Science Beneath Organic Production

ABOUT THE EDITORS DAVID ATKINSON was formerly Vice Principal at the Scottish Agricultural College and Chair of Falkland Rural Enterprises, an organic farming company. He continues to study the ethical implications of emerging biotechnologies. CHRISTINE A. WATSON leads soil science research at SRUC. She has extensive experience of research in organic farming and is involved in managing and teaching SRUC's postgraduate course in Organic Farming.

• List of Contributors xiPreface xiii1 Science and Organic Agriculture: An Introduction 1 David Atkinson and Christine A. Watson1.1 What is the Role of this Volume? 11.2 What is Organic Agriculture? 21.3 So What is Distinctive About its Science Base? 51.4 The Ecological Roots of Organic Production 61.5 Key Elements in the Science Context of Organic Agriculture 81.6 Some Areas of Different Science 101.7 Production Systems Compared 131.8 A Science Base for All Production 151.9 The Changing Context of Farming 18References 212 Science, Research and Organic Farming 25Lawrence Woodward2.1 Introduction 252.2 The Roots of the Approach 252.2.1 Is it a philosophical or political movement and cannot therefore be scientific? 262.2.2 Does it lack coherence except as a marketing exercise? 272.2.3 Is it inherently unscientific because it is based on concepts that are not explicable in rational scientific terms? 282.3 Agricultural Science: Some Reflections 302.4 Conclusion 32References 323 Framing and Farming: Putting Organics in a Societal Context 33Pete Ritchie3.1 Introduction 333.2 The Origin of Organics 343.3 The Argument from Economics: Is More Better? 353.4 The Argument from the Environment: Externalities Matter 373.5 The Argument from Ethics: There’s Something Wrong with the System 373.5.1 What is the Place of Humans in Nature? 383.5.2 What is Farming For, and What Makes for Good Farming? 403.5.3 How can the way we produce food promote social justice? 413.6 Aligning Organics with Social Justice 423.7 Conclusion 43References 43Further Reading 434 Soil Health and Its Management for Organic Farming 45Elizabeth A. Stockdale, Tony C. Edwards and Christine A. Watson4.1 Introduction 454.2 Soil Components 474.2.1 Soil Parent Material and Profile Formation 474.2.2 Soil Organic Matter 484.2.3 Soil Organisms 484.3 Key Soil Processes in Agricultural Systems 514.3.1 Decomposition 514.4 Soil Structure Formation and Stabilisation 534.5 Below‐Ground Ecological Interactions 544.6 Nutrient Cycling and Management 564.6.1 Potassium (K) and Other Cations (Mg, Ca) 564.6.2 Nitrogen (N) 574.6.3 Phosphorus (P) 594.7 Impact of Agricultural Management Practices on Soil Function and Health 614.8 Cropping Systems 634.9 Intensive Grassland 654.10 Conclusion 66References 685 Cropping Systems and Crop Choice 79Robin L. Walker5.1 Farming Systems 795.2 Land Capability and Cropping System Choice 815.2.1 Rainfall 815.2.2 Temperature 815.2.3 Altitude and Topography 825.2.4 Soil 835.2.5 Markets 835.2.6 Traditions 835.2.7 Government Policy 845.3 How Land Capability is Used in Practice 845.4 Conclusion 85References 856 Crop Rotations: The Core of Organic Production 87David Atkinson and Robin L. Walker6.1 Introduction 876.2 The History of Crop Rotations 886.3 Rotations in Organic Production 916.4 The Ecological Science Base of Organic Production 946.5 Impact of Rotations on Soil Properties 956.5.1 Impact of Rotations on Soil Condition 956.5.2 Impact of Rotations on Nutrient Availability 986.5.3 Nitrogen Supply in Rotations 996.5.4 Phosphorus Supply in Rotations 1006.6 Impact of Rotations on Crop Protection 1036.7 Stockless Rotations 1056.8 Conclusion 105References 1077 What Can Organic Farming Contribute to Biodiversity Restoration? 111Ruth E. Feber, Paul J. Johnson and David W. Macdonald7.1 Why Conserve Farmland Biodiversity? 1117.2 What Can Organic Farming Contribute to Biodiversity Conservation? 1167.3 Effects of Organic Farming Vary with Taxa 1187.4 How Rapid is the Effect of Conversion to Organic on Biodiversity? 1207.5 Landscape Context and Species Traits 1217.6 Wider Considerations 123Acknowledgements 126References 1268 Optimising Crop Production in Organic Systems 133David Atkinson and Robin L. Walker8.1 Introduction 1338.2 Basic Issues 1348.3 Light Interception: The Basis of All Production 1368.3.1 Energy Capture 1368.3.2 Canopy Duration 1378.3.3 Stomatal Functioning 1388.3.4 Crop Species 1388.3.5 Crop Growth and Resource Partitioning 1408.3.6 Soil‐Related Factors 1418.3.7 Consequences 1428.4 What Current Issues Affect Choice of Crop Production System? 1428.5 What Options Exist for Regulating Yields? 1448.6 How Different are Conventional and Organic Yields? 1458.7 The Environmental Impact of Organic Systems 1478.8 Conclusion 148References 1489 Crop Production: Meeting the Nutrient Needs 151David Atkinson and Robin L. Walker9.1 Introduction 1519.2 Getting Nutrients into Organic Crops 1529.3 What is the Impact of Differences in Soil Nutrient Supply? 1549.4 Organic Manures: Recycling of Nutrient Sources 1559.5 Crop Rotations 1579.6 Cover Crops 1589.7 Legumes 1589.8 Soil Microbial Populations and Inoculation 1599.9 The Impact of Different Soil Nutrients 1609.9.1 Nitrogen: How Much N Does a Crop Need? 1609.9.2 Phosphorus 1629.9.3 Potassium 1639.9.4 Sulphur 1649.10 Conclusion 164References 16510 Crop Attributes Facilitating the Use of Soil Resources 169David Atkinson10.1 Introduction 16910.2 Nutrient Capture and Utilisation 17110.2.1 Basic Issues 17110.2.2 Nutrient Availability 17210.3 The Functional Requirements of a Root System 17210.3.1 Basic Issues 17210.3.2 Relation of Root Activity to Soil Processes 17210.3.3 The Impact of Root System Form 17410.3.4 Variation Between Crop Species 17510.3.5 Variation Within Crop Species 17810.4 Case Studies 18010.4.1 Case Study 1: Betula pendula 18010.4.2 Case Study 2: Spring Barley 18210.5 Root Dynamics and Carbon Inputs to the Soil 18310.5.1 Root Dynamics 18310.5.2 Root Longevity 18410.6 Variation in Root Systems in Practice 18510.6.1 Variation in Root Systems with Functional Significance 18510.6.2 The Ability of the Crop Plant to Extract Nutrients from the Soil 18810.7 Case Study 3: Apple 18810.8 So How Much Root Does a Plant Need? 19110.9 Conclusion 192References 19311 Mycorrhizal Activity, Resource and Microbial Cycles 199David Atkinson11.1 Introduction 19911.2 Mycorrhizal Establishment 19911.3 Mycorrhizal Effects 20111.4 The AMF Association 20211.5 Effects on Plant Nutrition: Basic Mechanisms 20311.6 Impact on Crop Nutrition 20411.7 The Impact of AMF on Soil Structure 20411.8 Carbon Flows into the Soil 20411.9 The Impact of AMF on Adaptation to the Soil Physical Environment 20511.10 The Impact of AMF on Plant Pathogens 20611.11 Impact of AMF on Roots 20611.12 Arbuscular Mycorrhizal Fungi and the Management of Soils 20911.13 Conclusions: AMF and Root Functioning 209References 20912 Crop Protection and Food Quality: Challenges and Answers 213David Atkinson and Robin L. Walker12.1 Introduction 21312.2 Crop Protection Against Pests, Weeds and Diseases 21412.3 Weed Control 21512.4 Living with Crop Diseases 21912.4.1 The Impact of AMF on Plant Pathogens 22012.4.2 Plant Varietal‐Based Resistance 22212.5 Pest Control 22412.6 The Quality of Organic Crops and Crop‐Based Foods 22612.6.1 Varietal Selection 22712.6.2 The Production System 22812.6.3 Inputs Used as Part of the Cultural System 22812.6.4 Inherent Attributes 23012.6.5 Microbial Content and Chemical Contamination 23112.7 Conclusion 231References 23213 Plant Breeding and Genetics in Organic Agriculture 237Thomas F. Döring and Martin S. Wolfe13.1 Introduction 23713.2 Plant Diversity in Agro‐Ecosystems 23813.2.1 Genetic Diversity 23913.2.2 Species and Ecosystem Diversity 24113.2.3 Effects of Crop Diversity: Types of Mechanisms 24213.3 Crop Genetics in Complex and Dynamic Environments 24413.3.1 The Organic Principle of Ecology 24413.3.2 The Ecology of G × E Interactions 24413.3.3 Implications of G × E Interactions for Testing Varieties for Organic Agriculture 24513.3.4 Genetic Properties of Crops for Suitability in Organic Systems 24813.3.5 Crop Genetics for Ecological Cropping Systems Design 24913.3.6 Limitations of Crop Genetics and the Role of Plant Genetic Diversity 25013.4 Crop Genetics for Health 25013.4.1 The Organic Principle of Health 25013.4.2 What is Health? 25113.4.3 Connections Between Crop Genetics and Health 25113.4.4 The Role of Plant Genetic Diversity for Health 25613.5 Socioeconomics, Policies and Regulations 25713.5.1 The Organic Principle of Fairness 25713.5.2 Traditional Landraces and the Protection of Plant Genetic Resources 25813.5.3 Sharing the Costs and Benefits of Plant Breeding 25913.5.4 Hybrid Varieties in Organic Farming 25913.6 Indeterminism and Crop Genetics 26013.6.1 The Organic Principle of Care 26013.6.2 Implications of the Care Principle for Crop Breeding 26013.6.3 The Role of Plant Genetic Diversity for the Care Principle 26113.7 Conclusion 261References 26214 Exploring the Systems Concept in Contemporary Organic Farming Research 273Christine A. Watson and Bruce D. Pearce14.1 Introduction 27314.2 The Importance of the Systems Concept in Organic Farming 27414.3 How are Systems Reflected in Regulation? 27514.4 Applying the Systems Concept to Organic Production 27514.5 How is the Systems Concept Reflected in Organic Farming Research? 27714.5.1 Example 1. Comparison of Production Systems 28014.5.2 Example 2. Food Quality and Its Relation to Production Systems 28114.5.3 Example 3. Weed Control 28214.5.4 Example 4. Plant Breeding 28214.6 Cautionary Tales 28314.7 Are the Research Needs of Organic Farming Different from Conventional Farming? 283References 28415 Science Base of Organic Agriculture: Some Conclusions 289David Atkinson and Christine A. Watson15.1 Introduction 28915.2 Increasing the Contribution of Organic Agriculture to Global Food Production 29115.3 Challenges to Organic Production 29515.4 Conclusion 297References 297Index 299