Effects of Inoculation of Phosphate Solubilizing Microorganisms on Increasing the Efficiency and Recovery Percent of Phosphate Fertilizers in Canola

Phosphorus (P) is one of the most important nutrients in crop production. Large amounts of P applied as fertilizer enters into the immobile pools through precipitation reaction with Ca2+ in calcareous soils. In order to economically use the phosphate depositions accumulated in the calcareous agricultural soils and increase the efficiency of P-fertilizers in Iran، an experiment was carried out in the greenhouse of Agricultural College، Tarbiat Modares University، in 2011. The study had a Randomized Complete Block Design with 8 treatments and 4 replications. The experimental treatments were: T1) control، T2) Phosphate Solubilizing Microorganisms (PSM)، T3) Triple Super Phosphate (TSP)، T4) TSP+PSM، T5) Golden Bio Phosphate (GBP)، T6) GBP+PSM، T7) Rock Phosphate (RP) and T8) RP+PSM. The results revealed that P uptake by canola inoculated with phosphate solubilizing microorganisms increased by 80. 44 percent compared to the control treatment. There was a significant difference (p=5%) between inoculated treatments and the control. The highest P uptake was obtained in T4 (TSP+PSM) treatment، which was 84. 57 mg pot-1. Also، the highest amount of relative agronomic efficiency and recovery percent of fertilizer was obtained in T4 treatment، which was 109. 29% and 71. 91%، respectively. Inoculation with phosphate solubilizing microorganisms (PSM) significantly increased dry weight، pod numbers، P concentrations، P uptake، relative agronomic efficiency، and recovery percent of fertilizer in all treatments compared with the control pots. The overall results demonstrated that due to the higher price worldwide of P fertilizers and considering environmental issues، it is recommended that the experiment be further tested in the field.