Effect of Sulfur and Thiobacillus Inoculum on Phosphorous Uptake and Yield of Wheat in Calcareous Soils



Application of sulfur as a means of lowering soil pH (even if at micro sites) is one way to increase the availability of insoluble nutrients/ Effectiveness of elemental sulfur in lowering soil pH depends on the activity of sulfur oxidizing bacteria especially, Thiobacillus genus/ To evaluate the possibility of partially substituting sulfur along Thiobacillus inoculum for phosphorus and micronutrient fertilizers, a randomized complete factorial experiment was carried out on Wheat under greenhouse condition/ The treatments included eight levels of sulfur (the rates of sulfur which reacts with 0.5,1,2,4,8,12,16,20 percent of neutralizing materials) , two levels of Thiobacillus inoculum (at rates of 0and 104 cfu gr-1 soil), three calcareous soils with different calcium carbonate content, a control and balanced fertilization based on soil tests/ Following soil preparation and establishment of 216 pots, each fertilizer was applied according to the treatment schedule, and finally 10 germinated seeds of Chamran variety of wheat was planted on each pot/ At the end of the growing season the plants were harvested, then the dry weight, as well as the concentrations of phosphorus were determined in the straw, and grains/Results showed that there were significant treatment effects with respect to dry weight of grain and straw Phosphorus concentration and absorption , in the shoots. Interaction effects of sulfur and thiobacillus inoculum was significant on grain yield ,The forth treatment of sulfur in addition to thiobacillus inoculum increased the grain yield 16.7percent in compare with control. Also the interactions effects of soil and bacteria inoculum was significant on phosphorus concentration (percent)of shoot. The soil treatment of Pasve in addition to thiobacillus inoculum with 0.21 percent had the most percent of shoot Phosphorus . This treatment increased shoot phosphorus concentration 14.21 percent in compare with control.