Efficiency of primed rock phosphate for grain production in rice

Abstract

Potted plant studies were conducted in five major rice soils of Kerala namely karappadom, laterite, kayal, coastal sandy and kole soils to evaluate the efficiency of primed rock phosphate in moist aerobic soil with superphospate applied at flooding. Fractionation studies on the fate of applied phosphate revealed that priming of rock phosphate in moist aerobic soil resulted insubstantial conversion of phosphate to iron phosphate and aluminium phosphate and these products increased availability of phosphorus to rice on submergence. Primed rock phosphate was found to be as efficient as superphosphate in karappadom, kayal and coastal sandy soil in yield and uptake of phosphorus. But in laterite soil it was found to be significantly superior to superphosphate.