不同土壤水分条件下酸性硫酸盐土硫形态转化特征

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

以 4种土壤湿度、3种干湿交替周期和原状土自然风干 8个处理进行酸性硫酸盐土室内模拟实验 ,对模拟过程内土壤 6种硫形态和pH等指标的动态变化过程的跟踪测定和分析结果表明 ,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制约作用显著 .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 .在 3种周期的干湿交替处理中 ,单一排干期水溶性硫和交换性硫土壤含量平均上升幅度分别为 0 90～ 1 6 3g·kg-1和 0 5 8～ 1 4 7g·kg-1,而黄铁矿硫含量下降幅度为 1 2 9～ 3 2 0 g·kg-1.淹水期黄铁矿硫含量相对稳定而水溶性硫和交换性硫含量明显下降 ,并在排水过程中造成总硫的部分流失 .硫形态转化量和硫的淋失量受到干湿交替周期的显著影响 .同时分析了黄钾铁钒硫、有机硫和元素硫的动态 .

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·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·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.