@INBOOK {BALASUBRAMANIAN:1992, title = {Five years of research on improved fallow in the semi-arid highlands of Rwanda}, author = {Balasubramanian, V. and Sekayange, L. }, editor = {Mulongoy, K. and Gueye, M. * and Spencer, D. }, year = {1992}, type = {Biological nitrogen fixation and sustainability of tropical agriculture}, pages = {405--422}, publisher = {John Wiley & Sons; Sayce Publishing; International Institute of Tropical Agriculture (IITA); AABNF}, address = {Ibadan, Nigeria}, }