CHARLES F. YAMOAH and JAMES R. BURLEIGH 2
~This article is a contribution jkom the Universi O' o[ Arkansas' USA ID-supported Farming
Systems Research Program ( FSRP), USA1D 696-0110. B.P. 625, Kigali. Rwanda
:Soil Scientist~Agronomist and Pr~fi'ssor of Plant Sciences respectiveO. Present address:
College qJAgric.. Cal(/brnia State Univ., Chico, CA 95926-0310, USA