Effects of sulfur and Thiobacillus bacteria application on some nutrients availability in soils with different buffering capacities

Despite occurrence of Plenty of nutrients, such as phosphorus and micronutrients in calcareous soils, their available form will became less than plant requirements for optimum growth. Thus deficiency of nutrient elements is a limiting factor for plant growth. The efficiency of sulfur application in calcareous soils depends upon factors namly; soil buffering capacity and neutralizing acid coming from sulfur oxidation. Thus determination optimum sulfur application rates in calcareous soils with different buffering capacities is an especial issue. In this study the effects of sulfur and Thiobacillus bacteria on the availability of some nutrients in 4 calcareous soils with different buffering capacity was evaluated. Factors were: sulfur application rates (the amounts of sulfur which potentially neutralize 0, 3.1, 6.25, 12.5, 25, 50 and 100 percent of soil buffering capacity) and soil type (soils with 8, 14, 22 and 38 % of calcium carbonate equivalent). The results indicated that effects of sulfur, soil type and also their interactive effects on available P, Fe, Zn, Cu, Mn and SO4 2- were significant (P