Effect of Plant Growth-Promoting Bacteria and Sulfur on growth and Micronutrient Concentration in Wheat Grain in saline-sodic Soils

Soil salinity and sodicity disrupt the balance of nutrients in the soil and create restrictions on plant growth. An experiment was conducted to evaluate the application of sulfur along with Thiobacillus bacteria and plant growth-promoting bacteria isolated from saline-sodic soils on the performance and concentration of micronutrients in wheat (Chamran cultivar) in saline-sodic soils in a factorial design within a completely randomized design, in three replications in greenhouse condition. The experimental factors included three types of saline-sodic soil (S1: SAR=13 and EC=8 dS m^-1), (S2: SAR=15 and EC=10 dS m^-1), and (S3: SAR=17 and EC=14 dS m^-1), four levels of plant growth-promoting bacteria (B0: control, Pseudomonas alcaliphila, Rhizobium pusense, and Bacillus subtilis) and two levels of sulfur along with Thiobacillus thiooxidans bacteria (T0: no application and T1: application of 31.4 grams per pot (10 tons per hectare) of powdered sulfur along with T. thiooxidans bacteria). Based on the sequencing of the 16S rRNA gene, the superior plant growth-promoting bacteria were identified as Pseudomonas alcaliphila, Bacillus subtilis, and Rhizobium pusense. The results showed that adding sulfur along with T. thiooxidans bacteria and other plant growth-promoting bacteria at different levels of salinity and sodicity led to an increase in grain yield and concentration of micronutrients compared to the control. At the salinity and sodicity levels of S1 and S3, the highest grain yield was observed in plants inoculated with R. pusense bacteria (13.1% and 88.8%, respectively). The combination of plant growth-promoting bacteria and sulfur along with T. thiooxidans bacteria did not have a significant effect on grain yield and concentration of micronutrients in saline-sodic soils. Overall, the individual application of R. pusense bacteria isolated from saline-sodic soils and sulfur along with T. thiooxidans bacteria plays a significant role in improving the performance and concentration of micronutrients in wheat in saline-sodic soils.