Effects of Successive Fertilization of Potassium Sulfate on Change of Sulfur Content in Soil and Tobacco Plant

In order to evaluate the effect of successive fertilization of potassium sulfate on change of sulfur (S) content in soil and tobacco plant, a 3 year continuous fertilization field experiment was established and analyzed. The results showed that the soil available S content in rhizosphere of tobacco changed little with the growth stages and the fertilizer rates, but it increased with the S fertilizer rates, and decreased with the growth stages in out-rhizosphere, with the highest values at the vigorous growth stage. The total soil S was significantly affected by tobacco root and the S fertilizer rate. The total S content in rhizosphere was obviously lower than that in out-rhizosphere, and both of them increased with the S fertilizer rates except for the rhizosphere soil in CK. The application of potassium sulfate fertilizer significantly increased the total S content and its accumulation in leaves, and they both increased with the S fertilizer rates in general. But it had less effect on stem, and the least on root. Moreover, the S fertilizer rate dad little influence on the distribution of total S in each part of tobacco at maturity stage. After 3 year's application of sulfate fertilizer with 125.4 kg/hm² per year in this study, the total S content at different leaf positions reached at 0.7% or above, which was the critical valve affecting the quality of tobacco leave. In conclusion, the S fertilizer rates in tobacco plantation should be adjusted reasonably according to the soil condition and the S content in tobacco leaves in the future.