Well over 600 million people live in Africa south of Sahara. The vast majority of these people depend directly on the land for their sustenance. In the rainforests of central Africa and in the dry lands of the Kalahari, communities live by hunting and gathering fruits, nuts, tubers and leaves. Elsewhere, in more favorable environments, a vast array of agricultural systems has evolved, ranging from nomadic and transhumant livestock production through to intensive small holder mixed crop–livestock systems. Wood accounts for almost 95% of fuel used in rural areas throughout the continent.

Overall, only about 6% of Africa’s land is cultivated. Even so, the agricultural sector is the largest source of employment and provides a high percentage of export and foreign currency earnings. Although commercial agriculture is important in some areas, agriculture is predominantly small-scale subsistence or near subsistence farming, much of it based on shifting cultivation. In the past, agricultural development has aimed at replacing traditional practices with farming systems based on exotic cash and food crops with chemical inputs, large-scale irrigation and mechanization. More and more, however, it is being recognized that indigenous African farming systems, practices, crops and varieties are finely tuned to prevailing ecological conditions and must largely form the basis of sustainable agricultural development. SSA subsistence farmers are mainly women, who produce more than 75% of the household food through field cropping and home gardening.

The highest species diversity occurs in equatorial areas because species diversity tends to be highly correlated with annual rainfall. Endemism, which is the proportion of species not found anywhere else in the world, is high in the region. Madagascar, for example, is very rich in the number of endemic species, as are other islands, such as Mauritius and Sao Tome and Principe. On the mainland, areas rich in endemic species include lowland rainforests (e.g. in Côte d’Ivoire, Liberia, Nigeria, Cameroon and Gabon), montane forests (mainly in eastern Zaire, western Uganda and Rwanda) and coastal areas (particularly in Kenya and Tanzania). In the arid areas, major centres of endemism include Somalia, Ethiopia and Namibia.

SSA has given the world some of its most important crops. Those that contribute significantly to subsistence requirements, at least locally, include five cereals, four legumes, three cucurbits, five oil seeds, twelve vegetables, four roots and tubers and five to ten fruits. Among these crops are sorghum, millets (finger, pearl), teff, fonio, Bambara groundnut, cowpea, Cleome gynandra, water melon, melon, gourds, sesame, African oil palm, Noug, yam, Hausa potato and cocoyam. Introduced crops such as maize, rice, cassava, beans and cacao also contribute significantly to African agriculture, and some have developed secondary centres of diversity on the continent. In addition to the widespread staple crops, there are many species that are very important in relatively restricted geographic areas. Among these are teff, fonio, bambara groundnut and some other minor millets as well as vegetables, fruit trees and medicinal plants.

Western and central Africa are home to a rich and diverse flora. The world’s major regions of crop diversity include the Ethiopian highlands, the Sahelian transition zone, with the delta of the Niger river, and the humid forest zone of West and central Africa. The highlands of Ethiopia are a centre of origin for coffee, and a centre of diversity for sorghum, lentil, wheat and barley. Tropical West Africa is a centre of origin and diversity for African rice (Oryza glaberrima), oil palm, yams and cowpeas.

There is considerable inter- and intraspecific diversity of crops, herbaceous and forestry species. A number of species endemic to the subregion include millet (Pennisetum spp.), sorghum (Sorghum spp.), cowpea (Vigna unguiculata), voandzou (V. subterranea), African rice (O. glaberrima), fonio (Digitaria exilis) and yams (Dioscorea spp.), among others. Such endemic species have specific genetic constitutions that confer resistance to diseases and pests, the ability to produce in marginal soils, and resistance to some environmental hazards such as drought. These species are also consumption preferences (culinary and organoleptic qualities) of the population, and they probably hold the key to food security and sustainable development in the subregion. The genetic base of these crops is, however, being seriously eroded, largely as a result of climate change, socio-economic factors, natural disasters and armed conflict.