Evaluation the Efficiency of Phosphate Solubilizing Bacterial Isolates

Abstract-- Different phosphate solubilizing bacteria; as biofertilizer; solubilize insoluble inorganic phosphate compounds and rock phosphate to improve soil fertility and increase crop production. This research was aimed in evaluation of isolate’s efficiency in liquid medium and at greenhouse level with CRD design. All isolates showed progressive increase in Phosphorous as incubation dates increased. However, in most cases maximum value for all isolates detected at 5 days incubation in Pikovskaya’s broth. Consequently, maximum Phosphorous released by isolate HUPSB-57 (0.51%/day) from TCP, HUPSB-35 (0.41%/day) from ERP and HUPSB-27 (0.53%/day) from bone meal. Inverse relationship between released Phosphorous and medium pH observed. Isolates HUPSB-35 and HUPSB-57 reduced pH to 3.57 units in ERP, HUPSB-45 to 3.7 units in bone meal, and HUPSB-57 to 4.0 units in TCP. Significant difference observed between negative control and isolates inoculation on white lupin shoot height. Highest shoot height (99.67cm) recorded by isolate HUPSB-35 inoculated with ERP at green house. Maximum shoot phosphorus (0.3%) recorded by HUPSB-45 inoculated with ERP. In general, isolates HUPSB-27, HUPSB-35, HUPSB-45 and HUPSB-57 were found to be effective phosphate solubilizers both on media and at green house and them can be recommended as bio-inoculants by testing them on different crops. Keywords-- Bone meal; ERP; Isolates; PSB; TCP I