Journal of the Indian Society of Soil Science

A laboratory incubation study was conducted to periodically assess the Olsen's P status in an alkaline (pH 8.2) Typic Ustochrept as affected by different sources of rock phosphates alone or mixed with pyrites. There was increase in Olsen's P status of the soil over no-P control, irrespective of source of rock phosphates and levels of P application. Further, application of pyrites along with rock phosphates resulted in higher Olsen's P status of the soil for all ratios of P:S in the mixtures. Pre-incubated rock phosphate-pyrites mixtures proved better in extracting available P than the unincubated ones. But in bothsets of incubation, the performance of rock phosphates was of the same order: Jhabua > Mussoorie > Maton > Purulia. The wider the ratio of P:S in rock phosphate-pyrites mixtures and higher the level of P application, the higher was the Olsen's P status of the soil throughout the period of incubation for all sources of rock phosphates.