@INBOOK {CARSKY:2001a, title = {Nutrient balance model for design of sustainable yam cropping systems}, author = {Carsky, R. and Wolo, N. and Manyong, V. and Tian, G. }, year = {2001}, type = {Root crops in the 21st Century: proceedings of the 7th Triennial Symposiu, of the International Society for Tropical Root Crops (ISTRC) - Africa Branch, Oct 1998}, pages = {198--209}, publisher = {International Society for Tropical Root Crops (ISTRC) - Africa Branch; Government of Benin}, note = {RTB; Root and Tuber; Yam}, }