Phosphate Fertilizer Value of Indigenous Rock Phosphates and Superphosphate for Lucerne and their Residual Effect on Guar

Pot culture experiments were carried out using a soil of pH 6.8 with application of Udaipur, Mussoorie and Laccadive phosphate deposits and superphosphate å 60,120 and 180 kg P₂O₅/ha. Lucerne for direct and guar for residual effects were grown as fodder crops. The percent age efficiency of Mussoorie, Laccadive and Udaipur rock phosphates as compared to superphosphate was 78, 62 and 54, respectively, when adjudged from fodder yield of lucerne. The availability coefficient ratio (ACR) of these rock phosphate was 0.60 for Udaipur, 0.75 for Mussoorie and 0.21 for Laccadive at 60 kg P₂O₅/ha level. In Laccadive phosphate earths, the highest ACR of 0.97 was observed at 180 kg P₂O₅/ha while in other phosphate sources ACR tended to decline with increasing levels of P application. Application of P fertilizers along with FYM resulted in increased fodder yields of both lucerne and guar.