Phosphate Buffering Capacity and Supply Parameters Affecting Phosphorus Availability in Vertisols

Phosphorus availability to plants has been variously correlated with the soil P supply factors of quantity, intensity and buffering capacity. The underlying cause of the differing importance of quantity, intensity or buffer capacity to P availability is probably the relative effect of these factors on the diffusion of P. Phosphorus is primarily transported to the root surface through the process of diffusion (Wild 1981). Olsen and Watanabe (1963) estimated on the concentration ofP in the soil solution (intensity), the ability of the soil to replenish solution P (i.e. buffer capacity and the diffusion coefficient ofP in soil)