Rock Phosphate as a Fertilizer for Direct Application in Acid Soils

Rockphosphate was used as a source of phosphorus to paddy, wheat, maize peas and potato crops grown in acid soils of Palampur (pH 5.1), Ranchi, (pH5.4), Titabcr (pH 4.5), Ooty (pH4.5) and Bastar (pH 5.9). It has been invariably observed that in these acid soils, there have not been significant differences between yields obtained under the application of 80, 160 and 240 kg P₂O₅ through rock phosphate. The application of P₂0₅ @ 80 kg/ha through superphosphate and rock phosphate gave similar yields of paddy, wheat and maize but peas were benefited more with rock phosphate. On evaluation of residual effect, it was found that rock phosphate was significantly better than superphosphate with respect to crop yield and residual phosphate status of the soils. However, potato crop was benefited more by superphosphate application than rock phosphate.