Abstract

O. C. Nwoke , J. Diels, R. C. Abaidoo and N. Sanginga

The differential ability of genotypes of soybean (Glycine max) and cowpea (Vigna unguiculata) to thrive under lowphosphorus (P) conditions by utilising P from sources with low solubility was assessed in a greenhouse study with a low- P savanna soil collected from a research field in Fashola, south-western Nigeria. The P sources added (21 mg P kg-1 soil) were calcium phosphate (Ca-P), iron phosphate (Fe-P), aluminium phosphate (Al-P), and triple superphosphate (TSP). Soil without P addition served as a control. The soybean genotypes were TGm 1039, TGm 1196, TGm 1293, TGm 1360, TGm 1420, TGm 1511, and TGm 1540. The cowpea genotypes were Dan -ila, IT89KD-349, IT89KD- 391, IT90K-59, and IT82D-716. Nearly all the soybean genotypes significantly increased their shoot dry matter yield (DMY) and accumulation of P from the various sources when compared with the control; the ranking for P acquisition was control