?PHOSPHORUS ADSORPTION IN REPRESENTATIVE SOILS OF PESHAWAR VALLEY (NWFP)

Abstract

Soil incubation experiment was conducted to study some aspects of phosphorus (P) cycling in soil series of Peshawar
Valley. Phosphorus adsorption before and after incubation was studied, physico-chemical properties and AB-DTPA
extractable P were determined. Soil samples containing 19 to 22% (w/w) moisture were incubated at 25°C for 7 weeks. The
amount of P adsorbed by the soil from KH2PO4 solution (0 to 50 ?g/ml) before and after incubation was calculated by the
difference between the amount of P in solution after 24 h shaking and the initially amount was present. These soils contain
CaCO3, which might adsorb organic P, or form insoluble Ca phosphates. The adsorption isotherm plots highlight the ability
of these soils for P sorption. Soil having high amount of CaCO3 and clay have more affinity for P adsorption in the soil
system.