ABSTRACT
In French-speaking West Africa, over the last 25 years, research on present-day geomorphic processes has progressed on two fronts: generally qualitative studies by geomorphologists, either regional or thematic in character; and applied agronomic studies carried out by pedologists concerned with soil conservation and crop protection. Indeed, with the reduction in length of the fallow period, through combined demographic and socio-economic pressures, accelerated erosion phenomena have appeared in many places. The seasonally wet intertropical area of West Africa forms a transition zone between the humid tropics and the deserts. Attention may be directed to the general climatic features which in turn determine the importance and nature of present-day processes. The rainfall regime depends on the existence of two principal tropical air masses, continental and maritime, which confront each other along the Intertropical Convergence Zone (ITCZ). The annual migration of the ITCZ leads to the appearance of two contrasting seasons: the dry season and the wet season (winter).
