Effectiveness of Indian Rock Phosphates in Acid Soils

The effectiveness office Indian and one imported (Jordan) rock phosphates as P source for wheat and rice plants in three acid soils was evaluated in greenhouse. Using ³²P as tracer L-valaes of the soils fertilized with different rock phosphates were deter,-/lined. The over all ranking of different sources of rock phosphate was as follows: Jordan$$ Jhabua $$ Mussoorie > Udaipur $$ Purulia > Singhbhum Relative effectiveness of these rock phosphates was not related to their solubility in neutral ammonium citrate, citric acid (2%) or formic acid (2%) at 65°C. However when three successive extract ions with tnese reagents were carried out, the P dissolved in the second extraction with nemral ammonium citrate showed significant correlations with ‘L’ values for wheat as well as rice.