As the largest country in Africa, Sudan is endowed with significant economic potential in relation to its agricultural resources. It has a total cultivable area of about 207.4 million acres, of which less than 10% is currently being cropped. In addition, the water resources are substantial; all three Niles flow through the country. But these resources are underexploited; for example, less than 50% of the total water potential is now being utilized (D'Silva 1985). Sudan's agricultural potential also lies in its sectoral diversity. The agricultural sector contains three subsectors: irrigated, traditional rainfed, and mechanized rainfed. Each subsector produces food and cash crops for local consumption and exports. The irrigated subsector is dominated by large government schemes, such as the Gezira and Rahad, which are operated as parastatals. These schemes specialize in the production of cotton, groundnuts, wheat, sorghum, and sugarcane. This subsector covers more than 4 million acres; the mechanized rainfed subsector covers more than 7 million acres and is confined to the production of sorghum and sesame. The traditional subsector, containing the majority of the population, covers more than 9 million acres. Besides being the major source of the nation's livestock, this subsector also produces sorghum, millet, groundnuts, sesame, gum arabic, and other minor crops. Because of the large land area of the country, the mechanized and traditional rainfed subsectors are widely dispersed. They are found in the east, south-center, and the west, with the irrigated subsector located in the central and northern parts of the country (D'Silva 1985). Like other less developed sub-Saharan countries, agriculture is important in the economy of the Sudan. If the comparison is confined to productive sectors alone, the share of agriculture in gross domestic product (GDP) will increase to 75%. The contribution of agriculture to total employment and total foreign exchange earnings is estimated at 44% and 93%, respectively. In addition, agriculture provides most of the nation's domestic food supply, and most of the nonagricultural industry depends upon agriculture for raw materials.