| Sulphur is a necessary nutrient for plants, and the sulphur fertilizer is important on the growth, physiology process and quality of flue-cured tobacco. Soil culture,pot experiment and field experiment were conducted to study the characteristics of soil available sulphur content, soil available sulphur leaching and soil organic sulphur mineralization, and the effect of S fertilizer content on growth, physiology process and quality of flue-cured tobacco.Soil culture results showed soil available sulphur had been increased significantly after different sulphur ferti1izer were appl ied. The soil available sulphur content gained the biggest 7 days incubation after, and it raised at first, then got down following time gone, and the changebleness of soil available sulphur of moist field with more sulphur was more clear than that of marl field with less sulphur. On the same amount of sulphur fertilizer, the raising order of soil available sulphur content in all treatments with application different kind of sulphur fertilizer was: ammonia sulphate > magnesium sulphate and potassium sulphate > single superphosphate.Leaching could make sulphur of fertilizer lose greatly in soil. The sulphur leaching of single superphosphate was easyer than that of potassium sulphate. The leaching amount of sulphur indicated, sulphur leaching was mainly in the former times of experiment, and the leaching amount of sulphur within 21 days was 55-75 percent of total leaching amount. The laeching amount difference between the treatments was significant. For marl field, total leaching amount of CK treatment,applying potassium sulphate treatment, applying single superphosphate treatment were respectively 18. 12mg/kg, 31. 03 mg/kg, 32. 37 mg/kg. And for moist field, total leaching amount of CK treatment, applying potassium sulphate treatment, applying single superphosphate treatment were respectively 8. 99mg/kg, 20. 07 mg/kg, 23. 67 mg/kg. Leaching made a lot of available sulphur lose following water, promoted soil sulphur downward movement and accumulating.During 105 day incubation, the amount of organic sulphur mineralized of black mud field was high, which was 30. 81 mg/kg, that of purple mud field, marl-yellow field were respectively 26. 28mg/kg, 25. 49mg/kg, that of yellow mud field, marl field were low, which were respectively 21. 67mg/kg, 19. 60mg/kg. The percentage of the S mineralized in total organic sulphur of black mud field with more organic matter was high, 15.07% during whole incubation, and that of purple mud field with less organic matter was low, only 7.00%. And that of yellow mud field, marl-yel low field and marl field were respectively 9. 60%, 7. 40%, 15. 07%. The amount of the S mineralized in soils got down following time gone, The total amounts of S mineralized ranged from 9. 23mg/kg to 16. 91mg/kg (av. 12. 67mg/kg) during 21 day incubation, and the percentage of the S mineralized in total organic sulphur of soils was 3.48% - 8.27% (av. 4.80%), that in 105 day S mineralized was 45.84% - 55.01%.The results of pot experiment showed that chlorophy and carotene contents of S2 (0. 12g/kg) treatment and S) (0. 18g/kg) treatment were high, the net photosynthesis rates were high, the content of malondialdehyde( MDA) and activities of superroxide (SOD) , peroxidase (POD) and catalase (CAT) were still low during first bloom, which indicated flue-cured tobacco plant physiological metabolism of 0. 12g/kg-0. 18g/kg sulphur fertilizer treatments were well, and which kept the balance of active oxygen metabolism in flue-cured tobacco leaves, and reduced the lipid peroxide.Chlorophy and carotene contents of S0 (0. OOg/kg) treatment and S5 (0. 30g/kg) treatment were low, the net photosynthesis rates were low, the content of raalondialdehyde(MDA) and activities of superr oxide (SOD) , peroxidase(POD) and catalase (CAT) were still high, which broken the balance of active oxygen metabolism in flue-cured tobacco leaves. Sulphur was most closely related to composing of protein . In flue-cured tobacco leaves , Soluble-protein content...
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