摘要
Population growth has often been suggested to explain field expansion in Sahelian land use systems. Yet recent research increasingly acknowledges that villagers do not necessarily enlarge their fields as a response to increased food requirements. This paper suggests that drivers such as population growth should be connected to land cover changes by taking villagers' individual land use decisions into account. The links between drivers, individual land use decisions and land cover changes are explored in a small village in northern Burkina Faso, Yomboli, for the period 1956-2010. The analysis is based on measurements of the cultivated area, participant observation, interviews and questionnaires. Three waves of land cover changes are identified: field expansion between 1956 and 1991; field contraction from 1991 to 1995; and field expansion and contraction between 1995 and 2010. The results show shifting links between drivers, individual land use decisions and land cover outcomes throughout the period. The paper argues that villagers' earlier decisions on field enlargement have primarily been propelled by the driver of population growth, whilst recent decisions seem to be more influenced by individual rationales than general drivers of change. Moreover, the results show that villagers' decisions on field size are not solely economic judgements of cost and benefit. Rather, their decisions are anchored in three broad categories of rationality: economic, ecological and sociocultural rationality. This does not imply that villagers are economically ignorant, but that the concept of rationality assumes different meanings in a Sahelian context. The findings demonstrate as well the shifting influence of these rationalities as economic rationality has been replaced by sociocultural rationality over the last decade.