Africanist development specialists, including geographers, rarely treat the roles of land and labor and their ecological dimension with as much rigor as they analyze the role of capital (Mascarenhas, 1983, p. 10; Kamarck, 1976, p. 4). Land and labor are often treated as stable variates without proper consideration of their volatile attributes. In the case of physical resources, factors such as rainfall reliability, potential evapotranspiration, soil erosion, and stability of soil nutrients and soil trace elements are not adequately treated in farming systems research in SSA. In the case of human resources, ethnic issues and demographic dynamics have not been addressed as crucial constraints to development. And yet, land and labor are the rich endowments of Africa on which depends a great deal of the economic potential (see also FAO, 1986c; OTA, 1988b; Mascarenhas, 1983, p. 14).