Phosphorus Release from Rock Phosphate as Influenced by Organic Acid Loaded Nanoclay Polymer Composites in an Alfisol

Abstract

The aim of the present study was to develop a strategy to solubilize low-grade rock phosphate (RP) from Purulia and Udaipur through organic acids loaded nanoclay polymer composites (NCPC) and see their effectiveness as source of P. An incubation experiment was conducted under laboratory condition to study the release pattern of P in an Alfisol from Jharkhand amended with various RPs treated with organic acid loaded NCPC for 90 days. The RPs were applied at a dose of 0, 50 and 100 mg P kg−1 soil, along with the organic acid loaded NCPC having 10 % clay which was applied at a dose of 0, 20 and 40 mg organic acid kg−1 soil. The incubation experiment showed a positive impact of the organic acids in their ability to release P from all the RP sources, and oxalic acid performed better over citric acid in solubilizing P from RPs. The two indigenous RPs maintained almost comparable available P in soil throughout the period of incubation. With increase in levels of P application, there was an increase in the amount of release of P from both the RPs. Similarly, with the increase in levels of organic acid both Udaipur and Purulia RPs showed increase in the available P in soil. This study demonstrated that availability of P from low-grade indigenous RP could be improved with the interventions of organic acid loaded NCPC which could be used as P-fertilizer and reduce the dependence on commercial fertilizers like DAP.