(Faculty of Agriculture, University of Ife, 1981) Osiname, O. A.
Trials were conducted at three locations on Alfisols in southwestern Nigeria to study the optimum phosphorus - zinc balance in the soil for field grown maize (Zea mays L.) and cowpea (Vigna unguiculata s.sp. ungzciculata L. Walp). The incidence of P induced Zn deficiency in maize was observed to be more probable in the sandy soils of the savanna zone than in the sandy loam soils of the forest zone. Correcting P deficiency without correcting Zn deficiency resulted in lower maize yields. In soils with Bray-1 P test of >7.0 ppm and 0.1N HCL extractable Zn of G 1.0 ppm, further addition of P. was observed to induce Zn deficiency in maize. Cowpea was less sensitive to either the deficiencies of P and Zn or to the incidence of P induced Zn deficiency.