Different Levels Effects of Sulfur and Salinity of Irrigation Water on Yield and some Growth Characteristics of Soybean in Greenhouse Conditions

In order to investigating the effects of different levels of sulfur and salinity of irrigation water, a 3× 3× 4 factorial experiment based on randomized complete block design was conducted in 2016-2017, with three replications. Four soybean genotypes (Hill, Dayr, Williams and Ford), in three levels of irrigation water salinity (control, 4 and 8 ds/m) and three levels of sulfur (control, 5 and 10 grams of sulfur powder in each pot) were investigated. The traits of main and sub branch height, number of main and sub branch pods, fresh and dry weight of shoot, 100 seed weight and yield per plant were evaluated. The results of analysis of variance showed that the effect of genotype, sulfur, salinity and sulfur × salinity on all traits, triple interactions effects in all traits except the main branch height, dry weight of shoot and 100 grain weight became significant. Mean comparison showed with increasing salinity, mean of traits and yield in per plant decreased significantly. The highest main and sub branch height, number of pods in main and sub branch, wet and dry weight, 100 seed weight and yield per plant were obtained at the control level of salinity and the second level of sulfur. The highest correlation of yield per plant in control and 4 ds/m salinity was with dry weight trait. Based on the results of mean comparisons with salinity stress, the reduction of traits of main and sub branch height, number of main and sub branch pods, fresh and dry weight of shoot, 100 seed weight and yield per plant in 5 gram of sulfur was lower than 10 gram of sulfur.