@INBOOK {IWUAFOR:2001, title = {On-farm evaluation of the contribution of sole and mixed applications of organic matter and urea to maize grain production in the savanna}, author = {Iwuafor, E. * and Aihou, K. * and Jaryum, J. and Vanlauwe, B. and Diels, J. and Sanginga, P. and Lyasse, O. }, year = {2001}, type = {Integrated plant nutrient management in sub-Saharan Africa: from concept to practice}, pages = {185--197}, publisher = {Wallingford, UK: CABI}, }