Phosphorus Release in Sodium Ion Dominated Soils

Publisher Website
Google Scholar
Abstract
Calcareous sodic soils having high sodicity and high pH often maintain high solution P concentration. 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 three 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. In the sodic soil environment, release of P can be accounted for by the dissolution of various forms of Ca‐P compounds at high alkalinity and pH. Cultivation of alkali soils improves the organically bound P forms. 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.