Comparative Performance of Indigenous Rock Phosphates and Superphosphate with and without Phosphobacterins

Laboratory incubation studies carried out over a period of 165 days using a soil of pH 7.5 mixed with Udaipur, Mussoorie and Laccadive phosphate deposits and superphosphate as P sources along with phosphobacterin species viz., Pseudomonas striata, Bacillus polymyxa and Aspergillus awamori revealed that P availability from all the P sources initially reduced up to 75 days of incubation due to incorporation of P solubilizers and thereafter increased. Reduction in avail. P values with the use of phosphobacterins is attributed to microbial locking-up processes.