The project Poverty Alleviation and Enhanced Food Availability in West Africa through Improved Yam Technologies proposed to improve yam production in five West African countries (Nigeria, Bénin, Togo, Ghana, Côte d'Ivoire) during the period from 2000 to 2003. A recognized need for productive, stable yam-based systems is the maintenance of soil fertility. Trials were initiated in each country on the fertilizer needs of yam and in several countries on improved fallows or leguminous intercrops. A review of information was also recommended with the objective of guiding future research. A search of all available literature was agreed, including sources with poor accessibility (grey literature) that might be available in NARS libraries.