[Transformation characteristics of sulfur forms in acid sulfate soils under different soil water conditions].

Aimed to detect the quantitative impact of soil water condition on the transformation of sulfur forms in acid sulfate soils (ASS), a simulation test was made with 8 treatments. The results indicated that water was an important factor affecting the transformation processes. Wet but not inundated or over dried condition was benefit to the oxidation of pyrite S and the formation of water soluble S (WS-S) and exchangeable S (Ex-S) in ASS. In the three treatments with different inundated and drained off cycles, soil pyrite S content averagely decreased 1.29-3.20 g x kg(-1) during a single drained off period, while soil WS-S and Ex-S contents averagely increased 0.90-1.63 and 0.58-1.47 g x kg(-1), respectively. During inundated period, soil pyrite S content was relatively stable, but soil WS-S and Ex-S contents were decreased significantly due to the dilution of water. It was suggested that the total S (mainly WS-S) of ASS was discharged in drainage process, and the accumulative amount of the discharge and the transformation of the S forms were associated with the length of the inundated and drained off cycles. The dynamics of Jarosite S, organic S and element S in all treatments were also discussed here.