A large area around Kano in northern Nigeria has high rural population densities and long-established, intensive smallholder agriculture. This is notwithstanding a semiarid climate with variable rainfall and poor soils. The population is growing (although the rate is uncertain) and metropolitan Kano, with a population of over a million, is expanding rapidly. A conventional view of the relations between population growth, urban expansion, and ecology might expect evidence of stress in the agricultural system. On the contrary, this system exhibits stable characteristics. It is based on three interactive components (crops, farm trees, and livestock). Indigenous management is directed toward sustainability, and indigenous small-scale technologies provide a sound basis for further improvements in productivity. Economic diversification at the household level provides supplementary income.
Longitudinal studies of change in African conditions suffer from a scarcity of data and problems of continuity, compatibility, and completeness. For the present study, the baseline is a field survey carried out in Ungogo District, 10 km north of Kano, in 1964 ( Mortimore and Wilson 1965).1 My living in or near Kano for the following two decades permitted an informal monitoring of change, but having transferred my intensive field investigations further north since the 1970s, I have to draw on studies by others for more recent data, in particular, Hill ( 1977) and Amerena ( 1982).2 and by my colleagues in the Kano Rural Energy Research Project ( Cline-Cole et al. 1987). I also make use, for comparative purposes, of field studies carried out at greater distances from Kano, both within and outside the Close-Settled Zone (CSZ). The time frame for this study is two decades, 1964-86, but where the opportunity arises, trends will be viewed in longer perspective. Such a perspective is em-