Organic Farming

I

Introduction

Organic Farming, system of agriculture that excludes the use of synthetic pesticides, growth hormones, antibiotics, genetically modified seeds and animal breeds, and irradiation. Organic farmers instead rely on ecosystem management, including the use of pesticides and fertilizers derived from plants, animal wastes, and minerals. They incorporate biological methods, such as the use of one organism to suppress another, to help control pests. The methods used in organic farming seek to increase soil fertility, balance insect populations, and reduce air, soil, and water pollution.

In the United States, organic farming is a rapidly growing sector of agriculture. In 2006 organic food sales reached $16.7 billion, up from $7 billion in 2001. Exports of organic food products are also growing, particularly to Japan and Europe.

II

Organic Farming Techniques

Organic farming combines a variety of methods to maintain the health of soil, prevent soil erosion, and control pests with minimal or no use of synthetic pesticides. Conventional farmers also use some of these methods, but to a lesser degree.

A

Soil Preservation in Organic Farming

Fertilizers are used to provide the minerals lacking in some soils, and to replace the minerals removed from the soil by crops as they grow. Many conventional farmers rely on concentrated chemical fertilizers that are rapidly absorbed by plants. These fertilizers produce quick growth but may kill important soil organisms, such as earthworms and beneficial bacteria. Organic farmers use manure, compost (a mixture of decaying organic matter that is rich in beneficial soil microorganisms), and other natural materials to nourish soil organisms, which in turn make minerals available to plants.

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Organic farmers are more likely than conventional farmers to rotate crops, a technique that replenishes soil nutrients without the use of synthetic fertilizers. In crop rotation, a field is used for one to several years to grow one type of crop, such as corn or wheat, followed by a season in which a legume such as alfalfa or soybean is planted. Legume roots harbor beneficial bacteria that incorporate nitrogen from the air into the soil (see Nitrogen Fixation), enriching the soil and reducing the need for nitrogen-containing fertilizers. Crop rotation also conserves nutrients. For example, the roots of the first crop may be near the surface and the second crop’s roots may be deeper, so that nutrients are drawn from different depths in the soil.

Soil held in place by plant roots is less likely to blow or wash away, or erode, than bare soil. Organic farmers minimize soil erosion with cover crops—short-lived plants, often grasses or legumes—that protect the soil between the harvesting of one crop and the planting of the next. Many organic farmers also conserve soil by practicing no-till or low-till farming, avoiding the use of plows to turn the soil, or using implements that only slice or slightly turn the soil. They may also leave the unharvested portion of a crop in the field to cover the soil, preventing soil erosion from wind or rain.

B

Pest Management in Organic Farming

Conventional farms rely on an array of synthetic pesticides to kill weeds, disease-causing fungi, and harmful insects. These pesticides are manufactured by chemically processing petroleum, natural gas, ammonia, and a number of other raw materials. They include active and inactive ingredients, both of which can be highly toxic and long lasting. Organic farmers typically use pesticides primarily derived from chemically unaltered plant, animal, or mineral substances in which the active toxic ingredient breaks down rapidly to become nontoxic after being applied to the crop. Pyrethrum (a substance extracted from the chrysanthemum), a variety of soaps, and oil from the neem tree are among the insecticides used by organic farmers. Bordeaux mix, a combination of calcium carbonate and copper, is used by organic farmers to control disease-causing fungi.

In addition to using natural pesticides, organic farmers control pests by planting different crops in wide, alternating bands, a technique called intercropping. This approach interrupts the movement of disease-causing organisms through a field, since many insects and fungi feed on just one type of crop. Organic farmers also reduce insect damage by spraying crops with bacteria that kill larvae (immature insects) and planting crops that attract ladybugs, lacewings, and other beneficial insects that prey on unwanted insects.

Organic farmers use many methods for weed control. Mulching involves covering the soil around crops with straw or other materials that smother weeds. Cover crops can be planted in the fall and turned under in a few months; they help control weeds by competing with them—an oat crop, for example, grows faster than weeds and deprives them of the nutrients they need to produce seeds. Other types of cover crops, such as cereal rye, release substances from their roots that inhibit weed seed germination. Organic farmers sometimes use a variety of tractor-drawn equipment to uproot weeds that emerge with crops.

Organic farming is sometimes referred to as sustainable agriculture, although the two concepts have subtle but significant differences. Sustainable agriculture seeks to improve the entire food and agricultural system by balancing production and consumption. For example, a farmer practicing sustainable agriculture may use the manure from the animals to fertilize the fields of grain that are grown to feed the animals. Eliminating the purchase of fertilizer reduces the cost of growing grain, and growing grain for animal feed rather than buying it reduces the cost of raising livestock.

Sustainable agriculture also addresses the environmental, economic, and social issues related to agricultural systems. It attempts to ensure that arable land is protected so that current and future generations will be able to farm it successfully; many involved in sustainable agriculture also seek to preserve the vitality of family-owned farms and rural communities. A sustainable farm may not be organic, and an organic farm may not be sustainable, although they may use similar techniques.

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