酸性硫酸盐土中硫形态转化过程的水分制约作用

分别设土壤田间持水量的30%恒定(FH1)、土壤田间持水量的70%恒定(FH2),一直淹水(INU)、风干后放置(DRY,作为对照)、自然风干(NAD)5个处理进行酸性硫酸盐土室内模拟实验。实验结果显示,水分条件对酸性硫酸盐土中水溶性硫、交换性硫和黄铁矿硫的形态转化有显着的制约作用。淹水环境和过分干燥环境都不利于黄铁矿的氧化及水溶性硫和交换性硫的形成,潮湿但含水量不饱和环境有利于黄铁矿硫向水溶性硫和交换性硫的转换。模拟试验期内,水溶性硫含量的增加速度排列为:FH2>FH1>INU,交换性硫含量的增加速度排列为:FH1>FH2>INU,黄铁矿硫含量的下降速度排列为:FH2>FH1>INU,原状土自然风干(NAD)过程中,水溶性硫、交换性硫和黄铁矿硫之间发生了明显的转化。对不同处理中黄钾铁矾硫、有机硫和元素硫的动态变化也进行了分析。

Effects of soil moiisture on the transforlmation between sulfur forms in acid sulfate soils

Simulation test of the acid sulfate soil (ASS) included 5 treatments. They were 30% of field capacity (FHl), 70% of field capacity(FH2), inundated (INU), air-dried (DRY), and naturally air-dried (NAD). The test indicated that water was an important factor on the transformation between the forms of sulfur of ASS such as water soluble S, exchangeable S, and pyrite S.The test showed that wet but not inundated or over dried was benefit to the oxidation of pyrite and the formation of water soluble S and exchangeable S in ASS. During the whole simulation period, the increases of water soluble S content of the ASS from big to small were: FH2 > FH1 > INU; the increases of exchangeable S content of the ASS from big to small were: FHl > FH2 > INU; the decreases of pyrite S content of the ASS from big to small were: FH2 > FHl > INU.Significant transformation of S forms happened during the air-drying process of the NAD treatment. The dynamic of Jarosite-S, organic S and element S in all treatments are also discussed here.