Effect of Phosphorus and Lime Application on Phosphorus Availability at Varying Periods and Soil Moisture Conditions

The results of an incubation experiment conducted to study the individual and combined effect of phosphorus (0, 25, 50 and 75 ppm P₂O₅), calcium carbonate (0, 5, 10, 15 and 20%) and moisture (saturation, field capacity-FC and 50 per cent of field capacity-50% FC) showed that availability of P (Olsen extractable P) decreased with time up to a certain limit but it showed increasing trend thereafter. The availability of P was found to increase significantly with the increasing levels of P and moisture. The effect of lime application was apparent only beyond 5% CaCO₃ level, although further increase in lime application from 10 to 20 per cent could not affect P fixation. Very high fixation of P could be attributed to high clay content as lime produced relatively low P fixation.