Effects of adding different levels of Sulfur on the number of Thiobacillus thioparus and soil pH on the growth of the Canola crop (Brassica napus L.)

Abstract The experiment was applied during the winter season 2021/2022 in Al-Shahimiya city, Wasit governorate, Iraq. The aim of study was to add different levels of sulfur and the bacteria Thiobacillus thioparus on the degree of soil interaction and their influence on the growth of Brassica napus L. The experiment has been used randomized completed block design (RCBD) in the field experiment. The experiments included two factors, the first factor was added four concentrations of sulfur (0% - 12% - 24% - 36%), and the second factor was to add two levels of T. thioparus. It was adding 5 and 10 ml of bacteria) with three replications for all treatments. They were randomly distributed to the treatments. The total number of units was 36 experimental units. The results showed that adding 36% sulfur and T. thioparus 10 ml/ hole have been recorded the highest number of bacteria colonies in the field experiment that after 30 days of germination, which is the best time for bacteria growth. It has been reached 1866.66 * 104 cells/ g of soil, while it reached 1066.66 * 104 cells/ g in the control treatment. The results showed that adding 36% sulfur concentration and T. thioparus 10 ml / hole at the time of harvest has been indicate the highest rate of decrease in the degree of soil interaction. The pH recorded 6.89 compared control treatment, which reached 7.8. Also, the treatment of adding 36% sulfur and 10 ml / hole of T. thioparus recorded the highest rate of ready sulfur in the soil at the time of harvest. It has been reached 42 mg/ kg soil in the compared the control treatment, which record 20.44 mg/ kg soil. In addition, the treatment of adding 36% sulfur and 10 ml / hole of T. thioparus recorded the highest concentration of nitrogen, phosphorous and potassium in B. napus. The concentrations of NPK were 3.81, 0.85 and 2.66%, respectively, while the NPK rates in the control treatments were 1.13, 0.51 and 1.20%, respectively.