ALLEVIATING SOIL FERTILITY CONSTRAINTS TO FOOD-PRODUCTION IN WEST AFRICA - EFFICIENCY OF NITROGEN FERTILIZERS APPLIED TO FOOD CROPS

An overview is provided of the N efficiency research conducted within the West African Fertilizer Management and Evaluation Network (WAFMEN). Factors such as N rate, mode of N fertilizer application and choice of N sources for different agroecological zones of West Africa are discussed in relation to crop yield response. The interactive effects of cropping density and rainfall on N efficiency and yield are examined with particular emphasis on production of millet in Niger. The potential role of new, slow-release fertilizers as well as urea amended with urease inhibitors is mentioned in relation to present and future fertilizer N requirements in West Africa.