@INBOOK {MEERSCH:1993, title = {Evolution of plant biomass and nutrient content in relation to soil fertility changes in two alley cropping systems}, author = {van der Meersch, M. and Merckx, R. and Mulongoy, K. }, editor = {Mulongoy, K. and Merckx, R. }, year = {1993}, type = {Soil organic matter dynamics and sustainability of tropical agriculture}, pages = {143--154}, publisher = {John Wiley & Sons with Satce Publishing (UK), the Catholic University of Leuven (Belgium), IITA, Ibadan}, address = {Ibadan, Nigeria}, }