The purpose of this research is to clarify the mechanism of how drought and flood damage occur from the perspective of man-made disasters, verify whether the fallow band system that is a topsoil preservation and increased food production technology newly developed by the applicant is effective as a technology for preventing droughts and floods, and to also clarify the optimal diffusion methods for this system. Specifically, the results of measurements in the field conducted jointly with the International Crop Research Institute for the Semi-Arid Tropics will be expanded using a three-dimensional soil moisture dynamics prediction model to clarify the mechanism of how droughts and flood damage occur in the Sahel region, and verify effects of the introduction of the fallow band system in agricultural areas in terms of drought and flood damage mitigation and increased yields. In addition, agricultural economic and sociological approaches will be used to clarify the optimal methods for the diffusion of the fallow band system in the Sahel region.