@INBOOK {KYUMA: 1986, title = {Evaluation of the fertility of the soil}, author = {Kyuma, K. and Kosaki, T. and Juo, A. S. R. }, year = {1986}, type = {The Wetlands and Rice in sub-Saharan Africa edited by A.S.R. Juo and J.A. Lowe}, pages = {43--58}, }