Abstract:Soil total sulfur and available sulfur based on a long-term experiment with various tillage systems were studied in a purple paddy soil at the farm of Southwest University, Chongqing, China. The experiment included four tillage treatments: conventional tillage with rice only system (DP), conventional tillage with rotation of rice and rape system (SH), no-till and ridge culture with rotation of rice and rape system (LM), and tillage and ridge culture with rotation of rice and rape system (LF). Soil samples were collected at depths of 0-10, 10-20, 20-30, 30-40, 40-50 and 50-60cm. The results showed that the contents of soil total sulfur and available sulfur both decreased with the increase of soil depth. The orders of the contents and storages of soil total sulfur in 0-60cm soil layers were both in an order of LM>SH>DP>LF, and the orders of soil available sulfur were both LM>DP>LF>SH, respectively. Overall, long-term LM treatment was a valid strategy for increasing the contents and storages of soil total sulfur and available sulfur in a purple paddy soil in Southwest China. Compared with DP treatment, LM increased the contents of soil total sulfur and available sulfur 20.80% and 1.31%, and increased the storages of soil total sulfur and available sulfur 19.54% and 5.36%, respectively. The contents of soil available sulfur in plow layer (0-20cm) of DP, SH, LM and LF treatments were 27.15, 13.45, 31.43 and 24.01 mg/kg, respectively. Except SH treatment was sulfur deficient, the tillage systems of DP, LM and LF were not short of soil sulfur. Application of sulfur fertilizer for sulfur deficiency soil should be highly valued to improve yield and quality of crops.