0.11 Biological  (Page 3/4)

There are two types of food production: traditional agriculture and industrialized agriculture . Industrialized agriculture is known as high input agriculture because it utilizes large amounts commercial fertilizers, pesticides, water and fossil fuels. Large fields of single crops ( monoculture ) are planted, and the plants are selectively bred to produce high yields. The large amounts of grain produced by this method also foster the production of large numbers of livestock animals in feedlots. Most of the food produced by industrialized methods is sold by farmers for income. This type of food production is most common in developed countries because of the technology and high expenses involved. However, large industrialized plantations specializing in a single cash crop (e.g. a crop specifically raised for income such as bananas, cocoa, coffee) are found in some developing countries.

Traditional agriculture is the most widely practiced form of food production, occurring mostly in developing countries. It can be classified further as either traditional subsistence or traditional intensive agriculture. The differences between the two involve the relative amounts of resources input and food produced. Subsistence agriculture uses only human and animal labor and only produces enough food for the farmer's family.

Traditional, intensive agriculture utilizes more human and animal labor, fertilizers and irrigated water. It may also involve growing methods such as intercropping designed to maintain soil fertility. Intercropping involves planting two crops simultaneously (e.g., a nitrogen-fixing legume crop with a grain crop). The increased production resulting from the more intensive methods provides enough food for the farmer's family and for selling to others in the local area.

Rangelands tend to be grasslands in semiarid to arid regions that are not suited to growing crops without irrigation. The grasses provide food for grazing animals such as cattle and sheep. These animals not only provide meat for food, but are also a valuable source of leather and wool. In regions with regular rainfall, livestock can be raised in set areas of open range. In more arid climates, nomadic herding of livestock may be necessary in order to find sufficient supplies of grass.

Overgrazing of rangeland by livestock can result in desertification of the area. In developed countries, livestock raised on rangeland are often fattened with grain in feedlots before slaughter.

The ocean provides the biggest location of fisheries. Commercial methods used to harvest these fisheries depend upon the types of fish (e.g. surface dwelling, bottom dwelling) being produced and their tendency to form schools. Trawlers drag nets along the ocean bottom to catch bottom dwelling (demersal) fish such as cod and shellfish such as shrimp. Large schools of surface dwelling (pelagic) fish, such as tuna, are caught by purse-seine fishing in which a net surrounds them and then closes like a drawstring purse. Drift nets up to tens of kilometers long hang like curtains below the surface and entangle almost anything that comes in contact with it. The major problem with all of these fishing methods is that they tend to kill large numbers of unwanted fish and marine mammals that are inadvertently caught.