Farming Systems

Farming systems are the various methods of crop production to obtain human food and animal feed, fibers and other industrial products, or energy crops. Geographical differences are due to historical processes, environmental conditions, and the level of capitalization. Each farming system has specific production objectives, inputs and means of production, and a degree of intensification. Market farming is very input-intensive with pesticides, herbicides, fertilizers, and mechanization, while selfconsumption farming ensures food for the household, and is very intensive in labor and land. There is also a broad range of combinations of agriculture with other production systems, such as livestock breeding, aquaculture, or forestry.

The most universal farming system is polyculture, which provides a diversity of food and maximizes labor and land occupation. Crop rotation increases soil productivity and reduces pest pressure. Less than a 25 percent of the product is marketed. The farming practices have a strong cultural component and are adapted to the local environmental conditions, producing heterogeneous landscapes.

Conversely, monoculture systems rely on a very small number of crops and an efficient use of inputs; they are very adaptable to market variations, but are vulnerable to changes in environmental conditions and produce homogeneous landscapes. Monoculture is common in large countries with a market-oriented economy.

Mixed agriculture, which combines polyculture with animal husbandry, is a widespread system because it generates various synergies: animals graze stubble and are employed for cultivating the fields, harvesting crops, transporting farm products, and manure is used as a fertilizer.

Swidden or shifting agriculture—locally known as milpa in Mexico or fang in Asia—is a remnant of very old practices, and its survival is threatened by sedentarization, the expansion of other agricultural systems, and cattle farming and forestry. It is an itinerant form of cultivation that sustains small communities in tropical rainforests in Central America, the Amazon Basin, Africa, southeast Asia and Indonesia. Small forested areas are cleared, vegetation is burned and seeds are scattered over ashes, a practice known as slash and burn. After the first harvest, productivity progressively decays in the following years so that, after four to five years, the community changes to another area to resume cultivation, allowing the forest to regenerate for 10–20 years.

Ley farming is practiced in areas with sufficient soil moisture or where irrigation is accessible. Cereals alternate with fodder or legumes, such as alfalfa, which biologically fixes nitrogen. Dry farming is an adaptation to climates with low precipitation—below 500 millimeters—using no irrigation; however, it entails a high risk of erosion.

Irrigated agriculture has some of the highest levels of productivity per unit area, as in the cases of Asian paddy rice fields and Mediterranean vegetable gardens. It is commonly a form of polyculture or mixed agriculture that combines with various livestock, depending [Page 647]on the geographical area: swine, cattle, fowl, or aquaculture. The areas of cultivation—valleys, flood plains, or slopes where land is scarce—are linked to water availability and elaborate systems of water storage. In monsoon and eastern Asia, small family plots yield two or three rice crops a year after multiple labor-intensive operations, with little mechanization and using organic fertilizer.

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