Agriculture is by far the single most important economic activity in Africa. It provides employment for about two-thirds of the continent’s working population and for each country contributes an average of 30 to 60 percent of gross domestic product and about 30 percent of the value of exports. Nonetheless, arable land and land under permanent crops occupy only about 6 percent of Africa’s total land area.
Except for countries with sizable populations of European descent—such as South Africa, Zimbabwe, and Kenya—agriculture has been largely confined to subsistence farming and has been considerably dependent on the inefficient system of shifting cultivation, in which land is temporarily cultivated with simple implements until its fertility decreases and then abandoned for a time to allow the soil to regenerate. In addition, over most of Africa arable land generally has been allocatedthrough a complex system of communal tenure and ownership rather than through individually acquired title, and peasant farmers have had rights to use relatively small and scattered holdings. This system of land ownership has tended to keep the intensity of agricultural production low and has inhibited the rate at which capital has been mobilized for modernizing production. A number of countries have made efforts to raise productive levels by selecting better varieties of seeds and planting materials, using tractors and other mechanized equipment, or increasing the use of mineral fertilizers and insecticides. Such measures, however, have been relatively limited, and they have raised concerns about their part in accelerating soil erosion and desertification. In areas of cash crop production, land has become private rather than community property, and cultivation is intensive.
The persistence of relatively low-productivity agricultural systems over large parts of the continent also stems from a lack of integrationbetween crop production and animal husbandry. Traditionally, sedentary cultivators like the Hausa in Nigeria and the Kikuyu in Kenya live apart from their nomadic herdsmen neighbours (the Fulani and Maasai, respectively), with the result that over large areas of the continent farmers do not have access to animals for draft power or to manure for fertilizer. The incidence of such insect pests as the tsetse fly also discourages mixed farming in many areas.
The need to sharply increase food production to meet the demands of a rapidly growing population, however, has remained paramount. Intense research at such centres as the International Institute of Tropical Agriculture in Ibadan, Nigeria, has been directed at developing high-performing varieties of crops and designing more appropriate cropping systems. One product of such research is a genetically improved strain of corn (maize). Corn is not in itself a balanced food, being deficient in some amino acids, but a scientific breakthrough in the mid-1960s resulted in an increase of the amino acids lysine and tryptophan in certain new varieties of corn called opaque, or high-lysine, strains. These varieties initially produced low yields, were more prone to disease and vermin, and had a soft texture that was not desirable. Breeding programs, however, corrected these defects, and the new strains began to improve the nutritional value of diets in Africa (which consist mainly of corn preparations).