@INBOOK {MANYONG:2002, title = {Agricultural transformation and fertilizer use in the cereal-based systems of the northern Guinea savanna}, author = {Manyong, V. and Makinde, K. and Ogungbile, A. }, year = {2002}, type = {Integrated plant nutrient management in sub-Saharan Africa: from concept to practice}, publisher = {Wallingford, UK: CABI; International Institute of Tropical Agriculture (IITA)}, note = {chapter 5}, }