organic farming the practice of raising plants—especially fruits and vegetables, but ornamentals as well—without the use of synthetic pesticides, herbicides, or fertilizers. In the United States, as elsewhere, awareness of the environmental damage and threats to health (see pollution ; environmentalism ) caused by DDT, dieldrin, and other insecticides and by the excessive use of chemical fertilizers has fostered interest in organic gardening, particularly among home gardeners. Organic gardeners use short-lived, biodegradable pest-killers or biological pest control and prefer manure for fertilizer. Organic farming on a large scale is both difficult and costly, but a small, steady market for organically grown, or "natural," foods supports a limited commercial effort in the United States. See also Integrated Pest Management ; organic food .

Bibliography: See J. I. Rodale et al., ed., The Encyclopedia of Organic Gardening (1959, repr. 1971); C. O. Foster, The Organic Gardener (1972).

Organic Agriculture

Organic agriculture uses the principles of diversity and nutrient cycling found in nature to raise crops and livestock. All kinds of food are grown using organic practices, from fruits and vegetables to grains and dairy products. Organic agriculture is popularly understood to mean farming without the chemical herbicides and pesticides used in conventional agriculture. Just as important are the techniques used by organic growers that make chemical use unnecessary. These include intelligently managing the agroecosystem by using crop rotation, cover crops, and tillage.

Principles of Organic Agriculture

Crop rotation means growing a different crop in a field each year. When the same crop is grown year after year in an artificial monoculture , a habitat is created for weeds, pests, and diseases that attack that crop. Organic growers imitate the complexity found in nature by changing the crops grown in a field from year to year. Rotation continually disrupts pest habitat and reduces weeds and diseases.

Crop yields also increase because of the "rotation effect." A basic two-year rotation involves alternating a grass family crop such as wheat or corn with a broadleaf crop such as tomatoes or soybeans. Any pests that become established in the wheat will no longer have a habitat the following year when tomatoes are planted. Similarly, most corn pests do not find what they need to survive in a soybean field.

Many organic growers use more sophisticated four- to eight-year rotations carefully designed to optimize yield and the ecological function of each crop. Often, the complexity of such an organic system is similar to the complexity found in nature, and weeds, insects, and diseases are almost eliminated from the system.

Using cultural control of pests rather than chemical control makes organic farming better for the environment and for wildlife.

Organic farmers will often plant a cover crop in the fall that protects the soil from wind and rain erosion during the winter. Usually the cover crop will provide other benefits as well. If the cover crop is a member of the bean plant family (a legume), it will bring nitrogen into the soil that will be available for the next crop to use. If the cover crop has allelopathic, or toxic, properties, as does rye, it can help control weeds.

From handheld hoes to tractor-pulled cultivators, organic farmers use a wide range of cultivation equipment to control weeds during the growing season. All of these implements operate on the same principle: drag weeds out of the soil onto the surface to dry out and die.

Commercial Organic Farming

A national law provides a set of standards that farmers in the United States must follow in order to sell what they grow as "organic." Organic growers must be certified, or have their farming practices verified by an application and inspection process, every year in order to sell into the organic market.

Increasing awareness of the pesticides used in conventional farming has made many people decide to buy organic food. Because of increased labor costs in organic farming, organic produce may be priced higher than conventional produce. Farmers' markets and roadside stands are places where consumers can purchase organic produce directly from the growers and eliminate retail mark-up costs.

Since the mid-1990s, sales of organic products have increased by at least 20 percent every year. Between 1995 and 1997, certified organic acres in the United States increased by 47 percent, making organic agriculture the largest growing segment of U.S. agriculture.

see also Agriculture; Agronomist; History of Agriculture; Nitrogen Fixation

Jane Sooby

Bibliography

Howard, Albert. An Agricultural Testament. New York: Oxford University Press, 1943. Reprint, Kutzton, PA: Rodale Press, 1979.

Magdoff, Fred, and Harold van Es. Building Soils for Better Crops, 2nd ed. Beltsville, MD: Sustainable Agriculture Network, 2000.

National Research Council. Alternative Agriculture. Washington, DC: National Academy Press, 1989.

Agriculture, Organic

Organic farming is a production system that sustains agricultural productivity while avoiding or largely excluding synthetic fertilizers and pesticides. Whenever possible, external resources, such as commercially purchased chemicals and fuels, are replaced by resources found on or near the farm. These internal resources include solar or wind energy, biological pest controls, and biologically fixed nitrogen and other nutrients released from organic matter or from soil reserves. Thus organic farmers rely heavily on the use of crop rotations , crop residues, animal manures, compost, legumes , green manures , off-farm organic wastes, mechanical cultivation, mineral-bearing rocks, and aspects of biological pest control to maintain soil productivity and tilth , to supply plant nutrients, and to control insect pests, weeds, and diseases. In essence, organic farming aims to promote soil health as the key to sustaining productivity, and most organic practices are designed to improve the ability of the soil to support plant and microorganism life.

In contrast, conventional farming is characterized by monoculture systems that are heavily dependent on the use of synthetic fertilizers and pesticides. Although such systems are productive and able to furnish low-cost food, they also often bring a variety of environmental effects such as pesticide pollution, soil erosion, water depletion, and biodiversity reduction. Increasingly, scientists, farmers, and the public in general have questioned the sustainability of modern agrochemically based agriculture. A large number of organic farmers do use modern machinery, recommended crop varieties, certified seed, sound livestock management, recommended soil and water conservation practices, and innovative methods of organic waste recycling and residue management. Clearly, though, there are sharp contrasts between organic and conventional agriculture.

Most management systems used by organic farmers feature legume-based rotations, the application of compost, and several diversified cropping systems, including crop-livestock mixtures. Through the adoption of such practices, organic farmers aim at:

• building up soil organic matter and soil biota
• minimizing pest, disease, and weed damage
• conserving soil, water, and biodiversity resources
• long-term agricultural productivity
• optimal nutritional value and quality of produce
• creating an aesthetically pleasing environment.

Features of Organic Farming

Organic farming is widespread throughout the world and is growing rapidly. In Germany alone there are about eight thousand organic farms occupying about 2 percent of the total arable land. In Italy organic farms number around eighteen thousand, and in Austria about twenty thousand organic farms account for 10 percent of total agricultural output. In 1980 the U.S. Department of Agriculture (USDA) estimated that there were at least eleven thousand organic farms in the United States and at least twenty-four thousand farms that use some organic techniques. In California, organic foods are one of the fastest-growing segments of the agricultural economy, with retail sales growing at 20 percent to 25 percent per year. Cuba was the only country undergoing a massive conversion to organic farming, promoted by the drop of fertilizer, pesticide, and petroleum imports after the collapse of trade relations with the Soviet bloc in 1990.

Given new market opportunities, farmers grow all kinds of crops, including field, horticultural, and specialty crops, as well as fruits and animals such as cattle, pigs, poultry, and sheep.

Although research on organic farming systems was very limited until the early 1980s, pioneering studies of R. C. Oelhaf (1978), the USDA (1980), W. Lockeretz and others (1981), D. Pimentel and others (1983), and the National Research Council (1984) on organic farming in the United States provide the most comprehensive assessments of organic agricultural systems. These studies concluded the following:

1. As farmers convert to organic farming, initially crop yields are lower than those achieved in conventional farms. In the corn belt, corn yields were about 10 percent less and soybean yields were about 5 percent less on organic farms than on paired conventional farms. Under highly favorable growing conditions, conventional yields were considerably greater than those on the organic farms. Under drier conditions, however, the organic farmers did as well or better than their conventional neighbors. Beyond the third or fourth year after conversion and after crop rotations became established, organic farm yields began to increase, so that their yields approached those obtained by conventional methods.
2. Conventional farms consumed considerably more energy than organic farms largely because they used more petrochemicals. Also, organic farms were considerably more energy-efficient than conventional farms. Between 1974 and 1978 the energy consumed to produce a dollar's worth of crop on organic farms was only about 40 percent as great as on conventional farms.
3. Studies conducted in the Midwest between 1974 and 1977 found that the average net returns of organic and conventional farms were within 4 percent of each other. Organic farms had a lower gross income by 6 percent to 13 percent, but their operating costs were less by a similar amount.
4. The USDA formulated Midwest farm budgets in order to compare crop rotations on organic farms with continuous conventional crop practices. The analysis assumed that yields on organic farms were 10 percent lower. In addition, rotations tie up part of the cropland with forage legumes, such as alfalfa; on conventional farms this land would be producing either corn or soybeans. Since corn and soybeans command a higher price, potential income is reduced in proportion to the amount of land tied up in forage legumes. In essence, organic farmers are turning part of their potential income into renewal of the soil (by adding organic matter) in order to assure sustainability of future crop production. The conventional system maximizes present income and is not as concerned about viewing soil as a long-term investment. In conclusion, although initially yields are likely to be lower in organic farms, variable costs are likely to be much lower. With little or no expenditure on agrochemicals, and the availability of premium prices for certain crops, the net result may be similar or higher gross margins for organic farmers.
5. Many organic farms are highly mechanized and use only slightly more labor than conventional farms. When based on the value of the crop produced, however, 11 percent more labor was required on the organic farms because the crop output was lower. The labor requirements of organic farmers in this study were similar to those of conventional farmers for corn and small grains, but higher for soybeans because more hand weeding was necessary. A number of other studies indicated that organic farms generally require more labor than conventional farms, but such needs can be kept to a minimum if hand weeding or handpicking of insects is not used. The labor required to farm organically is a major limitation to the expansion of some organic farms and an important deterrent for conventional farmers who might consider shifting to organic methods.

In many ways, organic farming conserves natural resources and protects the environment more than conventional farming. Research shows that soil erosion rates are lower in organic farms, and that levels of biodiversity are higher in organic farming systems than in conventional ones. In addition, organic farming techniques tend to conserve nitrogen in the soil/plant system, often resulting in a buildup of soil organic nitrogen. Organically managed soils have more soil microorganisms and enhanced levels of potentially available soil nitrogen.

Conversion to Organic Farming

In order for farmers to become certified organic producers, they must complete a certification procedure. The United States and most European countries have created regulations that apply to the production and sale of organically grown produce. All organic produce must carry a quality mark authorized by the government and provided to farmers by legal organizations that conduct strong verification systems with on-site annual inspections. Farmers willing to convert to organic farming must adhere to specific production standards and can be certified as organic only after three years of strictly following such standards.

From a management perspective, the process of conversion from a high-input conventional management to a low-input (or low-external input) management is a transitional process with four marked phases:

1. Progressive chemical withdrawal
2. Rationalization of agrochemical use through integrated pest management (IPM) and integrated nutrient management
3. Input substitution, using alternative, low-energy inputs
4. Redesign of diversified farming systems with an optimal crop/animal assemblage so that the system can support its own soil fertility, natural pest regulation, and crop productivity.

During the four phases, management is guided in order to ensure the following processes:

1. Increasing biodiversity both in the soil and aboveground
2. Increasing biomass production and soil organic matter content
3. Decreasing levels of pesticide residues and losses of nutrients and water
4. Establishment of functional relationships between the various farm components
5. Optimal planning of crop sequences and combinations and efficient use of locally available resources.

It is important to note that the conversion process can take anywhere from one to five years depending on the level of artificialization or degradation of the original high-input system. In addition, not all input substitution approaches are ecologically sound, as it is well established that some practices widely encouraged by some organic farming enthusiasts (such as flame-weeding and applications of broad spectrum insecticides) can have serious side effects and environmental impacts.

For scientists involved in transition research, an important outcome of these studies is the realization that the process of converting a conventional crop production system that relies heavily on synthetic, petroleum-based inputs to a legally certifiable, low-external input, organic system is not merely a process of withdrawing external inputs, with no compensatory replacement or alternative management. Considerable ecological knowledge is required to direct the array of natural flows necessary to sustain yields in a low-input system.

see also Agricultural Ecosystems; Agriculture, History of; Agriculture, Modern; Agronomist; Compost; Soil, Chemistry of; Soil, Physical Characteristics of.

Miguel Altieri

Bibliography

Altieri, Miguel A. Agroecology: The Science of Sustainable Agriculture. Boulder, CO: Westview Press, 1995.

Gliessman, Stephen R. Agroecology: Ecological Processes in Sustainable Agriculture. Chelsea, MI: Ann Arbor Press, 1998.

Lampkin, N. Organic Farming. Ipswich, UK: Farming Press Books, 1990.

Lockeretz, W., G. Shearer, and D. H. Kohl. "Organic Farming in the Corn Belt." Science 211 (1981): 540-47.

National Research Council. Alternative Agriculture. Washington, DC: National Academy Press, 1984.

Oelhaf, R. C. Organic Agriculture. New Jersey: Allanheld, Osmon and Co. Pub., 1978.

Pimentel, D., G. Berardi, and S. Fost. "Energy Efficiency of Farming Systems: Organic and Conventional Agriculture." Agriculture, Ecosystems and Environment 9 (1983): 359-72.

Pretty, J. N. Regenerating Agriculture: Policies and Practice for Sustainability and Self-reliance. London: Earthscan, 1995.

Report and Recommendations on Organic Farming. Washington, DC: U.S. Department of Agriculture, 1980.

Youngberg, G. "Organic Farming: A Look at Opportunities and Obstacles." Soil and Water Conservation 35 (1980): 254-63.