Biosuper as a phosphate fertilizer in a calcareous soil with low available phosphorus

Laboratory assays were conducted to produce phosphorus (P) biofertilizers from rock phosphate (RP), applying sulphur at different rates of 10, 15 and 20% and inoculated with Thiobacillus. A greenhouse experiment was carried out to evaluate the effect of the biofertilizers in a calcareous soil with low available P from the Qazvin plain of “Qazvin State”, grown with corn (Zea mays L.). The treatments were: rock phosphate (RP), biofertilizers produced in laboratory with sulphur and Thiobacillus (Biof1, Biof2 and Biof3), rock phosphate with sulphur (10, 15 and 20%) without Thiobacillus (Nbiof1, Nbiof2 and Nbiof3), Triple Super Phosphate (TSP) and a control without phosphorus. In this experiment, shoot dry matter, total P, Fe and Zn in shoots, and also soil available P, Fe and Zn were determined. Higher rates of measured parameters were obtained from biofertilizers with sulphur and Thiobacillus (Biof) and in Triple Super Phosphate (TSP). Biofertilizers with sulphur and Thiobacillus (Biof) and TSP increased plant parameters significantly compared with control or rock phosphate.