Oxalic acid treated low grade rock phosphate can be a potent supplemental P source to grow wheat in inceptisol

Abstract

High grade rock phosphates (HGRP) are only used to prepare phosphorus (P) fertilizers. But the finite reserve of HGRP is pushing the agricultural sectors to use low grade rock phosphates (LGRP) for growing crops. In this study an attempt was made to treat LGRP with oxalic acid and use it as a supplement to P fertilizer for growing wheat in Inceptisol. Incubation study revealed that oxalic acid treated rock phosphate (RP) can significantly increase soil available P status as compared to inert untreated RP treatment. Pot study established that oxalic acid treated RP (@60 mg P2O5 kg−1) under DAP30+ RP60(OA) treatment has supplemented 50% P fertilizer without affecting wheat yields and P uptake. DAP30+ RP60(OA) treatment also had maintained significantly higher Saloid-P, organic-P and statistically at par available P, dehydrogenase, acid phosphatase and alkaline phosphatase activities as compared to chemical fertilizer treatment (DAP60). Thus it can be inferred that, application of oxalic acid treated LGRP (@ 60 mg P2O5 kg−1) can supplement 50% of the P fertilizer demand to grow wheat in Inceptisol.