaf nitrate. In the early-spring experiment the average nitrate content in outer leaves was decreased by 9%-92% and in the late-spring experiment the decrease was 23%76% compared to control. At the same time, the controlled, light-dependent nitrate deprivation did not result in a loss of a lettuce yield (except in the treatment with strong nitrate reduction) and had limited effects on photosynthesis and photosynthetic pigments. 1.1.2. Light quality Usually, in glasshouse UV-B (280-320 nm) was absent in light spectrum after penetration through the glass [30, 31]. Likewise, other coverings, like plastic mulch, also affect light spectrum. However, there are only few investigations examined the effects of light spectrum on nitrate accumulation and vegetable growth. Qi et al. (2007）[32] studied the effects of red, blue, white and yellow light from colored fluorescent lamp on yield and nitrate accumulation of spinach. The results showed that red light was in favor of carbohydrate formation and accumulation, also facilitated decrease in nitrate content in comparison with white and yellow light. Blue light significantly suppressed shoot growth due to its damage on chloroplast grana lamellae in leaf mesophyll cell, which reduced the photosynthetic efficiency [33] (Dai et al.,2004). Soluble sugar content in spinach was greater under red light than blue light. Urbonavičiūtė et al. (2007) [34]examined the effects of LED based 92% red light 640nm）+ 8% near-UV, 86% red light +14% blue, 90% red light+10% cyan light and white fluorescent lamp on growth and nitrate accumulation of lettuce. Drastic sensitivity of total carbohydrates

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concentration and relative ratio between amounts of different sugars on the spectral position of the short-wavelength component was observed. The results also demonstrated that concentration of nitrate in plants grown under such bicomponent illumination was reduced in respect to the reference plants grown under illumination by conventional fluorescent lamps. Sugar content of lettuce illuminated by red light plus blue light was higher than other two bicomponent light source, and the latter also were lower than the control. Three LED-based bicomponent light made a decrease in nitrate content by 15-20 percent compared with control. Combination of 90% red light and 10% blue light is optimal bicomponent light source for decrease nitrate content. However, there were no significant differences in nitrate content of lettuce under three LED based light source, which indicated that red light is the fundamental factors for nitrate control. Today, many colored agricultural films, light conversion polyethylene films have been used to regulate light quality for good quality and high output of vegetables[35]. Furthermore, supplementary light using artificial light systems have been used conventional measures in protected conditions.

1.2. Temperature and CO2 Concentration

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Up to present, only few investigations have been conducted about air temperature and CO2 concentration on nitrate accumulation. Huang and Yuan (1996) [36] indicated that there are negative correlation between air temperature and nitrate content, and nitrate content of vegetables differed largely with seasons. Richardson and Hardgrave（1992) [37] showed that CO2 concentration enriched to tri-fold of the background level in glasshouse would increase the biomass of lettuce, but without effect on nitrate content in winter. Pace et al.(1990)[38] found that nitrate accumulation of maize seedling increase under CO2 stress by hampering photosynthesis to supply insufficient C skeleton instead of nitrate reductase activity reduction.

2. NUTRIENT SOLUTION REGULATION TO DECREASE NITRATE CONTENT IN VEGETABLES Nitrogen level is the primary factor that determines nitrate accumulation of vegetables no matter which nitrogen form is used. However, different nitrogen forms differ in uptake, assimilation pathway and effects on nitrate accumulation.

2.1. Nitrogen Form It was evidenced that increased ammonium nitrogen could decrease nitrate content of leafy vegetables[39]. For example, after replacement of 25% nitrate nitrogen with ammonium nitrogen, the nitrate content in leaves, petioles and roots was reduced by 22 %, 15 % and 22%, respectively, and nitrate uptake was lowered by 7.5%[40]. In soilless cultivation, part substitution nitrate nitrogen with ammonium nitrogen, e.g. ammonia, urea and amino acids etc., usually decrease nitrate content of vegetables [41, 42, 43]. Liu et al. (2007) [44]suggested that 3mM mixed amino acids significantly increased nitrate uptake of red

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peeper, enhanced nitrate reductase activity of roots. Furthermore, nitrate content in leaves and roots was reduced. Liu et al.（2008) [45] evidenced that biogas slurry could used as nutrient solution for lettuce soilless cultivation, also reduced the nitrate content in leaves.

2.2. Nitrogen Deprivation

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Usually, nitrate accumulation in leafy vegetables will be improved continuously with the increase of nitrate supply. However, vegetable yield respond differently to nitrogen supply increase, with no responsiveness critical nitrogen concentration. From this, it can be seen that yield and nitrate content is not positively correlated in vegetable growth. Therefore, low nitrate level in nutrient solution is the direct method to lower nitrate content in vegetables grown soilless, as long as it does not result in obviously decrease in yield. Mozafar (1996) [46]developed a nitrogen deprivation method to control nitrate content in spinach. In this experiment, spinaches prior to harvest were transferred into nutrient solution without nitrogen, and the nitrate content in spinach were lowered markedly after two or three days treatment. The results indicated nitrogen deprivation management before harvest is an effective method to reduce nitrate content in vegetables. This approach has some important advantages. First, it takes short time and feasible for soilless cultivation. Second, the Vc content in vegetable could be improved after treatment simultaneously without lessening the yield. On the other hand, scaling down the nitrate concentration in nutrient solution in terms of daily uptake of vegetable during cultivation also could reduce nitrate content in lettuce by 30–40%, meanwhile, without yield decrease[47]. However, the treatments of eliminating N completely and adding organic acid salt reduced nitrate content significantly and also decreased pakchoi yield[48]. In conclusion, apart from nitrogen form selection, control of nitrogen level supplied in soilless cultivation both during cultivation and before harvest is an efficient method to produce vegetable with low nitrate content.

2.3. Osmotic Ions Osmotic ions, including Cl-, SO42-, malate, sorbate and acetate etc., can substitute for nitrate in vegetables serving as osmoticum. Based on this theory, before harvest, adding Cland SO42- basing on reducing N amount had better effect on reducing nitrate accumulation of pakchoi, and the effect of Cl- was better than SO42-[49]. Many data indicated that replace nitrate in nutrient solution with Cl- could decrease nitrate content in lettuce[49, 50]. Cl- could reduce nitrate content in vegetables mainly via competition of anion uptake sites besides as osmoticum[51].

2.4. Nutrients High yield is the first demand in soilless cultivation in development of nitrate control techniques, because significantly low yield is not cost-effective for farmers even with low nitrate content vegetable produce. In order to obtain high yield during cultivation, it is

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necessary to ensure nutrient balance and sufficient supply, since they are the premise for high yield with low nitrate content of soilless cultivation of vegetables. Deficiency of molybdate, manganate, copper and boride would lead to decrease the nitrate reductase activity, and increase nitrate content in vegetables[52]. Most essential elements attend the processes of nitrate reduction and assimilation in vegetables. For example, P participates in the photophosphorylation, and provides energy and electron donor. Furthermore, P is also the important component of nitrate teductase and nitrite reductase, which directly attend the nitrate reduction and assimilation[53].

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3. STRATEGY OF NITRATE CONTROL IN VEGETABLES Based on current knowledge, it is feasible to reduce nitrate content in vegetable grown soilless through dual control measures, including regulating environmental factors and nutrient composition. Terminal control and process control are two basal strategies for soilless cultivation practice of vegetables. No matter which strategy needs all two kinds of measures, i.e. environmental factors and nutrient composition regulation. Terminal control is more feasible with regard to maneuverability and high yield guarantee. However, it needs further to investigate the practical efficiency in large-scales. Process control is more laborious and costly because it needs some equipment and control devices during the whole growth period. Nowadays, after all, current research on control of nitrate in vegetables is delightful. Research on practical measures and relative biological principles has made substantially progressed. In light of the advantages of controllable nutrient solution and environmental factors, nitrate accumulation in vegetables grown soilless can be possibly achieved, entirely. In addition, well-controlled conditions could decrease the incidence of diseases and insect pest. Vegetables cultivated soilless usually have good appearance, non-pollution of heavy metals. Today, land resources increasingly decreased for soil degradation and pollution. Extreme whether will happen under the scenario of climatic change. Vegetables produced by soil cultivation often results in serious problems, including soil degradation and succession cropping obstacle. Soilless cultivation is the pattern for future mass production vegetables. It is believed that non-pollution vegetable production with soilless cultivation is feasible.

4. RESEARCH PROSPECTS After extensive research, well-controlled nitrate content in vegetables grown soilless will have an important impelling action on popularization of soilless cultivation in China. Today, more than 90% planting acreage of vegetables is soil cultivation, although soilless cultivation is prevalent in developed countries. Future study should pay more attention on below three issues. First, studies on nitrate uptake and assimilation physiology in vegetables grown soilless, mainly includes nitrate distribution and transport; Second, integration method of environmental factor control and nutrient solution regulation; Third, development of special equipment and device for artificial illumination and natural light plant factory. All in all, decreasing nitrate content and increasing nitrogen use efficiency of vegetables are the direct

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benefits for nitrate control, which also can lower the potential risk for human health and environmental pollution, as well as deterioration of agricultural production systems [54].

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[16] Maff, UK. Nitrate in lettuce and spinach. In Food surveillance information sheet Number 177, edited by Joint Food Safety and Standards Group: http://www.maff.gov.uk/food/infsheet/1999/no177/177nitra.htm. 1999. [17] Shen, MZ; Zhai, BJ; Dong, HR. Study on nitrate content of vegetables. I. Estimate on nitrate and nitrite content of different vegetables. Acta Horticulturae Sinica, 1982, 9, 41-47. [18] Schuerger, AC; Brown, CS. Spectral quality affects disease development of three pathogens on hydroponically grown plants. Hortscience, 1997, 32(1), 96-100. [19] Huq, E. Degradation of negative regulators: a common theme in hormone and light signaling networks? Trends in Plant Science, 2006, 11, 4-7. [20] Maynard, DN; Barker, AV; Minotti, PL; Peck, NL. Nitrate accumulation in vegetables. Advances in Agronomy, 1976, 28, 71-118. [21] Steingröver, EG; Ratering, P; Siesling, J. Daily changes in uptake, reduction and storation of nitrate in spinach grown at low light intensity. Physiologia Plantarun, 1986, 66, 550-556. [22] Delhon, P; Gojon, A; Tillard, P; Passama, L. Diurnal regulation of NO3 uptake in soybean plants. Ⅰ.Changes in NO3 influx, efflux and N utilization in the plant during the day/light cycle. Journal of Experimental Botany, 1995a, 46, 1585-1594. [23] Delhon, P; Gojon, A; Tillard, P; Passama, L. Diurnal regulation of NO3 uptake in soybean plants. Ⅱ.Relationship with accumulation of NO3 and asparagines in the roots. Journal of Experimental Botany, 1995b, 46, 1595-1602. [24] Cárdenas-Navarro, R; Adamowicz, S; Robin, P. Diurnal nitrate uptake in young tomato (Lycopersicon esculentum Mill.) plants. Journal of Experimental Botany, 1998, 49, 721-730. [25] Byrne, C; Maher, MJ; Hennerty, MJ; Mahon, MJ; Walshe, PA. Reducing nitrate content of protected lettuce. Teagasc Research Report, Teagasc, Kinsealy Research Centre, Dublin, Ireland http://www.teagasc.ie/research/reports/horticulture/4561/eopr4561.htm, 2004. [26] Anon. Commission Regulation (EC) No. 1822/2005 of 8th November 2005, amending Regulation (EC) No. 466/2001 as regards nitrate in certain vegetables. Official Journal of the European Communities L293/11: 9 November, 2005. [27] Kanaan, SS; Economakis, CD. Effect of climatic conditions and time of harvest on growth and tissue nitrate content of lettuce in nutrient film culture. ISHS Acta Horticulturae 323: Symposium on Soil and Soilless Media under Protected Cultivation in Mild Winter Climates. 1992. [28] Hardgrave, M. Glasshouse lettuce: Reduction of nitrate residues. Final Report on Project PC88 to the Horticultural Development Council, East Malling. 1994. [29] Demšar, J; Osvald, J; Vodnik, D. The effect of light-dependent application of nitrate on the growth of aeroponically grown lettuce (Lactuca sativa L.). Journal of the American Society for Horticultural Science, 2004, 129(4), 570-575. [30] Nitz, GM; Grubmuller, E; Schnitzler, WH. Differential flavoniod response to PAR and UV-B light in chive (Allium schoenoprasum L.). Acta Hort, 1994, 659, 825-830. [31] Nitz, GM; Schnitzler, WH. Effect of PAR and UV-B radiation on the quality and quantity of the essential oil in sweet basil (Ocimum basilicum L.). Acta Hort, 2004, 659, 375-381.

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[32] Qi, LD; Liu, SQ; Xu, L. Effects of light qualities on accumulation of oxalate, tannin and nitrate in spinach. Transactions of the CSAE, 2007, 23(4), 201- 205. [33] Dai, SJ; Wang, Y; Yan, XF. Ef fects of color film s on growth and camptothec in content in the leaves of Camptotheca acuminata seedlings. Acta Ecologica Sinica, 2004, 24(5), 869-875. [34] Urbonavičiūtė, A; Pinho, P; Samuolienė, G; Duchovskis, P; Vitta, P; Stonkus, A; Tamulaitis, G; Žukauskas, A; Halonen, L. Effect of short-wavelenght light on lettuce growth and nutritional quality. Sodininkystė ir Daržininkystė, 2007, 26(1), 157-165. [35] Patil, GG; Oi, R; Gissinger, A; Moe, R. Plantmorphology is affected by light quality selective plastic films and alternating day and night temperature. Gartenbauwissenschaft, 2001, 66(2), 53-60. [36] Huang, JG; Yuan, L. Relationship between nitrate, nitrite and environmental factors of Chongqing city. Acta Ecologica Sinica, 1996, 16(4), 383-388. [37] Richardson, SJ; Hardgrave, M. Effect of temperature , carbon-dioxide enrichment, nitrogen form and rate of nitrogen-fertilizer on the yield and nitrate content of 2 varieties of glasshouse lettuce. Journal of the Science of Food and Agriculture, 1992, 59, 345-349. [38] Pace, GM; et al . Nitrate reduction in response to CO2-liminted photosynthesis. Relationship to carbohydrate supply and nitrate reductase activity in maize seedlings. Plant Physiology, 1990, 92, 286-2921. [39] Chen, W; Luo, JK; Jiang, HM; Shen, QR. Effects of different NO-3 2N/ NH+42N ratios on the biomass and nitrate content of different cultivars of chinese cabbages. Acta Pedologica Sinica, 2004, 41(3), 420-4251. [40] Luo, JK; Chen, W; Zhang, PW; Shen, QR. Mechanism of nitrate accumulation of Chinese cabbage under properly enhanced ammonium, 2005, 11(6), 800-803. [41] van der Boon, J; Steenhuizen, JW; Steingröver, EG. Growth and nitrate concentration of lettuce as affected by total nitrogen and chloride concentration, NH4/NO3 ratio and temperature of the recirculating nutrient solution. Journal of Horticultural Science, 1990, 65, 309-321. [42] Gunes, A; Inal, A; Aktas, M. Reducing nitrate content of NFT grown winter onion plant by partial replacement of NO3- with amino acid in nutrient solution. Scientia Horticulturae, 1996, 65, 203-208. [43] Santamaría, P; Elia, A. Producing nitrate-free endive heads: effects of nitrogen form on growth， yield， and ion composition of endive. Journal of the American Society for Horticultural Science, 1997, 122, 140-145. [44] Liu, XQ; Ko, KY; Kim, SH; Lee, KS. Enhancement of nitrate uptake and reduction by treatment with miced amino acids in red pepper (Capsicum annuum L.). Acta Agriculturae Scandinavia Section B-Soil and Plant Science, 2007, 57, 167-172. [45] Liu, WK; Du, LF; Yang, QC. Biogas slurry added amino acid decrease nitrate concentrations of lettuce in sand culture. Acta Agriculturae Scandinavica Section B-Soil and Plant Science,（In press） [46] Mozafar, A. Decreasing the NO3- and increasing the vitamin C contents in spinach by a nitrogen deprivation method. Plant Foods for Human Nutrition, 1996, 49, 155-162. [47] Andersen, L; Nielsen, NE. A new cultivation method for the production of vegetables with low content of nitrate. Scientia Horticulturae, 1992, 49, 167-171.

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[48] Dong, XY; Li, SJ. Effect of nutrient management on nitrate accumulation of pakchoi under solution culture. Journal of Plant Nutrition and Fertilizer Science, 2003, 9, 447451. [49] Bloom-Zandstra, G; Lampe, JEM. The effect of chloride and sulphate salts on the nitrate content in lettuce plants (Lactuca sativa L.). Journal of Plant Nutrition, 1983, 6, 611-628. [50] Roorda van Eysinga, JPNL. Nitrate and glasshouse vegetables. Fertilizer research, 1984, 5, 149-156. [51] Corre, WT; Breimer，T. Nitrate and nitrite in vegetables. Centre for Agricultural Publishing and Documentation. Wageningen, the Netherlands. 1979. [52] Foyer, CH ; Noctor, G. Photosynthetic nitrogen assimilation and associated carbon and respiratory metabolism. Kluwer Academic Publishers, 2002, 12, 1- 22. [53] Rufty, TW; Jr, Israel, DW; Volk, RJ; Qui, J; Sa, T. Phosphate regulation of nitrate assimilation in soybean. J. Exp. Bot, 1993, 44, 879-891. [54] Luo, JK; Sun, SB; Jia, LJ; Chen, W; Shen, QR. The mechanisms of nitrate accumulation in pakchoi [Brassica campestris L. ssp. Chinensis (L.)]. Plant and Soil, 2006, 282, 291-300.

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In: Sustainable Agriculture Editors: A. Salazar, I. Rios, pp. 353-366

ISBN: 978-1-60876-269-9 ©2010 Nova Science Publishers, Inc.

Chapter 11

SUSTAINABLE USE OF WASTE CHICKEN FEATHER FOR DURABLE AND LOW COST BUILDING MATERIALS FOR TROPICAL CLIMATES Menandro N. Acda Dept. of Forest Products and Paper Science, College of Forestry and Natural Resources, University of the Philippines Los Banos, Philippines

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ABSTRACT Chicken feathers are waste products of the poultry industry. Billions of kilograms of waste feathers are generated each year by commercial poultry processing plants creating a serious solid waste problem in many countries. Traditional disposal strategies of chicken feathers are expensive and difficult. They are often burned in incineration plants, buried in landfills or recycled into low quality animal feed. These disposal methods are restricted, generate green house gases or pose danger to the environment. Several commercial applications have been explored to utilize fibers from chicken feathers. However, due to the low volume requirements of these products they had not significantly reduced the volume of feathers generated each year. An innovative way to utilize poultry feathers into a novel composite material is to bind them with Portland cement. Recent studies showed that cement bonded chicken feather composites (called featherboards) are suitable for non structural applications in low cost housing projects in developing countries. Tests showed that stiffness (MOE), flexural strength (MOR) and dimensional stability of featherboards were slightly lower or comparable to that of commercially available wood-fiber cement board in the market (HardieLite®, HardieFlex Philippines) of similar thickness and density. Cement bonded featherboards had excellent decay (Basidiomycetes) and termite (Coptotermes, Macrotermes, Microcerotermes, Nasutitermes spp) resistance which made them very attractive as construction materials in tropical climates. Despite the need for more research on the use of waste chicken feather as reinforcement in cement bonded composite, it offers an environmentally friendly method of disposing a serious waste product and promotes competitiveness of both the poultry and construction industries.

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Keywords: Barbs, Chicken Feather, Cement Composites, Coupling Agent, Dimensional stability, Featherboard, Hygroscopicity, Keratin, Silane, Superplasticizer

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INTRODUCTION The USDA Foreign Agricultural Service (2008) estimates that broiler chicken production in major poultry producing countries is about 74,237,000 metric tons annually. Most of these chickens go to supermarkets and fast food chains to meet demand for white meat. Considering that about 6% of the total weight of mature chicken is feather, the poultry industry generates about 4.45 billion kilograms of waste feathers as a by product when the birds are processed in commercial dressing plants. The tremendous volume of waste feather creates a serious solid waste problem in many countries (Parkinson 1998, McGovern 2000). Traditional disposal methods of waste feather are expensive and difficult. Waste feathers are often buried in landfills or piled in dumpsites. However, feathers are naturally resistant to deterioration and persist in the environment for decades. Consequently, they take up large space in landfills and the bad odor from residual manure, blood and other extraneous materials cause pollution in the area. In some countries waste feathers are burned in incineration plants. But burning waste feather is expensive and the process results in the emission of green house gases and problems with ash disposal. Some companies in the US and Europe convert feathers to protein for animal feeds. However, the process is expensive because feathers are hydrolyzed at high temperature and pressure requiring large amount of water and energy in commercial plants. In general, current disposal methods for waste chicken feather are environmentally unsound, restricted or results in products that are of low demand. Chicken feathers vary in form and function. They are generally classified as either contour, down, semiplume, filoplume and bristle. However, regardless of type, chicken feathers are approximately half feather fiber (barbs) and half quill (rachis) by weight (Figure 1). The quill is the stiff central core with hollow tube structure and the barbs are the fine fibrous materials that branch out of the quill. The feather fiber and quill are both made from keratin (about 90% by weight), which is an insoluble and highly durable protein found in hair, hoofs and horns of animals (Karshan 1930, Schmidt 2002). Keratin consists of over 90 amino acids but largely made up of cystine, lysine, proline and serine (Figure 2) (Ward et al 1955, Harrar and Woods 1963). These amino acids tend to cross-link with one another by forming disulfide or hydrogen bonds resulting in fibers that are tough, strong, lightweight and with good thermal and insulating properties (Schmidt 2002, Poole et al. 2009). The unique characteristics of keratin generated interests in investigating alternative uses of waste chicken feathers for a number of potential applications. Hong and Wool (2005) developed a new generation of microchips that use chicken feather keratin to replace silicon. Because of their strength and porous structure, feathers are good conductors of electrons which make them suitable for electronics as well as automotive and aeronautical applications. Circuit boards produced with keratin from chicken feather are reportedly 50% lighter and move electrical signals faster than conventional silicon chip (Jacobson 2002, Frazer 2004). A number of studies have shown that the intermolecular cross links in keratin can be broken to obtain a soluble fraction that can be processed into polymeric materials, such as packaging and

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mulching films (Khot et al. 2001, Liebner 2005, Wool and Sun 2005). Fibers from chicken feather are also being blended with rice straw fiber to make fabrics with similar feel on the skin as wool but with excellent heat and sound insulation (Staedter 2006, Choi 2006).

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Figure 1. Chicken feathers are waste products generated when broiler chicken are processed in commercial dressing plants.

Figure 2. Chemical structure of keratin from chicken feather.

Table 1. Typical formulation used in the fabrication of cement bonded featherboards. Component Chicken feather (fiber, ground or whole feather) Portland cement (Type 1) Sand (Fine) Accelerator (e.g CaCl2, Al2(SO4)3), etc.) Superplasticizer (e.g. lignosulfonate based) Coupling agent (silane based, etc.) Water

Percent by Weight 10-20 40-50 40-50 3-5% weight of cement 3-7% weight of cement 0-5% weight of cement 60-80% of weight of cement

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(a)

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(b)

(c) Figure 3. Featherboards consisting of a mixture of cement and ground feather (a), mixed ground and feather fiber (b) and whole feather.

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In 1998, the US Department of Agriculture (USDA) developed the technology for separating chicken feathers into fiber and particulate (quill) fractions (Gassner et al. 1998). This development paved the way for the use of chicken feather fibers as reinforcements in composite products. Winandy et al. (2003) investigated the use of chicken feather fibers as replacement for wood fibers in medium density fiberboard. The results showed that the fiberboards had a slight reduction in strength but improved dimensional stability and decay resistance. Other investigators used feather fibers to develop new bio-composites (Wrześniewska-Tosik et al. 2007, Aluigi et al. 2008, Huda and Yang 2008) or as reinforcement in plastics (Barone 2005a,b; Barone and Schmidt 2005, Barone et al. 2005a,b; Barone and Gregoire 2006). These studies claimed that since chicken feather reinforced composites uses conventional processing techniques, it would be cost-competitive with fiberglass, and eventually find their way into car dashboards, boat exteriors, and similar products (Barone and Schmidt 2005a,b; Barone et al. 2005a). Fibers from chicken feathers are very small (5 microns in diameter) and have high surface area with excellent adsorbent properties (Schmidt and Jayasundera 2004). They are finer than wood pulp and could collect more spores, dust and other particles, thereby improving air quality inside homes and offices. Feathers also have specific sites to adsorb molecular ion species (e.g. cupric, ferric and chromate ions) as well as particulate matters (Schmidt et al. 1997). Consequently, they have potential use for cleaning industrial effluents (Misra et al. 2001, Al-Asheh et al. 2003, De la Rosa et al. 2008). This ability of chicken feathers to adsorbs contaminants was demonstrated when an oil tanker carrying about 200,000 liters of bunker oil sank and spilled oil near the central island of Guimaras, Iloilo, Philippines. To help fight the worse oil spill in the country, the Philippine Coast Guard used human hair and chicken feather to soak up the bunker oil (Seares 2006). A number of commercial applications have been explored to utilize fibers from chicken feathers (Schmidt 1998). Unfortunately, due to the low volume requirements of these new products they have not significantly reduced the volume of waste feathers generated each year. Composite building materials, such as fiberboard and particleboard, are high volume, high value applications which could potentially consume a large amount of waste chicken feathers. A simple, practical way to incorporate poultry feathers into composite boards is to bind them with Portland cement. Limited studies on this aspect of feather utilization have been reported (Hamoush and El-Hawary 1994). However, if this could be proven feasible, it could offer an affordable new building material with both economic and environmental advantages.

FEATHERBOARD: A NEW BUILDING MATERIAL In 2007, a small project supported by the Ford Conservation and Environmental Grants provided the opportunity for the author to develop an affordable cement bonded composite using waste chicken feathers for low cost housing projects in the Philippines. Experimental variables used in the study included varying proportions and form of chicken feather (fiber, ground or mixed), board configuration (homogenous or layered) and amount of superplasticizer and coupling agent. After 2 years of intensive laboratory study, the project developed a board (called Featherboard) from a blend of cement, sand, chemical admixtures

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and waste chicken feathers (Figure 3). Results of the study showed that the physical and mechanical properties (strength, stiffness, dimensional stability) of the featherboard containing 5-10% fiber or ground feather compared favorably with commercial fiber cement board in the market (e.g. Hardiflex®) with excellent decay and termite resistance. Furthermore, the density and configuration (layered or homogenous) of the board can be varied to suit various applications such as paneling, sidings and insulation boards. The optimum proportions of feather in these boards maybe small at first glance, however, considering that chicken feathers are fluffy and very light in weight, the amount represents a relatively large amount of feather material equivalent to about 10-15 times the volume of cement used.

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Fabrication The process of making of cement bonded featherboard is relatively simple. It involves collecting feathers from poultry processing plants, and then thoroughly washing and disinfecting the feathers to remove manure, blood, oil, dirt and residual odor from the material. The feathers are then dried under the sun for several days or by using heated dryers with temperature not to exceed 100ºC. The feathers are separated into fibers and quill using a feather separator developed by the USDA or cut to size and then ground to powder form depending on desired board configuration (homogenous or layered). The feathers are then mix with cement, water and chemical admixtures following a specific formulation and target density (Table 1). The mixture is then poured uniformly into a mold and then press to the desired thickness using a hydraulic press. The board is removed from the press after three hours and allowed to completely dry for two weeks. After curing the board is trimmed to size and can readily to be use for general construction. A more detailed discussion of the fabrication process is reported in another publication (Acda 2009). The process described above is not new and had been used for many years with wood particles, rice straw or sugarcane bagasse consolidated by inorganic binders. However, the feature which made the project unique is the use of waste chicken feather and the combination of chemical admixtures (accelerator, superplasticizer and coupling agent) that provided the solution to the production of a lightweight, strong and very durable building material.

MECHANICAL PROPERTIES Based on test results using ASTM D 1037 (ASTM 1995), the stiffness (modulus of elasticity, MOE) and flexural strength (modulus of rupture, MOR) of cement bonded featherboards were directly affected by varying proportion of chicken feather used in the formulation (Figures 4 and 5). Boards containing 5% to 10% fiber or ground feather were comparable in stiffness (2.0-2.85 GPa) and flexural strength (7.8-9.2 MPa) to those reported for coconut coir and wood-fiber reinforced cement composites (Campbell and Coutts 1980, Coutts 1987, Eusebio et al. 1998, Li et al. 2006). In comparison with commercial wood-fiber cement board (HardiLite®, James Hardie Philippines with MOE = 3.84 GPa, MOR = 12.54 MPa) of similar thickness and density, featherboards containing 5% to 10% showed slightly

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lower stiffness and flexural strength properties. However, the strength values reported in this study were significantly higher compared to using neat cement and feather only. It is possible that the use of silane coupling agent contributed to the strength properties of cement bonded featherboards. Ordinarily, there is poor adhesion between the organic feather and inorganic cement due to large differences in their surface energies. This limitation can be overcome by the use silicon based coupling agent with both organic and inorganic functional groups. Silane coupling agents have two reactive groups (diamino and a trimethoxysilyl) capable of forming chemical bonds with the feather fibers or particles and the surface of the cement matrix (Wituki 1993). The coupling agent acts at the interface bridging two dissimilar materials to improve adhesion (Figure 6). Silane coupling agents not only increase the bond strength of coatings and adhesives but also their resistance to humidity and other adverse environmental conditions (Wituki 1993). The use of only fiber or mixing fiber and ground feather at levels used in our study seemed to have no significant effect on the MOE and MOR of the boards at each proportion tested. Addition of feather fiber could potentially improve fracture toughness by blocking crack propagation while ground feather could reduce void space and irregularities (Frybort et al. 2008). We observed that adding ground feather improved the surface texture of the boards but there was no improvement in strength at any of the levels tested. Further research is now underway to improve mechanical properties through modification of the original formulation or improvements in the process of fabrication. Assessment from local housing contractors, however, indicated that the strength of the boards is already acceptable for non structural application in low cost housing projects in developing countries. Nailability using 2.18 mm diameter concrete nails driven from various points 25 mm from the edges of boards containing 5-20% feather fiber or ground feather showed no signs of damage or cracks. This property is critical since conventional cement bonded boards are notoriously brittle and cracks easily when nailed to support frames during installation (Simatupang and Geimer1990). Featherboards at 5-20% feather loading can be nailed to wooden supports without danger of cracking and can be used as paneling and ceiling material. The fibrous nature of featherboard apparently would allow the passage of nails and screws without formation of fracture. 3.5 3.0

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Figure 4. Modulus of elasticity of cement bonded featherboards with varying amount of chicken feather fabricated at feather-cement ratio of 0.60-0.80 and target density of 1.20 g/cc Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Figure 5. Modulus of rupture of cement bonded boards with varying amount of chicken feather fabricated at feather-cement ratio of 0.60-0.80 and target density of 1.20 g/cc.

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Figure 6. Silane coupling mechanism in bonding organic chicken feather with inorganic cement.

DIMENSIONAL STABILITY Dimensional stability is an important consideration when cement bonded boards are used for paneling or ceiling material in the tropics. These boards often get wet during heavy rains due to poor construction or leaky roof, and therefore minimal swelling or water absorption that can cause sagging and collapse is desirable. In our study, water absorption (WA) and thickness swelling (TS) after 24 hours of soaking in water (ASTM 1995) increased significantly as the amount of chicken feather was increased from 5% to 20% (Figure 7). However, boards containing 5% to 10% feather fiber or mixed fiber and ground feather were resistant to water absorption (WA = 7.55 to 15. 29%) and thickness swelling (TS = 2.0 to 4.71%). The excellent dimensional stability of featherboards at 5% to 10% feather content is comparable or better than commercial wood-fiber cement board (HardiLite®, TS = 2.14%, WA = 13.05%). This effect may be due to the use of silane coupling agent in the formulation. The coupling agent acts at the interface bridging two dissimilar materials to improve adhesion. However, the formation of chemical bonds with the amino acids of the feather or silicate hydrates of the cement would also reduce or block potential adsorption sites of water.

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50 45 40 35 30 25 20 15 10 5 0

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Consequently, boards showed improved dimensional stability at 5% to 10% feather content. At higher feather loading, the boards showed very high water absorption and thickness swelling (>30%) after 24 hours of water soaking. These boards are likely to have contained too much feather for the level of coupling agent and cement used such that fibers were not completely coated with cement. This may have allowed water molecules to be adsorbed by the hygroscopic amino acids resulting in very high water absorption and thickness swelling.

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Figure 7. Thickness swelling and water absorption of cement bonded featherboards with varying amount of chicken feather fabricated at feather-cement ratio of 0.60-0.80 and target density of 1.20 g/cc.

Mix Ratio (Cement+Sand)/Feather Fiber/Ground Feather Featherboard

Untreated Wood

Figure 8. Weight loss of featherboards and untreated wood after twelve weeks of direct field exposure to decay fungi and subterranean termites. Sustainable Agriculture: Technology, Planning and Management : Technology, Planning and Management, edited by Augusto Salazar, and Ismael

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Figure 9. Decay and termite exposure setup showing conditions of samples before and after field test. Untreated wood completely destroyed and featherboard (partially covered with mud) remained intact and in excellent condition after twelve weeks of field exposure.

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DURABILITY AGAINST DECAY FUNGI AND TERMITES Threats from decay and termites to wood and wood-based composites are considerable in the tropics. The resistance of featherboard to decay fungi (Basidiomycetes, Actinomycetes) and subterranean termites (Coptotermes, Macrotermes, Nasutitermes, Microcerotermes spp) widely distributed in the area was evaluated using tests used for evaluating field efficacy of new termiticides (Kard 1989). Samples consisting of untreated wood and featherboard were placed directly on the ground in each concrete slab station (Figure 8). We believe that this test is more severe than laboratory bioassays and would give a more realistic performance of the boards under field conditions. After twelve weeks of exposure, all untreated woods were completely destroyed by decay fungi or termites in all stations (about 100% loss in weight). In comparison, featherboards remained intact and in excellent condition as indicated by the minimal loss in weight (