Availability of Phosphorus from Rock Phosphate Influenced by Sulphure and Microbes in Inceptisol

An incubation study under ambient conditions and simultaneously pot culture experiment on soybean was conducted to observe the availability of phosphorus from rock phosphate due to acidulation effect caused by the sulphure and microorganism like PSB and EM. It was to ascertain the possibility of making use of rock phosphate (low grade) for direct use in soil application were tested in highly phosphorus consumptive soybean crop. The RP @ 75 kg ha was applied in the soil (3 kg) in bowl. The treatments were comprised of application of graded levels of elemental S (0, 30, 60 kg ha^-1) with and without PSB or EM or PSB + EM. The soils were incubated for 90 days under ambient condition with keeping moisture at field capacity. The results indicated that highest available phosphorus content in RP + S₆₀ + PSB which was at par with RP + S₃₀ + PSB + EM, suggests that 30 kg S along with PSB and EM was the best treatment for phosphorus release through solubilization of RP and increase availability of phosphorus to soybean.