Mohammad Pasandideh - Scientific Staff of Soil and Water Research Institute, Tehran, Iran
Fereidoon Nourgholipour - Scientific Staff of Soil and Water Research Institute, Tehran, Iran
Hossein Besharati - Scientific Staff of Soil and Water Research Institute, Tehran, Iran

Phosphorus is one of the major elements in plant nutrition and crop productivity, participating in manybiochemical processes and translocation of energy. In addition, P is a constituent of cell nucleic acids.Application of phosphate fertilizers is a common practice to correct P-deficiency in plants. For a longtime, rock phosphate (RP) has been a major source to P fertilizer production. For evaluation of theefficiency of combined rock phosphate with different constituents, a garden experiment, as acompletely randomized block design, was carried out in Torough Station of Agricultural Center ofKhorasan with eleven treatments and three replications. Each replication included two apple trees(there should be 11 treatments or 22 apple trees in each replicate row). Treatments were: T1: control(without phosphorous use), T2: Using P as triple super phosphate, T3: 40% concentrated R P. + 40%S(powdered) + 16% cow manure (CM) + 4% zinc sulphate, T4: T3 + 20 grams Thiobacillus sp.inoculant (107 cfu g-1), T5: T3 + 40 grams Thiobacillus sp. inoculant, T6: T3 + Tea residues instead ofCM, T7: T4 + Tea residues instead of CM, T8: T5 + Tea residues instead of CM, T9: T3 + plant residuecompost instead of CM, T10: T4 + plant residue compost instead of CM, T11: T5 + plant residuecompost instead of CM. In all treatments, 1 kg of each fertilizer was used for each apple tree at a 40cm depth. Results indicated that there were significant differences among treatments includingconcentrated RP + S, Thiobacillus sp. bacteria and CM, with control treatment and treatments with noThiobacillus from the aspect of available-P and leaves-P concentrations. Based on the results (P<0.05)using of RP + S, Thiobacillus sp. bacteria + CM at a rate of 1 kg.tree-1 for each apple tree had the sameeffect as triple super phosphate.

Thiobacillus, Rock phosphate, Apple, Phosphorus