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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Sprache: Englisch
A groundbreaking book that addresses the science that underpins organic agriculture and horticulture and its impact upon the management of organic systems
With contributions from noted experts in the field, Organic Agriculture explores the cultural context of food production and examines the historical aspects, economic implications, and key scientific elements that underpin organic crop production. The book shows how a science-based approach to organic farming is grounded in history and elements of the social sciences as well as the more traditional areas of physics, chemistry and biology.
Organic Agriculture offers a detailed explanation of the differences between organic systems and other approaches, answering questions about crop production and protection, crop rotations, soil health, biodiversity and the use of genetic resources. The authors identify current gaps in our understanding of the topic and discuss how organic farming research may be better accomplished in the future. This important book:
- Explores the science that underpins organic farming
- Contains illustrative case studies from around the world
- Examines organic agriculture’s philosophical roots and its socio-economic context
Written for scientists and students of agriculture and horticulture, this book covers the issues linked to the use of science by organic producers and identifies key elements in the production of food.
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Table of Contents
Cover
List of Contributors
Preface
1 Science and Organic Agriculture
1.1 What is the Role of this Volume?
1.2 What is Organic Agriculture?
1.3 So What is Distinctive About its Science Base?
1.4 The Ecological Roots of Organic Production
1.5 Key Elements in the Science Context of Organic Agriculture
1.6 Some Areas of Different Science
1.7 Production Systems Compared
1.8 A Science Base for All Production
1.9 The Changing Context of Farming
References
2 Science, Research and Organic Farming
2.1 Introduction
2.2 The Roots of the Approach
2.3 Agricultural Science: Some Reflections
2.4 Conclusion
References
3 Framing and Farming
3.1 Introduction
3.2 The Origin of Organics
3.3 The Argument from Economics: Is More Better?
3.4 The Argument from the Environment: Externalities Matter
3.5 The Argument from Ethics: There's Something Wrong with the System
3.6 Aligning Organics with Social Justice
3.7 Conclusion
References
Further Reading
4 Soil Health and Its Management for Organic Farming
4.1 Introduction
4.2 Soil Components
4.3 Key Soil Processes in Agricultural Systems
4.4 Soil Structure Formation and Stabilisation
4.5 Below‐Ground Ecological Interactions
4.6 Nutrient Cycling and Management
4.7 Impact of Agricultural Management Practices on Soil Function and Health
4.8 Cropping Systems
4.9 Intensive Grassland
4.10 Conclusion
References
5 Cropping Systems and Crop Choice
5.1 Farming Systems
5.2 Land Capability and Cropping System Choice
5.3 How Land Capability is Used in Practice
5.4 Conclusion
References
6 Crop Rotations
6.1 Introduction
6.2 The History of Crop Rotations
6.3 Rotations in Organic Production
6.4 The Ecological Science Base of Organic Production
6.5 Impact of Rotations on Soil Properties
6.6 Impact of Rotations on Crop Protection
6.7 Stockless Rotations
6.8 Conclusion
References
7 What Can Organic Farming Contribute to Biodiversity Restoration?
7.1 Why Conserve Farmland Biodiversity?
7.2 What Can Organic Farming Contribute to Biodiversity Conservation?
7.3 Effects of Organic Farming Vary with Taxa
7.4 How Rapid is the Effect of Conversion to Organic on Biodiversity?
7.5 Landscape Context and Species Traits
7.6 Wider Considerations
Acknowledgements
References
8 Optimising Crop Production in Organic Systems
8.1 Introduction
8.2 Basic Issues
8.3 Light Interception: The Basis of All Production
8.4 What Current Issues Affect Choice of Crop Production System?
8.5 What Options Exist for Regulating Yields?
8.6 How Different are Conventional and Organic Yields?
8.7 The Environmental Impact of Organic Systems
8.8 Conclusion
References
9 Crop Production
9.1 Introduction
9.2 Getting Nutrients into Organic Crops
9.3 What is the Impact of Differences in Soil Nutrient Supply?
9.4 Organic Manures: Recycling of Nutrient Sources
9.5 Crop Rotations
9.6 Cover Crops
9.7 Legumes
9.8 Soil Microbial Populations and Inoculation
9.9 The Impact of Different Soil Nutrients
9.10 Conclusion
References
10 Crop Attributes Facilitating the Use of Soil Resources
10.1 Introduction
10.2 Nutrient Capture and Utilisation
10.3 The Functional Requirements of a Root System
10.4 Case Studies
10.5 Root Dynamics and Carbon Inputs to the Soil
10.6 Variation in Root Systems in Practice
10.7 Case Study 3: Apple
10.8 So How Much Root Does a Plant Need?
10.9 Conclusion
References
11 Mycorrhizal Activity, Resource and Microbial Cycles
11.1 Introduction
11.2 Mycorrhizal Establishment
11.3 Mycorrhizal Effects
11.4 The Association
11.5 Effects on Plant Nutrition: Basic Mechanisms
11.6 Impact on Crop Nutrition
11.7 The Impact of on Soil Structure
11.8 Carbon Flows into the Soil
11.9 The Impact of on Adaptation to the Soil Physical Environment
11.10 The Impact of on Plant Pathogens
11.11 Impact of on Roots
11.12 Arbuscular Mycorrhizal Fungi and the Management of Soils
11.13 Conclusions: and Root Functioning
References
12 Crop Protection and Food Quality
12.1 Introduction
12.2 Crop Protection Against Pests, Weeds and Diseases
12.3 Weed Control
12.4 Living with Crop Diseases
12.5 Pest Control
12.6 The Quality of Organic Crops and Crop‐Based Foods
12.7 Conclusion
References
13 Plant Breeding and Genetics in Organic Agriculture
13.1 Introduction
13.2 Plant Diversity in Agro‐Ecosystems
13.3 Crop Genetics in Complex and Dynamic Environments
13.4 Crop Genetics for Health
13.5 Socioeconomics, Policies and Regulations
13.6 Indeterminism and Crop Genetics
13.7 Conclusion
Acknowledgements
References
14 Exploring the Systems Concept in Contemporary Organic Farming Research
14.1 Introduction
14.2 The Importance of the Systems Concept in Organic Farming
14.3 How are Systems Reflected in Regulation?
14.4 Applying the Systems Concept to Organic Production
14.5 How is the Systems Concept Reflected in Organic Farming Research?
14.6 Cautionary Tales
14.7 Are the Research Needs of Organic Farming Different from Conventional Farming?
References
15 Science Base of Organic Agriculture
15.1 Introduction
15.2 Increasing the Contribution of Organic Agriculture to Global Food Production
15.3 Challenges to Organic Production
15.4 Conclusion
References
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Changes in soil properties in soil managed as grassed or bare for f...
Table 1.2 The magnitude of the standing crop and the turnover of grassland in...
Table 1.3 Energy use in different farming systems
Chapter 4
Table 4.1 A typical range of agricultural practices and the degree to which t...
Chapter 5
Table 5.1 Typical characteristics of the main UK farming systems with an indi...
Table 5.2 Land capability classification for agriculture in Scotland
Chapter 6
Table 6.1 Key factors influencing the functioning of a rotation
Table 6.2 The role and impact of different crops within a traditional crop ro...
Table 6.3 The stocked rotations employed at Haughley in different periods
Table 6.4 The impact of crop rotations on soil properties
Table 6.5 The uptake of phosphate and calcium by different plant species and ...
Table 6.6 The sum of the uptake of measured anions and cations (meqiv/kg plan...
Table 6.7 The relationship between the design of an organic production system...
Chapter 8
Table 8.1 Key elements of an organic crop production system
Table 8.2 Factors in the plant environment affecting growth and productivity...
Table 8.3 Environmental and other factors which have different impacts on cro...
Table 8.4 The impact of agriculture on factors contributing to or affecting g...
Table 8.5 The impact of crop production system on the yield (Mg/ha) of a rang...
Table 8.6 The effect of growing system on the percentage of the crop which ha...
Chapter 9
Table 9.1 Available mechanisms for supplying the nutrient needs of crops in o...
Table 9.2 The quantities of major nutrients available from different sources ...
Table 9.3 The quantities of major nutrients (kg/ha) contained in the harveste...
Table 9.4 The response of a range of crops to different forms of nutrient sup...
Table 9.5 The mean air temperature and soil temperature °C at 10 and 20 cm de...
Table 9.6 The impact of system of production on the total N uptake of the cro...
Table 9.7 The effect of growing system on the quantity of nutrients brought i...
Table 9.8 Organic manures derived from waste products
Table 9.9 The impact of cover crops on yield and nitrogen supply
Table 9.10 The impact of phosphate type and crop on P uptake (mg/pot) and the...
Table 9.11 The effect of the composition and particle size of gypsum applicat...
Chapter 10
Table 10.1 Variation in the concentration of available nutrients in a Malling...
Table 10.2 Key root system parameters and their functional significance in th...
Table 10.3 The probable value of root system characteristics leading to optim...
Table 10.4 Variation between species in root system properties with significa...
Table 10.5 Consequences of changes in root properties for water and nutrient ...
Table 10.6 The principal root system characteristics reported as showing vari...
Table 10.7 The functional significance of some genetically determined root ch...
Table 10.8 The range of variability recorded for a series of root system para...
Table 10.9 The effect of different levels of N supply on the root development...
Table 10.10 Variation in the characteristics of 26 different spring barley va...
Table 10.11 Variation in the range of root system features of spring barley v...
Table 10.12 The quantities of carbon, nitrogen and phosphorus released to the...
Table 10.13 Estimates of the contribution of root production to soil organic ...
Table 10.14 The influence of the root system on soil condition
Table 10.15 The effect of root system characteristics on the contribution of ...
Table 10.16 The effect of rootstock and soil management on the exploitation o...
Table 10.17 The relationship between the size of the root system and its func...
Table 10.18 Seasonal variation in nutrient inflow rates mol/cm/s × 10
–13
...
Chapter 11
Table 11.1 The impact of AMF infection on the release of carbon, nitrogen and...
Table 11.2 The relationship between water use and soil water potential for
Table 11.3 The effect of AMF infection on root branching (% of control)
Table 11.4 The effect of on the functioning of roots in organic systems
Chapter 12
Table 12.1 Traditional pesticides available for use as a last resort in a ran...
Table 12.2 Major ecological processes which influence the composition of natu...
Table 12.3 Approaches to the management of unwanted plants (weeds) in organic...
Table 12.4 The means available for the control of plant diseases in organic s...
Table 12.5 The impact of AMF on root necrosis due to
Phytophthora fragariae
i...
Table 12.6 Potential approaches to the control of insect pests
Table 12.7 The influence of growing system on the content of conventionally a...
Table 12.8 The effect of soil management and rootstock on the composition of ...
Table 12.9 The frequency with which residues were detected in horticultural p...
Table 12.10 Pesticide residues found in food samples in
Table 12.11 The percentage of samples of conventional (26 571 samples), integ...
Table 12.12 The impact of crop protection issues on the production of a range...
Chapter 13
Table 13.1 Examples of pathosystems for which resistance breeding is consider...
Chapter 15
Table 15.1 Future research needs aimed at improving the production of organic...
Table 15.2 Current societal objectives with the potential for organic farming...
List of Illustrations
Chapter 1
Figure 1.1 The gradation of types of farming system grouped on the basis of t...
Figure 1.2 The basic process underpinning all crop production.
Figure 1.3 Crop production in a conventional system.
Figure 1.4 The basic model of crop production using an organic approach.
Figure 1.5 Schematic description of the components leading to the release and...
Chapter 4
Figure 4.1 The decomposition web in soil.
Chapter 7
Figure 7.1 Buff arches
Habrosyne pyritoides
, a moth species of open woodland ...
Figure 7.2 Effect of farming system on numbers of species (
grey bars
) and abu...
Figure 7.3 The association between the presence of stock on a farm and mean b...
Chapter 8
Figure 8.1 The relationship between photosynthetically active radiation and p...
Figure 8.2 A freeze fracture scanning electron micrograph of the interior of ...
Figure 8.3 The relationship between stomatal conductance and air temperature ...
Figure 8.4 A scanning electron micrograph of the lower surface of a strawberr...
Figure 8.5 The increase with time during a season of N content and dry matter...
Chapter 10
Figure 10.1 A new apple root in the process of turning brown and beginning th...
Figure 10.3 A similar picture of an apple root where the cells have begun to ...
Figure 10.4 The excavated root systems of apple trees grown at low or high pl...
Chapter 11
Figure 11.1 A stained onion root showing AMF hyphae and an arbuscle within a ...
Figure 11.2 The surface of an apple root grown in soil and showing the presen...
Figure 11.3 A stereoscan electron micrograph of cortical cells where a cell o...
Figure 11.4 A stereoscan electron micrograph of the root surface of an apple ...
Chapter 12
Figure 12.1 Scanning electron micrograph of the germination of a mildew spore...
Figure 12.2 Scanning electron micrograph of the beginning of the development ...
Figure 12.3 Scanning electron micrograph of a collembolan grazing the surface...
Chapter 13
Figure 13.1 Heuristic framework of relationship between organic crop breeding...
Figure 13.2 Phenotypic diversity with respect to awnedness in two plants from...
Figure 13.3 Crop breeding for health in organic systems, illustrating the con...
Figure 13.4 Relationship between a measure of between‐environment variability...
Guide
Cover
Table of Contents
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The Science Beneath Organic Production
Edited by
David Atkinson
SRUCAberdeen, ScotlandUK
Christine A. Watson
SRUCAberdeen, ScotlandUK
This edition first published 2020© 2020 John Wiley & Sons Ltd
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.
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List of Contributors
David AtkinsonSRUCAberdeen, Scotland, UK
Thomas F. DöringDepartment of Agroecology and Organic FarmingInstitute of Crop Science and Resource ConservationUniversity of BonnBonn, Germany
Tony C. EdwardsSRUCAberdeen, Scotland, UK
Ruth E. FeberWildlife Conservation Research UnitRecanati‐Kaplan CentreDepartment of ZoologyUniversity of OxfordOxford, UK
Paul J. JohnsonWildlife Conservation Research UnitRecanati‐Kaplan CentreDepartment of ZoologyUniversity of Oxford,Oxford, UK
David W. MacdonaldWildlife Conservation Research UnitRecanati‐Kaplan CentreDepartment of ZoologyUniversity of Oxford,Oxford, UK
Bruce D. PearceOrganic Research CentreNewbury, UK
Pete RitchieNourish Scotland and organic farmerEdinburghScotland, UK
Elizabeth A. StockdaleNIABCambridge, UK
Robin L. WalkerSRUCAberdeen, Scotland, UK
Christine A. WatsonSRUCAberdeen, Scotland, UKandSwedish University of Agricultural Sciences (SLU), Uppsala, Sweden
Martin S. WolfeOrganic Research CentreNewbury, UKandWakelyns AgroforestryEye, UK
Lawrence WoodwardElm Farm Research CentreNewbury, UK
Preface
There are many books dealing with organic farming so why another one? Agriculture is a major business in most countries of the world and a total global activity. Agricultural products are traded globally and so they need to be defined in relation to provenance, identity, composition and quality. This has resulted in many rules and regulations which influence what can be sold in what market and the prices of the various commodities. This all makes agriculture very political and means that the science base which informs how crops and farm animals are grown is shaped by issues beyond mere science. The ways in which crops are produced inevitably interact with all these political issues, leading to acrimony between those who produce in different ways.
While the production of any given crop can differ in a range of ways, much recent tension has arisen between those who farm in a way that allows their produce to carry an organic certified label and those who use a range of chemical inputs such as inorganic fertilisers and pesticides. The introduction of genetically modified crops increased the level of disagreement between producers in a debate which at times became an argument between what were being stereotyped as traditional farming and scientific farming. The former was characterised as being a relic of the past while the latter was seen as being more progressively logical and based on clear science. The advent of gene editing and the use of CRISPR/Cas9 and related technologies have reignited this debate.
Discussion around the place of these approaches commonly and rapidly moves to a consideration of the relative crop yields produced per unit area of land. The ability of the approaches to feed an expanding global population is then linked to such yields as if this were the sole criterion for something as economically and socially complex as world food production. In no other part of global endeavour is a simple interpretation of production the basis of how a major enterprise should be effected. Profitability and its social setting, part of social science, are always important issues. Food production involves much of the world’s population and therefore it has many cultural links. Behind all of this lies an inherent suggestion that, unlike modern forms of agriculture, organic production is centred on folk lore and is a continuation of outdated methods. Agriculture is a major global source of greenhouse gases and so viewing different approaches to agriculture is important as part of current discussions about the amelioration of the impact of global climate change.
So is organic production scientific? In the sense that the question is most commonly asked, the answer is an unequivocal ‘yes’. When the debate over food production methods in the UK reignited at the end of World War II, the organic movement was at pains to point out the distinguished scientific qualifications of its pioneers like Sir Albert Howard and Sir Robert McCarrison. These people had worked from a starting point in agricultural or the physical sciences to the conclusion that an ecological approach to food production was likely to be most sustainable. Organic production has thus always had a strong basis in science. However, the science which informs organic production is different from that underpinning current western food production. This difference means that it has benefited to only a small extent from much of the agricultural research done over the past half century. The emphasis of much of that research has been on the use of fertilisers to supply mineral nutrients and on chemicals and genetic modification to provide crop protection. Development of the explicitly organic farming science base has been limited.
Much of the science base is, however, shared by all forms of agriculture. For growth, all crops need to intercept light and absorb nutrients from the soil. Agricultural systems need to provide these basic resources and how effectively that is done inexorably affects yields. Data on how agricultural practice influences these aspects of production are of value to all producers, including those who produce to organic standards. There are, of course, significant differences in how these basic needs are met, which inevitably link back to why organic crops are being produced in a way which is distinct from other approaches to food production. The scientific information which is used in any form of production at any time depends on its underlying production aims and its perceived values. This results in the science important to organic production being selected by reference to a different sociological and economic model to that which informs other types of farming.
There is a distinctive element in the science base of organic production. Does this mean that information from other forms of agriculture cannot be used in evaluating the working of organic systems? No! Basic information is valid in a range of situations although the selection of what is most relevant may differ. In this volume, we detail science that is shared with other forms of production and that which is different and central to organic production.
The chapters in this volume have a number of authors. Farming is complex and few have a total overview of all elements. In respect of organic production, elements of social science are critical to the aims and objectives of producers. History is important to an understanding of how we reached this point and so we review the development of organic farming as a distinctive approach. History and social science determine the parts of the total science base which are pertinent. In editing this volume, our aim has been not only to detail key elements of the science which lies behind crop production but also to give an insight into why this approach to the use of science is important. Why producers elect to produce in accord with organic standards is a key question. Its answer lies as much in the cultural context as in mere economics. In a world of global climate change, global resource use, shifting populations and a digital revolution which systematically aims to reduce the need for human labour, such questions require a broad study of science.
Inevitably, this takes us beyond mere considerations of which approach can produce the largest yield per unit area. It also goes beyond how many could be fed were the approach to be replicated on a global scale. It asks questions about sustainability, preservation of our restricted reserve of soil, use and management of genetic resources and our use of people as both producers and consumers. It asks questions about the cultural context of food production on a global scale. Scientific facts may be absolute but their use and interpretation are culturally driven. The acquisition of new knowledge is a cultural phenomenon and commonly driven by economic forces. Where there is an absence of an industrial link, new research information is restricted. This has been an issue for organic production and so the authors of chapters in this volume, as well as summarising what is known about the various elements which make up organic crop production, have attempted to identify current gaps in understanding and future research needs.
While we have dealt with the production of crops and of forage, we have not discussed organic animal production other than in terms of the return of animal wastes to the soil system. Organic animal husbandry involves issues centred on animal health, care and husbandry which require a treatment as substantial as those covered here for crops and so we have chosen to leave that for others to discuss. Nevertheless, we believe that here we have covered many of the key issues linked to the use of science by organic producers and have identified a distinctive way of looking at the production of food and the science upon which it depends.
Looking ahead requires consideration not just of gaps in our information base but also of how that information needs to be obtained. All of agriculture is dominated by interactions which is why approaches which work well in models or in laboratory or controlled environment settings may either fail to work under field conditions or more commonly may fail to work consistently or reliably across a very diverse globe. Approaches devised to study the impact of inputs may not work for complex situations in which it is necessary to define the nature of such variation and, more importantly, what can be done to manage it. Here, we discuss how research related to organic production might best be carried out in future.
This volume has had a long gestation. During the period over which it was written, the ways in which people both obtain and use information have changed more profoundly than over any comparable period since the invention of printing. The digital revolution and the use of international databases such as Google have changed fundamentally how we work. Initially, we had aimed to produce an encyclopaedia. The increase in new publications (a single conference run by the International Society for Horticultural Science in 2010 gave rise to 89 new papers) made this approach impossible even when being selective. We had then hoped to pull together key themes in the available literature. Finally we concluded that to be of real and lasting value, what was needed in the current climate was a volume which would provide enough information to help its readers interact with the internet and to be able to use Google and similar information systems in a critical way, so enhancing knowledge and understanding.
Asking questions of Google is easy. Asking questions formulated in such a way that real information is produced is much harder. In this book, we have aimed to help readers ask better questions. However, there is also a need to understand what types of answers are likely to be helpful. We give examples of the type of answer which might be helpful in response to such key questions. While the internet is a wonderful source of information, it is important to remember that the digitisation of science only began seriously in the 1980s. For some subjects, such as molecular biology where most information has appeared over the past two decades, this is not a problem. Discussion of organic agriculture and related science is, however, of a much older vintage. Key issues were actively debated in the immediate postwar period, many long‐term trials were established and this was the era when government funding for science was at its maximum. Here, we aim to provide a view of these discussions as a basis for the results of more recent studies. We see this as critical to an understanding of the division in approach to food production which dated from that time. What we have aimed for is thus something which will answer many of the most important questions but which will allow the reader to better interact with both scientific information and today’s issues. This volume is the product of discussions over many years with colleagues with whom we have worked at East Malling Research Station (now EMR), The Macaulay Institute for Soil Research (now JHI) and the Scottish Agricultural College (nowSRUC). We thank them and many other colleagues interested in Organic Farming.
David AtkinsonChristine A. Watson
1Science and Organic Agriculture: An Introduction
David Atkinson and Christine A. Watson
SRUC, Aberdeen, Scotland, UK
1.1 What is the Role of this Volume?
Our objective is to demonstrate that a substantial body of science underpins organic food production. Much of this is shared with other systems of production but there are real and major differences in terms of the parts of the science base which are mission critical. The reliance of organic systems on natural soil processes means that it has much in common with the science base of natural ecosystems. Information derived from research on such systems has a greater significance for organic production than it has for some other systems of production.
Here we do not aim to be encyclopaedic. We have not aimed to cover all aspects of organic agriculture. It would not be possible to cite every published paper relevant to those subjects selected for discussion. The cited papers have been selected as being illustrative and representative. By adopting this approach, we have been able to make use of literature from a number of decades rather than just the latest papers. We hope that this has given a timeless perspective and may even help today’s readers gain access to work from before the digital era. We have tried to approach the subject through asking questions and by allowing the authors of chapters to bring their individual approaches to the discussion. In most ways, this is more a book about ‘why’ rather than ‘how’ – that is, why would you want to follow that approach? – rather being a practical organic farming textbook.
Our principal aim is to demonstrate that organic farming has a science base and that that science base is to be located in the social sciences as well as in the more traditional areas of physics, chemistry and biology. Hence, we begin by examining the societal context of organic production, which argues for this form of agriculture as both a source of employment and as the basis of societal relationships with food and food producers. We then deal with the basic science which underpins this form of production through chapters exploring the restrictions imposed by land capability, the functioning of rotations, the processes relating to the availability and storage of nutrients such as N and P in soils and the mechanisms which allow crops to access these nutrients. The culmination of this process is the production of food in the form of either plant material or animal products. Claims have been made for the value of organic production in relation to food quality and so we examine these claims in relation to what is known of the impact of methods of production on food quality. In organic production, the genetics of the crop is important in relation to both its production features and its ability to resist disease and so we examine this as part of organic production's science base. If the link with producer communities is one reason for the adoption of this approach to agriculture, then the other is its environmental impact. We assess the basis of the interaction of this form of land use with environmental impact.
Finally, on the basis of all this we look ahead to where there is need for more information and to where the approach which organic production represents can help to solve some of the world's current problems related to food production and environmental impact.
In compiling this volume, we have not felt constrained only to include information derived from studies carried out on organic experiments but have used information relevant to organic systems, from the full range of sources. We have focused on the issues related to crop and forage production. There is a significant science base related to animal production but covering this would have either made this volume very long or resulted in a coverage which was inadequate to the importance of this issue. We leave it for others to fill that niche. We begin by reviewing what we mean when we use the term ‘organic’.
1.2 What is Organic Agriculture?
The term organic agriculture came into being around 1940 following ongoing discussions in the 1920s and 1930s. It was a means of describing farms which were managed in such a way that the farm could be a self‐contained unit with few external inputs. When the term was originated, the use of mineral fertilisers and pesticides by other types of agriculture was relatively modest. The difference between organic and other systems was small. A defining moment, in respect of identity, came during World War II when there was need to gain exemption for the Haughly experiment, which was begun in 1939, from wartime regulations which required the use of fertilisers so as to maximise crop production (Balfour 1976). From this point in time, ‘organic’ began to have a distinctive ethos even though in practice differences were often small.
One of the earliest statements about the distinctive nature of the organic approach came with the publication of Lady Eve Balfour's book The Living Soil: Evidence of the importance to human health of soil vitality, with special reference to post war planning in October 1943. Reviewing this book, Lawrence Woodward (Chapter 2) commented that:
The Living Soil is not a book about farming. It is about citizenship and community – the community of all living things; it is about health – the health of individuals and the health of the communities they make up; and it is about life itself – the vitality that flows through all living things from the soil through plants, animals and man.
This approach, which is amplified in Chapter 2, indicates that any evaluation of organic farming, its practices and its science will have a wider context with the science being set against goals significantly beyond mere food production. This, it can be argued, is true of all farming and food production but perhaps the major difference is in the intentionality. Organic production by its very nature incorporates all of these elements and they all are key deliverables.
Tinker (2000) reviewed the ways in which organic production differed from other approaches and some of the many legislatively driven definitions. He concluded that it had characteristics which allowed it to be easily differentiated from other types of agriculture, which he termed ‘conventional’ but that it was hard to define it precisely. Official definitions tend to emphasise this difficulty. For example, the Food and Agriculture Organization/World Health Organization (FAO/WHO) defines organic agriculture as follows.
Organic agriculture is a holistic production management system, which promotes and enhances agri‐ecosystem health, including biodiversity, biological cycles and soil biological activity. It emphasises the use of management practices in preference to the use of off‐farm inputs, taking into account that regional conditions require locally adapted systems. This is accomplished by using, where possible, agronomic, biological and mechanical methods as opposed to using synthetic materials to fulfil any specific function within the system.
With time, differences seem to have become greater although organic production is still most commonly distinguished more by the things it does not permit, such as fertilisers, pesticides and genetically modified organisms (GMOs), than its positive virtues.
The overall aims of organic agriculture were set out by Howard (1945) in his foundation text.
The birthright of all living things is health.
This is true for soil, plant, animal and humanity. The health of all of these is a connected chain.
Any weakness in the health of an earlier link in the chain is carried on through the chain.
The pests and diseases of agriculture are evidence of failure in the second and third links.
Impaired human health is also a consequence of this failure.
General failure in the final three links can be attributed to a failure in the first link, the soil; the undernourishment of the soil is at the root of all
Going back is not difficult as long as we are mindful of nature’s requirements for (i) the return of wastes to the land, (ii) the mixture of animal and plant systems, (iii) maintaining an adequate system to feed the plant, i.e. we must not interrupt the mycorrhizal association.
These overlap with but have a very different emphasis from the features of organic systems identified by Tinker (2000).
To avoid the use of synthetic, highly toxic or soluble chemicals on crops.
To ensure that the soil and its biota are healthy.
To use sound husbandry methods so that crops and stock are healthy.
To ensure the welfare of farm animals.
To use biological natural cycles rather than distorting them.
Tinker (2000) did not produce a parallel list for what he termed conventional agriculture although the key issues he suggested are as follows.
Its main drive is towards productivity and efficiency as in most industries.
It covers a wide range of practices and can include the use of chemicals combined with nature conservation measures.
It requires the use of science and technology to the fullest extent and so permits the use of any chemical found to be beneficial and without serious disadvantages.
Safety is dependent on careful regulation by appropriate authorities.
The contrast between these definitions identifies that soil health and its microbial populations will always be critical to successful organic production and may outweigh the emphasis on production which is at the heart of current business models. Distinguishing between approaches to food production is helped by Tinker's (2000) analysis of the deficiencies of earlier systems
The main constraints on productivity were shortages of the essential nutrient elements in the soil, pests and diseases.
This helps us to focus on the areas where the science important to organic production may be different from that in other systems. It also indicates areas where there will not be differences in relevance or importance. This helps to set the context for this volume where we aim to confirm areas of science which are common to all forms of agriculture but to highlight areas where the different approaches to nutrient supply and crop protection lead to a different use of the science base and some of the consequences of this choice.
The stress placed on the role of science in ‘conventional agriculture’ and its apparent omission from some of the key issues associated with organic production is both an attitude of mind and recognition of the limited amount of research carried out in support of organic production. It recalls the comments of the Secretary of the British Board of Agriculture in an earlier era:
I cannot conceive of the circumstances in which the Board will be at all interested in scientific work
(quoted in Plumb 1998).
Too often this view has been expressed about organic production. In the same paper, Plumb considered the energy needs of conventional agriculture and commented that new products:
increase our dependence on fossil fuels for production and processing. We must begin to think more seriously of how we use the whole range of our natural resources.
This comment made by Plumb in 1973 has a very contemporary climate change significance, an issue discussed at the end of this chapter.
The need to characterise the distinctiveness of organic from other ways of production has in recent years been driven as much by commercial considerations and marketing as by ethical deliberations. Organic farming and the food it produced had to be defined so that they could be distinguished, at the point of sale, from food produced in other ways. Organic agriculture is the only form of agriculture defined in this way although current definitions are not helpful in understanding the science. The simplest definition would be that organic agriculture is the form of agriculture defined as such in national and international legislation. The development of organic agriculture in the UK has been chronicled by Conford (2001).
The intensification of agriculture during World War II led to an industrialised view of the future of agriculture, which was continued after the end of the war and enshrined in the 1947 Agriculture Act. This emphasised productivity per man and led to the replacement of mixed farming by specialist enterprises. Barker (2010) detailed the steps which led to the enactment of parallel legislation in the USA. US legislation was linked to legislation in the EU and elsewhere to provide a basis for international trade. Produce currently classed as organic was initially described in ways such as ‘ecologically grown’. Expansion of organic agriculture in the 1970s as an alternative to food produced with increasing use of agrochemicals led to a need to certify provenance and for bodies to carry out this certification. In the USA, this lead to the Organic Foods Production Act 1990 and a national Organic Programme which was to be responsible for standard setting and an Organic Materials Review Institute which was to define acceptable products. There were parallel developments in UK and EU.
Organic farming as described in legislation can be inflexible. This is a consequence of the need to be able to define it in the market place. As its core attributes are the ways in which it has been produced and a series of quality attributes, which can be hard to demonstrate at the point of sale, clear definition of such features is important and so have the elements of a brand. The difficulties of using less rigorous descriptors have been emphasised by decisions of the UK Advertising Standards Authority (Anon 2012).
Organic agriculture is thus at the same time a brand, a marketing concept, a means of identifying food produced in a particular way and within a code but probably for most of its practitioners an ethical approach to thinking about farming and our use of the natural environment. While organic production is commonly described as production without added chemical inputs, it would be better to define it in terms of what it does do rather than what it doesn't do and to define it as agriculture which obviates the need for added chemical inputs as a result of its success in managing soil resources and ecological processes.
Both Howard (1945) and Balfour (1976) emphasised the importance of the soil and of mycorrhizal fungi as the basis of sustainable agriculture and health in crops, farm animals and the human population. Soil and especially its microbial populations affect cropping. It matters that agriculture should work with the soil as the basis of productivity. It is here we need to look for the distinctiveness of the science which underpins organic agriculture.
1.3 So What is Distinctive About its Science Base?
The features critical to the success of organic agriculture are not unique. Most are important in all systems of food production although in other systems they may be less critical to success. Tinker (2000) identified the factors limiting yields in organic systems as the supply of nutrients, especially nitrogen, and resistance to pests and diseases. The approaches adopted in conventional agriculture do not determine whether any crop at all is produced, how much is produced and its quality to the same extent as in organic systems. Greenland (2000) widened the discussion of where there might be differences. He commented:
For arable production the great advantage of conventional systems using fertilisers and pesticides is that the methods are simple and economic to use, the crop is well fed and vigorous, and the effects of weed competition, insect attack and disease problems, minimised. Continued use of these methods in arable agriculture does reduce the soil organic matter content and this may cause deterioration in some soil properties. However, under UK conditions the changes usually have little if any effect on present or future productivity of the soil and the deleterious effects are mostly reversible.
Almost 20 years later, there is a much wider recognition of the importance of reduced organic matter in soils and its limiting effect on crop production. There is growing interest in returning to more mixed farming systems to benefit soil organic matter, albeit with potentially different models to the original model of crop and livestock integration on almost every farm (Moraine et al. 2017).
All of this led Greenland to the general conclusion that:
Soil fertility and crop production should be supported by the integrated use of organic manures and inorganic fertilisers.
While distinguishing between organic and other production, it suggests that some things critical to organic production will be particularly important. This centres on issues related to nutrition. Systems can underplay the importance of soil organic matter on soil structure and on the ability of the soil both to provide the crop with water and to function as a matrix which holds and supplies nutrients, including those from fertilisers. Global climate change, with its associated effects on rainfall patterns, including the intensity of storms, makes this an increasingly important consideration. Soil structure and its impact on water holding and release seem likely to be the basis of the acknowledged greater relative performance of organic systems in hot and tropical environments.
To succeed, all crops need to develop a canopy of leaves so as to absorb the sun's radiant energy, to be able to absorb from the soil sufficient quantities of water and nutrients such as N to permit leaves to be constructed and to survive sufficiently long so as to allow the development of that part of the plant which is to be used as a food. The importance of these aspects to organic production means that in this volume we have focused on how organic production meets these challenges and the consequences of the approach.
In conventional agriculture, externally produced chemical resources achieve such aims. Herbicides eliminate competition from other vegetation, so allowing the easier development of the crop canopy and reducing total water use early in the season. Fertilisers are placed so as to allow rapid and early uptake. Insecticides, fungicides and growth regulators help to sustain the canopy and facilitate assimilation into harvested product. This approach makes little use of natural systems and processes, which become critically important if external crop protection and sources of nutrients are not available, just as they are in uncropped vegetation. This helps us to ask questions such as what can be done to both crop and soil to facilitate the uptake of nutrients from natural sources and what can be done to sustain the functioning of the leaf canopy in the absence of chemical protection? These issues influence the growth, development and survival of uncropped vegetation. Thus knowledge from uncropped system ecology will be a major resource for organic production.
1.4 The Ecological Roots of Organic Production
In 1988, as part of its 75th anniversary celebration, the British Ecological Society sought to identify the key ecological concepts that were important to an understanding of the natural world (Cherrett 1989). The 10 concepts within natural ecosystem ecology which were selected were as follows.
The ecosystem
Succession
Energy flow
Conservation of resources
Competition
Niche
Materials cycling
The community
Life history strategies
Ecosystem fragility
A comparison of these with the key elements identified by Howard (1945) and by Balfour (1976) shows a considerable degree of similarity. Howard emphasised the importance of a holistic view of the agricultural system characterised by linking the production of crops and animals. This defines the organically farmed unit as a distinct ecosystem. Both Balfour and Howard emphasised the importance of rotation – crops following each other in a reasoned sequence and with the intention that particular crops should have their needs met as a result of their place in that succession and as a consequence of the impact of earlier crops. These issues are discussed further in Chapter 6. This parallels an ecological understanding of succession.
Both Howard and Balfour emphasise the importance of optimum conditions for the functioning of arbuscular mycorrhizal fungi (AMF) as a key requirement for a healthy organic system. In natural ecosystems, AMF are important to energy flows, conservation of resources, materials cycling and the community. The organic approach to living with organisms which in conventional agriculture would be classed as weeds, pests or diseases parallels the concepts of competition and niche. The ecological concept of life history strategies has much in common with the organic farmer’s need to identify the crop species and cultivars which best fit into the rotation at a particular point. The absence of ecosystem fragility, i.e. sustainability, is a key requirement. The organic ecosystem needs to be able to sustain itself without excess inputs and to resist the problems found in conventional systems when particular pathogenic fungi develop resistance to a particular fungicide or identify weaknesses in a genetically modified construct.
In 1968, the British Ecological Society held a symposium to discuss the ecological impact of mineral nutrition. In his introduction to the event, Clapham (1969) identified the three major ways in which nutrient supply could affect the performance and composition of vegetation. All of these elements fall within the workings of the above ecological principles.
The specification of the whole plant soil system in the context of uptake and utilisation within the range of naturally occurring conditions.
The identification, specification and measurement of differential behaviour both within and between species in the uptake and utilisation of ions.
The identification, specification and measurement of competitive effects both between and within species in respect of ion uptake.
A comparison of conventional agriculture with the above ecological constructs would find less similarity. It is harder to regard the monoculture of a single crop grown in the same spatial area for a number of years as an ecosystem. Similarly, it is hard to identify the concept of community where the use of pesticides is the means of establishing dominance over all other organisms and where any adverse impact on soil microbes would be regarded as collateral damage. In addition, the concept of energy flow and material cycling has a very different flavour when the source of nutrient input to the system is the use of significant proportions of global fossil fuel reserves.
Atkinson and Watson (2000) assessed whether the future research needs of organic production were similar to those of other systems of production and suggested that they were rather different, principally for the reasons identified above. In assessing the needs of natural ecosystem ecology, Cherrett (1989) noted that ecology lacked the equivalent of the Newtonian Laws of Physics or the chemist's Periodic Table, which resulted in each fact having to be discovered for itself and remembered in isolation. This is also true of organic farming. Balfour (1976) wrote, when detailing the thinking behind the Haughley Experiment:
Crop and livestock in an ecological situation may differ from behaviour in a fragmented system. Unless applied research in any biological field has its roots in fundamental research it can lead to practices with disastrous effects.
We are aware of much about soil but our knowledge is inadequate for precise management. The plasticity found in organic systems means that the level of mechanistic information, such as is available for agrochemicals, will never be known to the same extent. However, by identifying what is most relevant to our needs, as Cherrett (1989) did, we will improve our ability to seek what is needed from the science base.
1.5 Key Elements in the Science Context of Organic Agriculture
While organic production may share much with natural ecosystem ecology in relation to basic processes, ultimately, as in other farming systems, a key aim is to achieve the dominance of one plant species and to ensure that species gains a disproportionate share of available resources. Our focus is on the science which underpins organic systems. This requires discussion of why science has a different context in organic systems. This does not imply a natural superiority of organic systems over all other options. The complexity of global agriculture and its wide range of intended deliverables make any such judgements unhelpfully simplistic. However, food production must be seen in a wider context and this is at the heart of organic methodology.
Scientific experimentation is usually carried out in an objective way but subjective factors are important in selecting the experiments carried out, and how the results of those experiments are applied. Thus, while science is objective, the context of past research is subjective because all research is carried out in a specific societal context. Sociological and ethical considerations rather than fact tend to dominate decisions on application. In this volume we compare different systems of agriculture. Some of the comparisons identify where there are differences in values. These will have different impacts as a result of what is most important to society. These objectives influence the choices made in both the use of natural resources and the values placed on human capital (Atkinson 2009).
It is possible, however, to see all of the systems currently being employed in the agriculture of developed countries as gradations in two distinct sets of values, ranging from those which primarily emphasise efficiency and cost control to those which place their primary emphasis on integrating food production into the biological environment and setting agricultural production into a cultural context. This is summarised in Figure 1.1.
Figure 1.1 The gradation of types of farming system grouped on the basis of their dominant values.
Source: Modified from Atkinson and Watson (2000).
In the management of intensive (conventional) farming systems, the primary objective is commonly the maximisation of production within limits set by the genetic make‐up of the crop or animal species and prevailing legislation on environmental impact or animal welfare. The yield obtained and the financial return are of primary importance. It is a testimony to the 1947 UK Act that over half a century later, productivity rather than environmental impact or public engagement remains dominant. This makes comparisons with the output from systems such as organic farming difficult.
Balfour (1976) argued that it is important to assess the production of organic systems over the course of a rotation during which the production of cereals or other crops is likely to represent only a part of total output. Labour is a major cost in conventional production and so efficiency is commonly understood in labour productivity terms. Simple linear models govern management. These may include linking the presence of particular weeds to specific herbicide applications or the expected attainment of yields to particular levels of fertiliser application. Minimising human involvement is seen as a necessity. Indeed, the release of people from agricultural activities was identified as a positive virtue of the increased use of herbicides for weed control (Holm 1976). This approach aims to externalise as many costs as possible, such as the costs of removing leachate emanating from added fertilisers or pesticides from water and the consequences of reducing employment in food production.
Set against the objectives of past legislation, this model has been a success. It is associated with increases in crop and animal yields and a fall in the percentage of disposable income spent on food. However, it has also been associated with significant environmental impacts through the damage caused by inputs and the amounts of fossil fuel energy used to produce inputs such as fertiliser nitrogen and pesticides. In addition, it has affected the viability of rural communities, relationship networks and available employment in food production. The approach has been associated with an increase in farm size and an increase in the importance of the providers of key inputs. Its major justification is its ability to produce high yields and feed western consumers. Those who champion this approach see it as the solution to feeding an increasing world population.
However, this assumes that the only global priority is food supply. It ignores the social context of agriculture. As a consequence, issues beyond food supply such as the importance of the environment and communities and relationships within the world's population tend to be minimised. In addition, while this form of agriculture is now the dominant approach in the western world, i.e. European and North American agriculture, it produces only around 30% of the food consumed by the global population. Most global production goes unrecorded because
