Abstract

The influence of reaction time and ionic environment on P adsorption was studied on eight representative soils of Tamil Nadu. P adsorpiton rate was rapid initially followed by a slow process. High level laterite soil adsorbed more P than the rest and within 48 hours 80 per cent of the P adsorption was observed. An equilibration period of six days was found to be essential for attaining complete or near complete equilibrium in these soils. The ionic environment was found to influence the P adsorption greatly. Solutions containing Ca ions instead of K and Na ions increased P adsorption and decreased P concentration in the equilibrium solution. Increasing ionic strength of Ca also increased the P adsorption and decreased the P concentrations in the equilibrium solutions and the pH.

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