AGRICULTURAL SUSTAINABILITY - SUSTAINABLE AGRICULTURE

ABSTRACT

Agriculture has changed dramatically, especially since the end of World War II. Food and fiber productivity soared due to new technologies, mechanization, increased chemical use, specialization and government policies that favored maximizing production. These changes allowed fewer farmers with reduced labor demands to produce the majority of the food and fiber in the U.S.

Although these changes have had many positive effects and reduced many risks in farming, there have also been significant costs.Prominent among these are topsoil depletion, groundwater contamination, the decline of family farms, continued neglect of the living and working conditions for farm laborers, increasing costs of production, and the disintegration of economic and social conditions in rural communities.

A growing movement has emerged during the past two decades to question the role of the agricultural establishment in promoting practices that contribute to these social problems. Today this movement for sustainable agriculture is garnering increasing support and acceptance within mainstream agriculture. Not only does sustainable agriculture address many environmental and social concerns, but it offers innovative and economically viable opportunities for growers, laborers, consumers, policymakers and many others in the entire food system.

This paper is an effort to identify the ideas, practices and policies that constitute our concept of sustainable agriculture. We do so for two reasons: 1) to clarify the research agenda and priorities of our program, and 2) to suggest to others practical steps that may be appropriate for them in moving toward sustainable agriculture.Because the concept of sustainable agriculture is still evolving, we intend the paper not as a definitive or final statement, but as an invitation to continue the dialogue.

INTRODUCTION

Sustainable agriculture is the act of farming using principles of ecology, the study of relationships between organisms and their environment. The phrase was reportedly coined by Australian agricultural scientist Gordon McClymont.^[1] It has been defined as "an integrated system of plant and animal production practices having a site-specific application that will last over the long term" For Example:

• Satisfy human food and fiber needs
• Enhance environmental quality and the natural resource base upon which the agricultural economy depends
• Make the most efficient use of non-renewable resources and on-farm resources and integrate, where appropriate, natural biological cycles and controls
• Sustain the economic viability of farm operations
• Enhance the quality of life for farmers and society as a whole

Sustainable agriculture can be understood as an ecosystem approach to agriculture.^[3] Practices that can cause long-term damage to soil include excessive tilling of the soil(leading to erosion) and irrigation without adequate drainage (leading to salinization). Long-term experiments have provided some of the best data on how various practices affect soil properties essential to sustainability. In the United States a federal agency, USDA-Natural Resources Conservation Service, specializes in providing technical and financial assistance for those interested in pursuing natural resource conservation and production agriculture as compatible goals.

The most important factors for an individual site are sun, air, soil, nutrients, and water. Of the five, water and soil quality and quantity are most amenable to human intervention through time and labor.

Although air and sunlight are available everywhere on Earth, crops also depend on soil nutrients and the availability of water. When farmers grow and harvest crops, they remove some of these nutrients from the soil. Without replenishment, land suffers from nutrient depletion and becomes either unusable or suffers from reduced yields. Sustainable agriculture depends on replenishing the soil while minimizing the use or need of non-renewable resources, such as natural gas (used in converting atmospheric nitrogen into synthetic fertilizer), or mineral ores (e.g., phosphate). Possible sources of nitrogen that would, in principle, be available indefinitely, include:

1.      recycling crop waste and livestock or treated human manure

2.      growing legume crops and forages such as peanuts or alfalfa that form symbioses with nitrogen-fixing bacteria called rhizobia

3.      industrial production of nitrogen by the Haber process uses hydrogen, which is currently derived from natural gas, (but this hydrogen could instead be made by electrolysis of water using electricity (perhaps from solar cells or windmills)) or

4.      genetically engineering (non-legume) crops to form nitrogen-fixing symbioses or fix nitrogen without microbial symbionts.

The last option was proposed in the 1970s, but is only recently becoming feasible.^[4][5] Sustainable options for replacing other nutrient inputs (phosphorus, potassium, etc.) are more limited.

More realistic, and often overlooked, options include long-term crop rotations, returning to natural cycles that annually flood cultivated lands (returning lost nutrients indefinitely) such as the Flooding of the Nile, the long-term use of biochar, and use of crop and livestock landraces that are adapted to less than ideal conditions such as pests, drought, or lack of nutrients.

Crops that require high levels of soil nutrients can be cultivated in a more sustainable manner if certain fertilizer management practices are adhered to.

Water

In some areas sufficient rainfall is available for crop growth, but many other areas require irrigation. For irrigation systems to be sustainable, they require proper management (to avoid salinization) and must not use more water from their source than is naturally replenishable. Otherwise, the water source effectively becomes a non-renewable resource. Improvements in water well drilling technology and submersible pumps, combined with the development of drip irrigation and low pressure pivots, have made it possible to regularly achieve high crop yields in areas where reliance on rainfall alone had previously made successful agriculture unpredictable. However, this progress has come at a price. In many areas, such as the Ogallala Aquifer, the water is being used faster than it can be replenished.

Several steps must be taken to develop drought-resistant farming systems even in "normal" years with average rainfall. These measures include both policy and management actions: 1) improving water conservation and storage measures, 2) providing incentives for selection of drought-tolerant crop species, 3) using reduced-volume irrigation systems, 4) managing crops to reduce water loss, or 5) not planting crops at all.

Indicators for sustainable water resource development are:

• Internal renewable water resources. This is the average annual flow of rivers and groundwater generated from endogenous precipitation, after ensuring that there is no double counting. It represents the maximum amount of water resource produced within the boundaries of a country. This value, which is expressed as an average on a yearly basis, is invariant in time (except in the case of proved climate change). The indicator can be expressed in three different units: in absolute terms (km3/yr), in mm/yr (it is a measure of the humidity of the country), and as a function of population (m3/person per yr).
• Global renewable water resources. This is the sum of internal renewable water resources and incoming flow originating outside the country. Unlike internal resources, this value can vary with time if upstream development reduces water availability at the border. Treaties ensuring a specific flow to be reserved from upstream to downstream countries may be taken into account in the computation of global water resources in both countries.
• Dependency ratio. This is the proportion of the global renewable water resources originating outside the country, expressed in percentage. It is an expression of the level to which the water resources of a country depend on neighbouring countries.
• Water withdrawal. In view of the limitations described above, only gross water withdrawal can be computed systematically on a country basis as a measure of water use. Absolute or per-person value of yearly water withdrawal gives a measure of the importance of water in the country's economy. When expressed in percentage of water resources, it shows the degree of pressure on water resources. A rough estimate shows that if water withdrawal exceeds a quarter of global renewable water resources of a country, water can be considered a limiting factor to development and, reciprocally, the pressure on water resources can have a direct impact on all sectors, from agriculture to environment and fisheries.^[7]

Soil

Soil erosion is fast becoming one of the worlds greatest problems. It is estimated that "more than a thousand million tonnes of southern Africa's soil are eroded every year. Experts predict that crop yields will be halved within thirty to fifty years if erosion continues at present rates."^[8] Soil erosion is not unique to Africa but is occurring worldwide. The phenomenon is being called Peak Soil as present large scale factory farming techniques are jeopardizing humanity's ability to grow food in the present and in the future.^[9] Without efforts to improve soil management practices, the availability of arable soil will become increasingly problematic.^[10]

Some soil management techniques

1.      No-till farming

2.      Keyline design

3.      Growing wind breaks to hold the soil

4.      Incorporating organic matter back into fields

5.      Stop using chemical fertilizers (which contain salt)

6.      Protecting soil from water run off(soil erosion)

Phosphate

Phosphate is a primary component in the chemical fertilizer which is applied in modern agricultural production. However, scientists estimate that rock phosphate reserves will be depleted in 50–100 years and that Peak phosphorus will occur in about 2030.^[11] The phenomenon of Peak phosphorus is expected to increase food prices as fertilizer costs increase as rock phosphate reserves become more difficult to extract. In the long term, phosphate will therefore have to be recovered and recycled from human and animal waste in order to maintain food production.

Land

As the global population increases and demand for food increases, there is pressure on land resources. Land can also be considered a finite resource on Earth. Expansion of agricultural land has an impact on biodiversity and contributes to deforestation. The Food and Agriculture Organisation of the United Nations estimates that in coming decades, cropland will continue to be lost to industrial and urban development, along with reclamation of wetlands, and conversion of forest to cultivation, resulting in the loss of biodiversity and increased soil erosion.^[12]

Energy for agriculture

Main article: Renewable energy

Energy is used all the way down the food chain from farm to fork. In industrial agriculture, energy is used in on-farm mechanisation, food processing, storage, and transportation processes.^[13] It has therefore been found that energy prices are closely linked to food prices.^[14] Oil is also used as an input in agricultural chemicals. Higher prices of non-renewable energy resources are projected by the International Energy Agency. Increased energy prices as a result of fossil fuel resources being depleted may therefore impact negatively on the global food security unless action is taken to 'decouple' fossil fuel energy from food production, with a move towards 'Energy-Smart' agricultural systems.^[14] The use of solar powered irrigation in Pakistan has come to be recognized as a leading example of energy use in creating a closed system for water irrigation in agricultural activity.

CONCEPT OF AGRCULTURAL SUSTAINABLITY

Sustainable agriculture integrates three main goals--environmental health, economic profitability, and social and economic equity. A variety of philosophies, policies and practices have contributed to these goals. People in many different capacities, from farmers to consumers, have shared this vision and contributed to it. Despite the diversity of people and perspectives, the following themes commonly weave through definitions of sustainable agriculture.

Sustainability rests on the principle that we must meet the needs of the present without compromising the ability of future generations to meet their own needs. Therefore, stewardship of both natural and human resources is of prime importance. Stewardship of human resources includes consideration of social responsibilities such as working and living conditions of laborers, the needs of rural communities, and consumer health and safety both in the present and the future. Stewardship of land and natural resources involves maintaining or enhancing this vital resource base for the long term.

A systems perspective is essential to understanding sustainability. The system is envisioned in its broadest sense, from the individual farm, to the local ecosystem, and to communities affected by this farming system both locally and globally. An emphasis on the system allows a larger and more thorough view of the consequences of farming practices on both human communities and the environment. A systems approach gives us the tools to explore the interconnections between farming and other aspects of our environment.

A systems approach also implies interdisciplinary efforts in research and education. This requires not only the input of researchers from various disciplines, but also farmers, farmworkers, consumers, policymakers and others.

Making the transition to sustainable agriculture is a process. For farmers, the transition to sustainable agriculture normally requires a series of small, realistic steps. Family economics and personal goals influence how fast or how far participants can go in the transition. It is important to realize that each small decision can make a difference and contribute to advancing the entire system further on the "sustainable agriculture continuum." The key to moving forward is the will to take the next step.

Finally, it is important to point out that reaching toward the goal of sustainable agriculture is the responsibility of all participants in the system, including farmers, laborers, policymakers, researchers, retailers, and consumers. Each group has its own part to play, its own unique contribution to make to strengthen the sustainable agriculture community.

The remainder of this document considers specific strategies for realizing these broad themes or goals. The strategies are grouped according to three separate though related areas of concern: Farming and Natural Resources, Plant and Animal Production Practices, and the Economic, Social and Political Context. They represent a range of potential ideas for individuals committed to interpreting the vision of sustainable agriculture within their own circumstances.

COMPARATIVE ON SUSTAINABLE AGRICULTURE

Agricultural biodiversity

1.      The CBD defines agricultural biodiversity (AgBD) as “all components of biological diversity of relevance to food and agriculture, and all components of biological diversity that constitute the agro-ecosystem: the variety and variability of animals, plants and micro-organisms, at the genetic, species and ecosystem levels, which are necessary to sustain key functions of the agro-ecosystem, its structure and processes..”^[1].

2.      Agricultural systems are very complex and for proper functioning rely not only on the biodiversity of agriculturally used areas but also on the services of biota from the wider agricultural environment (e.g. pollinators, crop wild relatives). Broadly speaking, AgBD can be subdivided in two major categories that share a number of properties (also see Table 1).

3.      The first category consists of the genetic resources for food and agriculture (GRFA)^[2] that provide food and other essential harvested products from domesticated crops, crop wild relatives (CWR), domestic animals (including fish and other managed aquatic animals), fungal and microbial genetic resources (the latter particularly for post-harvest processes). GRFA have been the traditional focus of most of the work on AgBD for a number of reasons. The genetic resources embodied in agricultural seed and animal stocks are the most important assets of agricultural systems to deliver their principal ecosystem service, which is the provision of food and other agriculture-based commodities. As such they have overwhelming importance for human nutrition, dietary diversity and farmer income and economies. Moreover, the domestication of crops and livestock is inextricably linked to human intervention and management, and they have cultural and aesthetic significance. In response to genetic erosion, and because of the dependence of GRFA on human management, ex situ conservation efforts have focused on GRFA.

4.      The second category of AgBD comprises all those non-harvested components that contribute to, and sustain, agricultural productivity by provisioning supporting and regulating ecosystem services.  This is attracting growing attention to the extent to which the continued intensification and industrialization of agriculture is being questioned on sustainability grounds. The most significant organisms of this category of AgBD include soil micro-biota, pollinators and the antagonists of pest and diseases. Soil micro-biota are of immense diversity, and perform a number of vital functions that regulate soil fertility through the decomposition of litter and harvest residues and the cycling of nutrients such as nitrogen. Pollinators, both managed honey bees and the great diversity of wild pollinators, are essential for the production of a large number of crops, especially tree crops and horticultural species. Management of wild pollinators requires an ecosystem approach with boundaries of the system drawn beyond fields, into the broader agroecosystem. Finally, improved pest control is dependent on a diversity of natural enemies of pests from non-crop habitats (in addition to crop habitats) and the presence and survival of these biological control agents (predators, parasitoids) is essential for decreasing agriculture’s current reliance on pesticides. Unlike GRFA, soil biota, pollinators and pest control agents are mostly not unique to agricultural systems, and their continued abundance and diversity in agricultural systems is more a utilitarian rather than conservationist concern.

5.      The previous paragraphs illustrate the complexity and multifaceted nature of AgBD in terms of the taxonomic groups involved (plants, animals, fungi, micro-organisms), the varying degrees of its reliance on human intervention, the occurrence in agricultural areas and the wider ecosystem, the type and importance of services AgBD components provide, etc. It is therefore probably more difficult to make generalized statements on the management or sustainable use of AgBD as compared with other types of biodiversity.

Table 1: Attributes of AgBD components

Attribute	Cropsa	Livestock breedsb	Crop wild relatives and gathered food	Soil biota	Pollinators	Diseases, pests and their antagonists
Uniqueness in agric. systems	yes	yes	partial	no	no	partial
Principal contribution to ecosystem services	Provisioning food & agricultural products	Provisioning food & agricultural products	Food & agricultural products	Supporting soil formation, & nutrient cycling	food	Regulating pests and diseases
Relevance of intra-specific diversity to delivery of ecosystem services	high	high	high	low	low	high
Threats to intra-specific diversity	high	high	intermediate	low	?	?
Species richness	intermediate	low	high	very high	high	intermediate
Importance of ex situ conservation	high	high	high	low	low	low
Importance of in situ management	high	high	high	intermediate	high	high

a) Crop varieties, landraces, breeding materials, b) including aquatic animals in managed inland fisheries

6.      Further complicating the description of AgBD is the huge variation of agricultural systems. For example, management practices and AgBD use in an intensively cropped sugarcane production system for biofuel production are radically different from those in an extensively managed cacao agro-forest. Recommendations for best practices of sustainable use of AgBD need to take these differences into account and may therefore arrive at different or even opposing conclusions depending on the context of a particular agricultural system.

7.      It is generally observed that greater diversity or complexity of agricultural landscapes is associated with greater diversity of all organisms that constitute AgBD, and the uniformization of traditional into intensively managed agricultural systems is accompanied with overall loss of AgBD. It is often argued that a more diverse agricultural ecosystem offers a shield against perturbations, natural or human-made, contributing to agro-ecosystem resilience. Greater AgBD may create “pest suppressive” conditions and greater resistance to invasion of farming systems by noxious species. It can provide protection against uncertainties in the market, especially for less capitalized producers (e.g. AnGR), and increase the opportunities to add value and exploit new markets (crop variants, neglected species). However, greater AgBD in terms of the variety of crops and breeds can also translate into a hindrance for the participation in markets that require standardized and uniform products.

 Sustainability

8.      In a broad sense, sustainability is the capacity to endure^[3]. The concept is applied to ecosystems and human development efforts and its meaning is to a considerable extent contextual. Ecosystems are sustainable when they maintain ecological processes, functions, biodiversity and productivity into the future. For humans, sustainability is the potential for long-term maintenance of wellbeing, which will in turn depend on the responsible use of natural resources.

9.      The Global Environment Outlook 4 (UNEP, 2005, p. 524-525) defines sustainability as “a characteristic or state whereby the needs of the present and local population can be met without compromising the ability of future generations or populations in other locations to meet their needs” thus capturing two fundamental issues: the intra-generational equity (meeting human needs now) and inter-generational equity (fulfilment of basic needs of all global citizens in the future; see also Orr 2006).

10.  Sustainability is often defined as resting on three pillars or having three dimensions: environmental, social and economic sustainability. While some have argued the need to integrate these dimensions or redress the balance between them, others have pointed out the vagueness of the concept. Adams (2006) contrasts the hugely expanded awareness for sustainable development in recent years with the mounting evidence for the “global human enterprise becoming rapidly less sustainable” putting this down, in part, on the looseness of the concept and that it means different things to different people.

11.  The conventional understanding of sustainable development, based on the ‘three pillars’ implies that trade-offs can be made between environmental, social and economic dimensions of sustainability. A distinction is often drawn between ‘strong’ sustainability (where such trade-offs are not allowed or are restricted) and ‘weak’ sustainability (where they are permissible) (Adams 2006). The concept of ‘critical natural capital’ is also used to describe elements of the biosphere that cannot be traded off (e.g. critical ecosystems). However, in practice, development decisions by governments, industries and other actors do allow trade-offs and have traditionally put greatest emphasis on the economy above other dimensions of sustainability. This is a major reason why the environment continues to be degraded and development does not achieve desirable equity goals (Adams 2006).

 Sustainable agriculture

12.  Agreement on a universally accepted definition of sustainable agriculture has proved to be elusive, given the extraordinary diversity and complexity of agricultural land use, and the perspective taken (producer, consumer, etc.). For the purpose of this information paper, sustainable agriculture is defined as the ability of farmland to produce food and other agricultural products to satisfy human needs indefinitely as well as having sustainable impacts on the broader environment. This requires agriculture to avoid severe or irreversible damage to the endogenous or external ecosystem services upon which it depends, notably soil fertility, irrigation water, genetic variability, pollinators, etc. and have acceptable impacts on the broader environment (environmental stewardship).

13.  The principle of sustainability implies the use of resources at rates that do not exceed the capacity of ecosystems to replace them. By definition, dependency on non-renewable inputs is unsustainable, even if in the short term it is necessary as part of a trajectory toward sustainability. There are many difficulties in making sustainability operational. Over what spatial scale should food production be sustainable? Clearly an overarching goal is global sustainability, but should this goal also apply at lower levels, such as regions, nations, or farms? Could high levels of consumption or negative externalities in some regions be mitigated by improvements in other areas, or could some unsustainable activities in the food system be offset by actions in the non-food sector (through carbon-trading, for example)? Though simple definitions of sustainability are independent of time scale, in practice, how fast should we seek to move from the status quo to a sustainable food system? The challenges of climate change and competition for water, fossil fuels, and other resources suggest that a rapid transition is essential (Godfray et al. 2010).

14.  It is for human societies to negotiate and decide the nature of the trade-offs involved in reaching global agricultural sustainability. Such considerations are difficult or impossible to capture in the definition of the concept, as trade-offs may change with scale, time, societal preferences, internationally agreed targets, etc.

15.  There is a growing portfolio of enhanced agricultural practices that farmers can use to make agriculture more sustainable, for example those resulting in greater nutrient and water efficiencies, targeted plant protection (see section 4.2). However, it is argued that improved farming practices are only a part of the solution. Despite the insight that the biosphere is limited, the richer part of humankind manifestly fails to adjust consumption to the biosphere’s limits. Continued physical expansion of commodity supply systems means that rich consumers in developed and developing countries continue to perceive resource flows as bountiful, and develop no sense of limits to consumption. Few consumers show awareness of production systems as ecologically constrained. Belief in the opportunity to consume without limits in an ecologically limited world is a global risk. Adams (2006) argues that politicians fear backlash from citizens reacting as consumers to anything that alters their lifestyle in ways they perceive as adverse. This results in demands for low fuel prices, profligate material and energy consumption, ignorance and/or disregard of the social and environmental conditions under which global products are created.

16.  It is also well established (and implicit in some definitions of sustainable agriculture) that prices for agricultural inputs and outputs do not account for their true environmental cost and result in market failure. Farmers operate in economic and regulatory frameworks and such frameworks determine to a large extent whether farmers can engage in more sustainable practices.

 Sustainable use of agricultural biodiversity

17.  CBD texts and commentaries use the terms “sustainable use of agricultural biodiversity” and “sustainable agriculture” interchangeably suggesting synonymous meaning of these overlapping but different concepts. As described in the previous section, sustainable agriculture is a broad issue which includes considerations of productivity goals, environmental stewardship, farm profitability and rural welfare objectives as well as consumer health. AgBD is a component of agriculture, and as such it cannot be equated with agriculture. Some principles underpinning sustainable agriculture will apply to enhanced or sustainable use of AgBD. However, the links between sustainable use of AgBD and sustainable agriculture may not be always as straightforward as they are occasionally perceived. For example, well-managed agricultural systems can be relatively poor in AgBD and yet provide ecosystem services in the broadest sense (food, nutrient cycling, sustainably managed soil biota and pollinators) (Wood and Lenne 2005). Conversely, economically or environmentally unsustainable agricultural systems can be rich in AgBD (e.g. “organically”-certified systems that deplete soil nutrients). Most tellingly, work on agricultural sustainability and certification standards of “organic” production methods are often remarkably silent on AgBD implications, especially in reference to the management of intra-specific crop diversity.

18.  In other words, the use or deployment of AgBD can be of strategic importance in making agriculture more sustainable, but sustainable agriculture will depend on a range of other management components, notably nutrient, pest and disease management, etc. Statements that refer to “sustainable agriculture” and “sustainable use of agricultural biodiversity” at the same time must necessarily have blurred meaning. In this paper, the two concepts are diferentiated.

19.  Definitions of sustainable use relative to ecosystems or particular biological resources (fish stocks, forest products) generally reflect the concern over the widely observed excessive consumptive use of biological resources leading to levels below critical thresholds, beyond which their long-term viability or very existence is put in jeopardy^[4]. However, concerns of over-exploitation of a resource do not directly apply to AgBD, for the biological diversity embodied in crops and animals is perpetuated as agricultural seeds and reproduced animals. The term “sustainable use” conjures the notion of the need for reconciling conservation and use of AgBD as somehow antagonistic goals when indeed conservation of AgBD, particularly of PGR and AnGR, is only possible through use, and benefits arising from its actual or potential use (or value) provide the only incentive for its conservation. The principal threat to AgBD is ultimately not over-use but rather the under-use in agricultural systems and breeding programs. “Sustainable use” is a concept rarely used in the AgBD community, which prefers to speak of the “management”, "deployment” or “enhancement” of genetic resources (Rischkowsky 2008).

20.  A distinctive feature of the use of AgBD vis-à-vis the use of biodiversity in natural ecosystems is that agricultural practice typically requires trade-offs between the on-farm diversity and livelihood and development goals, particularly at the plot and farm level. Productivity needs and crop uniformity requirements arising from crop and post-harvest management as well as market integration all tend to reduce AgBD in agricultural systems. Trade-offs vary in intensity, or may not be observed in exceptional situations, but they need to be recognized as a reality that is unlikely to go away, particularly against the background of continued population growth, and the need to meet development and poverty alleviation goals. In general such trade-offs have lead, and continue to lead, to diminished overall crop and animal diversity in agricultural systems, causing genetic erosion, which provides the rationale for ex situ conservation.

21.  This is not to say that current trade-offs should be taken for granted. The improved management of agro-ecosystems can result in greater crop and ecological diversity of production areas. Agricultural and trade policies need to be amended to mitigate trade-offs rather than accentuate the decline of on-farm maintenance of crop and animal diversity as is currently the case^[5]. Even markets, particularly emerging demands for highly differentiated products, can provide incentives for greater use of AgBD.

22.  Based on the above considerations, and for the purpose of this information paper, “sustainable use of agricultural biodiversity” is defined as “all uses of AgBD that contribute to its conservation and perpetual availability as an input to agriculture”.

 Organic agriculture

23.  Unease over agriculture’s growing reliance on pesticides and synthetic fertilizers led to the emergence of the “organic” movement starting in the 1940s. There is a variety of organic schools and philosophies, but they all eschew the use of synthetic fertilizers and pesticides, herbicides, plant growth regulators, genetically modified organisms and livestock feed additives. To replace these inputs, organic farming relies on crop rotation (in particular using nitrogen-fixing legumes), the use of manure, composting, mechanical cultivation and biological pest control. Consumer demand for organic food is very much driven by the notion of the purportedly superior quality and safety of organic food (a claim not borne out by a recent meta-study, see Dangour et al. 2009). However, the rationale for organic production methods goes far beyond consumer concerns about healthy food, to include reducing the ecological “footprint” of farmed areas through managing nutrient cycles, protecting pollinators and beneficial micro-organisms, maintaining healthy soils and conserving water.

24.  Organic farming practices are regulated, based in large part on the standards set by the International Federation of Organic Agriculture Movements (IFOAM^[6]). For farmers to obtain on the market the price premiums for organic produce, they need certificates that require farm audits to prove compliance with organic production standards.

25.  In 2007, agriculture certified as “organic” covered some 32 million hectares or 0.8% of total global farmland^[7]. However, the de facto area of organic agriculture is much larger, if traditional agricultural systems that largely are in conformity with IFOAM standards but not certified, would count as such. Much subsistence farming, some slash and burn farming, traditional pastures and cacao production, inter alia, are overwhelmingly “organic”, not necessarily by intent but rather because of the unavailability of farm-external inputs.

26.  Modern organic farming has been much more influential than its share of total farmland would suggest. The long-standing controversy surrounding the benefits of “organic” versus “conventional” farming has drawn awareness to the problems associated with 'chemical-happy' farming. Where substantiated by scientific methods, principles of organic farming have been assimilated by the “integrated” nutrient and pest management methods that are now standard repertoire of conventional agriculture. Conventional farming uses extremely varied methods and modes: mixed or stockless farms, dairy or arable, intensive or extensive, no-till or minimum-tillage, mono-crops or mixed crops. It is therefore not quite appropriate to portray conventional or mainstream farming as diametrically opposed to organic farming.

27.  A review of comparative studies of the two systems by Holea et al (2005) identified a wide range of wild taxa that benefit from organic management through increases in abundance and/or species richness. It also highlighted three broad management practices (prohibition/reduced use of chemical pesticides and synthetic fertilizers; sympathetic management of non-cropped habitats; and preservation of mixed farming) that are intrinsic (but not exclusive) to organic farming, and that are particularly beneficial for farmland wildlife. However, the review remained inconclusive as to whether a ‘holistic’ farm approach (i.e. organic) provides greater benefits to biodiversity than carefully targeted prescriptions applied to relatively small areas of cropped and/or non-cropped habitats within conventional agriculture. It further concluded that many comparative studies encounter methodological problems, limiting their ability to draw quantitative conclusions and that more research is needed to determine the impacts of organic farming, before a full appraisal of its potential role in biodiversity conservation in agro-ecosystems can be made.

28.  There is much debate around the proposition by advocates of organic agriculture that it can contribute significantly to the global food supply. There is evidence in support of and against that proposition. Analysing a global dataset of 293 comparative studies, Badgley et al. (2007) found that yields from organic farming were slightly inferior to conventional low-input systems in developed countries, but the inverse was true for developing countries. The authors concluded that “organic methods could produce enough food on a global per capita basis to sustain the current human population, and potentially an even larger population, without increasing the agricultural land base”. Extrapolating from modeling results they further concluded that leguminous cover crops could fix enough nitrogen to replace the amount of synthetic fertilizer currently in use.

29.  Others have dismissed the notion that organic farming could sustain a world population of 9 billion without substantially increasing the area dedicated to agriculture, arguing that biological nitrogen fixation and sources of manure are insufficient to increase agricultural productivity to meet future needs (Trewavas 2001, 2002). According to MEA (2005), the human population may have already exceeded the maximum number that can be supported without chemical fertilizers. In Sub-SaharanAfrica, where soils are mostly of poor quality and nutrient-depleted, and food production will have to meet the needs of a population 80% greater in 20 years than today, judicial application of P and N fertilizers appears to be inescapable if further soil mining and expansion of low-intensity agricultural areas through destruction of habitat is to be avoided (Smaling et al. 2006, Grenz & Sauerborn 2007, Henao 2002-quoted in MEA 2005, p.335-336).

30.  The nature and quantification of nitrogen flows in agricultural systems is of considerable importance in the assessment of their sustainability. Nitrogen in the form of nitrate and ammonia is often the limiting factor in agricultural productivity, but because of leakage and gaseous loss, particularly under sub-optimal agricultural practices, has much negative environmental impact (MEA 2005). Organic nitrogen sources, such as livestock manure and legume cover crops used in organic production systems, can be a substitute to commercial nitrogen fertilizers. But these practices are not always feasible in the high-potential cereal production systems of developing countries, where population density is high and arable land resources are limited (Ali 1999).

31.  Organic production systems that rely entirely on organic nitrogen sources are becoming more popular in Europe and North America. Organic systems are feasible, and even profitable, in these countries because people can afford to pay higher prices for their food, and there is adequate land to support the crop rotations, legume cover crops, and forages that are needed to supply adequate nitrogen. It is not clear, however, that environmental benefits would accrue from widespread adoption of organic agriculture if these systems were forced to produce as much grain as conventional systems do today, because it is just as difficult to control losses of nitrogen from organic sources as it is from nitrogen fertilizer (Cassman et al. 2003). Use of both organic or fertilizer nitrogen need not be an ‘‘either-or’’ decision. In most conventional systems, farmers use organic nitrogen sources and rotate with legume crops to minimize the need for nitrogen fertilizer when it is cost-effective to do so.

32.  Avoidance of synthetic nitrogen fertilizers as mandated by organic standards certainly implies reduced emissions of greenhouse gases embodied in nitrogen fertilizers. But biological N fixation has also been harnessed by mainstream agriculture. Worldwide plantings of N-fixing crops, such as soybeans, now capture about 40 million tons of nitrogen a year, an ecosystem service worth several billion dollars annually in avoided fertilizer costs (MEA 2005). However, the negative consequences from biological N-fixation are ultimately similar to those resulting from industrial N fixation: increased emissions of N₂O and leaching of N from the land into water bodies once organic N has been mineralized (MEA 2005).

33.  A recent comparative study in the United Kingdom has shown that the carbon foot print of milk (per litre) is only slightly smaller in organic dairy farming, owing to the fact that emissions of methane from enteric fermentation and nitric oxide from soils and manure accounted in both farms for most of greenhouse gas emissions (in terms of CO2 equivalents) (Plassmann & Edwards-Jones 2009).

34.  It is interesting to note that the Haber–Bosch process in which atmospheric nitrogen is fixed and used to manufacture synthetic nitrogen fertilizer does not necessarily require the use of fossil fuel. If coupled to renewable energy sources the process has the potential to provide unlimited supplies of climate-neutral nitrogen fertilizer. The use of synthetic fertilizers in the future could therefore be perfectly compatible with sustainable agricultural practices.

35.  It has also been argued that the categorical opposition of organic agriculture to GMOs is unreasonable^[8], where these have the potential to contribute, in a complementary manner to other approaches, to the much needed agricultural intensification and resource-use efficiency (Fedoroff et al. 2010; see also section 4). For example, reviewing the findings of a number of studies on the use of transgenic cotton in India, Morse et al. (2005) concluded that insecticide use against ballworms was greatly reduced in insect-resistant BT cotton as compared to non-BT cotton. In addition, BT cotton also provided substantial benefits to farmers in terms of increased gross margins (39% and 63% higher vis-à-vis non-BT cotton). It would also seem unreasonable to ignore transgenic technologies, particularly if funded and owned by the public sector, that make crops more nutrient-efficient and productive, and food more nutritious (Trewavas 2002, Good et al. 2007, Gregory et al. 2009). Godfray et al. (2010) therefore contend that “genetic modification is a potentially valuable technology whose advantages and disadvantages need to be considered rigorously on an evidential, inclusive, case-by-case basis: Genetic modification should neither be privileged nor automatically dismissed.”

36.  The demand for organic food continues to grow fast although it is more expensive than conventionally produced food^[9]. The fact that consumers are willing to pay farmers a premium to do what they perceive as the “right thing” is encouraging, but still limited to relatively wealthy consumers in rich countries who spend a small part of their income on food. However, Capper (2009) shows that consumers often are mislead in thinking they are making virtuous food choices, when, in truth, they are supporting production practices that consume more natural resources, cause greater pollution and create a larger carbon footprint than more efficient, technology-driven, conventional methods.

37.  Likewise, ‘locally grown’ food is thought to have a lower environmental impact than food transported over long distances due to carbon emissions from fuel used in transport. However, it is incorrect to assume that the distance that food travels from point of origin to point of consumption is an accurate reflection of environmental impact. This simplistic approach fails to consider the productivity of the transportation system, which has tremendous impact on the energy expended per unit of food. As an example, one dozen eggs, transported several hundred miles to a grocery store in a tractor-trailer that can carry 23,400 dozen eggs is a more fuel-efficient, eco-friendly option than a dozen eggs purchased at a farmers’ market (4.5 times more fuel used) or local farm (17.2 times more fuel used). Instead, it is life-cycle assessments, which evaluate all inputs and outputs within the food-production system that allow correct comparisons of different production systems (Capper 2009).

In conclusion, organic and conventional agriculture should not be seen as contradictions, or intrinsically “good” or “bad” for agricultural sustainability, but as complementary sources from which the best elements should be borrowed and applied in appropriate contexts.

Sustainable Agriculture Techniques

Sustainable agriculture provides high yields without undermining the natural systems and resources that productivity depends on. Farmers who take a sustainable approach work efficiently with natural processes rather than ignoring or struggling against them – and use the best of current knowledge and technology to avoid the unintended consequences of industrial, chemical-based agriculture. One important result is that farmers are able to minimize their use of pesticides and fertilizers, thereby saving money and protecting future productivity, as well as the environment.

Below are some of the most common sustainable agriculture techniques employed by farmers today to achieve the key goals of weed control, pest control, disease control, erosion control and high soil quality:

• Crop Rotation
• Cover Crops
• Soil Enrichment
• Natural Pest Predators
• Biointensive Integrated Pest Management

Crop Rotation

Crop rotation—growing different crops in succession in the same field—is one of the most powerful techniques of sustainable agriculture, and avoids the unintended consequences of putting the same plants in the same soil year after year. It is a key element of the permanent and effective solution to pest problems because many pests have preferences for specific crops, and continuous growth of the same crop guarantees them a steady food supply, so that populations increase. For example, right now European corn borers are often a significant pest in the United States because most corn is grown in continuous cultivation or in two-year rotations with soybeans. Four- or five-year rotations would control not only corn borers, but many other corn pests as well. In fact, rotation reduces pest pressure on all the crops in the rotation by breaking the pest reproductive cycles.

In rotations, farmers can also plant crops, like soybeans and other legumes, that replenish plant nutrients, thereby reducing the need for chemical fertilizers. For instance, corn grown in a field previously used to grow soybeans needs less added nitrogen to produce high yields.

On a related note, the importance of crop rotation as a defense against pest infestations should be a key part of any discussion about growing crops for bioenergy purposes. Government policies to encourage bioenergy crops should not inadvertently encourage farmers to forgo crop rotation in favor of planting corn year after year. 

Cover Crops

Many farmers also take advantage of the benefits of having plants growing in the soil at all times, rather than leaving the ground bare between cropping periods, which produces unintended problems. The planting of cover crops such as hairy vetch, clover, or oats helps farmers achieve the basic goals of:

• preventing soil erosion,
• suppressing weeds, and
• enhancing soil quality.

Using appropriate cover crops is worth the extra effort because it reduces the need for chemical inputs like herbicides, insecticides, and fertilizers.

Soil Enrichment

Soil is arguably the single most prized element of agricultural ecosystems. Healthy soil teems with life, including many beneficial microbes and insects, but these are often killed off by the overuse of pesticides. Good soils can improve yields and produce robust crops less vulnerable to pests; abused soils often require heavy fertilizer application to produce high yields. Soil quality can be maintained and enhanced in many ways, including leaving crop residues in the field after harvest, plowing under cover crops, or adding composted plant material or animal manure.

Natural Pest Predators

Understanding a farm as an ecosystem rather than a factory offers exciting opportunities for effective pest control. For example, many birds, insects, and spiders are natural predators of agricultural pests. Managing farms so that they harbor populations of pest predators is a sophisticated and effective pest-control technique. One of the unfortunate consequences of intensive use of chemical pesticides is the indiscriminate killing of birds, bats, and other pest predators.

Biointensive Integrated Pest Management

One of the most promising technologies is the control of pests through integrated pest management (IPM). This approach relies to the greatest possible extent on biological rather than chemical measures, and emphasizes the prevention of pest problems with crop rotation; the reintroduction of natural, disease-fighting microbes into plants/soil, and release of beneficial organisms that prey on the pests. Once a particular pest problem is identified, responses include the use of sterile males, biocontrol agents like ladybugs. Chemical pesticides are only used as a last resort.

How Sustainable Agriculture Works

Main Components of Sustainable Agriculture

The main components of both sustainable farming and conventional farming are exactly the same: soil management, crop management, water management, disease/pest management and waste management. It's the methods used that are often radically different. We'll discuss them in order, starting with soil management.

On a conventional farm, managing and maintaining soil fertility is as simple as running a soil test and applying the recommended doses of nitrogen, phosphorus, potassium and other nutrients to meet crop needs. In sustainable agriculture, soil fertility is maintained and improved through a careful rotation of crops and generous amounts of compost and green manure, which are cover crops that are plowed back into the soil to enrich organic matter.

Monoculture is the term for agriculture that only produces one crop, year after year. The danger of monoculture is that it requires more and more chemical fertilizer to replenish lost nutrients, and more and stronger chemical pesticides and fungicides to kill off the bugs and diseases that evolve alongside the same crop year after year. Sustainable agriculture employs a broad crop diversity and careful rotation, so that nutrients are replenished naturally and no single pest or disease is allowed to get out of control.

Unhealthy soils are easily eroded, and careless water management can allow chemical fertilizers, pesticides and fresh manure slurry to leach into rivers, streams and the drinking water supply [source: Sustainable Agriculture Initiative]. Sustainable water management views water as a precious resource, efficiently watering crops using drip irrigation, which cuts down on erosion and evaporation. Efficient water use is hugely important in arid climates, where sustainable farmers plant drought-resistant crops and limit animal grazing [source: Feenstra].

On a factory farm, the key to fighting infections and disease among confined animals is to treat them with prophylactic antibiotics. Conventional growers rid the soil of any potentially harmful diseases by spraying it with fungicides before planting, then bathing the growing plants in strong pesticides to kill off bugs. In sustainable farming, plants and animals are encouraged to use their natural resistance rather than chemical solutions. Animals that freely graze on a healthy diet are more resistant to infection and disease. Healthy plants grown in microbe- and nutrient-rich soil are more resistant to invading bugs and disease. When necessary, sustainable farmers will use natural solutions to pest and disease problems, including row covers and sprays made from natural ingredients.

Dairy farms, in particular, create an impressive amount of manure. In a sustainable waste management plan, the manure would be properly composted (which requires sufficient internal heat and turning of the compost piles) and applied to field or food crops. One promising new technology called an anaerobic digestor can convert animal waste into methane, which can provide a renewable on-farm source of electricity

How to Practice Sustainable Agriculture

If you want to farm sustainably, there are certain measures you need to undertake in order to move toward that goal. And if you're looking for a farm that practices sustainable methods, then you can use these steps as your criteria.

Designing Your Dream Farm

Don't confuse "sustainable" with "organic". An organic label means that the food was grown or raised without the use of synthetic chemicals (but there are exceptions).

• Lots of people confuse sustainable agriculture with organic farming. Both are aimed at using more ecologically sensible practices, but they are judged by a distinct set of standards.
• Organic farming, especially when carried out on a large, industrial scale, can still damage the environment and threaten public health in a variety of ways: Ecosystems can still be ruined by widespread monoculture; pesticides can still be applied; soils can still be depleted of nutrients and organic matter; pollution can still be created; and exorbitant amounts of fossil fuels can still be spent (and wasted), all under an organic label.

Know what sustainability means: Farming a single area so that it produces food indefinitely. In order to move in this direction, a farm has to:

• avoid irreversible changes to the land (for example, erosion)
• withdraw no resources from the environment that cannot be replenished (for example, not using more water than can be replaced regularly by rainfall)
• produce enough income to remain on a farm in face of worldwide farm consolidation and infrastructure development

Consider the source. Determine where your resources come from and whether you're taking more than can be replaced, either through natural processes or your own practices.

• Where are your resources and inputs coming from? Think specifically about water, energy, soil amendments, and feed (if you have livestock). Also think about long-term, capital investments, such as structural building materials, tools, etc.
• Keep in mind that no farm is an island: complete self-sufficiency is not a requirement of sustainable agriculture. Long-term stability and productivity is. The more renewable and varied your resources are, the longer your farm will last.

Make Changes

Eliminate waste. There is no "away" to "throw" to. Everything is connected. The three "R"s apply here more than ever: reduce, reuse, recycle. It'll not only be more sustainable, but it's cheaper, too.

• Examine every bit of garbage and waste that your operation produces and ask "What else can I do with this?"
• If you can't do anything to do with it, try to think of ways someone else in the community can use it. Be creative.

Encourage diversity within the farm. Choosing "polyculture" over "monoculture" results in less waste and often, reduced fossil fuel consumption.

• Use varieties and breeds that are well-adapted to the conditions in your locale, rather than bred for maximum productivity and storage (with a sacrifice in hardiness and flavor).
• Rotate crops and pasture. Use companion planting and green manures to keep the land perpetually fertile and to prevent topsoil loss. Don't let any one piece of land lose an irreplaceable amount of nutrients.
• Keep plants and animals around that indirectly benefit the farm's stability and productivity. For example, yarrow and nettles add to the nutritional value of plants grown near them, as well as increase the volatile oil content of plants grown for oils. Plant extra basil to serve as an insecticide, and keep guinea fowl around to keep ticks at bay. As they roam your farm (and the surrounding countryside), guineas eat the ticks left by browsing deer off tall grasses. They are traditionally reputed to kill or keep rattlesnakes away as well.
• If guinea fowls are not common to your area, try growing ducks (if you have a fish pond) and/or chickens. Chickens can eat crop trimmings and vegetable waste. If they can't eat them all, they claw and step on it, enough to make it into organic fertilizers rich in nitrogen (especially when added to their poop).
• Raise both livestock and crops, and set up a mutually beneficial relationship between them. The simplest way to do this is to use manure from your livestock to fertilize crops, and use some of your crops to feed the livestock. If you are unable to raise both, find a neighbor who's specializing in the opposite and set up an exchange.

Encourage the diversity surrounding the farm. The ecology of your farm does not end at the property lines.

• Plant trees around the farm that act as windbreaks and also provide habitat for local birds (which can prey on insects that prey on crops).
• Tolerate natural predators that keep pests at bay (for example, snakes that feed on gophers, ladybugs that feed on aphids, spiders that feed on insects which spread diseases to crops).

Diversify financially. An ecologically sustainable farming operation won't do anybody much good if it can't generate a profit and keep itself running. Unless you or someone else is willing and able to sponsor the farm with an off-farm day job or another external source of income, you're going to have to crunch the numbers until you're in the black.

• Take advantage of the options available to you as far as direct marketing is concerned. That includes: CSA/subscriptions, farmers markets, roadside stands, and even the Internet.
• Adding value to products is a smart way to differentiate this farm's lettuce from that farm's lettuce. When you take your lettuce and make it part of delicious burger made from healthy meat that was pasture-raised in your own fields and top it with a slice of tasty, red tomato that grew in your own soil, you stand to appeal to a wider audience and rake in more profits. In other words, don't just grow a wider variety of stuff––do a wider variety of things with the stuff you grow, and consider selling it from an on-farm store or restaurant (as well as on the Internet).
• Cater to every economic level and ethnic group in the community. People of varying wealth seek different things from a farm. Certain ethnic groups value farm products that the mainstream community has no interest in (for example, many Caribbean immigrants seek male, uncastrated goats for meat as well as amaranth, a widespread weed, which they use to make a dish called calalloo).
• Publicize. Talk to everyone about what you're doing at the farm. Provide educational tours and workshops. Keep your farm looking nice, because if it ever comes down to it, the local community may fight development proposals because they perceive your farm to be a haven of agricultural heritage.

Find good, reliable labor. Find people who are committed to sustainable agriculture (not just dabbling in it) and who aren't afraid to get their hands dirty as they apply their minds.

• A reduced dependence on fossil fuels means an increased dependence on human labor, and not just physical, manual labor––you're going to need knowledgeable workers who understand the complexity of the system you're running and can enhance it with every decision they make.

Enjoy your life. Farming is hard work, but the most successful farmers know when to call it a day and circumvent burnout. Remember why you're farming and why, in particular, you're aiming for a sustainable operation. For most people, it's because they like knowing they're leaving land in better shape than they found it.

References

1.      Rural Science Graduates Association (2002). "In Memorium - Former Staff and Students of Rural Science at UNE". University of New England. Retrieved 21 October 2012.

2.      Gold, M. (July 2009). What is Sustainable Agriculture?. United States Department of Agriculture, Alternative Farming Systems Information Center.

3.      Altieri, Miguel A. (1995) Agroecology: The science of sustainable agriculture. Westview Press, Boulder, CO.

4.      "Scientists discover genetics of nitrogen fixation in plants - potential implications for future agriculture". News.mongabay.com. 2008-03-08. Retrieved 2013-09-10.

5.      Proceedings of the National Academy of Sciences of the United States of America, March 25, 2008 vol. 105 no. 12 4928–4932 [1]

6.      "What is Sustainable Agriculture? — ASI". Sarep.ucdavis.edu. Retrieved 2013-09-10.

7.      "Indicators for sustainable water resources development". Fao.org. Retrieved 2013-09-10.

8.      "CEP Factsheet". Musokotwane Environment Resource Centre for Southern Africa.

9.      "Peak Soil: Why cellulosic ethanol, biofuels are unsustainable and a threat to America". Culturechange.org.

10. "Soil erosion". Copperwiki.org.

11. "Cordell et al, 2009". Sciencedirect.com. Retrieved 2013-09-10.

12. "FAO World Agriculture towards 2015/2030". Fao.org. Retrieved 2013-09-10.

13. "FAO World Agriculture towards 2015/2030". Fao.org. Retrieved 2013-09-10.

14. "FAO 2011 Energy Smart Food" (PDF). Retrieved 2013-09-10.

15. "Advances in Sustainable Agriculture: Solar-powered Irrigation Systems in Pakistan". McGill University. 2014-02-12. Retrieved 2014-02-12.

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[1] COP V/5 Appendix, paragraph 1

[2] For example the ITPGRFA defines [PGRFA] as "any genetic material of plant origin of actual or potential value for food and agriculture".

[3] The word "sustain" is derived from the Latin verb sustinere (to keep in existence or maintain) and implies long-term support or permanence

[4] For example, the CBD defines sustainable use in article 2 as “the use of components of biological diversity in a way and at a rate that does not lead to the long-term decline of biological diversity, thereby maintaining its potential to meet the needs and aspirations of present and future generations.”

[5] Examples: 1) seed and seed systems policies unsupportive of informal seed systems and on-farm crop diversity; 2) trade and food safety policies that discriminate against neglected crops; 3) pricing in of externalities in the prices of agricultural products.

[6] IFOAM definition of organic agriculture: “Organic agriculture is a production system that sustains the health of soils, ecosystems and people. It relies on ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse effects. Organic agriculture combines tradition, innovation and science to benefit the shared environment and promote fair relationships and a good quality of life for all involved."

[7] http://www.organic-world.net/graphs-2009.html

[8] New Scientist 12 Sep 2009 “Learn to love genetic engineering”

[9] http://www.ifoam.org/sub/faq.html

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