Farming systems dynamics: Impact of increasing population density and the availability of land resources on changes in agricultural systems. The case of Sukumaland, Tanzania

Abstract

The changes in agricultural production systems over the period 1875 till 1990 have been analysed for three districts belonging to Sukumaland, Tanzania. The analysis is based on historic information for the early period, on data from agricultural studies conducted in 1945 and 1961, and on recent field studies in 1990–1992. Increasing population densities and therefore decreasing availability of agricultural land per capita has occurred generally. In addition, there exist important agro-ecological differences between the three districts that have also been responsible for the present diversity in farming systems. Among these, differences in rainfall and the relative availability, quality and type of land resources, as related to toposequential land units, are of major significance. Together these factors determined the potential and subsequently the changes that have occurred during the past 50 years in the major land use systems and crops for the various parts of Sukumaland. In anticipating the direction of agricultural developments and consequently the sustainability of actual and future agricultural systems, differences in the principle agro-ecological factors of soils in relation to the topography (landscape units) should be considered more closely. Such information should be used to complement the broad socio-economic considerations on which most policy decisions, including development aid, are currently based.