酸性硫酸盐土中硫的形态与酸性表现探讨

Research on the Sulfur Forms and the Acidity in Acid Sulphate Soils (ASS)

选取了4个酸性硫酸盐土剖面共20个土壤样品进行了硫的分级测定和土壤pH值的测定，对土壤中硫的形态、含量及其剖面分布规律，以及它们对土壤酸性的贡献进行了探讨．分析结果显示，酸性硫酸盐土中的全硫含量较高，其中土壤硫以无机态硫为主，无机态硫又以硫铁矿、水溶性硫和交换性硫为主，有机硫和元素硫含量较低．土壤全硫含量和硫铁矿的含量一般具有随剖面深度的增加而升高的趋势；黄钾铁矾与水溶性硫、交换性硫有类似的剖面变化规律，即含量高值多出现在某一pH范围或pH较低的土层．土壤pH值与黄钾铁矾硫、交换态硫和全硫含量的相关系数分别为－0．8067、－0．4374和－0．5729，分别达1％、5％和5％显著水平；硫铁矿的含量与土壤pH值之间存在着复杂的关系．黄钾铁矾在酸性硫酸盐土的发育与分类中具有重要的诊断意义．

Four profiles of acid sulphate soils and 20 Samplings were taken according to different soiltypes and land use patterns in Taishan city, Guangdong province. The different sulfur forms including to-tal sulfur, pyrite (FeS2), jarosite, water-soluble sulfur, exchangeable sulfur, element S and organic Sand soil pH etc. were analyzed and estimated. The data showed that the contet of the total sulfur is veryhigh in soils in this region, and the sulfur in ASS was mostly in inorganic forms and dominated by pyrite,water - soluble sulfur and exchangeable sulfur; the content of element S and organic S was relatively low.The total suifur and pyrite usually chang with a trend of increasing from soil surface horizon to bottom;jarisite, water - soluble sulfur and exchangeable sulfur had similar change trend in profile, they common-ly accumulated in layers with a certain pH or low pH values. Coefficients between pH and exchangeablesulfur, contents of jaresite and total suifur are -0.800 7, -0. 437 4 and - 0.572 9 respectively; thecomplicated relationship was found between pH and content of pyrite in soils. The occurrence of jarositehas important diagnostic sighficance in the soil development and classification.