Declining yam productivity in Benin Republic (West Africa)calls the need for a study to determine both the effect of fertilization on yam (Dioscorea spp.) yield and the best agronomic management options available for stabilizing yam productivity. This book addresses the above issues and analyzes the effect of fertilizer application on total biomass production, tuber yield and dry matter partitioning pattern, in two species of yam (Dioscorea alata var. Florido and Dioscorea rotundata var. Kokoro). An attempt has also been made to simulate the effect of fallow availability on yam production by using the Environmental Policy Integrated Climate (EPIe model. In order to increase yam productivity and maintain soil fertility in the Upper Oum basin, fallowing the crop land is not a viable option due to increased demographic pressures. Mineral fertilizer application appears to be essential, but its high cost and accessibility restraints, limit its use by the farmers. The solution lies in providing mineral fertilizers to the farmers at subsidized rates. Additionally, nitrogen fixing crops could partially provide the N inputs needed, if included within crop rotations.