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sustainable agriculture

 
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n.

A method of agriculture that attempts to ensure the profitability of farms while preserving the environment.


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Food & Culture Encyclopedia: Sustainable Agriculture
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From a technological and economic standpoint, agriculture today represents one of the success stories of the modern era. Despite an ever increasing global population, and a corresponding gradual decrease in the availability of nonrenewable natural resources such as energy, land, and water, farmers throughout the world have responded to the challenge by increasing total and per area production levels every year. This agricultural miracle is due to a long tradition of farmer self-reliance, ingenuity, and perseverance, and to the support provided to farmers by many private and public institutions. Especially noteworthy is the support provided by a network of agricultural research universities in North America and Europe. Furthermore, crop productivity has improved in the developed world, and in many Third World countries as well. By the 1970s, many Third World countries in Asia and Latin America had actually reached self-sufficiency with respect to several primary staple grains.

The race toward increased crop yields began in the mid-to late 1800s in precapitalist England. Ever since then, scientists, environmentalists, and economists have issued words of caution concerning environmental and social issues arising from modern agriculture. By the midto late twentieth century, some of the more negative environmental and economic side effects of modern capital-intensive agriculture became evident in many parts of the world. The increased realization that modern agriculture had serious side effects, resulting in reduced environmental quality, health concerns, and economic insecurity for the traditional family farm, led in part to what is known today as a global "Sustainable Agriculture" movement.

Definition

Because agricultural systems are so diverse, based on farm size, location, crop being grown, socioeconomic background, among many other factors, and because the movement has become so widespread globally, sustainable agriculture has come to represent different things to different people. Nevertheless there are some common threads, concepts, and beliefs. In the most general terms, sustainable agriculture describes systems in which the farmer reaches the goal of producing adequate yields and good profits following production practices that minimize any negative short-and long-term side effects on the environment and the well-being of the community. The major goals of this approach are thus to develop economically viable agroecosystems and to enhance the quality of the environment, so that farmlands will remain productive indefinitely.

Why Sustainable Agriculture? History and Future Prospects

Ancient history, ranging from the Egyptians to the Romans to the Mayans, indicates that poorly managed agriculture can lead to the eminent decline of entire civilizations. By the midpart of the twentieth century, symptoms began to appear, documented by scientists, that some aspects of modern agriculture were unsustainable, leading in many cases to a decline in environmental quality and human quality of life. The undesirable side effects of modern agriculture, some believed, were threatening the lands and the very livelihood that farmers were trying to sustain. In contrast, from a historical perspective, scientists knew that civilizations that did follow sustainable practices were indeed able to thrive for centuries. Thus, by incorporating the use of production techniques developed by the latest agricultural research, along with some of the farming practices that proved effective through centuries of farming in many areas, a set of recommended management practices was established in individual production regions.

The future goal of farming communities is to strive to use current sustainable practices and to utilize the latest production techniques to remain competitive in the global agricultural market. For this to take place, a close communication link has to be maintained between rural communities, researchers, and society at large. This link gives urban communities a better understanding of issues affecting farmers, including the farmers' role as stewards of the environment, and of the economic realities of providing the public with a consistently healthy and safe food supply.

Implementing Sustainable Systems

An important aspect of sustainable agriculture is that it does not represent a specific set of agricultural practices that farmers need to follow step by step, like one would a recipe, to reach a specific goal. Instead, the concept represents more of a paradigm shift that encourages farmers to seek their own path, one that best fits the farm's particular conditions, and leads toward a more environmentally friendly approach without sacrificing yields or profits. Similarly, sustainable agriculture is not a specific target, but instead is more of a process that every farmer pursues as part of the daily farm operations. Thus, because agricultural systems are so diverse, farmers may choose among a myriad number of agricultural practices and techniques available to produce crops more effectively.

Some Key Undesirable Side Effects of Modern Agriculture

  • Unsustainable irrigation programs throughout the world are resulting in an undesirable buildup of salinity and toxic mineral levels in one out of five hectares under irrigation. Thus, agricultural water, a nonrenewable resource whose use has tripled globally since 1950, has to be used more efficiently to minimize salinization problems.
  • Excessive soil erosion, in the range of fifteen to forty tons per hectare annually, results in the loss of productive farmland in many parts of the world. Forested areas, a refuge for wildlife and biodiversity (biological diversity), are then often turned into agricultural fields to compensate for the loss of the abandoned eroded areas.
  • The indiscriminate use of pesticides is affecting human health and wildlife populations, as first reported to the population at large in Rachel Carson's book Silent Spring (1962).
  • The increased concentration of farms into larger and larger farm holdings is reducing the number of small family farms, believed by many to represent the heart of rural communities and to be key stewards of the environment.
  • The trend toward larger farms and plantation-type monocultures is leading to a loss of global biodiversity. Biodiversity, many argue, may be a critical ecological feature that allows the continued survival of humans on earth.
  • The excessive reliance on synthetic fertilizers, and the improper use and disposal of animal wastes is leading to the breakup of natural nutrient cycles. This causes an undesirable buildup of nutrients and salts in aquifers, affecting wildlife in aquatic habitats.

What Is Sustainable Agriculture? Some Key Definitions

Sustainable agriculture involves farming systems that are environmentally sound, profitable, productive, and compatible with socioeconomic conditions (J. Pesek, in Hatfield and Karlen, Sustainable Agriculture Systems).

Agroecology is a field of research used to implement sustainable systems. It is the application of ecological concepts and principles to the study, design, and management of sustainable systems.

A systems approach is used to study and research sustainable systems. The goal is to study the farm as an entity made up of all its components and their interrelationships, together with relationships between the farm and its environment.

Key components of sustainable systems include enhanced internal nutrient cycling on the farm; improved soil quality through additions of organic matter and reduced soil erosion; increased vegetational diversity to promote natural systems of pest control; and alternative marketing programs that increase profits and minimize overhead costs.

Basic Features and Concepts of Sustainable Systems

  1. The need to maintain or improve soil quality and fertility. This is often attained by increasing the organic matter content of the soil, and by minimizing losses from soil erosion.
  2. Production programs are designed to improve the efficiency of resource utilization. This will result in the most cost-effective use of water, fertilizers, and pesticides.
  3. An attempt is made to improve internal nutrient cycles on the farm, which will reduce the dependence on external fertilizers.
  4. Efforts are made to improve biological diversity on the farm. This will result in improved natural suppression of pests, and may also help to improve internal nutrient cycling within the farm.
  5. Farm management and marketing programs are designed to minimize overhead costs and to increase returns, often by following alternative marketing schemes.

Bibliography.

Carson, Rachel. Silent Spring. Greenwich, Conn.: Fawcett Crest, 1962.

Collins, Wanda W., and Calvin O. Qualset, eds. Biodiversity in Agroecosystems. Boca Raton, Fla.: CRC Press, 1999.

Gliessman, Stephen R. Agroecology: Ecological Processes in Sustainable Agriculture. Chelsea, Mich.: Sleeping Bear Press, 1998.

Gliessman, Stephen R. Agroecosystem Sustainability: Developing Practical Strategies. Boca Raton, Fla.: CRC Press, 2001.

Hatfield, J. L., and D. L. Karlen, eds. Sustainable Agriculture Systems. Boca Raton, Fla.: Lewis Publishers, 1994.

National Research Council. Sustainable Agriculture and the Environment in the Humid Tropics. Washington, D.C.: National Academy Press, 1987.

Powers, L. F., and R. McSorley. Ecological Principles of Agriculture. Albany, N.Y.: Delmar, 2000.

—Hector Valenzuela

 
Gardener's Dictionary: sustainable agriculture
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A system of farming or gardening that can be sustained indefinitely without damaging the soil and that does not rely on expensive inputs such as purchased fertilizers, fuel for tractors, or irrigation water. Traditional farmers around the world provide many successful examples. See also permaculture.

 
Wikipedia: Sustainable agriculture
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Sustainable agriculture integrates three main goals: environmental stewardship, farm profitability, and prosperous farming communities. These goals have been defined by a variety of disciplines and may be looked at from the vantage point of the farmer or the consumer.

Contents

Description

Sustainable agriculture refers to the ability of a farm to produce food indefinitely, without causing severe or irreversible damage to ecosystem health. Two key issues are biophysical (the long-term effects of various practices on soil properties and processes essential for crop productivity) and socio-economic (the long-term ability of farmers to obtain inputs and manage resources such as labor).

The physical aspects of sustainability are partly understood.[1] Practices that can cause long-term damage to soil include excessive tillage (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.

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 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 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 would be well beyond the capability of early 21st century technology, even if various concerns about biotechnology were addressed. Sustainable options for replacing other nutrient inputs (phosphorus, potassium, etc.) are more limited. An often overlooked option is landraces that are adapted to less than ideal conditions such as drought or lack of nutrients.

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 salinisation) and musn't use more water from their source than is naturally replenished, otherwise the water source becomes, in effect, a non-renewable resource. Improvements in water well drilling technology and the development of submersible pumps have made it possible for large crops to be regularly grown where reliance on rainfall alone previously made this level of success unpredictable. However, this progress has come at a price, in that in many areas where this has occurred, such as the Ogallala Aquifer, the water is being used at a greater rate than its rate of recharge.

Socioeconomic aspects of sustainability are also partly understood. Regarding less concentrated farming, the best known analysis is Netting's study on smallholder systems through history.[2]

Sustainable agriculture was also addressed by the 1990 farm bill [3].

It was defined as follows:

Stated by: “the term sustainable agriculture means an integrated system of plant and animal production practices having a site-specific application that will, over the long term:

  • 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 nonrenewable 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.”[4]

Economics

Given the finite supply of natural resources at any specific cost and location, agriculture that is inefficient or damaging to needed resources may eventually exhaust the available resources or the ability to afford and acquire them. It may also generate negative externality, such as pollution as well as financial and production costs.

The way that crops are sold must be accounted for in the sustainability equation. Food sold locally requires little additional energy, aside from that necessary for cultivation, harvest, and transportation (including consumers). Food sold at a remote location, whether at a farmers' market or the supermarket, incurs a different set of energy cost for materials, labour, and transport.

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

What grows and how and where it is grown are a matter of choice. Two of the many possible practices of sustainable agriculture are crop rotation and soil amendment, both designed to ensure that crops being cultivated can obtain the necessary nutrients for healthy growth.

Methods

Many scientists, farmers, and businesses have debated how to make agriculture sustainable. One of the many practices includes growing a diverse number of perennial crops in a single field, each of which would grow in separate season so as not to compete with each other for natural resources.[5] This system would result in increased resistance to diseases and decreased effects of erosion and loss of nutrients in soil. Nitrogen fixation from legumes, for example, used in conjunction with plants that rely on nitrate from soil for growth, helps to allow the land to be reused annually. Legumes will grow for a season and replenish the soil with ammonium and nitrate, and the next season other plants can be seeded and grown in the field in preparation for harvest.

Monoculture, a method of growing only one crop at a time in a given field, is a very widespread practice, but there are questions about its sustainability, especially if the same crop is grown every year. Growing a mixture of crops (polyculture) sometimes reduces disease or pest problems [6] but polyculture has rarely, if ever, been compared to the more widespread practice of growing different crops in successive years (crop rotation) with the same overall crop diversity. Cropping systems that include a variety of crops (polyculture and/or rotation) may also replenish nitrogen (if legumes are included) and may also use resources such as sunlight, water, or nutrients more efficiently (Field Crops Res. 34:239).

Replacing a natural ecosystem with a few specifically chosen plant varieties reduces the genetic diversity found in wildlife and makes the organisms susceptible to widespread disease. The Great Irish Famine (1845-1849) is a well-known example of the dangers of monoculture. In practice, there is no single approach to sustainable agriculture, as the precise goals and methods must be adapted to each individual case. There may be some techniques of farming that are inherently in conflict with the concept of sustainability, but there is widespread misunderstanding on impacts of some practices. For example, the slash-and-burn techniques that are the characteristic feature of shifting cultivators are often cited as inherently destructive, yet slash-and-burn cultivation has been practiced in the Amazon for at least 6000 years[7]; serious deforestation did not begin until the 1970s, largely as the result of Brazilian government programs and policies.[8] To note that it may not have been slash-and-burn so much as slash-and-char, which with the addition of organic matter produces terra preta, one of the richest soils on Earth and the only one that regenerates itself.

There are also many ways to practice sustainable animal husbandry. Some of the key tools to grazing management include fencing off the grazing area into smaller areas called paddocks, lowering stock density, and moving the stock between paddocks frequently.[9]

Several attempts have been made to produce an artificial meat, using isolated tissues to produce it in vitro; Jason Matheny's work on this topic, whichin the New Harvest project, is one of the most commented.[10]

Soil Treatment

Soil steaming can be used as an ecological alternative to chemicals for soil sterilization. Different methods are available to induce steam into the soil in order to kill pest and increase soil health.

Off-farm impacts

A farm that is able to "produce perpetually", yet has negative effects on environmental quality elsewhere is not sustainable agriculture. An example of a case in which a global view may be warranted is over-application of synthetic fertilizer or animal manures, which can improve productivity of a farm but can pollute nearby rivers and coastal waters (eutrophication). The other extreme can also be undesirable, as the problem of low crop yields due to exhaustion of nutrients in the soil has been related to rainforest destruction, as in the case of slash and burn farming for livestock feed.

Sustainability affects overall production, which must increase to meet the increasing food and fiber requirements as the world's human population expands to a projected 9.3 billion people by 2050. Increased production may come from creating new farmland, which may ameliorate carbon dioxide emissions if done through reclamation of desert as in Israel, or may worsen emissions if done through slash and burn farming, as in Brazil. Additionally, Genetically modified organism crops show promise for radically increasing crop yields, although many people and governments are apprehensive of this new farming method.

Some advocates of sustainable agriculture favour organic farming as the only system which can be sustained over the long-term. However, organic production methods, especially in transition, yield less than their conventional counterparts and raise the same problems of sustaining populations globally[11] While evidence supports organic farming during periods of drought[12], these figures must be interpreted with care, and modern food storage technology reduces risks associated with transient droughts. If periods of prolonged drought occur due to global warming, organic production methods can be considered as a way to adapt to a changing climate.

Urban planning

There has been considerable debate about which form of human residential habitat may be a better social form for sustainable agriculture.

Many environmentalists advocate urban developments with high population density as a way of preserving agricultural land and maximizing energy efficiency. However, others have theorized that sustainable ecocities, or ecovillages which combine habitation and farming with close proximity between producers and consumers, may provide greater sustainability[citation needed].

The use of available city space (e.g., rooftop gardens and community gardens) for cooperative food production is another way to achieve greater sustainability[citation needed].

One of the latest ideas in achieving sustainable agricultural involves shifting the production of food plants from major factory farming operations to large, urban, technical facilities called vertical farms. The advantages of vertical farming include year-round production, isolation from pests and diseases, controllable resource recycling, and on-site production that reduces transportation costs[citation needed]. While a vertical farm has yet to become a reality, the idea is gaining momentum among those who believe that current sustainable farming methods will be insufficient to provide for a growing global population[citation needed]. For vertical farming to become a reality, billions of dollars in tax credits and subsidies will need to be made available to the operation.[13] It may be difficult to justify spending billions of dollars on a vertical farm that will only feed 50,000 people when agriculture land remains abundant.

See also

Sustainable development portal
Sustainable development portal

References

  1. ^ Altieri, Miguel A. (1995) Agroecology: The science of sustainable agriculture. Westview Press, Boulder, CO.
  2. ^ Netting, Robert McC. (1993) Smallholders, Householders: Farm Families and the Ecology of Intensive, Sustainable Agriculture. Stanford Univ. Press, Palo Alto.
  3. ^ Food, Agriculture, Conservation, and Trade Act of 1990 (FACTA), Public Law 101-624, Title XVI, Subtitle A, Section 1603
  4. ^ usda.gov
  5. ^ http://www.landinstitute.org/pages/Glover-et-al-2007-Sci-Am.pdf Glover et al. 2007. Scientific American
  6. ^ Nature 406, 718-722 Genetic diversity and disease control in rice, Environ. Entomol. 12:625)
  7. ^ Sponsel, Leslie E. (1986) Amazon ecology and adaptation. Annual Review of Anthropology 15: 67-97.
  8. ^ Hecht, Susanna and Alexander Cockburn (1989) The Fate of the Forest: developers, destroyers and defenders of the Amazon. New York: Verso.
  9. ^ Pastures: Sustainable Management
  10. ^ "PETA’s Latest Tactic: $1 Million for Fake Meat", NYT, April 21, 2008.
  11. ^ organicconsumers.org
  12. ^ "newfarm.org Organic crops perform up to 100 percent better in drought and flood years". Rodale Institute. 2003. http://www.newfarm.org/depts/NFfield_trials/1103/droughtresearch.shtml newfarm.org. Retrieved on 2009-02-17. 
  13. ^ Vertical Farming

Notes

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Further reading

External links

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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved.  Read more
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