@INBOOK {CARSKY:1998a, title = {Maintenance of soil organic matter and N supply in the moist savanna zone of West Africa}, author = {Carsky, R. and Jagtap, S. and Tian, G. and Sanginga, N. and Vanlauwe, B. }, editor = {Lal, R. }, year = {1998}, type = {Soil quality and agricultural sustainability}, pages = {223--236}, publisher = {Ann Arbor Press}, address = {Chelsea, MI, USA}, }