PHOSPHORUS RELEASE IN SODIUM-ION DOMINATED SOILS

The effect of high exchangeable Na, high pH, and alkali anions and carbonates on the release of inorganic P was investigated in soils representing the 3 major benchmark sodic soil series found in the Indo-Gangetic plains of India. Sodium saturation of the exchange complex, high pH, carbonate ions, and low electrolyte level shifted the solid P-solution P equilibrium in favor of maintenance of high P concentrations in aqueous solutions. Together or in combination, high sodicity, high pH, and the presence of carbonate ions at low salinity markedly increased P desorption and P availability in sodic soils. Cultivation of these soils improves the organically bound P forms. -from Authors