KINETICS OF POTASSIUM ADSORPTION BY ALFISOLS OF GREECE

The kinetics of potassium desorption from solution to exchangeable pha ses was investigated on Alfisol Haploxeralf samples, which were first saturated with calcium in the form of CaCl2. Potassium adsorption was studied using 5, 25, 100, 125, 150 and 200 mugK/ml solutions and equil ibrated for 10, 20, 30, 45, 60, 120, 180 and 1440 minutes. Soil pH var ied between 4.0 and 9.0. Equilibrium in potassium adsorption occurred faster in lower concentrations and higher pH values. Adsorption data w ere plotted according to modified Freundlich, Elovich and parabolic di ffusion equations. Comparisons of coefficients of determination (r2) i ndicated that all of the tested models successfully demonstrated potas sium adsorption with the modified Freundlich equation and the Elovich equation being superior.