Fractional Release Kinetics of Phosphorus from Compost Amended with Phosphate Rock

A study was undertaken to investigate the rate of dissolution of the various Phosphorus (P) sources in an alluvial soil of Bihar under an incubation experiment in the laboratory for 35 days with 5 treatments viz., Control; RP (Rock Phosphate) @ 100% of the RDP (Recommended Dose of Phosphorus); 100% of RDF (Recommended Dose of Fertilizer NPK); REC (Rock phosphate Enriched Compost) @ 100% of the RDP and 50% RDP+REC @ 50% of the RDP. The P release pattern was determined for every treatment at a sampling interval of 7 days. The integrated treatment involving REC and P-fertilizer (50:50) performed better than other treatments. This combination released greater labile P (16.14 mgkg−1), Fe-Al-bound P (74.48 mgkg−1), and Ca bound P (147.04 mgkg−1) in soil. It could be concluded that enriched compost (50%) along with the reduced application (50%) of inorganic P fertilizer could be very helpful in supplementing the P requirement of plants by increasing its release and availability under naturally P deficient conditions.