Optimizing Fertilizer Use in Africa (OFRA).
Charles S. Wortmann, Keim 369, University of Nebraska - Lincoln, Lincoln, NE, Lydia Wairegi, CABI, Nairobi, Kenya, Kayuki Crammer Kaizzi, Kawanda ARI, National Agricultural Research Organization, Kampala, Uganda and Kassoum Maman Nouri, INRAN, Maradi, Niger