During the latter half of the twentieth century, what is known today as modern agriculture was very successful in meeting a growing demand for food by the world's population. Yields of primary crops such as rice and wheat increased dramatically, the price of food declined, the rate of increase in crop yields generally kept pace with population growth, and the number of people who consistently go hungry was slightly reduced. This boost in food production has been due mainly to scientific advances and new technologies, including the development of new crop varieties, the use of pesticides and fertilizers, and the construction of large irrigation systems.
Basic Practices of Modern Agricultural Systems
Modern agricultural systems have been developed with two related goals in mind: to obtain the highest yields possible and to get the highest economic profit possible. In pursuit of these goals, six basic practices have come to form the backbone of production: intensive tillage, monoculture , application of inorganic fertilizer, irrigation, chemical pest control, and genetic manipulation of crop plants. Each practice is used for its individual contribution to productivity, but when they are all combined in a farming system each depends on the others and reinforces the need for using the others. The work of agronomists, specialists in agricultural production, has been key to the development of these practices.
The soil is cultivated deeply, completely, and regularly in most modern agricultural systems, and a vast array of tractors and farm implements have been developed to facilitate this practice. The soil is loosened, water drains better, roots grow faster, and seeds can be planted more easily. Cultivation is also used to control weeds and work dead plant matter into the soil.
When one crop is grown alone in a field, it is called a monoculture. Monoculture makes it easier to cultivate, sow seed, control weeds, and harvest, as well as expand the size of the farm operation and improve aspects of profitability and cost. At the same time, monocultures tend to promote the use of the other five basic practices of modern agriculture.
Use of Synthetic Fertilizers.
Very dramatic yield increases occur with the application of synthetic chemical fertilizers. Relatively easy to manufacture or mine, to transport, and to apply, fertilizer use has increased from five to ten times what it was at the end of World War II (1939-45). Applied in either liquid or granular form, fertilizer can supply crops with readily available and uniform amounts of several essential plant nutrients.
By supplying water to crops during times of dry weather or in places of the world where natural rainfall is not sufficient for growing most crops, irrigation has greatly boosted the food supply. Drawing water from underground wells, building reservoirs and distribution canals, and diverting rivers have improved yields and increased the area of available farm land. Special sprinklers, pumps, and drip systems have greatly improved the efficiency of water application as well.
Chemical Pest Control.
In the large monoculture fields of much of modern agriculture, pests include such organisms as insects that eat plants, weeds that interfere with crop growth, and diseases that slow plant and animal development or even cause death. When used properly, synthetic chemicals have provided an effective, relatively easy way to provide such control. Chemical sprays can quickly respond to pest outbreaks.
Farmers have been choosing among crop plants and animals for specific characteristics for thousands of years. But modern agriculture has taken advantage of several more recent crop breeding techniques. The development of hybrid seed, where two or more strains of a crop are combined to produce a more productive offspring, has been one of the most significant strategies. Genetic engineering has begun to develop molecular techniques that selectively introduce genetic information from one organism to another, often times from very unrelated organisms, with a goal of capitalizing on specific useful traits.
But for almost every benefit of modern agriculture, there are usually problems. Excessive tillage led to soil degradation, the loss of organic matter, soil erosion by water and wind, and soil compaction . Large monocultures are especially prone to devastating pest outbreaks that often occur when pests encounter a large, uniform area of one crop species, requiring the continued and excessive use of chemical sprays. When used excessively, chemical fertilizers can be easily leached out of the soil into nearby streams and lakes, or even down into underground water supplies. Farmers can become dependent on chemical pest and weed control. Modern farm systems lack the natural control agents needed for biological pest management, and larger amounts of sprays must be used as pests rapidly evolve resistance. People also worry about chemical pollution of the environment by sprays and fertilizers, and the possible contamination of food supplies. Modern agriculture has become such a large user of water resources that overuse, depletion, saltwater contamination, salt buildup in soil, fertilizer leaching, and soil erosion have become all too common. Agricultural water users compete with urban and industrial use, and wildlife as well. Hybrid seed has contributed greatly to the loss of genetic diversity and increased risk of massive crop failure, as well as an increased dependence on synthetic and non-renewable inputs needed for maintaining high yield. Genetically engineered crops have the same negative potential, especially as the selection process takes place less and less in the hands of farmers working in their own fields, but rather in far away laboratories.
In the future, in order to take advantage of new technologies and practices, farming systems will need to be viewed as ecosystems , or agricultural ecosystems. By monitoring both the positive and negative impacts of modern farming practices, ecologically based alternatives can be developed that protect the health of the soil, air, and water on farms and nearby areas, lower the economic costs of production, and promote viable farming communities around the world. Organic agriculture, conservation tillage, integrated pest management (IPM), and the use of appropriate genetic techniques that enhance local adaptation and variety performance are a few of the possible ways of ensuring the sustainability of future generations of farmers.
see also Agricultural Ecosystems; Agriculture, History of; Agriculture, Organic; Agronomist; Breeder; Breeding; Fertilizer; Herbicides.
Stephen R. Gliessman
Brown, Lester R. "Struggling to Raise Cropland Productivity." In State of the World: 1998, eds. Lester Brown, Christopher Flavin, and Hilary French. New York: W.W. Norton and Company, 1998.
Gliessman, Stephen R. Agroecology: Ecological Processes in Sustainable Agriculture. Chelsea, MI: Ann Arbor Press, 1998.