Influence of Soil Properties on P Sorption Characteristics and Yield of Soybean (Glycine Max (L.) Merr.) In Some Alfisols in Benue State, Nigeria

Studies were conducted using somealfisols in Benue state to evaluate the influence of soil properties on P sorption characteristics and yield of soybean (Glycine max (L.) Merr.).Significant and positive relationships existed between the soil organic matter content and the phosphate adsorption capacity (K) of these soils (r= 0.981). There was also a significant and positive relationship between the aluminum oxides and the clay content of the soils (r= 0.974). There was a negative but significant relationship between the Bray-1 P and the phosphorus buffer capacity (PBC) of these soils (r= -0.975) while the Olsen P related negatively and significantly with the iron oxide content (r= - 0.978) and the calcium P fraction (r= - 0.987) .No significant relationship existed between the solution phosphate concentration(SPC), standard phosphate requirement(SPR) and any of the yield parameters. PBC related negatively and significantly with total P in the plant biomass (r= -0.667) and showed a positive and significant relationship with the seed weight (r= 0.605). K showed a positive and significant relationship with P in plant biomass (r= 0.661). Clay content showed negative and significant relationships with pod number, seed weight and dry matter yield (r= -0.602, - 0.650 and – 0.658) respectively. The relationship between the iron P fraction and the total P in plant biomass was positive and significant (r = 0.587) while that with the seed weight was negative and significant (r= - 0.579). There was no significant relationship between the aluminum P fraction and any of the yield parameters but the calcium P fraction showed significant and positive relationships with the pod number and seed weight. (r = 0.633 and 0.687). Bray -1 P also showed a positive and highly significant relationship with the dry matter yield (r = 0.736). Understanding the phosphorus adsorption chemistry of these soils would be essential in the estimation and management of fertilizer rates and practices aimed at obtaining an optimum yield of soybean on these soils.