Effect of sulfur on some chemical properties of soil and nutrients concentration in wheat grain (Triticum astivum L.)

Low availability of some nutrients is one of the major factors for the widespread occurrence of plant nutrient deficiency in calcareous soils. Therefore, in order to achieve optimal yield in such soils, the use of sulfur as a correction agent is necessary to reduce the local pH of the soil and increase the solubility of the nutrients. The aim of this study was to evaluate the Sulfur effect on some chemical properties of soil (pH, EC, P, S-SO4, Fe and Zn) and nutrients concentration in wheat grain. For this purpose, an experiment was carried out in four sites (Chogha Narges, Mahidasht, Najaf Abad and Ghomsheh) with different levels of available sulfur (7, 13, 18, 27 mg kg-1soil) in Kermanshah Province. Sulfur was applied at 0, 250, 500, and 1000 kg ha-1 as PS using randomized complete block design with three replications in a during cropping season 2015-2016. Seeds of wheat were planted in plots. Before cultivation soils were used and its characteristics were analyzed. Soil samples at tillering, stem elongation and post harvesting stage from each treatment plot was collected for determining pH, EC, P, S-SO4, Fe and Zn. Finally, grain yield and nutrient measurements with conventional methods were measured. The result showed that PS significantly decreased the soil pH and adversely, increased EC, P, S-SO4, soil DTPA- extractable Fe, and Zn in the Chogha Narges, Mahidasht (p< 0.01) and in Najaf Abad and Ghomsheh (p<0.05) at tillering, stem elongation and post harvesting stage compared with the control.
The lowest pH and highest EC, P, S-SO4, Fe and Zn value was observed with 1000 kg ha-1 So at stem elongation. After harvesting due to the reduced amount of sulfur oxidation and buffering capacity of soil, pH and nutrients gradually reduced compared with stem elongation stage. However, nutrients concentration in wheat grain was significantly increased with the application of PS compared with the control. The highest nutrients concentration was observed with 1000 kg ha-1 . The effect of sulfur together with Thiobacillus bacteria on the chemical properties of the soil and the amount of nutrients concentration by wheat was promising, which indicates its good potential for use in agriculture. Thus each calcareous soil has its own potential for elemental sulfur oxidation that related to soil characteristics, and only soil calcium carbonate content is not a suitable criterion for sulfur application in order to improvement nutrient availability.