黄土性土壤中硫的形态分析

The Morphological analysis of Sulfur in Loessal Soil

采用分步萃取，ＢａＳＯ４比浊法测定了陕西省３种干旱半干旱区主要土壤—黄绵土、黑垆士和 土中各无机硫形态，有效态硫及总硫含量，并由差减法得到有机态硫含量。结果表明，黄绵土中总硫含量很低，仅８７．８８ｍｇＳ／ｋｇ（烘干土），黑垆土中含量居中，为１７６．５ｍｇＳ／ｋｇ，而 土中含量较高，达２００．８ｍｇＳ／ｋｇ。吸附性硫含量均很低，在０．５８２～２．４１５ｍｇＳ／ｋｇ之间。水溶性硫和ＨＣｌ可溶性硫的含量范围分别为１１．４０～１１．７９ｍｇＳ／ｋｇ和３０．９７～３８．９５ｍｇＳ／ｋｇ。有效硫含量差异较大，分别为８．８５２、１５．８２和１９．９０ｍｇＳ／ｋｇ。有机态硫占土壤全硫的４１．６０％～８８．１５％。

The sulfur extraction was conducted in steps. BaSO4 turbidimetry wasused to determine inorganic sulfur ,available sulfur and total sulfur contents in themain soils Huangmian soil,Heilu soil and lou soil in three types of arid and semiaridareas in Shaanxi Province. The results showed that total sulfur content in the Huangmi-an soil was very low with only 87.88 mg S/kg in dried soil,while that in Heilu soil wasintermediate, being 176.5 mg S/kg in dried soil,and that in Lou soil was fairly high,reaching 200.8 mg S/kg in dried soil.The adsorbed sulfur contents in the soils of threetypes were very low in the range of 0.582～2.415 mg S/kg. The contents of water solu-ble sulfur and HCl soluble sulfur were in the range of 11.40～11.79 mg S/kg in driedsoil and 30.97～38. 95 mg S/kg in dried soil respectively.The avaliable sulfur contentsare greatly different in three kinds of soil,being 8.852;15.82 and 19. 90 mg S/kg indried soil.The organic sulfur consists of 41.6%～88.15%of total sulfur in soils.