Institution: | 1. ZEF, Zentrum für Entwicklungsforschung, University of Bonn, Walter-flex str. 3, D-53113 Bonn, Germany;2. Tropical Soil Biology and Fertility Institute of CIAT (TSBF-CIAT), P.O. Box 30677-00100, Nairobi, Kenya;3. International Crop Research Institute for the Semi-Arid Tropics (ICRISAT)-West and Central Africa Unit. P.O. Box 12404, Niamey, Niger;4. Savanah Agriculture Research Institute (SARI), P.O. Box 52, Nyankpala, Tamale, Ghana |