Phosphate solubilizing bacteria roles on the mineral nutrition uptake and yield of sorghum

The usage of soil microorganisms which they have ability of dissolving fixed phosphorus, is one of the effective ways to increment the uptake of phosphorus in calcareous soils. In order to study the roles of phosphate solubilizing bacteria on the availability of P in the sorghum, a pot experiment was conducted as a factorial in completely randomized design with eight treatments and three replications. The experimental factors were different phosphorus levels and phosphate solubilizing bacteria (Bacillus megaterium). The treatments were combination of four P levels (zero, 25, 50 and 75 mg/kg P2O5 from triple super phosphate source) and the two treatments of phosphate solubilizing bacteria (with bacteria inoculation and without bacteria inoculation). The results indicated that utilizing the phosphate solubilizing bacteria increased significantly (P<0.01) the dry matter yield, nitrogen, phosphorus and potassium uptakes but had not significant effects on iron, manganese and zinc uptake. Phosphorus application also had a significant effect (P<0.01) on some indicators such as plant height and diameter, dry matter yield, shoot P concentration and shoot P uptake. Combined using of both phosphorus and phosphate solubilizing bacteria had a significant effect (P<0.01) on the stem diameter, dry matter yield, shoots phosphorus concentration, nitrogen, phosphorus, iron and manganese uptakes by sorghum.