@INBOOK {VANLAUWE:2001, title = {Combined application of organic matter and fertilizer}, author = {Vanlauwe, B. and Wendt, J. and Diels, J. }, year = {2001}, type = {Sustaining soil fertility in West Africa}, pages = {247--279}, publisher = {Soil Science Society of America (SSSA); American Society of Agronomy}, }