Analysis and evaluation of the agro-potential of inland valleys in the Upper Ouémé catchment (Benin, West Africa)

Using a multi-level approach, this study aims to analyse the current and future agro-potential of the inland valleys in the Upper Oueme catchment of central Benin. As no sufficient inland valley database was previously available for Benin, a detailed field survey of physical and socioeconomic properties of inland valleys was carried out. This was done in cooperation with the Cellule bas-fond, the governmental structure for inland valley management in Benin. In addition, remote sensing data were analysed in order to locate inland valleys in remote areas. The catchment properties of the inland valleys were determined using GIS-data of soils, geology and topography. For selected inland valleys, detailed field studies of soil properties (physical and chemical) were conducted. The results attained here will be used as input for a future integrated modelling approach to assess the agro-potential of the inland valleys in the Upper Oueme catchment. Based on the results of the survey, the GIS-analysis, and the modelling approach, a decision support tool will be developed in cooperation with stakeholders. The tool will aid the Cellule bas-fond and the Communes to decide the inland valleys where agricultural exploitation is feasible, and where to best install water management infrastructure. 1. Background and aim of the study The rapidly growing population in sub-Saharan Africa necessitates an increase of food production. In some regions, arable land has already become scarce and the degradation of soils continues due to the shortening fallow period. Inland valleys offer extensive, relatively unexploited potential for agricultural production due to their higher water availability, lower soil fragility and higher fertility compared to the upland areas. The scarcely populated Upper Oueme catchment in central Benin has been subject to high population growth in the last decade, due to high fertility and high immigration rates. This has caused an expansion of agricultural areas, and led to both deforestation, and shortages of immediately available land for agricultural production. Therefore, the exploitation of inland valleys will only become more important to this region’s future. The aim of this study is to analyse the current and future agro-potential of inland valleys in the Upper Oueme catchment, considering aspects of global change.