SOYABEAN RESPONSE TO DIFFERENT LEVELS OF APPLIED PHOSPHORUS AND NITROGEN IN THE SOUTHERN GUINEA SAVANNA OF NIGERIA

Abstract

Two cultivars of soyaben (Glycine max (L) Merrill) were grown for two years under field conditions to evaluate the effects of N and P on nodulation and yield components. Inhibitory effects of N and on nodulation were observed. Yield components of the profuse nodulating cultivar (TGM 597) were negatively correlated, while those of the poor nodulating cultivar (TGX 536 - 62D) were positively correlated with applied N, indicating differential cultivar response to N. Phosphorus increased nodulation and yield of the two cultivars. There were indications that the optimum level of P for optimum soyabean yield would vary significantly with the level of the native soil available P, emphasizing the importance of soil analysis in P recommendations for soyabean.