Towards Sustainable Food Production in Africa: Best Management Practices and Technologies (Sustainability Sciences in Asia and Africa) 981992426X, 9789819924264

Table of contents :
Preface
Editorial
Contents
Editors and Contributors
Part I: Technologies for Soil Fertility Management
Chapter 1: Animal Manure and Soil Fertility Management on Smallholdings in South Africa
1.1 Introduction
1.2 Animal Manure in the Context of South African Smallholder Farming Systems
1.3 General Factors Affecting the Fertiliser Properties of Animal Manure
1.4 Fertiliser Properties of Manure Found on South African Smallholdings
1.4.1 Ruminant Manure
1.4.1.1 Nutrient Content
1.4.1.2 First-Season Release of Nutrients
1.4.1.3 Residual Fertiliser Value
1.4.2 Chicken Manure
1.4.2.1 Nutrient Content
1.4.2.2 First-Season Release of Nutrients
1.4.2.3 Residual Fertiliser Value
1.5 Using Animal Manure to Apply Phosphorus, Potassium and Nitrogen to Soils
References
Chapter 2: Integrated Soil Fertility Management for Soil Fertility Restoration in Sub-Saharan Africa
2.1 Introduction
2.2 Principles of ISFM
2.2.1 Fertiliser Use
2.2.2 Use of Organic Inputs
2.2.2.1 Importance of Organic Inputs Quality
2.2.3 Complementary Application of Mineral Fertiliser and Organic Resources
2.2.4 Optimising Agronomic Efficiency
2.2.5 Use of Improved Germplasm
2.2.6 Importance of Local Adaptation
2.3 Soil and Crop Management Practices That Can Enhance Effectiveness of ISFM
2.3.1 Soil Acidity Correction
2.3.2 Appropriate Soil Tillage Practices
2.3.3 Water Harvesting and Soil Erosion Control
2.3.4 Planting Date and Planting Practices
2.3.5 Pest Management
2.4 Understanding ISFM´s Operational Environment and Impact
2.5 The Bottleneck in Implementation of ISFM Practices
2.6 Prospects for Increasing Adoption of ISFM Practices and Benefits
2.6.1 Need for Sound Technology Dissemination and Transfer Methods
2.6.2 Improve Linkages to Markets
2.6.3 Continuous Innovations and Improvements of ISFM Options
2.6.4 Strengthening Farmers´ Organisational Capacities
2.6.5 Influencing Policy Change
2.6.6 Leveraging on Mobile Phone-Based Technology
2.7 Conclusion
References
Chapter 3: Integrated Soil Fertility Management: A Basis for Sustainable Intensification of Maize-Based Cropping Systems of So...
3.1 Introduction
3.2 The Maize-Based Sub-Humid Zone in Southern Africa
3.2.1 Characteristics
3.2.2 Sols and Soil Fertility Status
3.3 Integrated Soil Fertility Management Approach to Reverse Productivity Decline in Southern Africa
3.3.1 The Critical Importance of Mineral Fertiliser
3.3.2 Synergistic Effects of Fertiliser and Cattle Manure
3.3.3 Fertiliser Use in Maize-Grain Legumes Systems
3.3.4 Fertiliser Use in Combination with Green Manure and Legume Trees
3.4 Site-Specific ISFM Recommendations and Dissemination
References
Chapter 4: Insights of Microbial Inoculants in Complementing Organic Soil Fertility Management in African Smallholder Farming ...
4.1 Introduction
4.2 Soil Fertility Challenges in African Smallholder Farming Areas
4.2.1 Effect of Current Soil Fertility Management in Sub-Saharan Africa on Microbial Populations and Diversity
4.2.2 Why Using Microbial Inoculants Is a Good Solution
4.3 Nitrogen Fixing Microbes Soil Fertility/Quality and Yield Benefits
4.3.1 Symbiotic Nitrogen Fixers
4.3.2 Free-Living Nitrogen Fixers
4.4 Phosphorus Solubilising Microbes Soil Fertility/Quality and Yield Benefits
4.4.1 Phosphorus Solubilising Fungi (PSF)
4.4.2 Mycorrhizal Fungi (MF)
4.4.3 Arthrobotrys: Aspergillus and Penicillium Species
4.4.4 Actinomycetes
4.5 Current Production Capacity of Inoculants
4.6 Challenges and Opportunities for Microbial Inoculants in Africa
4.7 Summary and Conclusions
References
Chapter 5: Agroforestry Technologies and Mineral Fertiliser Combinations for Improved Soil Fertility and Crop Production in Se...
5.1 Introduction
5.2 Agroforestry Technologies Available for Use by Farmers in Semi-Arid Areas of Africa
5.2.1 Improved Fallow
5.2.2 Biomass Transfer
5.2.3 Alley Cropping
5.3 Effects of Agroforestry on Crop Production in Semi-Arid Areas
5.4 Integrated Effects of Agroforestry and Mineral Fertiliser on Soil Fertility and Crop Production
5.5 Opportunities of Agroforestry Technologies for Smallholder Farmers in Semi-Arid Areas
5.6 Conclusion
References
Chapter 6: Integrated Soil Acidity Management for Sustainable Crop Production in South African Smallholder Farming Systems
6.1 Introduction
6.2 What Is the Benefit of Conservation Agriculture on Soil Acidity Management?
6.2.1 The Importance of Crop Residues in Aiding Lime Movement
6.2.2 Timely Application and the Rate of Lime Movement
6.2.3 A `Once-Off´ Tillage in No-Till Can Achieve Considerable Success in Aiding Lime Effectiveness
6.2.4 Split Applications of Lime Are More Efficient than Once-off Applications
6.3 The Benefits of Acid Resistant Cultivars for Acidity Management in Sustainable Plant Production Systems
6.4 The Benefits of Organic Amendments on Soil Acidity Reduction in Sustainable Agriculture
6.5 A Case for Biochar
6.6 Potential Biochar Sources for Use in Sustainable Agriculture
6.7 Concluding Remarks
References
Part II: Water Management in Smallholder Farming Systems
Chapter 7: Improving Productivity of Smallholder Irrigation in Africa Through Adoption of Best Management Practices and Techno...
7.1 Introduction
7.2 Best Management Practices for Smallholder Irrigators
7.3 Impact of Inadequate Management as a Factor in Productivity
7.4 Agronomic Best Management Practices for Smallholder Irrigated Crop Production
7.4.1 Appropriate Choice of Cultivars
7.4.2 Planting Time and Seeding Density
7.4.3 Soil Fertility Management for Improved Crop Production
7.4.4 Integrated Weed Management
7.4.4.1 Effectiveness of Reduced Herbicide Dosages
7.4.4.2 Effectiveness of Narrow Rows and Higher Target Populations
7.4.4.3 Use of the Stale Seedbed Technique in Vegetable Production
7.5 Other Opportunities for Improved Performance of Smallholder Irrigation
7.5.1 The Need for Partnership with Agribusiness
7.5.2 Production of High Value Vegetable Crops
7.6 Conclusions
References
Chapter 8: Being Small Does Not Make It Easy: The Management Conundrum on Smallholder Canal Schemes
8.1 Introduction
8.2 Small-Scale Agriculture, Irrigation, Livelihoods, and Food Security
8.3 The Conundrum of Smallholder Canal Scheme Management in South Africa
8.3.1 Scheme Management Functions
8.3.2 Management on Large and Small Canal Schemes
8.4 Improving the Management of Smallholder Irrigation Schemes: A Proposal
References
Chapter 9: Sustainable Winery Wastewater Management for Improving Soil Quality, Environmental Health, and Crop Yield
9.1 Introduction
9.2 Source and Volume of Winery Wastewater Produced
9.3 Characteristics of Winery Wastewater
9.4 Effects of Winery Wastewater on Soil Properties
9.4.1 Soil Physical Properties
9.4.2 Soil Chemical Properties
9.4.3 Biological Properties
9.5 Effects of Winery Wastewater on Crop Yield
9.5.1 Food Crops
9.5.2 Grapevine
9.6 Effects of Winery Wastewater on Environmental Health
9.7 Conclusion
References
Chapter 10: Water Harvesting Technologies for Sustainable Crop Production in African Smallholder Farming Systems
10.1 Introduction
10.2 Effects of Water Conservation Techniques on Crop Production
10.2.1 Tied Ridges
10.2.2 Tied Contours
10.2.3 Infiltration Pits
10.2.4 Mulching
10.2.5 Planting Pits
10.3 Fanya Juus
10.4 Dead Level Contours with Infiltration Pits
10.5 Opportunities for Increased Crop Yields Through Combined Water Management and Organic Nutrient Resources Use
10.6 Conclusion
References
Part III: Crop Production Practices and Technologies
Chapter 11: Advances in Sorghum Production in Smallholder Farming Systems of Africa
11.1 Introduction
11.2 Sorghum Output in Africa
11.3 Development and Use of Improved Varieties in Africa
11.4 Advances in Agronomic Management Practises in Africa
11.4.1 Integrated Soil Fertility Management (ISFM)
11.4.1.1 Inorganic Fertiliser Use
11.4.1.2 Organic Fertiliser
11.4.2 Conservation Agriculture
11.4.3 Rainwater Harvesting Technologies
11.4.4 Integrated Pest Management Technologies
11.4.4.1 Striga Weed
11.4.4.2 Stem Borers
11.4.4.3 Bird Control Strategies for Smallholder Farmers
11.5 Conclusion
References
Chapter 12: Knowledge and Innovation Approaches to Out Scale Sorghum Adoption in Africa
12.1 Introduction
12.2 Development of Sorghum Technologies (Varieties and Agronomic Practices)
12.2.1 Participatory Action Research
12.2.2 Deployment of Varieties and Stimulating Adoption
12.2.3 On-Farm Demonstrations
12.2.4 Farmer Field Schools
12.2.5 Lead Farmer Approach
12.2.6 Inclusive and Innovative Market Development
12.2.7 Demand Creation Through Multi-stakeholder Platforms
12.3 Mechanisms for Successful Scaling-Up
12.3.1 Replication
12.3.2 Mainstreaming
12.3.3 Layering and Sequencing
12.4 Drivers of Scaling-Up Strategies
12.5 Conclusions and Policy Implications
References
Chapter 13: Winter Cover Crop Recommendations for Soil Fertility Improvement on Maize-Based Smallholder Irrigation Farms
13.1 Introduction
13.2 Winter Cover Crops Choices for Smallholder Irrigation Maize-Based Systems
13.3 Soil Organic Matter Improvement Through Winter Cover Crops
13.4 Improved Nitrogen Supply Through Winter Cover Crops
13.5 Improved Phosphorus Cycling Through Winter Cover Crops
13.6 Enriching the Soil with Essential Micro-Nutrients Through Winter Cover Crops
13.7 Concluding Remarks
References
Part IV: Climate-Smart Livestock Production Systems
Chapter 14: Utilising Encroacher Bush in Animal Feeding
14.1 Introduction
14.2 Extent of Bush Encroachment in Namibia
14.2.1 Description of Dominant Encroacher Species
14.2.1.1 Senegalia mellifera (Black Thorn)
14.2.1.2 Dichrostachys cinerea (Sickle Bush)
14.2.1.3 Terminalia sericea (Silver Cluster-Leaf)
14.2.1.4 Rhigozum trichotomum (Three-Thorn Bush)
14.2.1.5 Colophospermum mopane (Mopane)
14.2.1.6 Vachellia reficiens (Red Umbrella Thorn)
14.2.1.7 Terminalia prunioides (Purple-Pod Terminalia)
14.2.2 Bush Encroachment Effect on Livestock Production
14.2.3 Bush Encroachment Effect on Wildlife Production
14.3 Nutrient Content of the Encroacher Bush Species
14.3.1 Chemical Composition of Encroacher Bush Species
14.3.2 Protein Fractions of Encroacher Bush Species
14.3.3 Essential Amino Acids of Encroacher Bush Species
14.3.4 Anti-Nutritional Factors of Encroacher Bush Species
14.3.5 Macro- and Micro-Minerals of Encroacher Bush Species
14.4 Bush Nutrient Utilisation
14.5 Animal Growth and Meat Production
14.6 Opportunities in Encroacher Bush Feed Utilisation
14.6.1 Dry Season Feeding
14.6.2 Conservation of Milled Bush Feed
14.6.3 Biologically Active Charcoal (Biochar) to Reduce Methane Emissions
14.6.4 Enhancement of Bush-Based Feed Utilisation with Forage Legumes
14.6.5 Feedlots
14.6.6 Entrepreneurial Opportunities
14.7 Conclusions
References
Chapter 15: Opportunities for Delivering Sectoral Climate-Smart Livestock Interventions in Southern Africa
15.1 Introduction
15.2 Livestock Production Systems in the SADC Region
15.3 Livestock Production and Sustainable Development
15.3.1 Southern African Livestock Contribution to Global Warming and Climate Change
15.3.2 Climate Risks, Vulnerability, and Impacts in Southern African Livestock Systems
15.3.3 Current Climate-Smart Livestock Management Practices in Southern Africa
15.4 Opportunities for Delivering Climate Actions in Southern African Livestock Sector
15.4.1 Strengthening Technical and Institutional Capacity for Implementation
15.4.2 Unlocking Climate Finance and Investment for Prioritised Livestock Actions
15.4.3 Addressing Incoherence and Ineffective National and Regional Governance
15.4.4 Enhancing Monitoring and Evaluation of Livestock Climate Actions
15.5 Conclusions
References
Chapter 16: The Benefits of Winter Cover Crops in Mixed Crop-Livestock Conservation Agriculture Systems of the Swartland Regio...
16.1 Introduction
16.2 Importance of Cover Crops in the Mediterranean Climate
16.2.1 Improvement of Soil Quality Using Cover Crops
16.2.2 Increasing the Supply of Nitrogen
16.2.3 Increasing Soil Water Availability and Moderating Soil Temperature
16.2.4 Weed Management
16.3 Management and Utilisation of Cover Crops
16.3.1 Cover Crops and the Farming System
16.4 Combining Cover Crops and Livestock
16.5 Conclusions
References
Part V: Urban Agriculture and Food Security
Chapter 17: Urban Food Production Technologies, Innovations and Management Practices in Africa
17.1 Introduction
17.2 The Case for Urban Farming
17.3 Technologies for Urban Farming
17.3.1 Technologies and Innovations for Overcoming the Challenge of Limited Space
17.3.1.1 Vertical Greening Systems
17.3.1.2 Rooftop Farming
17.3.1.3 Containers and Soilless Substrates
17.3.2 Technologies and Innovations for Overcoming the Challenge of Water Shortage
17.3.2.1 Hydroponic Systems
17.3.2.2 Capillary Wick Irrigation
17.3.2.3 Wicking Bed Gardens
17.3.3 Technologies and Innovations for Combating Protein Malnutrition
17.3.3.1 Mushroom Cultivation
17.3.3.2 Microgreens and Sprouts
17.3.3.3 Aquaponics
17.3.3.4 Cuniculture
17.3.3.5 Insects Farming
17.4 Conclusions
References
Chapter 18: Hydroponics in Household Vegetable Food Production
18.1 Introduction
18.2 The Concept of Hydroponics
18.3 Hydroponics in Food Production
18.4 Hydroponics Versus Conventional Planting
18.5 Organic Nutrients in Hydroponics
18.6 Conclusions
References

Citation preview

Sustainable Agriculture and Food Security

Morris Fanadzo Nothando Dunjana Hupenyu Allan Mupambwa Ernest Dube   Editors

Towards Sustainable Food Production in Africa Best Management Practices and Technologies

Sustainability Sciences in Asia and Africa

Sustainable Agriculture and Food Security Series Editor Rajeev K. Varshney, Semi-Arid Tropics, International Crops Research Institute, Patancheru, Telangana, India

This book series support the global efforts towards sustainability by providing timely coverage of the progress, opportunities, and challenges of sustainable food production and consumption in Asia and Africa. The series narrates the success stories and research endeavors from the regions of Africa and Asia on issues relating to SDG 2: Zero hunger. It fosters the research in transdisciplinary academic fields spanning across sustainable agriculture systems and practices, post- harvest and food supply chains. It will also focus on breeding programs for resilient crops, efficiency in crop cycle, various factors of food security, as well as improving nutrition and curbing hunger and malnutrition. The focus of the series is to provide a comprehensive publication platform and act as a knowledge engine in the growth of sustainability sciences with a special focus on developing nations. The series will publish mainly edited volumes but some authored volumes. These volumes will have chapters from eminent personalities in their area of research from different parts of the world.

Morris Fanadzo • Nothando Dunjana • Hupenyu Allan Mupambwa • Ernest Dube Editors

Towards Sustainable Food Production in Africa Best Management Practices and Technologies

Editors Morris Fanadzo Department of Agriculture Cape Peninsula University of Technology Wellington, South Africa Hupenyu Allan Mupambwa Sam Nujoma Marine and Coastal Resources Research Center, Sam Nujoma Campus, University of Namibia Henties Bay, Namibia

Nothando Dunjana School of Natural Resource Management Nelson Mandela University George, South Africa Ernest Dube School of Natural Resource Management Nelson Mandela University George, South Africa

ISSN 2730-6771 ISSN 2730-678X (electronic) Sustainability Sciences in Asia and Africa ISSN 2730-6798 ISSN 2730-6801 (electronic) Sustainable Agriculture and Food Security ISBN 978-981-99-2426-4 ISBN 978-981-99-2427-1 (eBook) https://doi.org/10.1007/978-981-99-2427-1 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Preface

Food security is a critical African (and global) issue exacerbated by climate change and an ever-growing human population. Smallholder farming and agriculture in general faces a serious threat from climate change that has resulted in erratic rainfall and increased temperatures, among other abiotic stresses. These climate changeinduced pressures have reduced crop productivity mainly among the smallholder farmers, who are critical in driving the attainment of sustainable development goals. Ample research has been done in Africa and other parts of the world to develop technologies that can be important in sustainable food production under a changing climate. These technologies are critical in driving adaptation and resilience of the farmers, thus guaranteeing food security. This book presents a comprehensive and topical collection of practices, technologies and innovations in the field of sustainable food production and security under a changing climate. It is a one-stop handbook for farmers, researchers, extensionists, policy makers and other stakeholders seeking to identify and disseminate best management practices and technologies for local and regional landscapes. The book offers an understanding of the challenges, risks and uncertainties as well as opportunities to foster productive and sustainable food production. Effective, practicable and sustainable practices and technologies that can be adopted by farmers as mitigation measures against the effects of climate change are also presented in the book. With 18 chapters, the book is divided into five themes. Part I deals with technologies for soil fertility management, covering various aspects such as the usefulness of animal manure for use as a fertiliser (Chap. 1), integrated soil fertility management (Chaps. 2 and 3), use of microbial inoculants in complementing organic soil fertility management (Chap. 4), agroforestry technologies (Chap. 5) and integrated soil acidity management to reduce reliance upon lime (Chap. 6). In Part II, various options for improving water productivity in smallholder farming systems are presented in four chapters. The section presents best agronomic management practices for improved irrigated crop production, and options and proposals for dealing with ineffective scheme management in smallholder canal irrigation schemes v

vi

Preface

(Chaps. 7 and 8), sustainable winery wastewater management and water harvesting technologies available for use by smallholder farmers (Chaps. 9 and 10). Part III presents various best crop production practices and technologies for improved food production, covering aspects such as adoption of improved varieties and good agronomic management as key advances that are enhancing sorghum productivity in Africa, as well as knowledge and innovation approaches to out-scale sorghum adoption in Africa (Chaps. 11 and 12). Chapter 13 presents the prospects and opportunities for cover cropping and rotation recommendations to guide farmers and researchers on how to select appropriate cover crops for irrigated maize-based conservation agriculture systems. Part IV deals with climate-smart livestock production systems. Chapter 14 demonstrates that utilisation of rangeland encroacher bush species in bush-based feeds provides sufficient nutrients to support improved ruminant livestock production and contributes to rangeland ecosystems restoration. Opportunities that could be utilised by countries to institutionalise largescale climate-smart interventions in the livestock sector and enable them to turn climate change ambitions into realism are presented in Chap. 15, while the benefits of winter cover crops in mixed crop-livestock conservation agriculture systems are presented in Chap. 16. Part V presents opportunities for addressing food insecurity in urban areas where land is increasingly becoming a limited resource while the urban population is growing rapidly due to rural-urban migration. It is demonstrated that various urban farming technologies and innovations have potential to provide nutrient-dense foods rich in protein and other vital nutrients to the urban dwellers while utilising waste streams generated in urban areas, thereby contributing to waste management in urban areas (Chap. 17). The basics of hydroponics are presented with the objective of demystifying hydroponics as a complicated system, but rather as a system that the ordinary farmer can easily understand and adopt in food production (Chap. 18). This book is a result of contributions by various researchers in different disciplines related to climate-smart agriculture. We are therefore grateful to the authors for their timely contributions. Wellington, South Africa George, South Africa Henties Bay, Namibia George, South Africa

Morris Fanadzo Nothando Dunjana Hupenyu Allan Mupambwa Ernest Dube

Editorial

The global food production systems require expanding their capacity to produce almost twice the current levels to safeguard the food security of the burgeoning population worldwide. More than 800 million suffering from undernourishment worldwide pose a great risk to the attainment of sustainable development goal (SDG) 2 of the UN that targets “End hunger, achieve food security and improved nutrition and promote sustainable agriculture” within the next seven years. The challenge is further exacerbated by the rising weather extremities and unpredictability in rainfall patterns and pest-pathogen dynamics associated with global climate change that has profound negative impact on the agricultural productivity and farm incomes worldwide. Also, the future targets of food production should be secured in a resource-constrained agricultural setting and with least environment footprint, thus calling for sustainable innovations in agri-farming systems and enhanced participation of women in agriculture. The challenge to reduce hunger is alarming in the case of developing nations particularly Asia and Africa that house the largest proportion of people suffering from malnutrition and other nutrition-related issues. Furthermore, the agri-food systems in Asia and Africa are severely constrained by subsistence nature of farming, declining land and other agricultural resources, increasing environmental pollution, soil and biodiversity degradation, and climate change. Therefore, this book series, “Sustainable Agriculture and Food Security,” has been planned to support the global efforts towards sustainability by providing timely coverage of the progress, opportunities, and challenges of sustainable food production and consumption in Asia and Africa. The series narrates the success stories and research endeavors from the regions of Africa and Asia on issues relating to SDG 2: Zero hunger. It fosters research in transdisciplinary academic fields spanning across sustainable agriculture systems and practices, post-harvest and food supply chains. The focus of the series is to provide a comprehensive publication platform and act as a knowledge engine in the growth of sustainability sciences with a special focus on developing nations.

vii

viii

Editorial

Soil and water represent important natural resources for agricultural production systems and are vital to the long-term viability of agricultural land. The productivity and economic benefits of smallholder farming systems in Africa are severely constrained by the poor quality and productivity of African soils that have degraded due to strong acidity, adverse climatic conditions, and unsustainable agricultural practices. The African continent faces a “soil health crisis,” with three quarters of its farmland being scarce of nutrients. Alongside soil-related issues, water management is imperative to overcoming the risks associated with rain-fed crop production systems in Africa in the wake of rising uncertainties in rainfall patterns and frequent occurrence of drought conditions. The degraded soils hold less water and organic matter, supply inadequate quantity of essential nutrients to biological systems, and remain highly vulnerable to erosion. Soil fertility depletion in combination with unsustainable water management remains a serious threat to current agricultural systems, and food security and climate change mitigation efforts in resource-poor areas of Africa. The synergies between soil health and water management practices are essentially required for building a healthy ecosystem and productive agriculture. Livestock farming systems remain crucial to African agriculture and economic growth, and the livestock sector accounts for 40% of its agricultural gross domestic product (GDP), with the contributions from individual countries ranging between 10% and 80%. Increased demand for livestock-derived food products has driven the growth of the African livestock sector in recent years and is estimated to follow the upward trajectory for the next 30–40 years. Central to this increasing demand for animal source foods are the population growth, increased consumer purchasing power, and urbanization. Since more than 70% of greenhouse gas (GHG) emission comes from the livestock sector in Africa, the impacts of livestock systems on environmental sustainability are unprecedented, and hence innovative solutions must be in place to curtail the environmental footprints of the livestock sector while making them productive and resilient. Also, the livestock sector accounts for a significant proportion of agricultural land and freshwater resources. Besides impacting the food systems, urbanization in Africa has led to profound changes in land use and rural livelihoods. The smallholder farming and agriculture in Africa has been greatly benefited by the adoption of modern production technologies and practices, which have enabled efficient utilization of the available natural resources while protecting environmental health. Given this, the present book Towards Sustainable Food Production in Africa: Best Management Practices and Technologies edited by Morris Fanadzo, Nothando Dunjana, Hupenyu Allan Mupambwa, and Ernest Dube underscores innovations, technologies, and practices resulting from the research done in Africa and is integral to soil health and water management for building sustainable crop and livestock systems. The entire content of the book has been organized under five distinct themes: (1) Technologies for soil fertility management, (2) Water management in smallholder farming systems, (3) Crop production technologies and practices, (4) Climate smart livestock production systems, and (5) Urban agriculture and food security in Africa. A total of 39 authors from various countries in the African continent share their work and experience under five themes in this book. I would

Editorial

ix

like to congratulate the Editors, Morris Fanadzo, Nothando Dunjana, Hupenyu Allan Mupambwa, and Ernest Dube, and all authors for their valued contributions that will indeed serve as a great resource for farmers, researchers, agriculture educators and extension agents, policy makers, and other stakeholders engaged in transforming agriculture and food systems in the developing world, particularly Africa. I wish to extend my sincere thanks and gratitude to the Springer staff, particularly Aakanksha Tyagi, Senior Editor (Books), Life Sciences, and Naren Aggarwal, Editorial Director, Medicine, Biomedical and Life Sciences Books Asia, for their constant support for the accomplishment of this compendium. The cooperation received from my senior colleagues such as David Morrison, Peter Davies, Daniel Murphy, and my laboratory colleagues Abhishek Bohra, Anu Chitikineni, and Vanika Garg from Murdoch University (Australia) is also gratefully acknowledged. I would like to thank my family members—Monika Varshney, Prakhar Varshney, and Preksha Varshney—for their love and support to discharge my duties as Series Editor.

WA State Agricultural Biotechnology Centre & Centre for Crop & Food Innovation, Food Futures Institute, Murdoch University, Perth, WA, Australia

Rajeev K. Varshney

Contents

Part I 1

2

3

4

5

6

Technologies for Soil Fertility Management

Animal Manure and Soil Fertility Management on Smallholdings in South Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wim Van Averbeke Integrated Soil Fertility Management for Soil Fertility Restoration in Sub-Saharan Africa . . . . . . . . . . . . . . . . . . . . . . . . . Nothando Dunjana, Charity Pisa, Morris Fanadzo, Hupenyu Allan Mupambwa, and Ernest Dube Integrated Soil Fertility Management: A Basis for Sustainable Intensification of Maize-Based Cropping Systems of Southern Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shamie Zingore Insights of Microbial Inoculants in Complementing Organic Soil Fertility Management in African Smallholder Farming Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Akinson Tumbure, Sinikiwe Dube, and Tonny P. Tauro Agroforestry Technologies and Mineral Fertiliser Combinations for Improved Soil Fertility and Crop Production in Semi-Arid Areas of Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Andrew Tapiwa Kugedera, Nyasha Sakadzo, and Letticia Kudzai Kokerai Integrated Soil Acidity Management for Sustainable Crop Production in South African Smallholder Farming Systems . . . . . . Nicholas Swart, Johan Jordaan, Morris Fanadzo, Nothando Dunjana, and Ernest Dube

3

21

39

59

85

95

xi

xii

Contents

Part II

Water Management in Smallholder Farming Systems

7

Improving Productivity of Smallholder Irrigation in Africa Through Adoption of Best Management Practices and Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Morris Fanadzo, Ernest Dube, Nothando Dunjana, and Hupenyu Allan Mupambwa

8

Being Small Does Not Make It Easy: The Management Conundrum on Smallholder Canal Schemes . . . . . . . . . . . . . . . . . . 135 Lerato Lebogang Van Averbeke and Wim Van Averbeke

9

Sustainable Winery Wastewater Management for Improving Soil Quality, Environmental Health, and Crop Yield . . . . . . . . . . . . 153 Takalani Sikhau, Mbappe Tanga, Adewole Adetunji, Carolyn Howell, Reckson Mulidzi, and Francis Lewu

10

Water Harvesting Technologies for Sustainable Crop Production in African Smallholder Farming Systems . . . . . . . . . . . . . . . . . . . . 171 Andrew Tapiwa Kugedera, Nyasha Sakadzo, Letticia Kudzai Kokerai, and Njodzi Ranganai

Part III

Crop Production Practices and Technologies

11

Advances in Sorghum Production in Smallholder Farming Systems of Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Farayi Dube, Angeline Mujeyi, Martin Philani Moyo, and Olivia Mukondwa

12

Knowledge and Innovation Approaches to Out Scale Sorghum Adoption in Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 Angeline Mujeyi, Farayi Dube, Martin Philani Moyo, and Olivia Mukondwa

13

Winter Cover Crop Recommendations for Soil Fertility Improvement on Maize-Based Smallholder Irrigation Farms . . . . . 221 Ernest Dube, Morris Fanadzo, Nothando Dunjana, and Hupenyu Allan Mupambwa

Part IV

Climate-Smart Livestock Production Systems

14

Utilising Encroacher Bush in Animal Feeding . . . . . . . . . . . . . . . . . 239 Johnfisher Mupangwa, Emmanuel Lutaaya, Maria Ndakula Tautiko Shipandeni, Absalom Kahumba, Vonai Charamba, and Katrina Lugambo Shiningavamwe

15

Opportunities for Delivering Sectoral Climate-Smart Livestock Interventions in Southern Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . 267 Walter Svinurai, Nation Chikumba, and Godwill Makunde

Contents

16

xiii

The Benefits of Winter Cover Crops in Mixed Crop-Livestock Conservation Agriculture Systems of the Swartland Region, South Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 Theunis Engelbrecht, Johann Strauss, and Ernest Dube

Part V

Urban Agriculture and Food Security

17

Urban Food Production Technologies, Innovations and Management Practices in Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 John Mwibanda Wesonga

18

Hydroponics in Household Vegetable Food Production . . . . . . . . . . 329 Hupenyu Allan Mupambwa, Morris Fanadzo, Ernest Dube, and Nothando Dunjana

Editors and Contributors

About the Editors Morris Fanadzo is a systems agronomist with over 22 years’ experience in teaching, research and development. He is currently an Associate Professor of Agronomy at Cape Peninsula University of Technology in South Africa, where he is also coordinating one of the programmes in the Department of Agriculture. He is extensively involved in curriculum development, editorial and reviewing services, examination of theses and dissertations, and supervision of postgraduate students. His main research interests are centred on enhancing sustainable agricultural productivity growth of smallholder farming systems in low-input systems of Africa. Prof Fanadzo has been involved as a researcher and co-investigator for many projects funded by organisations such as the Rockefeller Foundation, the Department for International Development (United Kingdom) and the Water Research Commission (South Africa). He has authored several publications including books, peer-reviewed journal articles, book chapters and popular publications. He is a registered Professional Natural Scientist with the South African Council of Natural and Scientific Professions, and currently serves as a College Council member for the Elsenburg Training Institute, Western Cape Department of Agriculture, South Africa. Nothando Dunjana holds a PhD in Soil Science and is currently a Research Fellow at Nelson Mandela University, South Africa. Dr Dunjana has over a decade of experience in agronomic systems research as well as university teaching. She is a highly motivated and results-oriented scientist dedicated to the fostering of productive, resilient and sustainable food systems through scientific investigation, promotion of climate-smart soil-crop systems and student training. Her areas of interest include soil fertility and plant nutrition, grain and legume crop agronomy, organic amendments, soil carbon dynamics, water management including irrigation, soilwater-plant relations as well as the application of climate and crop modelling techniques in the analysis and decision support for climate change mitigation and adaptation. Dr Dunjana has published numerous research papers and book chapters xv

xvi

Editors and Contributors

in international peer-reviewed journals and books, as well as presenting at several conferences. Hupenyu Allan Mupambwa holds a PhD in Soil Science. His PhD research focused on vermicomposting as a waste beneficiation technology important in driving organic soil fertility. Currently, he leads the Desert and Coastal Agriculture Research Programme at the University of Namibia. He has a combined 15 years’ experience in agriculture research and training as well as university undergraduate and postgraduate teaching and research in the field of crop science. He has published more than 26 peer-reviewed articles in international journals, 11 book chapters and has edited 2 books to date. His research has been presented at several conferences, and he has also supervised and examined several postgraduate students. His research focuses on waste beneficiation, vermi-technology, hydroponics and organic soil fertility management with a drive towards improving the soil quality among resource-poor farmers. Ernest Dube is an agronomist (PhD) with over 20 years’ experience in agricultural plant production and research. He is an internationally renowned expert of conservation agriculture and champion of sustainable plant production. As Senior Lecturer in Plant Production and Management at the Nelson Mandela University in South Africa, he is highly committed to excellence in teaching, agronomy research and scholarship. Dr Dube also serves as Research Associate for the Agricultural Research Council (South Africa) and University of Arkansas (USA). His main research interests centre on improving soil quality and sustainability of farming, especially in low-input systems of African smallholder farmers. In this regard, he has over 50 publications which include peer-reviewed articles, book chapters and popular publications. He served as a council member of the South Africa Society of Crop Production (2015–2018) and is currently a member of the Crop Estimates Committee.

Contributors Adewole Adetunji Department of Agriculture, Faculty of Applied Sciences, Cape Peninsula University of Technology, Wellington, Western Cape, South Africa Lerato Lebogang Van Averbeke Pretoria, South Africa Wim Van Averbeke Department of Crop Sciences, Tshwane University of Technology, Pretoria, South Africa Vonai Charamba Department of Animal Production, Agribusiness & Economics, School of Agriculture & Fisheries Sciences, University of Namibia, Windhoek, Namibia

Editors and Contributors

xvii

Nation Chikumba Marondera University of Agricultural Sciences and Technology, Marondera, Zimbabwe Ernest Dube School of Natural Resource Management, Nelson Mandela University, George, South Africa Farayi Dube International Crops Research Institute for The Semi-Arid Tropics (ICRISAT), Matopos Research Station, Bulawayo, Zimbabwe Sinikiwe Dube Department of Environmental Science and Technology, Faculty of Earth & Environmental Sciences, Marondera University of Agricultural Sciences and Technology, Marondera, Zimbabwe Nothando Dunjana School of Natural Resource Management, Nelson Mandela University, George, South Africa Theunis Engelbrecht School of Natural Resource Management, Nelson Mandela University, George, South Africa Morris Fanadzo Department of Agriculture, Cape Peninsula University of Technology, Wellington, South Africa Carolyn Howell ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa Johan Jordaan School of Natural Resource Management, Nelson Mandela University, George, South Africa Absalom Kahumba Department of Animal Production, Agribusiness & Economics, School of Agriculture & Fisheries Sciences, University of Namibia, Windhoek, Namibia Letticia Kudzai Kokerai Department of Crop and Livestock, Ministry of Agriculture, Resettlement, Lands, Water and Fisheries, Masvingo, Zimbabwe Andrew Tapiwa Kugedera Department of Agriculture Management, Zimbabwe Open University, Masvingo, Zimbabwe Francis Lewu Department of Agriculture, Faculty of Applied Sciences, Cape Peninsula University of Technology, Wellington, Western Cape, South Africa Emmanuel Lutaaya Department of Animal Production, Agribusiness & Economics, School of Agriculture & Fisheries Sciences, University of Namibia, Windhoek, Namibia Godwill Makunde International Potato Centre, Maputo, Mozambique Martin Philani Moyo International Crops Research Institute for The Semi-Arid Tropics (ICRISAT), Matopos Research Station, Bulawayo, Zimbabwe

xviii

Editors and Contributors

Angeline Mujeyi International Crops Research Institute for The Semi-Arid Tropics (ICRISAT), Matopos Research Station, Bulawayo, Zimbabwe Olivia Mukondwa Crops Research Division, Department of Research and Specialist Services, Crop Breeding Institute, Harare Agricultural Research Centre, Harare, Zimbabwe Reckson Mulidzi ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa Hupenyu Allan Mupambwa Sam Nujoma Marine and Coastal Resources Research Center, Sam Nujoma Campus, University of Namibia, Henties Bay, Namibia Johnfisher Mupangwa Department of Animal Production, Agribusiness & Economics, School of Agriculture & Fisheries Sciences, University of Namibia, Windhoek, Namibia Charity Pisa Department of Natural Resources Management, Faculty of Earth and Environmental Sciences, Marondera University of Agricultural Sciences and Technology, Marondera, Zimbabwe Njodzi Rangana Department of Information Systems and Computer Science, Manicaland State University of Applied Sciences, Mutare, Zimbabwe Nyasha Sakadzo Department of Agricultural Economics and Development, Manicaland State University of Applied Sciences, Mutare, Zimbabwe Katrina Lugambo Shiningavamwe Department of Agricultural Research & Development, Ministry of Agriculture, Water and Land Reform, Windhoek, Namibia Maria Ndakula Tautiko Shipandeni Department of Animal Production, Agribusiness & Economics, School of Agriculture & Fisheries Sciences, University of Namibia, Windhoek, Namibia Takalani Sikhau Department of Agriculture, Cape Peninsula University of Technology, Wellington, Western Cape, South Africa Johann Strauss School of Natural Resource Management, Nelson Mandela University, George, South Africa Western Cape Government Department of Agriculture, Elsenburg, South Africa Walter Svinurai Marondera University of Agricultural Sciences and Technology, Marondera, Zimbabwe Nicholas Swart School of Natural Resource Management, Nelson Mandela University, George, South Africa Mbappe Tanga Department of Agriculture, Faculty of Applied Sciences, Cape Peninsula University of Technology, Wellington, Western Cape, South Africa

Editors and Contributors

xix

Tonny P. Tauro Department of Natural Resources Management, Faculty of Earth and Environmental Sciences, Marondera University of Agricultural Sciences and Technology, Marondera, Zimbabwe Akinson Tumbure Environmental Microbiology Research Group, Department of Biological Sciences, University of Limerick, Limerick, Ireland John Mwibanda Wesonga Department of Horticulture and Food Security, School of Agriculture and Environmental Sciences, College of Agriculture and Natural Resources, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya Shamie Zingore African Plant Nutrition Institute, UM6P Experimental Farm, Ben Guerir, Morocco

Part I

Technologies for Soil Fertility Management

Chapter 1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa Wim Van Averbeke

Abstract To improve the effectiveness of manure applications in managing the fertility of cropped soils, information on the nitrogen, phosphorus and potassium content of ruminant and chicken manure accumulating on smallholder farms in South Africa is combined with data on the release from manure of these important nutrients in plant-available forms following application of manure to soil. Manure application rates based on the phosphorus content of the various types of manure are proposed, and for each type of manure, the air-dry mass required to add 1 kg of plantavailable phosphorus is provided. The expected application rates of plant-available nitrogen and potassium associated with these phosphorus-based quantities are provided as well. Whilst manure can be used effectively to raise soil phosphorus to desired levels, and with it provide more than adequately for the potassium requirements of crops when using ruminant manure, the nitrogen requirements of crops cannot be met by using manure alone, without adding excess phosphorus and potassium. Combining manure with chemical nitrogen fertilisers or incorporating a leguminous green manure crop in a three-field crop rotation are proposed as possible strategies to address the nitrogen deficit, which is expected to narrow with successive manure applications. The necessity of liming acid soil to obtain optimal benefit from applying manure is highlighted. Keywords Ruminant · Chicken · Nitrogen · Phosphorus · Potassium · Fertiliser value · Application rate

1.1

Introduction

The aim of this chapter is to provide a better understanding of animal manure for use as a fertiliser in the production of crops with specific reference to animal manure found on South African smallholdings, where the use of this resource as a fertiliser is W. Van Averbeke (✉) Department of Crop Sciences, Tshwane University of Technology, Pretoria, South Africa e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 M. Fanadzo et al. (eds.), Towards Sustainable Food Production in Africa, Sustainable Agriculture and Food Security, https://doi.org/10.1007/978-981-99-2427-1_1

3

4

W. Van Averbeke

particularly common. Fertilisers are applied to cropped land to improve soil fertility, which refers to the condition of a soil that enables it to provide nutrients in adequate amounts and in proper balance for the growth of specified plants or crops, provided all other growth factors, such as temperature, light, water and the physical condition of the soil are favourable (Van der Watt and Van Rooyen 1995). Chemical fertilisers contain plant nutrients in forms that are immediately or rapidly available for plant uptake. As a result, when using chemical fertilisers, it is easy to match the application rates of various nutrients with the nutrient requirements of the crop, thus achieving the desired balance among the different nutrients. Animal manure differs from chemical fertilisers in several ways. One of these is that manure is a single substance that contains all the plant nutrients, but not necessarily in the desired proportions, making it difficult to achieve balance among applied nutrients. A second is that the nutrients contained in animal manure are not necessarily present in plant-available forms. A third reason is that animal manure may release nutrients in plant-available forms, particularly nitrogen, long after it has been applied to soil. These differences complicate the formulation of manure application rates. The aim of crop husbandry is to improve, if not optimise, plant growth factors, as well as to protect the crop against unwanted competition (weeds) and injury by pests and destructive weather events, such as hail and frost. Optimising growth factors occurs within resource constraints, and this explains why large numbers of South African smallholders (and gardeners) use animal manure instead of chemical fertilisers to manage the fertility of their cropped soils. Animal manure is available locally and free of charge to those who own livestock, whilst chemical fertilisers must be paid for, and access to these compounds is often limited (Mkhabela 2006). Yet, despite the widespread use of animal manure among South African smallholders, little has been done towards developing manure application rate recommendations for use in crop production (Materechera 2010). Furthermore, the question arises whether application of animal manure as the sole nutrient management practice can optimise soil fertility. Information presented in this chapter is intended to assist the formulation of manure application rates for use in crop production, with specific reference to ruminant manure found in enclosures on smallholdings in South Africa, as well as chicken manure.

1.2

Animal Manure in the Context of South African Smallholder Farming Systems

Despite efforts towards industrial bio-fabrication of food, particularly meat products, farming remains central to global food production (Bhat et al. 2017). In Fig. 1.1, farming is depicted as involving three inter-related processes, namely the mobilisation of resources, the conversion of these resources into end-products, and the marketing, consumption or re-use of the end-products (Tessier et al. 2021). The

1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa

Resources

Land

Capital

Management

Labour

outputs

Animals

Crops

Market

inputs processes

Processes End-products

5

Consumption

Re-use Fig. 1.1 Resources and inter-related processes that make up farming Fig. 1.2 Traditional land use pattern in the Nguni areas of South Africa

gardens huts

forest

Livestock kraal

field

field river

rangeland

make-up of the resources available to farm affects the processes that are used to produce end-products. In South African smallholder farming, agricultural land typically encompasses gardens, fields and rangeland, irrespective of whether the arrangement is traditional or planned. This configuration of different types of land encourages a mixed farming system involving both crop production and livestock rearing (Mkhabela and Materechera 2003; Materechera and Modiakgotla 2006; Van Averbeke et al. 2008). In Fig. 1.2, a schematic representation of the traditional land use pattern found in the Nguni areas (Eastern Cape and KwaZulu-Natal provinces) is shown. Human abodes and the livestock kraal make up the homestead, with gardens located close to the homestead. Fields tend to be found at a distance from the homestead.

6

W. Van Averbeke

residential land dwelling

grazing camp 1 Garden Livestock kraal

grazing camp 3 river

arable allotments

grazing camp 2

Fig. 1.3 Schematic representation of the planned land use pattern in the Eastern Cape Province, South Africa

Where state-imposed planning of land occurred, land was divided into three categories, namely residential, arable and rangeland (Fig. 1.3). Human abodes were concentrated in a village setup, and arable land allocations were consolidated and separated from other land by means of a boundary fence. The remaining land was rangeland and was often subdivided into several grazing camps separated by fences. Rangeland is a common property resource that can be accessed by all residents belonging to a community. One of its primary functions is to provide sustenance for the livestock owned by individual households. This livestock consists largely of ruminants, namely cattle, goats and sheep. Access to fields and gardens is private and these areas are used to grow crops. In some smallholder areas, such as the Eastern Cape Province, fields become common property after the summer crop has been harvested, with weeds and stover supplementing the declining fodder reserve for livestock on the rangeland. Gardens remain under private control, particularly in planned areas where they form part of the residential site. Proportional area allocation to rangeland, fields and gardens in smallholder areas of South Africa depends on the local agroecology but the rangeland area tends to be more extensive than the cultivated area. For example, in 2003 in the Transkei region of the Eastern Cape Province, which covered about 4 million ha of smallholder farmland, 86.2% consisted of rangeland, 9.3% of fields and 4.5% of gardens (Van Averbeke et al. 2008). Residential sites and traditional homesteads also provide room for livestock enclosures, called kraals, where the free-ranging ruminants spend the night, as well as space for the rearing of micro-livestock, mostly chickens and pigs. Animal manure accumulates in these enclosures and this ‘end-product’ is often

1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa

7

Genetic make up of the crop => yield potential CO2 nutrients Growth factors

temperature regime water

Crop production

light weather Protection against competition and injury

plant pests (weeds) animal pests (especially insects) plant pathogens (causing disease)

Fig. 1.4 Factors that affect crop growth and yield

re-used as a resource in crop production to improve soil fertility (Materechera and Modiakgotla 2006). Soil fertility affects the availability of plant nutrients, which is one of the growth factors that determine crop growth and yield (Fig. 1.4). Inadequate supply of plant nutrients has long been identified as a constraint of the first magnitude in South African smallholder crop production, especially in areas with relatively high rainfall, such as the Transkei region of the Eastern Cape Province and large parts of KwaZulu-Natal Province (Van Wyk 1967; Bembridge 1984; Roberts et al. 2003). In the Transkei region, Bembridge (1984) found that the use of both chemical fertilisers and animal manure was common practice among smallholders, but that the amounts being applied were too low to replace the soil nutrients removed by crop harvests. Analysing local maize enterprise budgets, he identified the purchase of chemical fertilisers as the largest variable cost item and concluded that poverty was the main reason that prevented farmers from applying chemical fertilisers at adequate rates. This emphasises the role animal manure can play in maintaining or improving soil fertility on smallholdings when applied at the appropriate rates.

1.3

General Factors Affecting the Fertiliser Properties of Animal Manure

Narrowly defined, animal manure is the faecal waste and urinary excretions of livestock. In practice, these excrements are often mixed with other materials, such as fodder residues, bedding material, feathers, bristles, hair and soil, contributing to the diverse make-up of animal manure (Probert et al. 2005). When the intention is to use animal manure as a fertiliser, the ability of the manure to supply nutrients in forms that are available to plants is the key concern. Of primary interest in crop

8 Fig. 1.5 Factors that affect the fertiliser properties of animal manure

W. Van Averbeke

Age

Livestock species

Diet

Excrements Addions Alteraons during storage

Animal manure applied to cropped land

production are nitrogen, phosphorus and potassium. Accordingly, the fertiliser properties of animal manure arise from the combination of the nitrogen, phosphorus and potassium content of the manure and the release of these nutrients in plantavailable form when the manure is applied to the soil. In the case of potassium, there is general agreement that content and release are similar, because nearly all (>90%) of potassium in manure is present in ionic or soluble form (Sun et al. 2021). Release of the nitrogen and phosphorus in manure is more complex as both can be present in mineral and organic forms. The fertiliser properties of the animal manure that is applied on cropped land are a function of a range of factors, which are summarised in Fig. 1.5. The combination of livestock species, age of the animals and the diet they subsist on affect the nutrient content of excrements produced by livestock. Dissimilarities in the digestive systems amongst livestock species affect the conversion of feed sources into absorbable forms for assimilation (Gandra et al. 2011). Ruminants utilise nutrients present in plant materials more effectively than monogastric animals due to bacterial action in the rumen (Herren 2012). Diet affects the nutrient content of the excreta of livestock, whereby the concentration of nutrient elements in the excreta tends to be positively related to those in the feed sources (Smits et al. 2003; Barletta et al. 2015). Age of the animal can influence the nutrient content of excrements, especially nitrogen, because young animals need more proteins to build up their body than mature animals (Malherbe 1964). Addition of materials other than livestock excrements during storage modifies the nutrient content of the animal excrements (Lekasi et al. 2003; Garcês et al. 2013). Most important from a practical perspective are the addition of bedding material, the quantity of bedding material applied relative to the quantity of excrements and the composition of the bedding material. Whilst the addition of bedding material is

1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa

9

expected to dilute the nutrient concentration of animal excrements, in the case of nitrogen it may also limit nutrient losses during storage by reducing gaseous emissions (Misselbrook and Powell 2005). Conditions and duration of storage affect the fertiliser properties of animal manure (Lekasi et al. 2003; Petersen et al. 2013). Key factors in aerobic storage of manure are whether the place of storage is roofed or not, the permeability of its floor and the duration of manure storage. Uncovered storage exposes manure to precipitation and the leaching of soluble compounds out of manure (Petersen et al. 2013). Nitrogen losses through volatilisation increase as temperature rises, which is more likely when manure is exposed to direct sunlight (Lekasi et al. 2003). Manure stored in the open air also promotes its aeration, which increases the loss of nitrogen due to ammonia volatilisation and denitrification of nitrate (Mkhabela 2006).

1.4

Fertiliser Properties of Manure Found on South African Smallholdings

Animal manure found on South African smallholdings can be separated into two broad categories, namely manure obtained from free-ranging ruminants and manure produced by monogastric livestock, primarily chickens. Among the ruminant livestock, cattle and goats are kept by smallholders throughout South Africa, but in the Eastern Cape Province, sheep rearing is also prevalent. Typically, the enclosures in which ruminant livestock are kept during the night have a soil floor and no roofing. For cattle, the lack of roofing is practically universal, but partial or complete cover of goat enclosures is common in the Mpumalanga and Limpopo provinces. The main sources of chicken manure are small broiler production units, in which chickens are reared on commercially available diets and are kept on a bed of wood shavings. Many smallholders also keep scavenger chickens, which they sometimes lock up at night, thereby securing a small supply of chicken excrements. To develop recommendations for the application rate of animal manure, knowledge of three properties of the manure is needed. These properties are: 1. The nutrient content of the manure; 2. The proportion of any nutrient contained in the manure that is released in plantavailable forms during the first season following application of the manure to soil; 3. The residual fertiliser value of the manure, being the proportions of the different nutrients contained in the manure that are released in plant-available forms during the second and subsequent seasons following its application to soil. All three properties are function of the type of manure, which is the result of a set of factors under which the animal manure accumulated and was stored and of the nutrient under consideration. In this chapter only three nutrients are covered, namely nitrogen, phosphorus and potassium, and a distinction is made between ruminant and chicken manure.

10

W. Van Averbeke

1.4.1

Ruminant Manure

1.4.1.1

Nutrient Content

Analysis of the nutrient content of ruminant manure accumulating on South African smallholdings has received considerable attention. A summary of the nitrogen, phosphorus and potassium content of cattle manure sampled in five provinces of South Africa is presented in Table 1.1. In Table 1.2, the same information is shown for goat and sheep manure. Both Tables 1.1 and 1.2 indicate that there is considerable variance in the nitrogen, phosphorus and potassium content of ruminant manure. Soil content of the manure (Mkile 2001) and the type and quantity of supplementary feeding offered to the animals, if any (Motha 2021), have been identified as factors that affect nutrient content. Goat manure (Table 1.2) tends to have a higher nutrient content than cattle and sheep manure, which tend to have similar nutrient contents. The higher nutrient concentration of goat manure can be ascribed, at least in part, to the diet of goats, which consists mainly of browse (Mphinyane et al. 2015) and possibly also to the complete or partial roofing of goat enclosures, which is common practice in the northern part of South Africa (Nwenya 2017; Motha 2021). For the practical purpose of using ruminant manure as a fertiliser, one can make use of the overall means for the three ruminant livestock species, worked out in kilogrammes of nitrogen, phosphorus and potassium per tonne of air-dry manure as shown in Table 1.3. Alternatively, locally specific information (Tables 1.1 and 1.2) can be used.

1.4.1.2

First-Season Release of Nutrients

Information on the proportional release in plant-available forms of nutrients contained in manure during the first season following application is less readily available than data on nutrient content. There is general agreement that the potassium contained in ruminant manure occurs in ionic (K+) or soluble forms and is almost entirely plant-available. This was confirmed by Ramphisa (2015), who recovered 76% of applied cattle manure potassium as solution and exchangeable potassium immediately after application across a wide range of application rates. Accordingly, application of chemical fertiliser potassium or ruminant manure potassium is similar. The phosphorus contained in ruminant manure is also largely present in mineral form and immediately plant-available after application to soil. Motha (2021) reported that relative to phosphorus applied as superphosphate, taken as 100% effective, the effectiveness of cattle manure phosphorus was 77% and that of goat manure 82%. First-season release of the nitrogen contained in ruminant manure differs from phosphorus and potassium. This is evident from Table 1.4, which shows the proportion of nitrogen contained in ruminant manure that had been released as mineral nitrogen (NH4+ and NO3-) after 42 days of incubation.

1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa

11

Table 1.1 The nitrogen, phosphorus and potassium content of cattle manure sampled from smallholdings in South Africa Nitrogen content (% of dry matter) [range] mean

Locality Cattle North West Province Makgobistadta [1.52–2.71] 1.93 [0.56–2.27] 1.59 Tlapenga Tlapeng-Tshweua [0.51–1.74] 1.40 [0.89–3.31] 1.74 Mogosanea [0.66–1.89] 1.19 Lokalenga Mafikengb [0.62–2.30] 1.15 [0.86–2.70] 0.98 Ditsobotlab Ganyesab [0.77–3.20] 1.22 [0.56–2.50] 0.83 Taungb Mean 1.34 Eastern Cape Province [0.61–1.46] 1.14 Mount Fletcherc [0.55–1.64] 1.10 Elliotdalec [0.41–1.63] 1.00 Umtatac Amatole Districtd [1.58–2.44] 1.87 Mean 1.26 Mpumalanga Province [1.97–2.54] 2.28 Siyabuswae [0.93–1.88] 1.41 Ntundae [1.35–2.17] 1.90 Steynsdorpe Mean 1.86 Limpopo Province [1.43–1.66] 1.57 Thulamelaf 1.70 Makhadog Mean 1.64 KwaZulu-Natal Province [0.12–2.11] 1.67 KwaZulu-Natalh Mean 1.67 Mean (five 1.55 provinces) a

Materechera and Modiakgotla (2006) Materechera (2010) c Mkile (2001) d Yoganathan et al. (1998) e Motha (2021) f Nwenya (2017) g Adebisi (2015) h Mkhabela and Materechera (2003) b

Phosphorus content (% of dry matter) [range] mean

Potassium content (% of dry matter) [range] mean

[0.05–0.16] 0.08 [0.04–0.10] 0.07 [0.05–0.10] 0.07 [0.03–0.13] 0.07 [0.03–0.08] 0.06 [0.05–0.31] 0.19 [0.03–0.34] 0.25 [0.06–0.27] 0.13 [0.05–0.16] 0.07 0.11

– – – – – [0.27–2.01] 0.63 [0.42–1.89] 0.91 [0.36–1.25] 1.02 [0.60–1.63] 1.17 0.93

[0.09–0.39] 0.11 [0.16–0.47] 0.28 [0.13–0.27] 0.19 [0.44–0.72] 0.56 0.29

[0.81–3.51] 1.65 [1.01–1.51] 1.40 [0.60–1.74] 1.43 [2.30–3.80] 2.85 1.83

[0.21–0.36] 0.29 [0.10–0.20] 0.16 [0.15–0.25] 0.21 0.22

[2.18–4.40] 3.13 – [0.96–1.42] 1.17 2.15

[0.24–0.31] 0.28 0.50 0.22

[2.31–4.69] 3.11 1.70 2.41

[0.24–0.31] 0.28 0.28 0.22

[2.09–4.67] 2.73 2.73 2.01

12

W. Van Averbeke

Table 1.2 The nitrogen, phosphorus and potassium content of goat and sheep manure sampled from smallholdings in South Africa Nitrogen content (% of dry matter) [range] mean

Locality Goats Eastern Cape Province Mount Fletchera [1.28–2.14] 1.71 [1.10–2.24] 1.81 Elliotdalea [0.03–1.49] 0.86 Umtataa 1.46 Limpopo Province [1.00–2.35] 1.96 Thulamelab 2.20 Makhadoc 2.08 Mpumalanga Province [1.96–3.33] 2.52 Siyabuswad [1.94–3.06] 2.63 Ntundad Steynsdorpd [1.22–2.37] 1.98 2.38 Mean (three 1.97 provinces) Sheep Eastern Cape Province [0.46–2.09] 1.26 Mount Fletcher, Eastern Capea [0.67–1.79] 1.08 Umtata, Eastern Capea Elliotdale, Eastern [1.31–2.24] 1.82 Capea Mean 1.39

Phosphorus content (% of dry matter) [range] mean

Potassium content (% of dry matter) [range] mean

[0.33–0.44] 0.39 [0.25–0.55] 0.36 [0.18–0.30] 0.23 0.33

[3.21–3.46] 3.34 [1.11–4.16] 2.75 [1.31–3.86] 2.43 2.84

[0.23–0.48] 0.37 0.40 0.39

[1.62–4.67] 3.67 4.00 3.84

[0.25–0.65] 0.46 [0.29–0.41] 0.30 [0.19–0.33] 0.27 0.34 0.35

[1.95–6.47] 3.80 [0.91–1.97] 1.34 2.57 3.08

[0.13–0.26] 0.21

[0.76–3.46] 2.02

[0.14–0.42] 0.27

[1.41–3.24] 2.38

[0.14–0.99] 0.40

[1.66–4.16] 2.68

0.29

2.36

a

Mkile (2001) b Nwenya (2017) c Adebisi (2015) d Motha (2021)

Table 1.3 Average mass of nitrogen, phosphorus and potassium per tonne of air-dry ruminant manure found on smallholdings in South Africa Type of manure Cattle Goat Sheep

Nitrogen (kg) 15.5 19.7 13.9

Phosphorus (kg) 2.2 3.5 2.9

Potassium (kg) 20.1 30.8 23.6

1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa

13

Table 1.4 Proportion of nitrogen contained in ruminant manure that had been released as mineral nitrogen (NH4+ and NO3-) after 42 days of incubation Locality, Province Cattle Makhado, Limpopoa Thulamela, Limpopob Siyabuswa, Mpumalangac Steynsdorp, Mpumalangac Ntunda, Mpumalangac Mean across sites Goat Thulamela, Limpopob Siyabuswa, Mpumalangac Steynsdorp, Mpumalangac Ntunda, Mpumalangac Mean across sites

Net mineral nitrogen release (% of total nitrogen in manure) [range] mean [8.5–20.6] 12.7 [-8.6–0.0] -5.48 [12.4–18.5] 14.9 [10.0–14.8] 12.0 [9.8–17.7] 13.1 9.4 [-3.4–18.4] 7.1 [18.1–27.9] 21.3 [17.6–18.2] 17.8 [19.8–23.1] 21.6 17.0

a

Ramphisa (2015) Nwenya (2017) c Motha (2021) b

Table 1.4 shows that only a small portion of the nitrogen contained in the ruminant manure found in enclosures on smallholdings in South Africa becomes plant-available during the first 42 days following application to soil. For cattle manure, this proportion appears to range between 10% and 15% in most instances. The main exception was cattle manure from Thulamela. Application of Thulamela cattle manure to soil reduced the mineral nitrogen concentration in the soil, indicating that the rate of nitrogen immobilisation by microbes exceeded the rate of nitrogen mineralisation from the manure samples. The proportional release of the nitrogen contained in goat manure of about 17–21% was higher than observed for cattle manure. Lower proportions of nitrogen release were again observed for the samples from Thulamela, where the mean was only 7.1%.

1.4.1.3

Residual Fertiliser Value

Since most of the phosphorus and potassium contained in ruminant manure is released in plant-available forms immediately after application to soil, the residual fertiliser value of ruminant manure, being the proportions of the phosphorus and potassium contained in the manure that are released in plant-available forms during the second and subsequent seasons following its application to soil, can be ignored. This does not apply to the nitrogen content, because only about 10% of the nitrogen contained in cattle manure and 20% of the nitrogen in goat manure is released during the first season. In the Netherlands, Schroder et al. (2007) found that annual applications of cattle manure had long-term effects on the nitrogen economy in

14

W. Van Averbeke

soils. They argued that over time, the contributions to nitrogen release of the current and all previous applications would progress to reach a stage where the proportion of nitrogen released as mineral nitrogen equalled applied manure nitrogen. They estimated that this would take 15 years for injected dairy cattle slurry and 20–40 years for farmyard manure. Little work has been done on the residual fertiliser value of ruminant manure found on South African smallholdings, but Mahope (2019) found that mineral nitrogen release from cattle manure from Thulamela, which had a first-season mineral nitrogen release of -1.7%, had increased to 19.6% following its second application.

1.4.2

Chicken Manure

1.4.2.1

Nutrient Content

The nitrogen, phosphorus and potassium content of chicken manure samples collected from smallholdings in Thulamela is presented in Table 1.5. A commercial layer litter, marketed as Promis, is included to assist comparison. Table 1.5 shows that on average, chicken manure contains 10–12 kg more nitrogen per tonne air-dry manure than ruminant manure, about 5–6 kg more phosphorus and about 10 kg less potassium. There are important differences between the manure of scavenger chickens and the manure of chickens that are raised on commercial diets (commercial broiler manure and Promis in Table 1.5). The manure produced by chickens on commercial diets contains about 33% more nitrogen, 217% more phosphorus and 154% more potassium than the manure of scavenger chickens, probably due to differences in diet. Commercial chicken feeds in South Africa consist primarily of maize grain (energy) and soya beans (protein). Scavenger chickens mainly subsist on insects and a variety of supplementary feedstuffs provided by their owners (Dessie and Ogle 2001; Badubi et al. 2006).

Table 1.5 Mass of nitrogen, phosphorus and potassium per tonne of air-dry chicken manure from smallholdings in Thulamela (Limpopo Province, South Arica) Type of chicken manure Scavenger chicken excrements only Scavenger chicken excrements only Scavenger chicken excrements only Commercial broiler chicken excrements only Commercial layer litter (Promis) Mean

Nitrogen (kg) 23.6 22.1 26.9 29.0 37.0 27.7

Phosphorus (kg) 4.8 5.4 6.2 13.3 15.0 8.9

Potassium (kg) 7.3 11.3 15.6 30.9 27.0 18.4

1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa

1.4.2.2

15

First-Season Release of Nutrients

As with ruminant manure, the potassium contained in chicken manure is nearly completely plant-available. Ramphisa (2015) reported a 94% recovery of Promisapplied potassium as solution and exchangeable K+ immediately after application to soil. Release of phosphorus from chicken manure on commercial (grain) diets differs from that of ruminant manure. Using Promis, Ramphisa (2015) reported that only half of the phosphorus in Promis was plant-available at application, with most of the remainder becoming plant-available during the 28-day period following application. This indicates that a considerable portion of the phosphorus in the manure of chickens raised on commercial (grain) diets is present in organic forms. According to Pen et al. (1993), the main organic form of phosphorus in this type of chicken manure is phytate-phosphorus, which is the main storage form of phosphorus in grains. Phytate-phosphorus is not readily hydrolysed by the endogenous enzymes in the digestive system of chickens, causing substantial quantities to be excreted (Ashworth et al. 2020). The proportional release of the nitrogen contained in chicken manure as mineral nitrogen during the first season following application is about four times greater than proportional nitrogen release from ruminant manure, as is evident from Table 1.6.

1.4.2.3

Residual Fertiliser Value

As for ruminant manure, no significant residual effect is expected from chicken manure as supplier of phosphorus and potassium. Nearly all the potassium contained in chicken manure is present in plant-available form, and most of the phosphorus becomes plant-available during the first month after application to soil. The relatively high first-season release in plant-available forms of the nitrogen contained in chicken manure suggests that chicken manure also has lower residual nitrogen fertiliser values than ruminant manure.

Table 1.6 Proportion of nitrogen contained in chicken manure that was released as mineral nitrogen (NH4+ and NO3-) after 42 days of incubation as reported by Ramphisa (2015)a and Nwenya (2017)b Type of chicken manure Scavenger chicken excrements onlyb Scavenger chicken excrements onlyb Scavenger chicken excrements onlyb Commercial broiler chicken excrements onlyb Commercial layer litter (Promis)a Mean

Net mineral nitrogen release (% of total nitrogen in manure) 41.3 37.1 44.5 15.4 24.0 32.5

16

1.5

W. Van Averbeke

Using Animal Manure to Apply Phosphorus, Potassium and Nitrogen to Soils

Fertiliser recommendations have been developed for a wide range of crops based on the use of chemical fertilisers containing nutrients that are readily or rapidly available to plants (Fertilizer Society of South Africa 2007). The fertiliser properties of animal manure allow for the use of these recommendations as they pertain to phosphorus and potassium, because most of the phosphorus and potassium contained in manure are readily available or become rapidly available to plants following application to soil. Multiplying the phosphorus and potassium content of animal manure by a factor of 80% takes care of observed differences in the effectiveness between chemical fertilisers and animal manure. Generally, for every part of phosphorus taken up, crops take up 7 parts of nitrogen and 5 parts of potassium (Epstein 1965; Fertilizer Society of South Africa 2007). In the ruminant manure on South African smallholdings, the phosphorus to potassium (P:K) ratio varies between 1:8 and 1:9. By implication, the application rate of ruminant manure should be based on the phosphorus requirement, as satisfying the phosphorus requirement will add more than enough potassium. The P:K ratio in chicken manure differs substantially from that of ruminant manure, being around 1: 2. Still it is recommended that the phosphorus content of chicken manure be used to determine application rates, because using the potassium content will result in the application of excess phosphorus, which can limit plant growth as it reduces availability, uptake and translocation of zinc, iron and copper (Srinivasarao et al. 2006; Laker 2008; Okorogbona 2011; Mai et al. 2011) and in extreme cases can cause toxic effects, particularly when manure derived from chickens reared on commercial diets is used (Claassens 1994). Table 1.7 shows the mass of the three types of ruminant manure and the two types of chicken manure (scavenger chicken and chickens raised on commercial grain-based diets) needed to apply the equivalent of 1 kg of superphosphate phosphorus to soil, as well as the concomitant addition of plant-available potassium and nitrogen. For nitrogen, the first-season nitrogen Table 1.7 Mass of animal manure needed to apply the equivalent of 1 kg of superphosphate phosphorus to soil and concomitant addition of plant-available potassium and nitrogen

Type of manure Cattle manure Goat manure Sheep manure Scavenger chicken excrements Excrements or litter of chickens on commercial (grain) diets

Mass of air-dry manure needed to add the equivalent of 1 kg superphosphate phosphorus (kg) 568 357 426 229

Mass of plantavailable potassium added (kg) 9.14 8.80 8.04 2.09

Mass of plantavailable nitrogen added (kg) 0.88 1.20 0.59 2.22

88

2.04

0.58

1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa

17

fertiliser values of the different types of manure were used (Tables 1.4 and 1.6) to calculate the addition of plant-available nitrogen. The factors used were 10% for cattle manure, 17% for goat manure, 10% for sheep manure, 40% for chicken manure and 20% for litter or excrements of chickens reared on commercial diets. Here it is important to note that successive applications of manure are expected to raise the nitrogen fertiliser value of manure but at this stage no information is available on the residual effects of the various types of manure found on smallholdings in South Africa. From Table 1.7 it is evident that the application rate of potassium is lower than the required 5 kg/kg of phosphorus when using chicken manure, but potassium is more than adequately provided for when using ruminant manure. Irrespective of type of manure applied, there is a considerable nitrogen deficit. Whilst this nitrogen deficit is expected to be gradually reduced with successive manure applications, nitrogen deficiency can be expected to limit plant growth if manure is applied at a rate aimed at satisfying the phosphorus requirement of the crop. Two possible options are available. The first is to supplement the nitrogen added as manure by applying chemical fertilisers, so as to obtain a phosphorus to nitrogen (P:N) ratio of 1:7. Roughly, this would require the application of 6 kg of nitrogen as chemical fertiliser for every 1 kg of phosphorus applied, when using ruminant manure or the excrements or litter of chickens on commercial (grain) diets, and 5 kg of nitrogen as chemical fertiliser when using the excrements of scavenger chickens. Fakude (2019) reported that the plant availability of nitrogen in soil that received a combination of chemical fertiliser nitrogen and animal manure nitrogen equalled the sum of the plant-available nitrogen supply by each of these two sources separately. As indicated, the required application rates of chemical fertiliser nitrogen are expected to decline with successive applications of manure. The second option is to adopt a crop rotation system, probably a three-field system, in which annually one-third of the cropping area is planted to a leguminous crop that is used as a green manure to raise soil nitrogen. Finally, to obtain optimal benefit from applying animal manure or chemical fertilisers to soil, it is critical that the pH of the soil as measured in water is kept above 5.5 or above 4.5 when measured in 1 mol potassium chloride. Liming, therefore, is an essential element of an appropriate soil fertility management strategy aimed at improving crop production in the smallholder areas of South Africa, particularly those areas where the mean annual rainfall exceeds 600 mm/annum.

References Adebisi LO (2015) Safe rate of application and fertiliser value of cattle kraal manure and Promis® poultry manure, M Tech (Agric) dissertation. Tshwane University of Technology, Pretoria Ashworth AJ, Chastain JP, Moore PA Jr (2020) Nutrient characteristics of poultry manure and litter. In: Waldrip HM, Pagliari PH, He Z (eds) Animal manure: production characteristics, environmental concerns and management. ASA Special publication 67. American Society of Agronomy, Soil Science Society of America, Madison, WI, pp 63–87

18

W. Van Averbeke

Badubi SS, Rakereng M, Marumo M (2006) Morphological characteristics and feed resources available for indigenous chickens in Botswana. Livest Res Rural Dev 18:3. http://www.lrrd.org/ lrrd18/1/badu18003.htm Barletta RV, Gandra JR, Freitas JE Jr, Verdurico LC, Mingoti RD, Bettero VP, Benevento BC, Vilela FG, Renno FP (2015) High levels of whole raw soya beans in dairy cow diets: digestibility and animal performance. J Anim Physiol Anim Nutr 100:1179–1190 Bembridge TJ (1984) A systems approach study of agricultural development problems in Transkei. PhD dissertation, University of Stellenbosch, Stellenbosch Bhat ZF, Kumar S, Bhat HF (2017) In vitro meat: a future animal-free harvest. Crit Rev Food Sci Nutr 57(4):782–789. https://doi.org/10.1080/10408398.2014.924899 Claassens AS (1994) The influence of varying P concentrations on the yield and abnormalities of lettuce leaves. S Afr J Plant Soil 11(3):117–152 Dessie T, Ogle B (2001) Village poultry production in the Central Highlands of Ethiopia. Trop Anim Health Prod 33:521–537 Epstein E (1965) Mineral metabolism. In: Bonne J, Varner JE (eds) Plant biochemistry. Academic Press, London, pp 438–466 Fakude SB (2019) Measurement and characterisation of nitrogen release from selected types of manure. M Tech (Agric) dissertation. Tshwane University of Technology, Pretoria Fertilizer Society of South Africa (2007) Fertilizer handbook, 6th edn. FSSA, Lynnwood Ridge Gandra JR, Freitas JE Jr, Barletta RV, Maturana Filho M, Gimenes LU, Vilela FG, Baruselli PS, Rennó FP (2011) Productive performance, nutrient digestion and metabolism of Holstein (Bos taurus) and Nellore (Bos taurus indicus) cattle and Mediterranean Buffaloes (Bubalis bubalis) fed with corn-silage based diets. Livest Sci 140:283–291 Garcês A, Afonso SMS, Chilundo A, Jairoce CTS (2013) Evaluation of different litter materials for broiler production in a hot and humid environment: 1. Litter characteristics and quality. J Appl Poult Res 22:168–176. https://doi.org/10.3382/japr.2012-00547 Herren R (2012) The science of animal agriculture, 4th edn. Delmar, Albany, NY Laker MC (2008) Challenges to soil fertility management in the third major soil region of the world, with special reference to South Africa. In: Haneklaus S, Hera C, Rietz R-M, Schnug E (eds) Fertilizers and fertilization for sustainability in agriculture: the first world meets the third world – challenges for the future. Terra Nostra, Lasi, pp 309–349 Lekasi JK, Tanner JC, Kimani SK, Harris PJC (2003) Cattle manure quality in Maragua District, Central Kenya: effect of management practices and development of simple methods of assessment. Agric Ecosyst Environ 94:289–298 Mahope J (2019) Fertiliser effectiveness of poultry manure and N-fertiliser value of cattle kraal manure under field conditions. M Tech (Agric) dissertation. Tshwane University of Technology, Pretoria Mai W, Tian X, Gale WJ, Yang X, Lu X (2011) Tolerance to Zn deficiency and P-Zn interaction in wheat seedlings cultured in chelator-buffered solutions. J Arid Land 3(3):206–213 Malherbe IV (1964) Soil fertility, 5th edn. Oxford University Press, New York, NY Materechera SA (2010) Utilization and management practices of animal manure for replenishing soil fertility among small-scale crop farmers in semi-arid farming districts of the North West Province, South Africa. Nutr Cycl Agroecosyst 87:415–418 Materechera SA, Modiakgotla LN (2006) Cattle manure increases soil weed population and species diversity in a semi-arid environment. S Afr J Plant Soil 23(1):21–28 Misselbrook TH, Powell JM (2005) Influence of bedding material on ammonia emissions from cattle excreta. J Dairy Sci 88:4304–4312 Mkhabela TS (2006) A review of the use of manure in small-scale crop production systems in South Africa. J Plant Nutr 29(7):1157–1185. https://doi.org/10.1080/01904160600767179 Mkhabela TS, Materechera SA (2003) Factors influencing the utilization of cattle and chicken manure for soil fertility management by emergent farmers in the moist Midlands of KwaZuluNatal Province, South Africa. Nutr Cycl Agroecosyst 65:151–162 Mkile Z (2001) The use and agronomic effectiveness of kraal manure in the Transkei region of the Eastern Cape, South Africa. M Sc dissertation, University of Fort Hare, Alice

1

Animal Manure and Soil Fertility Management on Smallholdings in South Africa

19

Motha MW (2021) Assessment of the nitrogen and phosphorus fertiliser value of ruminant manure in Mpumalanga, South Africa. M Tech (Agric) dissertation. Tshwane University of Technology, Pretoria Mphinyane WN, Tachebe G, Makore J (2015) Seasonal diet preference of cattle, sheep and goats grazing on the communal grazing rangeland in the Central District of Botswana. Afr J Agric Res 10(29):2791–2803 Nwenya ZD (2017) Nitrogen fertiliser value of three types of animal manure sourced from Thulamela, Limpopo Province, South Africa. M Tech (Agric) dissertation. Tshwane University of Technology, Pretoria Okorogbona AOM (2011) Biomass response of selected African leafy vegetables in pots to rate of application of three types of animal manure. M Tech (Agric) dissertation. Tshwane University of Technology, Pretoria Pen J, Verwoerd TC, Hoekema A (1993) Phytase-containing transgenic seed as novel feed additive for improved phosphorus utilization. Bioresour Technol 11:811–814 Petersen SO, Blanchard M, Chadwick D, Del Prado A, Edouard N, Mosquera J, Sommer SG (2013) Manure management for greenhouse gas mitigation. Animal 7:266–282. https://doi.org/10. 1017/S1751731113000736 Probert ME, Delve RJ, Kimani SK, Dimes JP (2005) Modelling nitrogen mineralisation from manures: representing quality aspects by varying C:N ratio of sub-pools. Soil Biol Biochem 37:279–287 Ramphisa PD (2015) The effect of animal manure application rate on the concentration of NH4+-N, NO3--N and plant-available P and K in the soil over time. M Tech (Agric) dissertation. Tshwane University of Technology, Pretoria Roberts VG, Adey S, Manson AD (2003) An investigation into soil fertility in two resource-poor farming communities in KwaZulu Natal (South Africa). S Afr J Plant Soil 20(3):146–151 Schroder JJ, Uenk D, Hilhorst GJ (2007) Long term nitrogen fertilizer replacement value of cattle manures applied to cut grassland. Plant Soil 299:83–99 Smits MCJ, Monteny CJ, Van Duinkerken G (2003) Effect of nutrition and management factors on ammonia emission from dairy cow herds: models and field observations. Livest Prod Sci 84: 113–123 Srinivasarao C, Ganeshamurthy AN, Ali M, Venkateswarlu B (2006) Phosphorus and micronutrient nutrition of chickpea genotypes in a multi nutrient-deficient typic ustochrept. J Plant Nutr 29: 747–763 Sun L, Sun Z, Hu J, Yaa O-K, Wu J (2021) Decomposition characteristics, nutrient release, and structural changes of maize straw in dryland farming under combined application of animal manure. Sustainability 13:7609. https://doi.org/10.3390/su13147609 Tessier L, Bijttebier J, Marchand F, Baret BV (2021) Identifying the farming models underlying Flemish beef farmers’ practices from an agroecological perspective with archetypal analysis. Agric Syst 187:103013. https://doi.org/10.1016/J.AGSY.2020.103013 Van Averbeke W, Mnkeni PNS, Harris PJC, Mkile Z (2008) Fertility status of cropped soils in smallholder farming systems of the Transkei region, Eastern Cape Province, South Africa. In: Haneklaus S, Hera C, Rietz R-M, Schnug E (eds) Fertilizers and fertilization for sustainability in agriculture: the first world meets the third world – challenges for the future. Terra Nostra, Lasi, pp 513–526 Van der Watt HVH, Van Rooyen TH (1995) A glossary of soil science, 2nd edn. The Soil Science Society of South Africa, Pretoria Van Wyk JH (1967) Die fisiese struktuur en landboupotensiaal van die Transkei. D Sc (Agric) thesis. University of Pretoria, Pretoria Yoganathan S, Sotana MM, Van Averbeke W, Mandiringana OT, Materechera S, Harris PCJ, Mnkeni PS (1998) Kraal manure as a fertiliser in small scale crop production in central Eastern Cape, South Africa. In: Proceedings of the 15th International Symposium of the AFSRE, Pretoria 29 November - 4 December 1998, vol 1, pp 361–368

Chapter 2

Integrated Soil Fertility Management for Soil Fertility Restoration in Sub-Saharan Africa Nothando Dunjana , Charity Pisa, Morris Fanadzo Hupenyu Allan Mupambwa , and Ernest Dube

,

Abstract Sustainable soil fertility management is a cornerstone for achieving food and livelihood security. Decades of inappropriate soil fertility management in Africa have resulted in extensive soil degradation and declining crop yields. This is worsened by climate change as characterised by unreliable and unpredictable rainfall patterns, thus rendering crop production difficult. To address the challenge of declining soil fertility and increase the resilience of smallholder crop production systems to climate change, there is need for adoption of ‘best fit’ technologies that recognise the diverse agroecological and socio-economic niches existing within targeted farming systems. Integrated soil fertility management (ISFM) presents an opportunity to achieve this. ISFM refers to the framework of soil fertility management practices that include the use of fertiliser, organic inputs, and improved germplasm, combined with the knowledge on how to adapt these practices to local conditions. It is aimed at maximising the agronomic use efficiency of the applied nutrients and improving crop productivity. Owing to decades of research, there is a vast collection of technologies, techniques and applications of ISFM that can be learnt from. This chapter outlines the principles and practices of ISFM, its benefits and challenges for adoption in sub-Saharan Africa (SSA). Also, it presents opportunities to foster continued and widespread adoption of ISFM including technology development, innovation and transfer, agricultural value chain enhancement, policy

N. Dunjana (✉) · E. Dube School of Natural Resource Management, Nelson Mandela University, George, South Africa C. Pisa Department of Natural Resources Management, Faculty of Earth and Environmental Sciences, Marondera University of Agricultural Sciences and Technology, Marondera, Zimbabwe M. Fanadzo Department of Agriculture, Cape Peninsula University of Technology, Wellington, South Africa H. A. Mupambwa Sam Nujoma Marine and Coastal Resources Research Center, Sam Nujoma Campus, University of Namibia, Henties Bay, Namibia © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 M. Fanadzo et al. (eds.), Towards Sustainable Food Production in Africa, Sustainable Agriculture and Food Security, https://doi.org/10.1007/978-981-99-2427-1_2

21

22

N. Dunjana et al.

support as well as utilisation of mobile phone technologies to reduce training and dissemination costs. Thus, building upon the lessons learnt and the existing opportunities for soil fertility management using ISFM strategies is fundamental to the building and strengthening of resilience of African food production systems. Keywords Soil fertility restoration · Smallholder farms · Local adaptation · Resilience · Sustainability

2.1

Introduction

Global population is projected to reach 9.7 billion in 2050, and sub-Saharan Africa (SSA) will account for more than half of this growth (United Nations Department of Economic and Social Affairs 2022). Consequently, an increase in demand for food will put pressure on land and water resources in SSA. A high demand for productive land has rendered traditional methods for soil fertility restoration such as land fallowing generally inapplicable in SSA, thus soil degradation processes have intensified (Vanlauwe et al. 2015a). The depletion of soil fertility in smallholder farms is a major constraint on crop production. For example, while it has been shown that food supplies grew significantly in other developing parts of the world due to the Green revolution, SSA failed to benefit from the improved technologies, most likely because of poor soil fertility on smallholder farms (Sanchez 2015). Soil fertility, which defines the capacity of soil to supply sufficient quantities and proportions of nutrients and water required for optimal growth of plants is crucial for agricultural productivity and food security (Fairhurst 2012). Integrated soil fertility management (ISFM) has been recognised as a key strategy to addressing land degradation, food insecurity, and poverty through the adaptation of soil fertility management strategies to local biophysical and socio-economic conditions (Bationo et al. 2007). Essentially, ISFM consists of a set of soil fertility management practices that include the use of fertiliser, organic inputs, improved germplasm combined with the knowledge on how to adapt these practices to local conditions. The aim is to optimise agronomic efficiency (AE) of applied nutrients and improve crop productivity (Fairhurst 2012). The ISFM approach signifies a move from the ‘one-size-fitsall’ or ‘silver bullet’ solutions that typically attempt widespread implementation of a particular approach without adaptation to the local situation (Fairhurst 2012). Instead, its focus is on offering locally adapted technologies or ‘best fit’ options targeted at farming systems through recognising their diverse agroecological, socioeconomic environments to ‘socio-ecological’ niches (Fairhurst 2012). Research has shown significant successes in various aspects of soil fertility restoration and crop productivity increase in SSA. For example, Mugwe et al. (2009) showed that combining organic materials and inorganic fertiliser gave significantly higher maize yields than the recommended rate of inorganic fertiliser, while the inclusion of improved maize germplasm, organic inputs, and targeting fertiliser to responsive infields was shown to substantially enhance nitrogen AE (Vanlauwe et al. 2011). Further, consistent co-application of manure and mineral fertilisers has been shown to be an effective option to improve crop yield, soil

2

Integrated Soil Fertility Management for Soil Fertility Restoration. . .

23

organic carbon (SOC), water infiltration, and moisture retention under smallholder farming conditions (Dunjana et al. 2014; Rusinamhodzi et al. 2013). Consequently, this chapter set out to highlight the principles and practices of ISFM, its successes and local innovations, as well as bottlenecks to adaptation. Further, the chapter outlines opportunities that should be leveraged for the continued improvement of ISFM in line with evolving times.

2.2

Principles of ISFM

ISFM operates within a framework of concepts or principles that recognise that neither the practices based solely on mineral fertilisers nor those that rely solely on organic matter management are ideal for sustainable agricultural production. The overall goal of ISFM is to maximise interactions resulting from the integration of fertilisers, organic inputs, improved germplasm, and farmer knowledge for local adaptation of the practices with resultant increase in crop yields, nutrient use efficiency, and soil quality (Sanginga and Woomer 2009). ISFM practices involve: 1. the judicious use of fertiliser and agro-minerals in terms of their form, placement, and timing of application; 2. the harnessing and management of locally available organic resources crop to optimise soil nutrient use efficiency; 3. the use of locally adapted germplasm that is resistant to local stress conditions, both biotic and abiotic; and 4. adaptation to local conditions such as differential fertility across and within fields, as well as the integration of measures that address other constraints, such as pest and disease management, soil erosion control, moisture conservation, and the enhancement of beneficial soil biota (Sanginga and Woomer 2009; Vanlauwe et al. 2010).

2.2.1

Fertiliser Use

Previous soil fertility management paradigms have recognised mineral fertiliser as a key entry point for increasing crop productivity through the alleviation of nutrient constraints. It is important to note that within ISFM, mineral fertilisers are not enough as a stand-alone means to crop nutrient management (Sanginga and Woomer 2009). Variable responses of crops to fertiliser suggest that sole fertiliser addition is not a silver bullet for soil fertility restoration. While fertiliser may be significantly effective and thus present a valid entry point for ISFM on responsive soils, it is less effective on less responsive soils. Such soils may be constrained by other factors than nutrients, such as shallow depth or a sandy texture, a collapsed physical structure and low soil organic matter (SOM), or highly weathered soils with toxic

24

N. Dunjana et al.

properties (Sanginga and Woomer 2009). This point was elucidated by Zingore et al. (2007) who reported maize grain increase on the more fertile fields closest to homesteads, thereafter termed ‘homefields,’ following application of fertiliser at a high rate of 100 kg/ha nitrogen, while no significant response at the same fertiliser application rate was observed on the less fertile fields further away from the homesteads, the ‘outfields’.

2.2.2

Use of Organic Inputs

Organic resources have multiple functions in soil, ranging from their influence on nutrient availability to modification of the soil environment in which plants grow (Fairhurst 2012). The slow release of nutrients from organic resources provides a continuous supply of nutrients over the cropping season, when compared with mineral fertilisers. Nonetheless, most organic resources available to farmers are of low nutrient value (Nyamangara et al. 2009). Furthermore, various factors drive organic resources dynamics in the soil, such as the quantity and frequency with which organic inputs are added to the soil, the quality of the organic resources, soil type, management system, and climatic conditions. Organic resources are rich in carbon, thus provide an energy source for soil microorganisms, which drive the various soil biological processes that enhance nutrient transformation and other quality parameters of soil (Fairhurst 2012). Apart from providing essential plant nutrients, they contribute directly towards the buildup of SOM and its associated benefits. Soil organic matter improves soil structure, infiltration, and faunal activities (Dunjana et al. 2014; Roose and Barthès 2001; Six et al. 2002). Various organic soil fertility practices have been used across SSA smallholder farming systems depending on factors such as availability, technical knowhow, and with various levels of local innovations to suit the local conditions. Below, we highlight the key aspects of some main organic soil fertility practices in SSA (Table 2.1).

2.2.2.1

Importance of Organic Inputs Quality

Several factors influence the rate of mineralisation and nutrient release of organic resources, including environmental conditions, the rate of activity of the microorganisms, as well as the chemical composition of the organic inputs (Palm et al. 2001). The quality of organic input is of key importance in soil fertility management as the type of input used depends on the farmers’ choices and management. Palm et al. (1997) developed a decision support tool for the management of organic resources focussing on the short-term effects of organic additions on nutrient availability, but that can also serve as a framework for testing the longer term effects of organic resource quality on soil organic matter maintenance and composition (Palm et al. 2001). As a rule of thumb, organic inputs with a nitrogen content of

2

Integrated Soil Fertility Management for Soil Fertility Restoration. . .

25

Table 2.1 Description of main organic soil fertility practices in sub-Saharan Africa Organic practice Animal manure

Compost

Crop residues

Natural fallow

Improved fallow

Intercropping systems

Relay systems

Dual purpose legumes Biomass transfer

Description The spreading and incorporation of solid and liquid excrement from animals, mainly cattle. Intensified livestock production systems involve the collection of manure in stalls or pens, while the more extensive systems involve direct deposition of manure by grazing animals. The collection and distribution of a range of organic compounds that may include soil, animal waste, plant material, food waste, industrial waste, and even doses of mineral fertilisers. Prior to application of compost onto the field, the organic materials are incubated and undergo a natural process of decomposition which enhances their suitability for application to the soil as a fertilising resource. The in situ utilisation of crop residues. The utilisation may be in the form of leaving residues on the surface (mulching) or by cutting, chopping, and incorporation of crop residues into the soil through ploughing. Crop residues may also be composted before application. Withdrawal of land from cultivation for a period to permit natural vegetation to grow on the plot. The breaking of the crop cycle leads to regeneration and the fallows can also recycle nutrients. The purposeful planting of a woody or herbaceous plant to grow on a plot for a period of time. In addition to benefits of natural fallows, improved fallows can achieve equal impacts of natural fallows in shorter time periods because of purposeful selection of plants, such as those that fix atmospheric nitrogen and generate large amounts of biomass. Nutrient sources are integrated with crops in both time and space. The organic source may be a permanent feature on the plot such as with alley farming or scattered trees or may also be annual legumes. Specific crop management practices in intercrops need to be adapted to the needs of each crop in terms of spacing, nutrient management, relative planting dates, or pest and diseases control practices. Relay systems are similar to intercrops in sharing space with the crop, but the organic source is planted at a different time than the crop and the timing of their primary growth period may differ. These may be grown in intercrops or rotations with cereals. They thus maintain the features described above except that they also produce a second major product such as a grain for human consumption. The transport and application of green organic material from its ex situ site to the cropping area. The organic source may natural or purposefully grown.

Adapted from Place et al. (2003)

>2.5% or a carbon to nitrogen (C:N) ratio 10,000 hectares) in a single scheme (Molden et al. 2007). Drivers of this expansion were the rising demand for food and other agricultural commodities, new technology, and the adoption of the modernisation paradigm of development, with the majority of the world’s large irrigation schemes being established between 1950 and 1980 (Denison 2018). After 2000, the growth in the global irrigated area abated, due to lower than envisaged benefits from capital-intensive irrigation schemes, corruption associated with large irrigation development, declining food prices and the squeeze on agriculture and the general lack of water and land for irrigation scheme development except for sub-Saharan Africa (Denison 2018). In South Africa, large irrigation scheme development, involving dams or large weirs on rivers and canals for conveyance of water, occurred mainly during the period between the two World Wars (Van Vuuren and Backeberg 2015), bringing about 550,000 hectares under irrigation (Benadé 2014). Most South African smallholder schemes were constructed between 1950 and 1985, with gravity-fed canal schemes covering about 12,802 hectares being built up to 1975, and pumped or gravity-pressurised schemes thereafter, of which 27,758 hectares were equipped with overhead irrigation systems and 3830 hectares with micro-irrigation (Van Averbeke et al. 2011). After 1985, smallholder irrigation development in South Africa occurred mainly in the form of ‘independent irrigation’, which refers to individual farmers accessing water for irrigation using pumps, river diversions or wastewater flowing from canals (Denison et al. 2016). This independent irrigator development trajectory has largely remained unnoticed, despite the area being irrigated independently by smallholders in the Limpopo Province alone already covering about 70,000 hectares, exceeding the country-wide smallholder scheme

140

L. L. Van Averbeke and W. Van Averbeke

area by more than 20,000 hectares (Cai et al. 2017; Van Koppen et al. 2017), emphasising the opportunity local people see in irrigation as a livelihood option. The general absence of new smallholder irrigation scheme development in democratic South Africa is regrettable because such schemes can serve as local economic development locomotives by creating desperately needed livelihoods, not only through primary production but also by means of backward and forward linkages. Primary production on schemes provides livelihoods to the families of plot holders and farm workers, who may be casual or semi-permanent. Primary production by a concentrated group of farmers creates opportunities for enterprises with backward linkages to farming, in response to the substantial demand for land preparation services, fertilisers, plant protectants, seed, and seedlings (Maake 2015). Opportunities for business are also created through forward linkages, especially for fresh-produce traders. For example, Manyelo et al. (2015) reported that at the Dzindi canal scheme, there were as many fresh-produce street traders making a living from produce purchased at the scheme as there were plot holders on the scheme. On the large schemes in South Africa, water is still conveyed from source to farm by means of a canal system, but the use of surface irrigation has almost been abandoned. Instead, canal water is stored on farm dams from where it is pumped for application using overhead or micro-irrigation systems. On smallholder canal schemes, surface irrigation continues to be practised and initiatives to convert surface irrigation to overhead irrigation have been disappointing (Van Koppen et al. 2018). In fact, the general performance of the South African smallholder irrigation scheme sector as a whole has been below expectations. Country-wide, Van Averbeke et al. (2011) reported poor management (50% of the cases), infrastructural problems (15%); water inadequacies (13%); conflict (12%); and theft (7%) as the key constraints to improved smallholder scheme performance. In Limpopo Province, the home of 56% of the 302 smallholder schemes in South Africa, dilapidated scheme infrastructure was identified as the paramount constraint by van Koppen et al. (2017), whilst Denison (2018), covering the same population of smallholder schemes, reported that ‘failure’ of smallholder irrigation schemes was associated with type of energy used to apply water (gravity performed better than pumped), the condition of the scheme infrastructure, and water resource constraints. Whilst management, infrastructural deterioration and water inadequacies appear to be independent factors, this is not the case. Management of an irrigation scheme has a direct influence on the condition of scheme infrastructure and the degree of water security experienced by farmers. Before narrowing the scope to canal schemes, it is important to point out that the performance of pumped schemes is primarily function of the ability of farmers to pay the energy bill and maintain the pump in good working condition.

8

Being Small Does Not Make It Easy: The Management Conundrum on. . .

141

Fig. 8.1 Irrigation scheme management functions and their effects on farming

8.3 8.3.1

The Conundrum of Smallholder Canal Scheme Management in South Africa Scheme Management Functions

Adopting the perspective of farmers being the sole users of water entering a canal scheme, the expectation from ‘scheme management’ is the provision of an effective irrigation service that ensures water security to all farmers on the scheme (Molden et al. 2007). Water security in the irrigation scheme context refers to equitable, reliable, and predictable access to water for irrigation. The equitability component refers to all farmers receiving their fair share of the available irrigation water. The reliability component refers to the ability of farmers to access irrigation water when required, and the predictability component refers to water being accessible in accordance with a pattern that is known to farmers. This pattern can include the introduction of water restrictions, as long as farmers have been forewarned, enabling them to adapt their crop production decisions to cope with the below-normal supply of irrigation water. Providing water security to irrigators is dependent on several factors (Mugejo and Ncube 2022). Klumper et al. (2017) identified hydrology, governance, and the interaction between hydrology and governance as the three principal factors affecting water security on irrigation schemes. The hydrology factor entails the rate at which the water source is being fed, and the rate at which water flows through the various parts of the conveyance system. The governance factor involves farmer’s access to water and the rules that govern access, such as the payment of water fees and the obligatory participation in maintenance operations, as well as the penalties imposed on delinquents. The hydrology factor is partly a function of the weather. Hydrological droughts can reduce the rate at which the water source is fed to a level that is below scheme requirements. When such a situation is developing, management must forewarn farmers that water restrictions might have to be implemented. The hydrology factor is also affected by the way the water conveyance system is maintained. Maintenance of the conveyance, regulation, and control system is a key function of scheme management (Fig. 8.1), illustrating the interaction of hydrology and governance. On canal schemes, the rate at which water flows through the conveyance system, apart from being function of the design parameters, is dependent on the condition of the canals. Discharge in a canal is a function of the longitudinal slope, the

142

L. L. Van Averbeke and W. Van Averbeke

cross-sectional area and hydraulic radius of the water stream, and the ‘roughness’ of the canal lining (Dingman and Sharma 1997; Pappenberger et al. 2005). The Manning equation (eq. 8.1) expresses the relationship between discharge and the factors that affect it. Q=

1 2=3 1=2 AR S n

ð8:1Þ

where Q = discharge (m3 s-1); n = Manning’s roughness coefficient; A = cross-sectional area of the water stream (m2); R = hydraulic radius (m); and S = water surface slope (ratio). Equation 8.1 shows that discharge is inversely related to the Manning’s roughness coefficient (n). Increasing roughness progressively reduces discharge. Roughness of the canal surface increases by the presence of vegetation, silting, obstructions, canal irregularities, and the extent of canal alignment (James and Makoa 2006; Akkuzu et al. 2008). According to Israelsen and Hansen (1962), a new concrete-lined canal has a Manning’s roughness coefficient that ranges between 0.012 (best) and 0.018 (worst). Values ranging between 0.014 and 0.016 are commonly used during the design of canal systems (Israelsen and Hansen 1962). When the factors responsible for increasing roughness are severe, the Manning’s roughness coefficient in a concrete canal can attain values as high as 0.1 (1/n = 10), which would reduce the discharge to 15% of what it would be if the same canal was in a good state and had a Manning’s roughness coefficient of 0.015 (1/n = 66.7). This underlines the importance of minimising canal roughness, which is achieved through maintenance of the conveyance system. Maintenance activities on canal schemes can be subdivided into three categories, namely routine, special, and deferred (Sagardoy et al. 1986). Routine maintenance refers to the regular removal of vegetation, especially aquatic plants, and sediments from the canals, repairing of small cracks, painting and greasing of regulating devices, and the cleaning and desilting of ley dams, if present (FAO 1986). Aquatic plants are classified into submerged, floating, and bank weeds. Submerged aquatic weeds have the greatest effect on open channel flow (Mohamed and El-Samman 2020). Also important is that plants and algae do not only increase roughness by obstructing flow. The organic acids they secrete are also responsible for the dissolution of cement, which roughens the lining of the concrete by exposing the aggregate fragments (Guillitte and Dreesen 1995). Cracks in the concrete, especially along the joints, need to be filled to avoid seepage and to prevent plants from finding foothold in the canals (International Commission on Irrigation and Drainage 1989). Special maintenance in canal systems refers to repairs, such as canal straightening and realignment, repairs to concrete linings, the replacement of minor sections of the canals and concrete furrows that have been damaged by corrosion or mechanical

8

Being Small Does Not Make It Easy: The Management Conundrum on. . .

143

impact, and the replacement of faulty control gates and valves. Special maintenance tasks demand the availability of the necessary expertise and equipment (FAO 1986). Deferred maintenance refers to large modifications to the canal system. Deferred maintenance usually occurs at the end of the life span of a scheme when revitalisation works have become necessary, or when a scheme has been severely damaged by a natural disaster. As with special maintenance, the availability of expertise and equipment are critical requirements in deferred maintenance projects (FAO 1986). The allocation of water to farmers is primarily a governance function that falls under the mandate of scheme management. To avoid conflict among scheme farmers, allocation of water must be equitable. Where land parcels are identical in size, equitable water distribution equates to farmers receiving the same amount of water. Where farms differ in size, equity involves the allocation of water proportional to the farm area under irrigation. Managing water allocation requires measurement of the volume of water delivered to each farm. Various simple measuring devices are available for that purpose, such as Parciall flumes and orifice gates (Zimmerman 1966), which provide volume data using flow rate, provided by the device, and time as inputs. Often this involves an administration system requiring farmers to log requests for water and a system of water fees. On small canal schemes, direct measurement of water allocated to the different farm units is rare. Instead, a roster is created that allocates particular time periods during which each farmer can draw water, removing the need to maintain an administrative system to record water allocations. In such cases, scheme design, including the devices that regulate flow in the conveyance system, is such that the system delivers equal flows to all parts of the scheme. Obviously, this condition only applies when all components of the system are well maintained and functioning as per design. If maintenance fails, discharge will be reduced progressively down the system, causing tailenders to get less water than front-enders, thus setting the scene for deviant behaviour, such as the stealing of water, and social conflict (Letsoalo and Van Averbeke 2006a, b). Managing an irrigation scheme can only be done based on a set of rules and regulations that are enforced. It is important that these are known to farmers on the scheme, including the consequences of breaking the rules. Management of schemes is only sustainable when the rules governing the scheme are adhered to by all farmers.

8.3.2

Management on Large and Small Canal Schemes

On large-scale canal schemes in South Africa, the scheme management functions are performed by an Irrigation Board or a Water User Association. These organisations are funded by farmers on the scheme through payment of water fees. The water fee includes the cost of water, as well as the cost of running the Board or the Association. In return, farmers receive a specified volume of water per annum, which is delivered

144

L. L. Van Averbeke and W. Van Averbeke

upon request, through a booking system. Water deliveries are measured and monitored. To ensure reliability of supply, the board or association takes responsibility for routine and special maintenance of the conveyance system. Annually, the entry of water in the system is closed off for a few weeks and the canals are emptied and cleaned. Farmers and their workers can participate in canal cleaning for which they receive a discount on their water fees. Simultaneously, important special maintenance work is done on the conveyance system, such as relining canal surfaces that have corroded. Delinquent behaviour, such as ‘stealing water’ invokes penalties, and non-payment of water fees results in litigation. At establishment of smallholder canal schemes in South Africa, the legal and institutional framework that governed smallholder canal schemes was a special form on trust tenure. To construct these canal schemes and enforce the trust tenure system, the state deemed it necessary to transfer tribal land, which had been identified as irrigable, to the Bantu Development Trust. The process of this transferral involved the removal and compensation of the occupants of this land and, often, negotiation with tribal authorities of the identified sites. Importantly, this transferral of land to the Bantu Development Trust removed the role of tribal leadership as the assigned and assumed (customary and culturally affiliated) authoritative body in a select region. The content of this irrigation scheme tenure system was formalised by Proclamation No R. 5 of 1963, called the ‘Regulations for the Control of Irrigation Schemes in the Bantu areas’, hereafter referred to as the regulations. The content of the regulations had been under construction for 30 years, commencing in the late 1930s, following the decree of the Native Trust and Land Act 18 of 1936 (Masiya and Van Averbeke 2013). The first of these smallholder irrigation scheme legislations is defined in Proclamation No. 173 of 1938, which was published for the establishment of the Grobler Irrigation Scheme in the District of Thaba ‘Nchu (Masiya and Van Averbeke 2013). At least five similar proclamations were subsequently promulgated before the publication of Proclamation No. R. 5, 1963 (Masiya and Van Averbeke 2013). These early proclamations illustrate how the regulation for irrigation scheme tenure systems was partially amended and modified to suit differing social arrangements that characterised the communities of particular ‘Bantu Areas’ where irrigation schemes were established (Masiya and Van Averbeke 2013). Important, however, was that the rules and regulations contained in all proclamations took care of the important scheme management functions. Plot holders had to farm fulltime, irrigate in accordance with a timetable and contribute labour towards maintenance functions when asked to do so. Adherence to this set of rules was policed by bailiffs with fines imposed on delinquents (Letsoalo and Van Averbeke 2006a). Decisions on the need for routine maintenance were taken by the agricultural technician appointed to the scheme and the cleaning work was done by plot holders. On cleaning day, the entry of water into the main canal was closed at the source, and the canal was subdivided into sections and allocated to plot holders for cleaning. Where ley dams were part of the conveyance and storage system, plot holders were also required to clean and desilt these dams on a regular basis. Participation in these

8

Being Small Does Not Make It Easy: The Management Conundrum on. . .

145

cleaning activities was compulsory and fines were imposed on those who failed to do their part of the work (Letsoalo and Van Averbeke 2006b). When the regulations were promulgated, political power had already shifted to the National Party with its vision of separate development, referred to as Apartheid. This vision assigned a central role to tribal authorities in the creation of independent homelands. The regulations were not aligned with this vision, as it called for the detribalisation of land and the exclusion of chiefs and headmen from the management of irrigation schemes. This contradiction was taken care of by the Promulgation of Proclamation No. R. 188, 1969. The publication of this proclamation is pertinent because it not only amended selected regulations contained in the Regulations but also contained legislation that formally reintroduced tribal authority as a governing structure within irrigation scheme communities (Masiya and Van Averbeke 2013). From about 1970 onwards, authority over smallholder irrigation schemes was transferred from the Department of Bantu Administration to the various homeland governments. Staff of the homeland administration were less authoritarian than those of the Department of Bantu Administration, and many of the stipulations contained in the Regulations were no longer enforced. Gradually, participation in collective action, such as routine maintenance of the canals, declined, a trend that was accelerated when post-1994, the government adopted the policy of Irrigation Management Transfer (IMT), formally handing over management of the schemes to its occupants (Letsoalo and Van Averbeke 2006a, b). Preference for serving personal interests over the interest of the collective became the norm, accelerating the demise of collective action. The shift away from the collective good to the personal good among plot holders was not only the result of government withdrawing from managing smallholder irrigation schemes. Other factors were the diverse livelihood portfolios of plot holder households and the differing personalities of people. Typical for smallholder irrigation scheme communities is that the livelihood of some plot holders is heavily dependent on farming and associated agrarian activities, whilst that of others is not (Mohamed 2006; Ncube 2014; Denison et al. 2016). When farming is of little significance in one’s living, the incentive of availing one’s labour to maintain a collective resource is minor. Livelihood diversification also existed at the time the smallholder canal schemes were established. At that time, it was common for young men who formed part of plot holder households to migrate to the cities, leaving farming to their spouses and parents, but policing of the plots ensured that farming was practised on all plots and that plot holders participated in maintenance activities (Mohamed 2006; Van Averbeke 2017). The personality of people also plays a role in the sustainability of voluntary collective action. Whilst some people continue to engage in activities that serve the collective good even in the absence of a system of penalties for non-participation, others take advantage and withdraw their participation. Critical for the sustainability of collective activities, such as routine maintenance of the conveyance and storage system, is which stance most plot holders adopt. When the balance tilts towards non-participation, the collective activity is doomed (Letsoalo and Van Averbeke 2006b).

146

L. L. Van Averbeke and W. Van Averbeke

Current administration, management, and day-to-day operation of smallholder canal schemes is an arrangement that involves multiple authorities, including the Department of Agriculture, the Department of Water Affairs and Sanitation, Tribal Authorities and the local municipality. Combined, they create a confusing institutional environment that is characterised by rent seeking (Masiya and Van Averbeke 2013). Descriptions of how these four institutions manage canal irrigation schemes and their surrounding communities set the scene for social conflict and operational chaos, which contributes to the deviant behaviour of plot holding communities and the animosity within scheme communities (Masiya and Van Averbeke 2013; Van Averbeke 2017; van Koppen et al. 2017; Cele and Wale 2018; Sato 2018; Denison 2018). Against this background, attempts at revitalising schemes are rarely successful and have resulted in a build-neglect-rebuild syndrome (van Koppen et al. 2017). Looking across the fence at how large irrigation schemes are managed, the solution to this institutional quagmire appears simple—create a Water User Association paid for by plot holders on each scheme and mandate this organisation with the provision of good irrigation services. However, whilst this arrangement works well on large schemes, the ‘smallness’ of most smallholder irrigation schemes limits the finances they can raise through water fees. Lack of finance precludes the creation of a professional organisation as found on large irrigation schemes, and this presents the management conundrum on smallholder schemes.

8.4

Improving the Management of Smallholder Irrigation Schemes: A Proposal

Any proposal for the sustainable management of smallholder canal schemes must prioritise the introduction of a strong managing organisation able to provide an effective irrigation service. This should include mechanisms to enforce rules and regulations aimed at providing all farmers on the scheme with water security. Several contemporary studies have argued that indigenous institutional development results in more sustainable management of small holder irrigation schemes (Phali et al. 2021; Phakathi et al. 2021). Pittock et al. (2020) make a case for innovation platforms to engage smallholders in improving scheme governance. However, we believe that a more radical solution is required that mirrors scheme management on large canal schemes. By law, the South African Department of Water and Sanitation governs water use and maintains the ‘user pays’ principle. Introduction of a water fee on smallholder canal schemes is, therefore, in line with the Law and also contributes towards the development of a sense of ownership and responsibility among participants for the sustainable management of their schemes (Mutambara et al. 2016). This water fee should provide farmers with user rights, exclusion rights, and enforcement rights on scheme land that is held by the state. Given that farmer communities are diverse, plot sizes should be flexible, allowing for growth and commercialisation as well as scale

8

Being Small Does Not Make It Easy: The Management Conundrum on. . .

147

reduction in line with farmers’ abilities, goals, aspirations and life cycle. This is in line with the findings of Denison (2018) who reported long-term land lease agreements as an important success factor among smallholder irrigation schemes in Limpopo Province, because leasing of land among plot holders reflects processes of growth and contraction of farm enterprises. Water User Associations serving large areas should be mandated to serve as the management agency of the smallholder schemes that are located within their areas of operation. This service would be paid for partly by the collection of water fees, but, partial subsidisation by the Department of Water and Sanitation may be necessary, and should be viewed as a pro-poor intervention. The role of the Department of Agriculture should be limited to assisting farmers in their various production and marketing endeavours. Whilst this proposal could be implemented quite easily on new smallholder schemes, introducing it on existing schemes would probably be met with a lot of resistance, because vested interests, real or imagined, will be threatened. To what extent the promise of an effective irrigation service following reconstruction of the scheme infrastructure would entice scheme communities to accept the proposed change is not known.

References Ahaibwe G, Mbowa S, Lwanga MM (2013) Youth engagement in agriculture in Uganda: challenges and prospects. Research series no 106. Economic policy research Centre, Makerere University, Kawempe Akkuzu E, Unal HB, Karatas BS, Avci M, Asik S (2008) Evaluation of irrigation canal maintenance according to roughness and active canal capacity values. J Irrig Drain Eng 134(1):60–66 Benadé N (2014) Water administration system (WAS): summary. https://www.wateradmin.co.za/ docs/was_module_summary.pdf. Accessed 16 Nov 2022 Bezu S, Holden S (2014) Are rural youth in Ethiopia abandoning agriculture. World Dev 64:259– 274 Bongaarts J (2001) Household size and composition in the developing world in the 1990s. Popul Stud 55:263–279 Cai X, Magidi J, Luxon Nhamo L, van Koppen B (2017) Mapping irrigated areas in the Limpopo Province, South Africa. IWMI Working Paper 172, International Water Management Institute, Colombo Cele L, Wale E (2018) The role of land- and water-use rights in smallholders’ productive use of irrigation water in KwaZulu-Natal, South Africa. Afr J Agric Resour Econ 13(4):345–356 Chinsingwa B, Chasukwa M (2012) Youth, land grabs and agriculture in Malawi. IDS Bull 43(6): 67–77 Choudhary HR, Choudhary A (2013) Why Indian farmers and youth are moving from farming. Pop Kheti 1(2):60–66 Christiaensen L, Demery L, Kuhl J (2011) The evolving role of agriculture in poverty reduction— an empirical perspective. J Dev Econ 96:239–254 Denison JAN (2018) An investigation into the performance of smallholder irrigation schemes in Limpopo Province, South Africa: success factors, typologies and implications for development. PhD thesis, Rhodes University Denison J, Dube SV, Masiya TC, Moyo T, Murata C, Mpyana J, Van Averbeke LL, Van Averbeke W (2016) Smallholder irrigation entrepreneurial development pathways and livelihoods in two

148

L. L. Van Averbeke and W. Van Averbeke

districts in Limpopo Province. WRC Report No. 2179/1/16, The Water Research Commission, Pretoria Dhahri S, Omri A (2021) Foreign capital towards SDGs 1 & 2—ending poverty and hunger: the role of agricultural production. Struct Chang Econ Dyn 53:208–221 Dingman SL, Sharma KP (1997) Statistical development and validation of discharge equations for natural channels. J Hydrol 199:13–35 Du Toit A, Neves D (2014) The government of poverty and the arts of survival: mobile and recombinant strategies at the margins of the south African economy. J Peasant Stud 41:833. https://doi.org/10.1080/03066150.2014.894910 Dzanku FM, Jirstrom M, Marstorp H (2015) Yield gap-based poverty gaps in Sub-Saharan Africa. World Dev 67:336–362 Eneyew A, Alemu E, Ayana M, Dananto M (2014) The role of small-scale irrigation in poverty reduction. J Dev Agric Econ 6(1):12–21 Fan S & Rue C (2020) The role of smallholder farms in a changing world. In: Gomez Y, Paloma S, Riesgo L, Louhichi K (eds) The role of smallholder farms in food and nutrition security. Springer Nature, Cham, p 13–28 Fanadzo M, Chiduza C, Mnkeni PNS (2010) Overview of smallholder irrigation schemes in South Africa: relationship between farmer crop management practices and performance. Afr J Agric Res 5(25):3514–3523 FAO (1986) Organization, operation and maintenance of irrigation schemes training manual no. 40. Food and agriculture Organization of the United Nations, Rome FAO, IFAD, WFP (2015) The state of food insecurity in the world: meeting the 2015 international hunger targets—taking stock of uneven progress. Food and Agriculture Organization of the United Nations, Rome Funahashi K (1996) Farming by the older generation: the exodus of young labor in Yasothon Province, Thailand. Jpn J Southeast Asian Stud 33(4):107–121 Gallaway A (1963) Unemployment among African school leavers. J Mod Afr Stud 1(3):351–371 Gebregziabher G, Namara RE, Holden S (2009) Poverty reduction with irrigation investment: an empirical case study from Tigray, Ethiopia. Agric Water Manag 96:1837–1843 Giller KE (2020) The food security conundrum of sub-Saharan Africa. Glob Food Sec 26:100431. https://doi.org/10.1016/j.gfs.2020.100431 Guillitte O, Dreesen R (1995) Laboratory chamber studies and petrographical analysis as bioreceptivity assessment tools of building materials. Sci Total Environ 167:365–374 Hazell P (2020) Importance of smallholder farms as a relevant strategy to increase food security. In: Gomez Y, Paloma S, Riesgo L, Louhichi K (eds) The role of smallholder farms in food and nutrition security. Springer Nature, Cham, p 29–43 Hazell P, Poulton C, Wiggins S, Dorward A (2010) The future of small farms: trajectories and policy priorities. World Dev 38(10):1349–1361 Heide-Ottosen S, Vorbohle T (2014) The ageing of rural populations: evidence on older farmers in low and middle income counties. HelpAge, London Huang Q, Rozelle S, Lohmar B, Huang J, Wang J (2006) Irrigation, agricultural performance and poverty reduction in China. Food Policy 31:30–52 Hull E (2014) The social dynamics of labor shortage in south African small-scale agriculture. World Dev 59:451–460 Hussain I, Hanjra M (2004) Irrigation and poverty alleviation: review of the empirical evidence. Irrig Drain 53:1–15 ILO (2010) Global employment trends for youth: special issue on the impact of the global economic crisis on youth. International labour Office, Geneva International Commission on Irrigation and Drainage (1989) Planning the management, operation and maintenance of irrigation and drainage systems: a guide for the preparation of strategies and manuals. World Bank technical paper no 99, the World bank, New York, NY Israelsen OW, Hansen VE (1962) Irrigation principles and practices. John Wiley and Sons, New York, NY

8

Being Small Does Not Make It Easy: The Management Conundrum on. . .

149

IWMI (2022) Irrigation in South Africa. IWMImedia, Pretoria. https://www.youtube.com/watch? v=GcMYUm48LWk James CS, Makoa MJ (2006) Conveyance estimation for channels with emergent vegetation boundaries. Water Manag 159(4):235–243 Kalamkar SS (2009) Urbanisation and agricultural growth in India. Indian J Agric Econ 64(3): 442–461 Klümper F, Herzfeld T, Theesfeld I (2017) Can water abundance compensate for weak water governance? Determining and comparing dimensions of irrigation water security in Tajikistan. Water 9:286. https://doi.org/10.3390/w9040286 Larson DF, Muraoka R, Otsuka K (2020) Rural development strategies and Africa’s small farms. In: Gomez Y, Paloma S, Riesgo L, Louhichi K (eds) The role of smallholder farms in food and nutrition security. Springer Nature, Cham, pp 45–77 Leavy J, Smith S (2010) Future farmers: youth aspirations, expectations and life choices. Discussion paper 013. Future Agricultures, Institute for Development Studies, University of Sussex, Brighton Letsoalo S, Van Averbeke W (2006a) Water management on a smallholder canal irrigation scheme in South Africa. In: Perret S, Farolfi S, Hassan R (eds) Water governance for sustainable development: approaches and lessons from developing and transitional countries, Earthscan. Routledge, London, pp 93–109 Letsoalo SS, Van Averbeke W (2006b) Infrastructural maintenance on smallholder canal irrigation schemes in the north of South Africa. In: Proceedings of the international symposium on water and land management for sustainable irrigated agriculture. Cukurova University, Adana. [CD ROM], no page numbers Lipton M (2005) Crop science, poverty, and the family farm in a globalising world. 2020 Discussion paper 40. International Food Policy Research Institute, Washington, DC Lowder SK, Skoet J, Raney T (2016) The number, size, and distribution of farms, smallholder farms, and family farms worldwide. World Dev 87:16–29 Maake MS (2015) Profitability and social acceptability on tractor and animal draught enterprises operating on selected smallholder canal schemes in Vhembe District, Limpopo Province, South Africa. M Tech Agric dissertation, Tshwane University of Technology, Pretoria Manyelo K, Van Averbeke W, Hebinck P (2015) Smallholder irrigators and fresh produce street traders in Thohoyandou, Limpopo Province, South Africa. In: Hebinck P, van der Ploeg JD, Schneider S (eds) Rural development and the construction of new markets. Routledge, London, pp 131–148 Masiya TC, Van Averbeke W (2013) Land tenure on canal schemes in Vhembe: the case of Dzindi. In: Van Averbeke W (ed) Improving plot holder livelihood and scheme productivity on smallholder canal irrigation schemes in the Vhembe District of Limpopo Province district, Limpopo Province, South Africa. WRC Report TT566/13, The Water Research Commission, Pretoria, pp 91–137 Mohamed SS (2006) Livelihoods of plot holder homesteads at the Dzindi smallholder canal irrigation scheme. D Tech (Agric) thesis, Tshwane University of Technology, Pretoria Mohamed SAE, El-Samman TA (2020) Manning roughness coefficient in vegetated open channels. Water Sci 34(1):124–131 Molden DJ, Burton MA, Bos MG (2007) Performance assessment, irrigation service delivery and poverty reduction: benefits of improved system management. Irrig Drain 56(2–3):307–320 Mugejo K, Ncube B (2022) Determinants of water security in smallholder farming systems in South Africa: a review. Fundam Appl Agric 7(3):235–249 Mutambara S, Darkoh MBK, Athlopeng JR (2016) A comparative review of water management sustainability challenges in smallholder irrigation schemes in Africa and Asia. Agric Water Manag 171:63–72 Ncube BL (2014) Livelihoods and production in smallholder irrigation schemes: the case of new forest irrigation scheme in Mpumalanga Province. M Phil dissertation, University of the Western Cape, Belville, TX

150

L. L. Van Averbeke and W. Van Averbeke

O’Higgins N (2017) Rising to the youth unemployment challenge: new evidence on key policy issues. International Labour Office, Geneva Pappenberger F, Beven K, Horritt M, Blazkova S (2005) Uncertainty in the calibration of effective roughness parameters in HEC-RAS using inundation and downstream level observations. J Hydrol 302:46–69 Phakathi S, Sinyolo S, Marire J, Fraser G (2021) Farmer-led institutional innovations in managing smallholder irrigation schemes in KwaZulu-Natal and Eastern Cape Provinces. South Africa. Agric Water Manag 248. https://doi.org/10.1016/J.agwat.2012.106780 Phali L, Mudhara M, Ferrer S, Makombe G (2021) Household-level perceptions of governance in smallholder irrigation schemes in KwaZulu-Natal Province. Irrig Drain 71:394–405 Pittock J, Bjornlund H, van Rooyen A (2020) Transforming failing smallholder irrigation schemes in Africa: a theory of change. Int J Water Resour Res 36. https://doi.org/10.1080/07900621. 2020.1819776 Proctor F, Lucchesi V (2012) Small-scale farming and youth in an era of rapid rural change. International Institute for Environment and Development & Humanist Institute for Development Cooperation, London Reinders FB, Van der Stoep I, Lecler NL, Greaves KR, Vahmeijer JT, Benadé N, Du Plessis FJ, Van Heerden PS, Steyn JM, Grové B, Jumman A, Ascough G (2010) Standards and guidelines for improved efficiency of irrigation water use from dam wall release to root zone application: Main report. WRC report No TT 465/10. Water Research Commission, Pretoria Rigg J (2006) Land, farming, livelihoods and poverty: rethinking the links in the rural south. World Dev 34(1):180–202 Rigg J, Nattapoolwat S (2001) Embracing the global in Thailand: activism and pragmatism in an era of deagrarianisation. World Dev 29(6):945–960 Sagardoy JA, Bottrall A, Uittenbogaard GO (1986) Organization, operation and maintenance of irrigation schemes. FAO irrigation and drainage paper 40. Food and Agriculture Organization of the United Nations, Rome Sato C (2018) Opportunities and constraints for black farming in a former south African homeland: a case study of the Mooi River irrigation scheme, Msinga, KwaZulu-Natal, South Africa. African Study Monographs, Suppl 57: 147–174 Siebert S, Kummu M, Porkka M, Döll P, Ramankutty N, Scanlon BR (2015) A global data set of the extent of irrigated land from 1900 to 2005. Hydrol Earth Syst Sci 19:1521–1545 Sinyolo S, Mudhara M, Wale E (2014) The impact of smallholder irrigation on household welfare: the case of Tugela ferry irrigation scheme in KwaZulu-Natal, South Africa. Water SA 40(1): 145–155 The World Bank (2009) Awakening Africa’s sleeping giant: prospects for commercial agriculture in the Guinea Savannah zone and beyond. The World Bank, Washington, DC UN (2017) Household size and composition around the world 2017—data booklet (ST/ESA/SER. A/405). United Nations, Department of Economic and Social Affairs, Population Division, New York, NY Van Averbeke LL (2017) Women of Dzindi: the changing perspective in tradition and expression of identity amongst three generations, circa 1930–2015. MHCS (History) dissertation, University of Pretoria, Pretoria Van Averbeke W, Denison J, Mnkeni PNS (2011) Smallholder irrigation schemes in South Africa: a review of knowledge generated by the water research commission. Water SA 37:797–808 Van Koppen B, Nhamo L, Cai X, Gabriel MJ, Sekgala M, Shikwambana S, Tshikolomo K, Nevhutanda S, Matlala B, Manyama D (2017) Smallholder irrigation schemes in the Limpopo Province, South Africa. IMWI Working paper 147. International Water Management Institute, Colombo Van Koppen B, Tapela BN, Mapedza E (2018) Joint ventures in the flag Boshielo irrigation scheme, South Africa: a history of smallholders, states and business. IMWI Working paper 171. International Water Management Institute, Colombo

8

Being Small Does Not Make It Easy: The Management Conundrum on. . .

151

Van Vuuren L, Backeberg G (2015) Sustainable irrigation in South Africa: evidence from history. Paper Presented at the 26th Euro-Mediterranean Regional Conference and Workshops, Montpellier Wegner L, Zwart G (2011) Who will feed the world? The production challenge. Oxfam Research Report. Oxfam, London Wenban-Smith H, FaВe A, Grote U (2016) Food security in Tanzania: the challenge of rapid urbanization. Food Security 8:973–984 White B (2012) Agriculture and the generation problem: rural youth and the future of farming. IDS Bull 43(6):9–19 Zimmerman JD (1966) Irrigation. John Wiley & Sons, New York

Chapter 9

Sustainable Winery Wastewater Management for Improving Soil Quality, Environmental Health, and Crop Yield Takalani Sikhau, Mbappe Tanga, Adewole Adetunji Reckson Mulidzi , and Francis Lewu

, Carolyn Howell,

Abstract Climate change, water scarcity, and soil degradation are among the key factors affecting agricultural productivity. This has led to an increase in the demand for irrigation water in farming systems. There is a growing interest in the use of winery wastewater (WWW) as an optional source of clean water for irrigation in the cropping systems, especially in vineyards. Irrigation with WWW promotes soil fertility by increasing organic carbon, nitrogen, phosphorus, potassium, and sodium levels in the soil. Since WWW contains high concentrations of sodium and potassium, the long term and/or unregulated use in agricultural fields may result in soil salinity or sodicity which can negatively affect bioavailability of nutrient elements and crop performance. However, the implication of WWW use for soil quality/health properties has not been widely discussed. Thus, this chapter reviews the impact of WWW irrigation on soil physical, chemical, and biological properties, as well as crop productivity and environmental health. Keywords Agriculture · Irrigation · Soil properties · Vineyards · Wastewater

T. Sikhau Department of Agriculture, Cape Peninsula University of Technology, Wellington, South Africa ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa M. Tanga · A. Adetunji · F. Lewu (✉) Department of Agriculture, Cape Peninsula University of Technology, Wellington, South Africa e-mail: [email protected] C. Howell · R. Mulidzi ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 M. Fanadzo et al. (eds.), Towards Sustainable Food Production in Africa, Sustainable Agriculture and Food Security, https://doi.org/10.1007/978-981-99-2427-1_9

153

154

9.1

T. Sikhau et al.

Introduction

The continuous increase in the world population and climate change are factors that lead to water shortage and a decrease in agricultural output (Anwar 2011). This change has resulted in the increase in water shortage and the need for irrigation in the food production systems. To minimise the use of limited clean water for irrigation of agricultural fields, the practice of supplementing clean water with treated or untreated industrial effluent for irrigation is becoming widespread (Mulidzi and Wooldridge 2016). Wastewater from vineyards can be a useful source for irrigation, especially in areas where sustainable disposal of wastewater is essential and access to clean water for irrigation is difficult (Laurenson et al. 2012). It is estimated that per tonne of crushed grapes, about 3–5 m3 of winery wastewater (WWW) with high level of organic weight, varying salinity, and nutrient concentrations are made (Howell et al. 2018). Annually, it is estimated that the South African wine industries can produce more than 980,000 m3 of WWW (Sehaswana 2022). However, the wastewater from the vineyard is poorly managed by being dumped into freshwater sources, causing contamination of the environment (Howell et al. 2018). Implementation of a good management strategy for WWW disposal could be a possible solution in using WWW for irrigation in agricultural soils. In various desert and semi-arid nations around the world, where freshwater supply is a constraint, this resolution is being taken more seriously as a mitigating measure for freshwater supply in agricultural soils (Levy et al. 2014). Of the world’s total 301 million hectares of irrigated agricultural land, 1.5–6.6% have been estimated to be irrigated with WWW (Sato et al. 2013). Using WWW, rich in valuable nutrients for irrigation of agricultural fields can be advantageous to the fertility of the soil. This can be a substitute for conventional fertilisation in agricultural fields. However, the application in the long term may influence the physiochemical properties of soil which can be detrimental to the soil ecosystem and productivity, most especially due to high sodicity and salinity which are associated with high salt concentration. Therefore, the irrigation of agricultural fields with WWW must not compromise on soil and water conservation strategies, which may negatively influence soil health, production, and environmental quality (Laurenson et al. 2012). Irrigation with WWW requires optimisation to minimise leaching while reducing nutrient removal by means of a catch crop. To reduce soil sodium adsorption ratio (SAR) and potassium adsorption rate (PAR), appropriate plants may be selected and used for the removal of salts (Myburgh and Howell 2014). Previous findings have also demonstrated that irrigation of agricultural fields with WWW can also affect soil quality properties such as microbial enzymes responsible for organic soil breakdown and mineralisation of nutrients (Bardgett et al. 2005). Furthermore, WWW contains important plant nutrients that can increase crop production (Chen et al. 2020). This allows farmers not only to produce more income and increase local or regional economic activity for their households but also provide cities with fresh fruits and

9

Sustainable Winery Wastewater Management for Improving Soil Quality,. . .

155

vegetables which would not be possible if farmers did not irrigate with WWW (Qadir et al. 2007). However, there is limited information on soil chemical and biological properties as affected by WWW which are known to be reliable soil quality indicators. More knowledge on this subject is imperative for a broader understanding and good management of WWW irrigation to minimise the negative impacts on the soil and environment and improve crop quality and yield while identifying knowledge gaps that deserve further research. This chapter presents a brief overview of the statistics of the global wine industry, source and volume of WWW produced globally, and properties of WWW. It also reviews the application and effect of WWW on soil quality or health properties, crop yield, and environmental health. Around the world, wine production plays a very vital role in the agricultural industry. About 62 countries are notable wine producers (Kierath and Wang 2013). In 2020, the global production of wine amounted to a volume of 258 × 106 hl (Gong 2022). The top eight producing wine countries are Italy (47.2 × 106 hl), France (43.9 × 106 hl), Spain (37.5 × 106 hl), United States of America (24.7 × 106 hl), Argentina (10.8 × 106 hl), Australia (10.6 × 106 hl), South Africa (10.4 × 106 hl), and Chile (10.3 × 106 hl) (Gong 2022).

9.2

Source and Volume of Winery Wastewater Produced

Winery wastewater is generated from grapes being crushed from the wine cellar to the bottle of the finished product (Hirzel et al. 2017). Wine making uses water in the different steps of the process (Conradie et al. 2014) which gives rise to the production of WWW. It is estimated that for each litre of wine produced, 1–14 L of WWW is produced (Ioannou et al. 2015). The production of a litre of wine has an associated production of four litres of strong purplish and fruit-smelling WWW (Luz et al. 2021). The volume and composition of WWW vary greatly based on the time of year, the size of the winery as well as the type of wine produced (Buelow et al. 2015). Also, it is reported that about 3–5 m3 of WWW is being manufactured per tonne of crushed grapes (Mosse et al. 2011). Furthermore, at the Berry Estate Vineyard in the Riverland area of Southern Australia, 175,000 m3 of WWW was obtained from the crushing of 50,000 tonnes of grapes (Howell and Myburgh 2018). Additionally, at Lutzville Vineyards in South Africa, it is estimated that about 50% of the 50,000 cubic metres of the raw water used in the process of wine production ends up as WWW (Kriel 2008).

156

9.3

T. Sikhau et al.

Characteristics of Winery Wastewater

The characteristics of WWW greatly depend on the different stages of wine production, from low-strength wastewater which involves the floor, barrel, and bottle washing, to high-strength wastewater which involves grape harvesting, crushing, and racking (Buelow et al. 2015; Lofrano and Meric 2016). It is characterised by high sugar content, alcohols, organic acids, polyphenols, tannins, and lignins (Arienzo et al. 2009; Amor et al. 2019). Winery wastewater can cause serious environmental problems for soil surface and groundwater by influencing pH, colour, oxygen, temperature, turbidity and causing eutrophication (Coetzee et al. 2004; Ioannou et al. 2015; Bolzonella et al. 2019). However, from an agricultural perspective WWW contains macro- and micro-nutrients such as calcium, magnesium, phosphorus, potassium, copper, iron, and water that are essential for plant growth (Laurenson and Houlbrooke 2012; Conradie et al. 2014; Prazeres et al. 2017). Furthermore, it has a low pH and high chemical oxygen demand (Conradie et al. 2014), complementing some of the adverse effects of WWW to the environment (Laurenson and Houlbrooke 2011; Mosse et al. 2011).

9.4 9.4.1

Effects of Winery Wastewater on Soil Properties Soil Physical Properties

According to literature search, there is limited available information regarding the influence of WWW on the physical properties of soils in agrarian fields (Buelow et al. 2015). This may be due to their great variability, and changes that occur only over a long period (Hawke and Summers 2006). The long-term application of WWW in agricultural fields may result in potassium (K+) and magnesium (Mg+) build-up, thereby influencing soil structural stability (Sparling et al. 2006; Arienzo et al. 2012) and hydraulic properties (Mathan 1994; Hawke and Summers 2006; Al-Haddabi and Ahmed 2007; Arienzo et al. 2009; Vogeler 2009). Although there is limited information on the accumulation of these cations, like sodium it can increase dispersion which can cause slaking and degradation of soil structure (Laurenson et al. 2012). This may result in surface slaking leading to low hydrolytic conductivity and poor aeration (Laker 2004; Gharaibeh et al. 2016). One of the problems associated with WWW reuse for irrigation is the negative effects on soil infiltration rate, hydraulic conductivity, water table depth, and water holding capacity resulting in physical clogging of the soil’s surface layer, which is only restricted to a soil depth of 0–2 cm (Viviani and Iovino 2004). The high concentrations of these monovalent ions (sodium and potassium) are also associated with the reduction of hydraulic conductivity when the potassium absorption ratio (PAR) or sodium absorption ratio (SAR) exceeds 20 (Arienzo et al. 2012). Also, in WWW, when sodium base cleaner is replaced with potassium base cleaner it may

9

Sustainable Winery Wastewater Management for Improving Soil Quality,. . .

157

contribute towards decreasing clay dispersion risks by reducing the accumulation of potassium which in a long run will result in sodium toxicity causing more structural damage than potassium accumulation (Arienzo et al. 2009). Furthermore, the breakdown of soil structure in the cropping system can occur when bivalent cations (calcium and magnesium) are replaced by monovalent cations (potassium and sodium) that can result in the breakdown of soil structure when there is continuous irrigation with WWW in an agricultural field (Laurenson et al. 2012; Mulidzi et al. 2015).

9.4.2

Soil Chemical Properties

WWW is known to be extremely rich in potassium, having a higher amount of insoluble and exchangeable forms of potassium which contributes to soil fertility. However, the prolonged use of WWW for irrigation has severe impacts on the chemical properties of soil (Smiles and Smith 2004; Kumar et al. 2009; Laurenson and Houlbrooke 2011; Mosse et al. 2011) as indicated in Table 9.1. The effects of a high concentration of potassium on agricultural soil irrigated with WWW are unknown (Kumar et al. 2009; Mosse et al. 2011; Laurenson et al. 2012). In a pot study where four soil types were irrigated with diluted WWW (3000 mg/L), the amount of potassium increased in shale soil (20%) was higher than in clay soil (13%) or less (Mulidzi et al. 2015). Furthermore, in a field study, well-drained sandy soil irrigated with WWW had an increase in the rate of potassium from 0 to 10 cm layer and from 10 to 20 cm layer during harvest (Mulidzi et al. 2019). For agricultural soils that have low potassium, the use of WWW could be a very good recycling exercise that could result in an increase in potassium uptake by grapevines despite the negative response of high malate concentrations and pH (Jackson and Lombard 1993; Mpelasoka et al. 2003; Kodur 2011). In addition to potassium, WWW also contains high sodium, magnesium, and calcium ions (Mosse et al. 2011). Irrigation of agricultural soil with WWW increased nitrogen at the soil depth of 0–10 cm sand at the 10–20 cm soil depth (Mosse et al. 2013; Mulidzi et al. 2019). Similarly, there was a linear increase of sodium in a vineyard of alluvial sandy soil with a decrease in WWW dilution particularly in the topsoil (Howell et al. 2018). According to Hirzel et al. (2017) in the Nepal Valley of the United States of America when WWW was used for irrigation, a higher concentration of sodium (48.7–72.6 mg/kg) was recorded compared to the controlled (7.52–16.1 mg/kg). A high amount of sodium resulting from WWW can decrease the aggregate stability of the soil (Laurenson and Houlbrooke 2012). Also, irrigation of Kikuyu grass with WWW increased sodium level at a soil depth of 0–10 cm and decreased at 10–20 cm (Mulidzi et al. 2018), compared to a high concentration of sodium recorded in a vineyard that was irrigated with river water (Kumar et al. 2014). Furthermore, in the Nepal Valley of Northern California the amount of calcium was higher (6.63 mg/kg) in soils irrigated with WWW at a soil depth (20–40 cm) to

158

T. Sikhau et al.

Table 9.1 Effect of WWW application on soil chemical properties Soil type Sandy

Treatment WWW diluted with river water to 100, 250, 500, 1000, 1500, 2000, 2500, and 3000 mg/L. River water control

Sandy

WWW application at different soil depth of 0–10, 10–20, 20–30, 30–60, 60–90 cm in 2011, 2012, and 2013 WWW irrigated by the specific winery

Silty clay loamy

Treated WWW application and untreated WWW application

Clay loamy and medium clay

WWW by flood irrigation at surface (0–10 cm) and subsurface (60–90 cm) soil samples collections

Result 1 A decrease in dilution of WWW increased sodium and potassium in soil 2 Diluted WWW irrigation increased ECe 1 K+ and Na+ accumulated in the soil while Ca2+ and Mg2+ leached 2 Large volumes of K+ and Na+ were leached at soil depth beyond 90 cm 1 Soil moisture content changed significantly in all treatments over time 2 K+ and Mg2+, NH+ in the soil increased with WWW application also with other metals (zinc, iron, copper, and boron) 1 Decrease in electrolyte concentration and hydraulic conductivity caused by percolating solutions with PAR or SAR at surface and subsoil 2 Hydraulic conductivity was considerably higher in SAR solutions than in PAR solutions

Reference Howell et al. (2018)

Mulidzi et al. (2019)

Mosse et al. (2012)

Arienzo et al. (2012)

WWW winery wastewater, SAR sodium absorption ratio, PAR potassium absorption ratio

that of the control with a 4.38 mg/kg (Hirzel et al. 2017). However, according to Mulidzi et al. (2018) in a two-year study period there was no increase in calcium level in the soil irrigated with WWW. An earlier study demonstrated that continuous use of WWW for irrigation recorded a high level of monovalent ions (sodium and K), replacing bivalent ions (calcium) out of the exchange complex (Mosse et al. 2012). Irrigation with WWW diluted up to 3000 mg oxygen demand per litre had no impact on soil calcium due to the low concentration that was present in the WWW (Howell et al. 2018). For over 100 years, irrigation of pasture with WWW recorded a significant increase compared to the control (Kumar et al. 2009). Irrigation of pastures with undiluted WWW for 15–20 years recorded an increase in calcium levels; however, these increases were not as significant to that for 100 years (Kumar et al. 2009). Soil magnesium reduced following 4 years of WWW irrigation (Quale et al. 2010). According to Hirzel et al. 2017 (Hirzel et al. 2017) the concentrations of magnesium were high in WWW irrigated soil depth of 20–40 cm having 9.10 mg/kg compared to 4.90 mg/kg soil for the control irrigated soil in the Nepal Valley of North California. Over a study period where Kikuyu grass was irrigated with WWW,

9

Sustainable Winery Wastewater Management for Improving Soil Quality,. . .

159

magnesium concentration in all layers demonstrated a limited variation (Mulidzi et al. 2018). The impact of WWW on soil phosphorus has not been given much attention. However, Mulidzi et al. (2019) reported a high soil phosphorus of more than 20 mg/kg (a norm for sandy soils) in all soil layers after irrigation with WWW (Howell and Myburgh 2018) reported that after the first, second, and third seasons of WWW application, the soil had 114 mg/kg, 135 mg/kg, and 153 mg/kg phosphorus, respectively, in the 0–90 cm soil depth. Irrigation with undiluted WWW raised soil phosphorus, but phosphorus fluctuated throughout the year in different soil horizons (Hoogendijk 2019; Mulidzi et al. 2019). Note that the Bray II phosphorus in this study did not exceed the norm of 25 kg/mg phosphorus recommended for vineyard soils with a clay content between 6% and 15% (Conradie et al. 2014). Irrigation with acidic WWW may result in a reduction of soil pH (Hoogendijk 2019). The addition of organic acids from WWW could be associated with the decrease of soil pH due to H+ dissociation from carboxyl functional groups (Rukshana et al. 2012). However, in some studies, the application of WWW increased soil pH from 4.6 to 5.0 in the topsoil and from 5.0 to 5.3 in the subsoil (Mosse et al. 2012; Mulidzi et al. 2015, 2019; Shilpi et al. 2018). This indicates that topsoil is more susceptible to the risk of high potassium, sodium, and organic/ bicarbonate salts which increases acidity causing low soil pH (Howell et al. 2018). Similarly, in two case studies where pastures and a vineyard were irrigated with WWW, soil pH also increased (Kumar et al. 2014). In the Alexander Valley region and Napa Valley in California, there was no significant difference in pH of soils treated with WWW and control in the 0–40 cm depths, whereas, in the 40–60 cm soil samples, the block had a higher pH (6.29) than the control soil samples pH (5.12) (Hirzel et al. 2017). There was no change in soil pH where WWW was used for the irrigation of soil with a clay content of 60% in a study by Quale et al. (2010). Soils irrigated with WWW had higher carbon concentration than the control soils at 0–20 cm soil depth than at the 20–40 cm and 40–60 cm soil depths (Hirzel et al. 2017). In the Alexander Valley region of California, soil irrigated with WWW contained more than twice as much carbon as the control soil on the surface (Hirzel et al. 2017). Soil carbon decreased by 9.5% and 6.8% at 0–90 cm and 90–180 cm soil depth, respectively, after 3 years of irrigation with diluted WWW (Howell et al. 2018). After the irrigation with WWW, total organic carbon at 30 cm soil depth declined to approximately 40% of its initial value probably through degradation (Quale et al. 2010). Soil organic carbon at 0–10 cm and 10–20 cm soil depth was substantially higher than 2% after irrigation with WWW (Mulidzi et al. 2019), which is relatively high for soils of the Western Cape wine regions. When a vineyard with sandy alluvial soil in the Breede River region in South Africa was irrigated with diluted WWW, the results showed inconsistent trends about soil organic carbon as affected by WWW dilution (Howell et al. 2018). The organic carbon content at 0–10 cm soil depth was significantly higher by 2% compared to the one in the deeper layers which during soil classification, visual observation revealed that this layer was rich in organic matter (Mulidzi et al. 2018). Agricultural practices including WWW application that promotes soil organic carbon build-up should be adopted as an

160

T. Sikhau et al.

increase in soil carbon promotes soil microbial activities, nutrient cycling, plant productivity and reduces carbon dioxide emission and climate change. However, the mechanisms or pathways of WWW effects on soil organic carbon are not understood. The electrical conductivity of WWW ranges from 1.5 to 3.5 deciSiemens per metre (Ds/m) with most of the cations being sodium (Arienzo et al. 2012). Irrigation with WWW can result in the addition of large amounts of salts, most specifically sodium which has an adverse impact on the soil’s physical properties and plant growth (Victoria 2003). Hoogendijk (2019) reported that the electrical conductivity of the topsoil improved marginally after one season of irrigation using the in-field fractional use (augmentation) of winery wastewater with raw water for vineyard irrigation. The mineralogy of the soil, sodium, and potassium concentrations in solution are the major determinants of the soil’s hydraulic conductivity (Buelow et al. 2015). In a study using diluted wastewater for the irrigation of four different soils in a vineyard field, there was a decrease in the hydraulic conductivity (k) of shale-derived soil and that of alluvial and aeolian sands with the dilution of WWW in 3 years period (Howell and Myburgh 2018). Also, the increase in the amount of potassium resulted in a decrease in the hydraulic conductivity and infiltration rate of soils (Levy and Van Der Watt 1990). Additionally, it was determined that K+ had an intermediate impact on the hydraulic properties of the soil compared to exchangeable calcium and sodium. In a laboratory investigation, the impact of PAR and SAR on the soil hydraulic conductivity at effluent disposal sites was explored because WWW can have high sodium and/or potassium concentrations (Arienzo et al. 2009). The findings demonstrated that when the SAR or PAR surpassed 20, the hydraulic conductivity of soil was significantly reduced (Arienzo et al. 2009, 2012).

9.4.3

Biological Properties

In the wine industry, the use of WWW for the irrigation of other crops or landscapes is a widespread practice (Mosse et al. 2012). The use of WWW leads to the addition of organic matter which increases soil fertility (Diacono et al. 2012), though organic overloading may occur which causes the blockage of soil pore spaces which is detrimental to soil health (Mosse et al. 2012). Furthermore, the continuous process may lead to salt concentration in agricultural soils which can cause an increase in soil salinity and sodicity leading to dispersion (Halliwell et al. 2001). The impact of WWW application on soil biological properties has not been given much attention; however, the long-term application of municipal wastewater has been shown to impact mycorrhizal associations (Ortega-Larrocea et al. 2001). Irrigation with WWW may lead to the addition of organic and inorganic materials causing physiochemical changes in the soil, which may have an impact on the soil microbial community (Friedel et al. 2000; García-Orenes et al. 2015). The change in the microbial population is unsustainable indicating signs of ecosystem interference

9

Sustainable Winery Wastewater Management for Improving Soil Quality,. . .

161

Table 9.2 Effect of WWW application on soil biological properties Experiment Physicochemical and microbiological effects of long- and short-term WWW application to soils Microbial assessments of soil with a 40-year history of reclaimed WWW irrigation

Treatment Soil respiration was measured in situ at each sampling time and soil depth

Result Soil respiration increased significantly ( p. < 0.05) over time and soil depth with WWW irrigation

Reference Mosse et al. (2012)

Reclaimed wastewater and groundwater irrigation

Microbial quantity and composition identified had no significant difference ( p > 0.05) Proteobacteria was the dominant phylum observed WWW markedly stimulated urease activity relative to municipal wastewater in all the tested soils. While WWW also stimulated β-glucosidase activity in SS and SG, it decreased phosphatase activity in the RS, SH, and SG soils AI3 scores were highly negative at 0–10 cm than at 10–20 cm soil depth after SS4 than SS

Li et al. (2019)

Soil enzyme activities of four Western cape soils as affected by WWW used for irrigation

WWW diluted to a chemical oxygen demand of 3000 mL/L and municipal water irrigation of soil from four vineyard areas. This was a pot study

AI3 facilitates interpretation of ß-glucosidase, acid-phosphatase, and urease activities in soils irrigated with diluted WWW

The details are the same for Rickson’s project

Mulidzi and Wooldridge (2016)

Van Huyssteen et al. (2020)

WWW winery waste water

(Friedel et al. 2000). Following WWW treatment, changes in the composition of the soil’s microbial population may offer important new information about the viability of WWW application to soil enzyme activities. Some investigations have been done on the influence of WWW on the biological properties of the soil as indicated in Table 9.2. β-glucosidase is involved in carbon cycling and responds rapidly to environmental factors and soil management practices (Lagomarsino et al. 2009; Nannipieri et al. 2012) which have facilitated the measurement and use of their activities as soil quality indicator (Adetunji et al. 2017). The β-glucosidase activity was significantly greater in the 0–10 cm than in the 10–20 cm soil layers after irrigation with diluted WWW (Mulidzi and Wooldridge 2016). β-glucosidase activities were higher in the WWW than in the municipal water treatments (Mulidzi and Wooldridge 2016). Furthermore, β-glucosidase activity increased remarkably in various soils amended with sewage sludge and irrigated with WWW rather than municipal water (Kızılkaya and Bayraklı 2005; Mulidzi and Wooldridge 2016). Proper management of WWW may increase β-glucosidase activity and carbon cycling thereby improving soil health.

162

T. Sikhau et al.

Phosphatase are involved in phosphorus cycling (García-Ruiz et al. 2008) and they also respond rapidly to environmental factors such as temperature, moisture, and pH and soil alterations (García-Ruiz et al. 2008; Adetunji et al. 2020). Furthermore, the changes in phosphatase activities after organic and nitrogen fertiliser applications have been reported under different cropping systems (Maseko and Dakora 2013; Kobierski et al. 2020). Mulidzi et al. (2016) showed that soil depth did not affect phosphatase activity in any of the soils after irrigation with diluted WWW. There are few results on the impact of WWW on soil phosphatase. Therefore, more research is required regarding WWW application on soil phosphatase. Urease catalyses the hydrolysis of dihydroxy urea, hydroxyurea, and semicarbazide, with nickel as a co-factor (Dilly and Munch 1998). Urease performs a critical role in nitrogen cycling (García-Ruiz et al. 2008). Urease activity increased in four different vineyard soils treated with WWW rather than municipal water (Mulidzi and Wooldridge 2016). Urease activity was greater in season 3 than in season 4, even though the influence of the season on Stellenbosch granite and Rawsonville sand was not significant (Mulidzi and Wooldridge 2016). The average activities of urease were significantly greater in the 0–10 cm soil layer compared to the 10–20 cm depth interval (Mulidzi and Wooldridge 2016).

9.5 9.5.1

Effects of Winery Wastewater on Crop Yield Food Crops

Reusing WWW would be extremely advantageous for the wine industry because it might be a cost-effective way to control wastewater while also offering a valuable water resource for the irrigation of agricultural farmland, especially in regions that experience water scarcity (Mosse et al. 2013). The common practice to discharge effluent from wineries into crops, tree lots, pastures, and vineyards is a widely used means of wastewater management (Crites 2000). There is evidence that a number of elements in winery effluent, particularly salt and polyphenols, are phytotoxic to plants (Oram et al. 2002; Caporaso et al. 2018). According to Mosse et al. (2010), irrigation with WWW inhibits seed germination and vegetative growth of millet, barley, phalaris, and lucerne. Therefore, in order to prevent environmental deterioration, the release of WWW into the environment must be carefully examined and monitored. In a field study where Pennisetum glaucum (Pearl millet) and Avena sativa cv. Pallinup (Pallinup oats) were cultivated in a vineyard with the use of diluted WWW for irrigation (Fourie et al. 2015). The dry matter production (DMP) of oats improved with WWW irrigation. Also, when 91% of diluted WWW was applied in the pear millet field, the growth and DMP increased (Fourie et al. 2015). Pearl millet has the ability to produce a R45 revenue per bale, which would sum to R19 485 per ha under the existing conditions as a feed crop with an average production of R433 bales per hectare when irrigated with WWW (Fourie et al. 2015). Myburgh and

9

Sustainable Winery Wastewater Management for Improving Soil Quality,. . .

163

Howeel (2014) reported that Pearl millet irrigated with diluted WWW could be an eco-friendly feed crop, as the diluted WWW did not influence the above-ground nitrogen, phosphorus, calcium, and magnesium concentrations. The average production of Saia oats was 2.92 t/ha from 1993/94 to 2002/03 cultivation seasons on sandy soil after irrigation with WWW (Fourie et al. 2015). Oschse (2015) reported the highest yield of 5.75 tonnes/ha on oats in the Rawsonville region of Western Cape Province of South Africa, which is comparable to 7.07 tonnes/ha obtained in the Robertson region of the same province (Fourie et al. 2015). Irrigation with WWW did not negatively influence the growth of oats for two seasons (Ochse 2015).

9.5.2

Grapevine

The amount of nutrients obtained from grapes is an indication of the requirement for nutrients (Mullins et al. 1992; Mcclymont et al. 2012) The insufficient supply of water required for grapevine growth has initiated and encouraged the use of WWW for irrigation to meet up with the water demand of the grapevines (Sakadevan et al. 2000). However, irrigation with WWW could adversely affect the yield and quality of grapevine production if large accumulations develop in the soil and plants. According to WWW irrigated soil and leaf samples had a high sodium and potassium accumulation, with the leaf having a higher sodium and magnesium but lower potassium and calcium than the control water treatment. Additionally, the presence of biological and chemical contaminants may have a negative impact on farmers and consumers health as well as the agricultural environment (Petousi et al. 2019). Table 9.3 presents the effects of WWW application on growth and yield attributes of various cultivated crops.

9.6

Effects of Winery Wastewater on Environmental Health

Recycling wastewater within a vineyard or winery operation is an example of a sustainable strategy that indicates a dedication to reducing the environmental effect off-site (Ene et al. 2013) Winery cleaning procedures and the processing of grapes both produce wastewater (WW) (Mosse et al. 2011). Depending on the season, the size of the winery, and the type of wine produced, the WW volume and composition will change significantly. Carbon dioxide is produced during the alcoholic fermentation process required to manufacture wine, leaving a carbon footprint (GueddariAourir et al. 2022). WWW if not well treated will have an influence on soil pH, soil salinity, accumulation of heavy metals, and ruining of soil structures as indicated in Table 9.4.

164

T. Sikhau et al.

Table 9.3 Effect of winery wastewater application on growth and yield attributes of cultivated crops Study Winery wastewater inhibits seed germination and vegetative growth of common crop species

Treatments Different dilutions of semi-synthetic winery wastewater on the growth and germination of four common crop species in a glasshouse study; barley (Hordeum vulgare), millet (Pennisetum glaucum), lucerne (Medicago sativa), and phalaris (Phalaris aquatica)

Effects of treated wastewater irrigation on the establishment of young grapevines

Secondary treated wastewater (STW Tertiary wastewater treatment (TTW)

Closing the water cycle in the agro-industrial sector by reusing treated wastewater for irrigation

Secondary treatment with UV disinfection and membrane ultrafiltration

Effect of irrigation using diluted winery wastewater on Vitis vinifera L. cv. Cabernet sauvignon in a Sandy alluvial soil in the Breede River valley— vegetative growth, yield, and wine quality

Winery wastewater diluted with river water to 100, 250, 500, 1000, 1500, 2000, 2500, and 3000 mg/L. There was also a river water control treatment

Results 1 There was a significant delay in germination. However, the overall germination percentage of all species was not affected 2 Vegetative growth was significantly reduced in all species, with millet being the most severely affected 3 The germination index of barley correlated very highly (r2 = 0.99) 1 Tertiary treated wastewater had positive impact on plant growth and yield, while secondary treated wastewater had negative impact on fruit safety in comparison with tap water 2 Sodium levels in soils irrigated with treated wastewater increased at the end of the irrigation period while decreased during the wet season Faecal indicator and suspended solids of Escherichia coli were influenced by the adopted technology in irrigation No inhibitory effects were observed on the growth of broccoli and broccoli from the usage of treated wastewater for irrigation 1 Irrigation with diluted WWW did not influence shoot, leaf, and plant water status 2 Differences were not observed on growth and yield attributes as well as juice pH

Reference Mosse et al. (2010)

Petousi et al. (2019)

Vergine et al. (2017)

Howell et al. (2016)

9

Sustainable Winery Wastewater Management for Improving Soil Quality,. . .

165

Table 9.4 Pollutants in WWW, origin, and possible environmental effects Contaminant Organics

Examples Phenols, tannins, catechins, proteins, fructose, glucose, glycerol, ethanol, flavourings, citric acid, ethyl carbamate

Sources Loss of juice, wine, and lees, residues in cleaning waters and filters, solids reaching drains

Nutrients

Nitrogen, phosphorus, potassium

Salinity

Sodium chloride and potassium chloride

Loss of wine, juice washing, and ion exchange Wine and juice, cleaning agents

Sodicity

Sodium, potassium

Cleaning water

Heavy metals

Aluminium, calcium, chromium, cobalt, copper, nickel, lead, zinc, mercury Organic, sulfur, and sulfuric acid, sodium, magnesium, and potassium hydroxide Sodium chloride, sodium hypochlorite Microbial cells and grape residues, flocculating/ coagulating agents, bentonite, diatomaceous earth

Aluminium and copper piping, lead soldering tanks, and brass fittings Loss of wine, juice, and lees, washing agents, wine stabilisation

pH effects

Disinfectants Soil cloggers

9.7

Sterilisation of tanks, bottles, transfer lines Filtering, floor cleaning wastewater sludge, loss of lees and marc, floor cleaning

Effects Organism deaths, ecological function disruption, odours generated by anaerobic decomposition, solubilisation of sorbed nutrients and heavy metals, soil clogging High SAR, nitrate accumulation in water and algal bloom Toxicity to plants and animals and taste of water is affected Toxic to plants and degrades soil structure Toxic to plants and animals Effect on solubility of heavy metals and toxicity to macro- and microorganisms Formation of carcinogens Decrease in porosity odour generation and light transmission

Conclusion

Water scarcity, soil nutrient depletion, and soil degradation are limitations to optimal and sustainable crop production. The usage of WWW as an optional source for irrigation water is being increasingly adopted to reduce the pressure on the demand for freshwater. The rising interest in the use of WWW for irrigation is also due to their ability to supply nutrients like nitrogen, phosphorus, potassium, and sodium which contributes to soil fertility improvement, minimum conventional fertilisers usage, and enhancement of crop yield. However, the uncontrolled or prolonged usage of WWW may alter soil characteristics and upsurge the intensity of the salts, which can be detrimental to the soil ecology and crop yield. Yet, the magnitude to which WWW irrigation affects soil quality/health indicators particularly physical and biological properties is not well understood owing to a lack of experimental data. It is crucial to know the appropriate and environmentally safe WWW concentrations to apply under different soils, climate, and cropping systems. Studies evaluating the

166

T. Sikhau et al.

potential for cash crop and cover crops to control soil salinity under WWW irrigation is ongoing. Biochar application should be considered in this regard due to its high carbon input and unique properties and ability to absorb salts and reduce soil contamination.

References Adetunji AT, Lewu FB, Mulidzi R, Ncube B (2017) The biological activities of β-glucosidase, phosphatase and urease as soil quality indicators: a review. J Soil Sci Plant Nutr 17:794–807 Adetunji AT, Ncube B, Mulidzi R, Lewu FB (2020) Potential use of soil enzymes as soil quality indicators in agriculture. Frontiers in soil and environmental microbiology. CRC, Boca Raton, FL Al-Haddabi M, Ahmed M (2007) Land disposal of treated saline oil production water: impacts on soil properties. Desalination 212:54–61 Amor C, Rodriguez-Chueca J, Fernandes JL, Dominguez JR, Lucas MS, Peres JA (2019) Winery wastewater treatment by sulphate radical based-advanced oxidation processes (SR-AOP): thermally vs UV-assisted persulphate activation. Process Saf Environ Prot 122:94–101 Anwar F (2011) Effect of laundry greywater irrigation on soil properties. J Environ Res Dev 5:863– 870 Arienzo M, Christen E, Quayle W, Kumar A (2009) A review of the fate of potassium in the soil– plant system after land application of wastewaters. J Hazard Mater 164:415–422 Arienzo M, Christen E, Jayawardane N, Quayle WC (2012) The relative effects of sodium and potassium on soil hydraulic conductivity and implications for winery wastewater management. Geoderma 173:303–310 Bardgett RD, Bowman WD, Kaufmann R, Schmidt SK (2005) A temporal approach to linking aboveground and belowground ecology. Trends Ecol Evol 20:634–641 Bolzonella D, Papa M, Da Ros C, Anga Muthukumar L, Rosso D (2019) Winery wastewater treatment: a critical overview of advanced biological processes. Crit Rev Biotechnol 39:489– 507 Buelow MC, Steenwerth K, Silva LC, Parikh SJ (2015) Characterization of winery wastewater for reuse in California. Am J Enol Vitic 66:302–310 Caporaso N, Formisano D, Genovese A (2018) Use of phenolic compounds from olive mill wastewater as valuable ingredients for functional foods. Crit Rev Food Sci Nutr 58:2829–2841 Chen K-H, Wang H-C, Han J-L, Liu W-Z, Cheng H-Y, Liang B, Wang A-J (2020) The application of footprints for assessing the sustainability of wastewater treatment plants: a review. J Clean Prod 277:124053 Coetzee G, Malandra L, Wolfaardt G, Viljoen-Bloom M (2004) Dynamics of a microbial biofilm in a rotating biological contactor for the treatment of winery effluent. Water SA 30:407–412 Conradie A, Sigge G, Cloete T (2014) Influence of winemaking practices on the characteristics of winery wastewater and water usage of wineries. S Afr J Enol Vitic 35:10–19 Crites RW (2000) Land treatment systems for municipal and industrial wastes. McGraw-Hill Education, New York, NY Diacono M, Ferri D, Ciaccia C, Tittarelli F, Ceglie F, Verrastro V, Ventrella D, Vitti C, Montemurro F (2012) Bioassays and application of olive pomace compost on emmer: effects on yield and soil properties in organic farming. Acta Agric Scand B Soil Plant Sci 62:510–518 Dilly O, Munch J-C (1998) Ratios between estimates of microbial biomass content and microbial activity in soils. Biol Fertil Soils 27:374–379 Ene SA, Teodosiu C, Robu B, Volf I (2013) Water footprint assessment in the winemaking industry: a case study for a Romanian medium size production plant. J Clean Prod 43:122–135

9

Sustainable Winery Wastewater Management for Improving Soil Quality,. . .

167

Fourie J, Theron H, Ochse C (2015) Effect of irrigation with diluted winery wastewater on the performance of two grass cover crops in vineyards. South Afr J Enol Vitic 36:210–222 Friedel J, Langer T, Siebe C, Stahr K (2000) Effects of long-term wastewater irrigation on soil organic matter, soil microbial biomass and its activities in Central Mexico. Biol Fertil Soils 31: 414–421 García-Orenes F, Caravaca F, Morugán-Coronado A, Roldán A (2015) Prolonged irrigation with municipal wastewater promotes a persistent and active soil microbial community in a semiarid agroecosystem. Agric Water Manag 149:115–122 García-Ruiz R, Ochoa V, Hinojosa MB, Carreira JA (2008) Suitability of enzyme activities for the monitoring of soil quality improvement in organic agricultural systems. Soil Biol Biochem 40: 2137–2145 Gharaibeh MA, Ghezzehei TA, Albalasmeh AA, Ma'in ZA (2016) Alteration of physical and chemical characteristics of clayey soils by irrigation with treated wastewater. Geoderma 276: 33–40 Gong R (2022) David Kennard (director): John Cleese's wine for the confused written by David Kennard and John Cleese. Produced by Victoria Simpson. Distributed by InCA productions, 2004, 42 min. J Wine Econ 17:259–261. https://youtu. Be/sHnz6KoYw_A Gueddari-Aourir A, García-Alaminos A, García-Yuste S, Alonso-Moreno C, Canales-Vázquez J, Zafrilla J (2022) The carbon footprint balance of a real-case wine fermentation CO2 capture and utilization strategy. Renew Sust Energ Rev 157:112058 Halliwell DJ, Barlow KM, Nash DM (2001) A review of the effects of wastewater sodium on soil physical properties and their implications for irrigation systems. Soil Res 39:1259–1267 Hawke R, Summers S (2006) Effects of land application of farm dairy effluent on soil properties: a literature review. N Z J Agric Res 49:307–320 Hirzel DR, Steenwerth K, Parikh SJ, Oberholster A (2017) Impact of winery wastewater irrigation on soil, grape and wine composition. Agric Water Manag 180:178–189 Hoogendijk K (2019) Soil and grapevine responses to irrigation with treated municipal and winery wastewaters. Stellenbosch University, Stellenbosch Howell C, Myburgh P (2018) Management of winery wastewater by re-using it for crop irrigation-a review. S Afr J Enol Vitic 39:116–131 Howell C, Myburgh P, Lategan E, Schoeman C, Hoffman J (2016) Effect of irrigation using diluted winery wastewater on Vitis vinifera L. cv. Cabernet sauvignon in a sandy alluvial soil in the Breede River valley-vegetative growth, yield and wine quality. S Afr J Enol Vitic 37:211–225 Howell C, Myburgh P, Lategan E, Hoffman J (2018) Effect of irrigation using diluted winery wastewater on the chemical status of a sandy alluvial soil, with particular reference to potassium and sodium. S Afr J Enol Vitic 39:1–13 Ioannou L, Puma GL, Fatta-Kassinos D (2015) Treatment of winery wastewater by physicochemical, biological and advanced processes: a review. J Hazard Mater 286:343–368 Jackson D, Lombard P (1993) Environmental and management practices affecting grape composition and wine quality-a review. Am J Enol Vitic 44:409–430 Kierath T, Wang C (2013) The global wine industry slowly moving from balance to shortage. Morgan Stanley Research, London Kızılkaya R, Bayraklı B (2005) Effects of N-enriched sewage sludge on soil enzyme activities. Appl Soil Ecol 30:192–202 Kobierski M, Lemanowicz J, Wojewódzki P, Kondratowicz-Maciejewska K (2020) The effect of organic and conventional farming systems with different tillage on soil properties and enzymatic activity. Agronomy 10:1809 Kodur S (2011) Effects of juice pH and potassium on juice and wine quality, and regulation of potassium in grapevines through rootstocks (Vitis): a short review. VITIS J Grapevine Res 50: 1–6 Kriel W (2008) Turning wine into water. Farmer’s Weekly, 23 May 2008, pp 26–27 Kumar A, Arienzo M, Quayle W, Christen E, Grocke S, Fattore A, Doan H, Gonzago D, Zandonna R, Bartrop K (2009) Developing a systematic approach to winery wastewater

168

T. Sikhau et al.

management: final report to grape and wine research & development corporation. Grape and Wine Research & Development Corporation, Adelaide. Project number: CSL05/02 Kumar A, Rengasamy P, Smith L, Doan H, Gonzago D, Gregg A, Lath S, Oats D, Correl R (2014) Sustainable recycled winery water irrigation based on treatment fit for purpose approach. Report CSL1002. Grape and Wine Research Development Corporation. CSIRO Land and Water Science, Adelaide Lagomarsino A, Moscatelli MC, Di Tizio A, Mancinelli R, Grego S, Marinari S (2009) Soil biochemical indicators as a tool to assess the short-term impact of agricultural management on changes in organic C in a Mediterranean environment. Ecol Indic 9:518–527 Laker M (2004) Advances in soil erosion, soil conservation, land suitability evaluation and land use planning research in South Africa, 1978-2003. S Afr J Enol Vitic 21:345–368 Laurenson S, Houlbrooke DJ (2011) Winery wastewater irrigation: the effect of sodium and potassium on soil structure. Marlborough District Council, Blenheim Laurenson S, Houlbrooke DJ (2012) Review of guidelines for the management of winery wastewater and grape marc. Marlborough District Council, Blenheim Laurenson S, Bolan N, Smith E, Mccarthy M (2012) Use of recycled wastewater for irrigating grapevines. Aust J Grape Wine Res 18:1–10 Levy G, Van Der Watt H (1990) Effect of exchangeable potassium on the hydraulic conductivity and infiltration rate of some south African soils. Soil Sci 149:69–77 Levy GJ, Fine P, Goldstein D, Azenkot A, Zilberman A, Chazan A, Grinhut T (2014) Long term irrigation with treated wastewater (TWW) and soil sodification. Biosyst Eng 128:4–10 Li B, Cao Y, Guan X, Li Y, Hao Z, Hu W, Chen L (2019) Microbial assessments of soil with a 40-year history of reclaimed wastewater irrigation. Sci Total Environ 651:696–705 Lofrano G, Meric S (2016) A comprehensive approach to winery wastewater treatment: a review of the state-of the-art. Desalin Water Treat 57:3011–3028 Luz S, Rivas J, Afonso A, Carvalho F (2021) Immediate one-step lime precipitation process for the valorization of winery wastewater to agricultural purposes. Environ Sci Pollut Res 28:18382– 18391 Maseko ST, Dakora FD (2013) Plant enzymes, root exudates, cluster roots and mycorrhizal symbiosis are the drivers of P nutrition in native legumes growing in P deficient soil of the cape fynbos in South Africa. J Agric Sci Technol 3:331 Mathan K (1994) Studies on the influence of long-term municipal sewage-effluent irrigation on soil physical properties. Bioresour Technol 48:275–276 Mcclymont L, Goodwin I, Mazza M, Baker N, Lanyon D, Zerihun A, Chandra S, Downey M (2012) Effect of site-specific irrigation management on grapevine yield and fruit quality attributes. Irrig Sci 30:461–470 Mosse KP, Patti AF, Christen EW, Cavagnaro TR (2010) Winery wastewater inhibits seed germination and vegetative growth of common crop species. J Hazard Mater 180:63–70 Mosse K, Patti A, Christen EW, Cavagnaro T (2011) Winery wastewater quality and treatment options in Australia. Aust J Grape Wine Res 17:111–122 Mosse KPM, Patti AF, Smernik R, Christen E, Cavagnaro T (2012) Physicochemical and microbiological effects of long-and short-term winery wastewater application to soils. J Hazard Mater 201:219–228 Mosse KP, Lee J, Leachman BT, Parikh SJ, Cavagnaro TR, Patti AF, Steenwerth KL (2013) Irrigation of an established vineyard with winery cleaning agent solution (simulated winery wastewater): vine growth, berry quality, and soil chemistry. Agric Water Manag 123:93–102 Mpelasoka BS, Schachtman DP, Treeby MT, Thomas MR (2003) A review of potassium nutrition in grapevines with special emphasis on berry accumulation. Aust J Grape Wine Res 9:154–168 Mulidzi AR, Wooldridge J (2016) Effect of irrigation with diluted winery wastewater on enzyme activity in four western cape soils. Sustain Environ 1:141 Mulidzi A, Clarke C, Myburgh P (2015) Effect of irrigation with diluted winery wastewater on cations and pH in four differently textured soils. South Afr J Enol Vitic 36:402–412

9

Sustainable Winery Wastewater Management for Improving Soil Quality,. . .

169

Mulidzi A, Clarke C, Myburgh P (2016) Effect of irrigation with diluted winery wastewater on phosphorus in four differently textured soils. S Afr J Enol Vitic 37:79–84 Mulidzi A, Clarke C, Myburgh P (2018) Annual dynamics of winery wastewater volumes and quality and the impact of disposal on poorly drained duplex soils. South Afr J Enol Vitic 39: 305–314 Mulidzi A, Clarke C, Myburgh P (2019) Response of soil chemical properties to irrigation with winery wastewater on a well-drained sandy soil. South Afr J Enol Vitic 40:1–1 Mullins MG, Bouquet A, Williams LE (1992) Biology of the grapevine. Cambridge University Press, Cambridge Myburgh P, Howell C (2014) Use of boundary lines to determine effects of some salinity-associated soil variables on grapevines in the Breede river valley. South Afr J Enol Vitic 35:234–241 Nannipieri P, Giagnoni L, Renella G, Puglisi E, Ceccanti B, Masciandaro G, Fornasier F, Moscatelli MC, Marinari S (2012) Soil enzymology: classical and molecular approaches. Biol Fertil Soils 48:743–762 Ochse CH (2015) Effect of chemical oxygen demand on the ability of some cover crops to prevent mineral accumulation in a sandy vineyard soil irrigated with augmented winery wastewater. Cape Peninisula University of Technology, Cape Town Oram RN, Edlington JP, Gardner PA (2002) Selection for resistance to salinity and waterlogging in Phalaris aquatica L. Aust J Agric Res 53:391–399 Ortega-Larrocea M, Siebe C, Becard G, Mendez I, Webster R (2001) Impact of a century of wastewater irrigation on the abundance of arbuscular mycorrhizal spores in the soil of the Mezquital Valley of Mexico. Appl Soil Ecol 16:149–157 Petousi I, Daskalakis G, Fountoulakis M, Lydakis D, Fletcher L, Stentiford E, Manios T (2019) Effects of treated wastewater irrigation on the establishment of young grapevines. Sci Total Environ 658:485–492 Prazeres AR, Albuquerque A, Luz S, Jerónimo E, Carvalho F (2017) Hydroponic system: a promising biotechnology for food production and wastewater treatment. Food biosynthesis. Elsevier, Amsterdam Qadir M, Wichelns D, Raschid-Sally L, Minhas PS, Drechsel P, Bahri A, Mccornick PG, Abaidoo RC, Attia F, El-Guindy S (2007) Agricultural use of marginal-quality water: opportunities and challenges. International Water Management Institute (IWMI), London Quale W, Jayawardane N & Arienzo M(2010) Impacts of winery wastewater irrigation on soil and groundwater at a winery land application site. Proceedings of the 19th World Congress of Soil Science, Soil solutions for a changing world, p 1–6 Rukshana F, Butterly C, Baldock J, Xu J, Tang C (2012) Model organic compounds differ in priming effects on alkalinity release in soils through carbon and nitrogen mineralisation. Soil Biol Biochem 51:35–43 Sakadevan K, Maheshwari B, Bavor H (2000) Availability of nitrogen and phosphorus under recycled water irrigation. Soil Res 38:653–664 Sato T, Qadir M, Yamamoto S, Endo T, Zahoor A (2013) Global, regional, and country level need for data on wastewater generation, treatment, and use. Agric Water Manag 130:1–13 Sehaswana MD (2022) A critical analysis of the challenges in implementing the south African waste information system (SAWIS). North-West University, Hoffman Shilpi S, Seshadri B, Sarkar B, Bolan N, Lamb D, Naidu R (2018) Comparative values of various wastewater streams as a soil nutrient source. Chemosphere 192:272–281 Smiles D, Smith C (2004) A survey of the cation content of piggery effluents and some consequences of their use to irrigate soils. Soil Res 42:231–246 Sparling G, Barton L, Duncan L, Mcgill A, Speir T, Schipper L, Arnold G, Van Schaik A (2006) Nutrient leaching and changes in soil characteristics of four contrasting soils irrigated with secondary-treated municipal wastewater for four years. Soil Res 44:107–116 Van Huyssteen I, Mulidzi A, Meyer A, Wooldridge J (2020) Alteration index three facilitates interpretation of ß-glucosidase, acid-phosphatase and urease activities in soils irrigated with diluted winery wastewater. S Afr J Enol Vitic 41:238–244

170

T. Sikhau et al.

Vergine P, Salerno C, Libutti A, Beneduce L, Gatta G, Berardi G, Pollice A (2017) Closing the water cycle in the agro-industrial sector by reusing treated wastewater for irrigation. J Clean Prod 164:587–596 Victoria EPA (2003) Guidelines for environmental management: use of reclaimed water. EPA, Victoria Viviani G, Iovino M (2004) Wastewater reuse effects on soil hydraulic conductivity. J Irrig Drain Eng 130:476–484 Vogeler I (2009) Effect of long-term wastewater application on physical soil properties. Water Air Soil Pollut 196:385–392

Chapter 10

Water Harvesting Technologies for Sustainable Crop Production in African Smallholder Farming Systems Andrew Tapiwa Kugedera and Njodzi Ranganai

, Nyasha Sakadzo, Letticia Kudzai Kokerai

,

Abstract Moisture stress is one of the key constraints that negatively affects sustainable crop production in many smallholder farming systems across Africa. Under rainfed agriculture, water conservation practices can be a solution to improve soil water content and reduce moisture stress. Water conservation technologies such as tied ridges, tied contours, infiltration pits, dead level contours, fanya juus, planting basins and their combinations can be adopted to capture rainwater and reduce moisture stress during dry spells. Improvements in crop yields have been reported with the use of water harvesting technologies across Africa. The effectiveness of these technologies is dependent on region, soil type and availability of labour to construct these structures. Benefits of water conservation technologies can be realised much more when they are integrated with organic nutrient sources which improve soil fertility to achieve climate smart agriculture and reduce food insecurity. This chapter presents a synthesis of water harvesting technologies which can be adopted by smallhoder farmers to cope with effects climate change and improve crop production in semi-arid areas across Africa. Keywords Organic nutrient sources · Water management · Crop production, marginalised areas

A. T. Kugedera (✉) Department of Agriculture Management, Zimbabwe Open University, Masvingo, Zimbabwe N. Sakadzo Department of Agricultural Economics and Development, Manicaland State University of Applied Sciences, Mutare, Zimbabwe L. K. Kokerai Department of Crop and Livestock, Ministry of Agriculture, Resettlement, Lands, Water and Fisheries, Masvingo, Zimbabwe N. Ranganai Department of Information Systems and Computer Science, Manicaland State University of Applied Sciences, Mutare, Zimbabwe © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 M. Fanadzo et al. (eds.), Towards Sustainable Food Production in Africa, Sustainable Agriculture and Food Security, https://doi.org/10.1007/978-981-99-2427-1_10

171

172

10.1

A. T. Kugedera et al.

Introduction

Agriculture is one of the major economic activities in semi-arid areas across globally. Agriculture in smallholder farming systems is mainly constrained by high populations and poor farming methods (Bado et al. 2022). Moisture and mineral stress have contributed towards yield decline in smallholder farming environments over the past few decades (Kugedera et al. 2022a). Moisture stress is caused by low and erratic rainfall received in most semi-arid areas where smallholder farming systems are mainly found across the world. Smallholder farming systems are mainly located in marginalised areas which are characterised by sandy soils with poor water retention ability, low nutrient content and low crop production (Kugedera et al. 2022b). Smallholder farmers realise very low crop yields such 300 kg/ha in Zimbabwe (Kugedera et al. 2022a), 312 kg/ha in Tanzania (Kilasara et al. 2015), 400 kg/ha in Mali, 140 kg/ha in Kenya (Kimaru-Muchai et al. 2021), 214 kg/ha in Sudan (Karrar et al. 2012) and 250kg/ha in Burkina Faso. Crop yields can be improved when increased if moisture and nutrient stress are reduced. However, smallholder farmers are resource poor and have little capacity to install irrigation systems and buy adequate mineral fertiliser; hence cheaper water conservation technologies can be a solution (Nyamadzawo et al. 2013). Water conservation techniques such as ripping, mulching and conservation tillage practices play an important role in reducing surface runoff and making water available to crops. These techniques capture rainwater, store it and make it available to crops during dry spells. Availability of this moisture during a dry spell reduce drought stress, improve crop growth and facilitates plant processes such as fertilisation and grain filling which may result in higher yields (Nyagumbo et al. 2020). Besides reducing drought stress effects, leaf area index and photosynthetic rate were reported to be improved which play a key role in achieving higher crop yields. Biotic and abiotic stresses can be reduced by availability of adequate soil moisture and nutrients in the plant root zone. Water harvesting techniques have the potential to increase moisture through capturing rainwater and this improves crop water use efficiency and yields. This alone cannot significantly improve crop yields in smallholder farming systems, thus there is need to integrate water harvesting techniques with locally available nutrient sources to maximize crop production. Organic nutrient sources play a key role in maintaining soil fertility because they improve soil physicochemical properties and microbial population which are important for nutrient mineralisation. Organic manure increase soil organic matter, reduce nutrient leaching, regulate soil pH and increase base saturation which are important for maintaining soil health (Mamuye et al. 2021). Improved soil health leads to increased crop growth, and synthesis of carbohydrates and proteins which are translocated to grains resulting in heavier seeds and higher yields (Kugedera et al. 2022c). Integrating organic fertiliser and water conservation techniques improve infiltration of water, soil fertility by increasing rate of decomposition, and increase nutrient uptake from the soil which contribute to better nutrient use efficiency and crop yields (Kugedera et al. 2022c; Desta

10

Water Harvesting Technologies for Sustainable Crop Production in. . .

173

et al. 2022; Kugedera et al. 2022b; Mwadalu et al. 2022). Additionally, residual effects of organic nutrient sources improve soil fertility parameters and crop yields for extended periods (Kugedera et al. 2022c). This chapter seeks to provide a synthesis of numerous water harvesting technologies that may be adopted by farmers to mitigate effects of climate change and improve crop production in smallholder farming systems. Further, it emphasises the importance of integrating water harvesting technologies and organic fertilisers in achieving sustainable crop production in smallholder farming systems.

10.2

Effects of Water Conservation Techniques on Crop Production

Moisture stress is one of the key constraints which affects sustainable crop production by causing a decline in crop yields and sometimes total crop failure. To reduce moisture stress it is important to adopt water conservation practices. Rainwater harvesting technologies are structures which farmers prepare to capture rainwater, store it and allow its utilisation by crops during dry spell periods (Mandumbu et al. 2021). These techniques can include tied ridges, tied contours, infiltration pits, Fanya juus, planting pits and contour ridges. In addition, mulching can also be adopted by farmers to reduce surface runoff as well as release nutrients through decomposition, thus improve soil fertility. Mulching also reduces direct heating of soil by sun, hence lowers evaporation rates. Selected examples of water management technologies on crop yields across Africa are shown in Table 10.1 below.

10.2.1

Tied Ridges

Tied ridges (Fig. 10.1) are an example of in-situ rainwater harvesting techniques constructed by farmers to reduce surface runoff, capture rainwater, improve infiltration rates and recharge groundwater (Motsi et al. 2004; Mandumbu et al. 2021). Tied ridges have the potential to reduce water stress, increase protein synthesis, fertilisation and improves grain filling which can maximize crop yields (Mesfin et al. 2009; Kilasara et al. 2015). Tied ridges were reported to improve water use efficiency and increase crop production (Mahinda et al. 2018; Mandumbu et al. 2021). Tied ridges are the easiest construct because farmers can use animal drawn mouldboard plough and use hand hoes to make cross ties (Motsi et al. 2004; Wuta et al. 2018). Use of animal drawn mouldboard plough reduced labour requirements and makes tied ridges one of the cheapest methods farmers can adopt. Tied ridges are flexible and can be used for production of various crops such as maize (Zea mays), sorghum (Sorghum bicolor), soya beans (Glycine max) and pearl millet (Pennisetum glaucum) to improve their productivity. Grain increases of maize and other crops attributed to tied ridges have been reported (Table 10.1).

174

A. T. Kugedera et al.

Table 10.1 Examples of crop yields obtained from water management options in sub-Saharan Africa Water management technology Tied ridges

Country Zimbabwe Tanzania Niger

Crop Maize Sorghum Pearl millet

Planting pits Tied contours

Zimbabwe Zimbabwe

Maize Sorghum Maize

Infiltration pits

Zimbabwe Tanzania

Sorghum Pearl millet

Mulching + basin tillage

Zimbabwe

Sorghum

Basin tillage

Zimbabwe

Sorghum

Ripper tillage

Zimbabwe

Sorghum

Zai pitting

Kenya Niger

Sorghum Pearl millet

10.2.2

Grain yield (kg/ha) 1400 875 553 699 1026 1430 1146 996 3000 4200 967 984 2750 2789 703 814 3100 3000 1700 1900 1200 1090 1960 1151

Reference Kugedera et al. (2020), Kilasara et al. (2015), Chilagane et al. (2020) and Coulibaly (2015)

Kugedera et al. (2020) Kugedera et al. (2022b, c), Kubiku et al. (2022b) and Nyamadzawo et al. (2015) Kugedera et al. (2022b) Kubiku et al. (2022b), Kilasara et al. (2015) and Chilagane et al. (2020)

Masaka (2013) Masaka (2013) Masaka (2013) Kimaru-Muchai et al. (2021) and Coulibaly (2015)

Tied Contours

Tied contours are an example of field edge rainwater harvesting (Fig. 10.2). Tied contours collect rainwater and stores it, reduce surface runoff losses and make water available to crops during dry spells (Kugedera et al. 2022c). Stored water will move laterally in the field, thus, reduce moisture stress, and improve water and nutrient use efficiency. This may lead to higher crop productivity as a result of increased leaf index area and rate of photosynthesis. Water availability allows to crops makes themgrow better and tolerate drought stress by maximum utilisation of water and absorbed nutrients (Kubiku et al. 2022b). Tied contours have the ability to improve crop yields and achieve food security in smallholder farming systems. Tied contours have been reported to improve sorghum yields by more than 150% (Kugedera et al. 2022b), and by more than 100% in maize, in Zimbabwe

10

Water Harvesting Technologies for Sustainable Crop Production in. . .

175

Fig. 10.1 Maize under tied ridging in Chiredzi, Zimbabwe during 2020/21 cropping season (Photo by Andrew Tapiwa Kugedera)

Fig. 10.2 Tied contour used in Marange, Zimbabwe (Source: Nyamadzawo et al. 2015)

(Nyamadzawo et al. 2015; Chiturike et al. 2023). Tied contours also improve rainwater use efficiencies, for example, up to 3.28 kg/ha/mm in Sandy loam soils with higher efficiencies from clay soils (Kugedera et al. 2022b). Additionally, tied contour also increase soil moisture content as by Kugedera et al. (2022b) who observed 7.13% and 9.34% soil moisture content increase in 0–20 cm and 20–40 cm depths respectively.

176

A. T. Kugedera et al.

Tied contour are cheap to construct and can be easily adopted by smallholder farmers (Nyamadzawo et al. 2013; Kubiku et al. 2022a). The depth of tied contour varies soil type. In sandy loam soils, farmers can use a depth up to 1 m to increase amount of water capacity and 0.5 m to reduce labour requirements in heavier soils. During off-season, farmers can add crop residues in tied contours to make compost for use in the following season. Tied contours are relatively cheap option for resource poor farmers as they are permanent structures.

10.2.3

Infiltration Pits

An infiltration pit is a permanent structure that is common in marginalised areas which receive low rainfall (57% and low organic matter digestibility (46–48%) which can negatively influence bush intake (Shiningavamwe 2022). There is therefore a need to add supplements such as protein concentrates, molasses, rock salt, cereal grain by-products and minerals to the milled bush to improve its nutritional value, feed intake and digestibility. There are a range of feed supplements used by livestock farmers in Namibia which can improve the nutritional quality of milled encroacher bush. Among these

14

Utilising Encroacher Bush in Animal Feeding

253

Table 14.7 Chemical composition (%DM) of cereal by-products produced in Namibiaa Cereal by-product Malt dust fine Pearl millet bran Malt dust coarse White maize chop Wheat bran Brewer’s spent grains Sorghum brew residue Sorghum spent grains

DM 95.5 93.2 96.3 92.7 92.4 97.6 97.7 86.8

Ash 4.8 3.2 5.4 2.3 4.3 3.6 2.3 1.4

OM 90.7 90.0 90.9 90.4 88.1 93.9 95.5 85.4

CP 15.6 12.6 18.8 9.3 15.5 22.0 17.4 7.9

EE 1.4 9.3 1.7 7.5 4.1 8.0 5.7 3.3

NDF 39.9 32.0 34.5 23.6 38.6 73.1 32.7 22.2

ADF 12.2 7.2 10.2 7.8 14.5 30.5 15.1 9.9

Hem 27.7 24.8 24.3 15.8 24.1 42.6 17.6 12.3

Ca 0.2 0.1 0.1 0.1 0.1 0.2 0.1 0.1

P 0.4 0.6 0.6 0.6 0.9 0.5 0.3 0.2

a

DM dry matter, EE ether extract, OM organic matter, Ca calcium, P phosphorus, CP crude protein, ADF acid detergent fibre, NDF neutral detergent fibre, Hem hemicellulose. Source: Kamati (2019)

Table 14.8 Chemical composition (%DM) of oil seed by-products produced in Namibiaa Oil seeds by-products Olive oil cake Marula oil press Jojoba oil cake !Nara oil cake Manketti oil cake Marula oil cake

DM 95.0 95.9 95.2 92.9 92.9 98.1

Ash 5.3 4.7 2.8 4.9 5.0 4.5

OM 89.7 91.2 92.4 88.1 87.9 93.5

CP 7.6 37.3 23.9 26.2 24.0 32.3

EE 13.4 48.8 13.0 8.2 8.1 53.6

NDF 46.5 37.3 35.2 49.5 58.3 11.4

ADF 37.1 8.2 24.3 44.8 52.3 9.6

Hem 9.4 29.1 10.9 4.6 6.0 1.8

Ca 0.2 0.2 0.1 0.1 0.3 0.1

P 0.2 1.1 0.4 0.7 0.5 0.8

a

DM dry matter, EE ether extract, OM organic matter, Ca calcium, P phosphorus, CP crude protein, ADF acid detergent fibre, NDF neutral detergent fibre, Hem hemicellulose. Source: Kamati (2019)

supplements are agro-industrial by-products (AIBPs) that originate from a variety of primary agricultural production steps such as processing of crops such as oilseeds, cereals and fruits. The AIBPs are usually rich in nutrients such as protein (oil seeds and fish meals) or carbohydrates (cereal grain residues, molasses and fruit pulps). The availability of AIBPs in Namibia is dependent on the type of agricultural processing plants in the country and on the imported feed ingredients. In addition, some supplements in Namibia are obtained from natural resources such as the tree pods of Vachellia erioloba (Camelthorn), V. nilotica (scented-pod Acacia) and Dichrostachys cinerea (sickle bush). The processing of cereal grains at industrial or small-scale level represents an important part of the food production chain that generates important cereal AIBPs. The main AIBPs produced in Namibia include brans from maize, millet, rice and wheat gluten meal or hominy chop and brewery by-products such as distiller’s grains. The AIBPs produced in Namibia can be classified into cereal by-products (Table 14.7) and oil seeds by-products (Table 14.8) that can be used as either energy or protein supplements, respectively, to milled encroacher bush to enhance the nutritional quality of the bush-based feeds. Some indigenous oil seed crops produce by-products that include Marula (Sclerocarya birrea) oil cake, Marula oil press, olive oil (Olea europaea) cake, !Nara (Acanthosicyos horridus) oil cake, Manketti (Schinziophyton rautanenii) oil cake and Jojoba (Simmondsia chinensis) oil cake.

254

J. Mupangwa et al.

Table 14.9 Ingredients composition of the five bush-based diets given to Damara weaner lambs Feed ingredient (kg as is) Coarsely ground grass hay Coarsely ground Lucerne hay Milled bush Yellow maize meal Molasses syrup HPC 30 Futterfos™ P14 Coarse salt Total

Treatment dietsa Grass S. mellifera 30 0 10 0 0 40 22 20 5 5 30 32 1.5 1.5 1.5 1.5 100 100

D. cinerea 0 0 40 20 5 32 1.5 1.5 100

T. sericea 0 0 40 19 5 33 1.5 1.5 100

R. trichotomum 0 0 40 20 5 32 1.5 1.5 100

a

Grass-control diet; Senegalia mellifera-based diet; Dichrostachys cinerea-based diet; Terminalia sericea-based diet and Rhigozum trichotomum-based diet, HPC 30-high protein concentrate; Futtterfos™ - P14- Phosphate lick with 14% Phosphorus. Source: Shiningavamwe (2022)

The bush-based feeds have been fed to livestock with supplements being added to the milled bush. Cattle, goats and sheep have been used to assess different bushbased feeds. Honsbein et al. (2017) used milled S. mellifera bush-based feed supplemented with different ingredients that produced the following rations: 85% milled bush, 2% urea and 12% molasses; 50% milled bush, 40% Camelthorn pods, 10% molasses; 50% milled bush, 10% sun-dried chopped Opuntia cladodes, 40% Camelthorn pods; 65% milled bush, 15% bush improver lick, 10% rangeland grower meal, 10% molasses. The rations were fed to growing lambs under an intensive feeding system for 90 days and the lambs achieved average daily gain of 73 g on a diet containing 50% milled bush. The observed growth of the lambs concludes that a daily allowance of 1 kg of bush-based feed was sufficient for growing sheep to achieve some growth under intensive feeding system. The positive growth achieved with natural supplements provides evidence that farmers in Namibia can use Camelthorn pods and Opuntia as supplements in making bush-based feeds. Feeding maintenance diets showed that cows can be fed 3 kg of bush-based feed per day using rations which do not exceed 50% milled bush inclusion. In a study by Shiningavamwe (2022), the bush-based diets used in weaned Damara sheep were formulated to constitute 40% of different roughage sources and similar 60% concentrate made from a combination of different feed ingredients (Table 14.9). The encroacher bushes that were used in the feeding study were Senegalia mellifera, Dichrostachys cinerea, Terminalia sericea and Rhigozum trichotomum. The nutrient contents of the formulated bush-based rations are given in Table 14.10. The intake potential of a feed is the key factor determining the quality of feed. The regulation of feed intake in animals is controlled by the energy concentration of the feed and the animal’s energy demand. The animal will consume a feed until the energy demand for maintenance and production is satisfied. In situations when dietary energy is low, such as in rangeland grazing during the dry season, the animal will mobilise its body reserves, mostly fat first before protein, in order to meet

14

Utilising Encroacher Bush in Animal Feeding

255

Table 14.10 Chemical composition (g/kg DM) of bush-based diets fed to Damara sheep

Dry matter (DM) Ash Organic matter (OM) Crude protein (CP) Ether extract (EE) Neutral detergent fibre (NDFom) Acid detergent fibre (ADFom) Acid detergent lignin (ADLom) Metabolisable energy (estimated MJ/kg)a

Treatment diets Grass S. mellifera 929.3 924.1 114.9 108 814.4 816.1 141.6 131.9 18.1 17.2 405.1 414.0

D. cinerea 925.6 99.8 825.8 132.6 16.6 425.3

T. sericea 926.3 106.7 819.6 122.7 18.8 415.1

R. trichotomum 932.3 95.4 836.9 123.9 17.8 434.5

224.7

237.5

274.5

288.2

288.0

44.3

73.3

93.3

93.3

84.1

9.3

9.9

9.6

9.1

9.8

Source: Shiningavamwe (2022) ME = 0.16  (IVOMD) IVOMD in vitro organic matter digestibility

a

Table 14.11 Daily intake of nutrient constituents of bush-based diets by Damara sheep Nutrient constituents Intake (g DM/day) DM OM CP Ether extract (EE) NDFom ADFom

Treatment diets Grass S. mellifera

D. cinerea

T. sericea

R. trichotomum

1796.7 1336.4 253.3 32.2 710.0 394.2

1699.2 1342.6 229.6 28.8 652 398.0

1765.6 1336.6 220.8 33.6 718.2 493.0

1769.8 1397.7 223.4 32.2 768.8 505.2

1689.7 1311.2 233.0 30.5 688.7 377.7

Source: Shiningavamwe (2022)

maintenance energy requirements (Mertens and Grant 2020). In Namibia, such a situation arises during the dry season when ruminant animals are grazing low-quality grasses (