Early Agricultural Systems

At present there is insufficient archaeological evidence to determine where and how frequently agriculture may have arisen independently, but, in addition to SW Asia and China, it is clear that agricultural systems based on distinctive assemblages of crops and domestic animals also developed in tropical America and northern tropical Africa. In each of these four regions, one or more locally domesticated cereal and herbaceous legume became staple crops: in SW Asia, wheat, barley, lentil, pea, and chickpea; in China, rice, common and foxtail millet, and soya bean; in tropical America, maize and Phaseolusbeans; and in northern tropical Africa, sorghum, finger and pearl millet, cowpea, and two species of groundnut. The legumes complemented the cereals nutritionally by providing oils and essential amino acids, such as lysine, that the cereals lacked. Domesticated roots and tubers were also staple sources of carbohydrate, notably manioc (see cassava), potato, and sweet potato in tropical America, yams in Africa, and taro and yams in SE Asia.