@PROCEEDINGS {NANGJU:1975d, title = {Interaction of fertilizer use on cowpea(Vigna unguiculata(L.) Walp.) and soybean (Glycine max.(L) Merill) Nodulation and Nitrogen fixation in the Lowland Tropics}, author = {Nangju, D. }, booktitle = {Presented at conference on Biological Nitrogen fixation in Farming Systems of the Tropics}, year = {1975}, publisher = {IITA}, }