Interaction between sulfur and zinc on cotton (Gossypium sp. L.) yield and some soil parameters

. In order to study the interaction of sulfur (S), zinc (ZnSO4) and Thiobacillus bacterium on yield and yield components of cotton and some soil parameters, a field experiment in a factorial randomized complete block design with 12 treatments and three replications was conducted in the mahvelat city with center of Faiz abad of Razavi Khorasan province. Experimental factors included three levels of sulfur Zero, 500 and 1000 kg ha-1, Thiobacillus bacterium in two levels control and Thiobacillus bacterium application and zinc sulfate in two levels Zero and 50 kg ha-1 in the form of zinc sulphate application applied to the experimental plots. After harvesting the cotton crop soil and plant sample were separately collected from each plots for analysis of elements in soil and plant samples. Results of analysis of variances showed that, the interaction of sulfur, zinc and Thiobacillus on some agronomic and soil traits including cotton yield (5208 kg ha-1), seed cotton yield (3622 kg ha-1), boll weight (5208 kg ha-1), fertile branches number (12.52), vegetative branches number (10.98) were significant as compare to control. Number of bolls in plant with application of sulphur, zinc and thiobacillus and their interactions were significant. Soil reaction (pH), electrical conductivity and available sulfate were significant at 1% level and plant height and First boll height were significant at the 5% level. According to the comparison results, application of 1000 kg ha-1 sulfur without of Thiobacillus and zinc also treatment with the application of 1000 kg ha-1 sulfur with Thiobacillus was caused Significant increase in cotton yield and seed cotton yield compared to the control. Application of 500 kg ha-1 sulfur and also the application of 500 kg ha-1 sulfur with zinc was caused a significant increase in boll weight, but 500 kg ha-1 of sulfur with zinc caused significant reduction in plant height .The Soil traits studied, the application of 1000 kg ha-1 sulfur alone caused a significant decrease in soil reaction (7.35) , but significant increase created in electrical conductivity of the soil (16.5), the amount of adsorbed sulfate and the amount of adsorbed zinc were significant at 1 percent level of significant but amount of absorb zinc were significant at 5 percent level. However, application of 500 kg ha-1 sulfur with Thiobacillus more than alone of sulfur created significant increase in the available sulfate and adsorbed sulfate of soil. Results of data shows that all main effect on cotton seed oil were not significant.