Evaluation of Green Manure Crops Fertilized with various Phosphorus Sources and their Effect on Subsequent Rice Crop

Three green manure crops namely dhanicha (Sesbania cannabina), sunhemp (Crotalaria juncea) and Azolla (Azolla maxicana) fertilized with three phosphorus sources (single superphosphate, Udaipur rock phosphate and their mixture in 1:1 ratio) were field evaluated in a medium land sandy acidic soil growing rice cv. Lalat as the test crop. It was observed that dhaincha and Azolla were better green manure crops than sunhemp. Further the P sources like single superphosphate and Udaipur rock phosphate mixture in 1:1 ratio was more efficient than lone source of Udaipur Rock phosphate and as good as lone source of single superphosphate in influencing their biomass production, N addition and recycling of nutrients like P, K, Ca and Mg which benefitted the subsequent rice crop with increased yield and N-economy.