采用4种浸提剂(CaCl₂、Ca(H₂PO₄)₂(pH=4.0)、KH₂PO₄、NaHCO₃(pH=8.5)),对采自我国不同区域的7种土壤样品及北京近郊昌平平西府中科院遗传所试验基地冬小麦不同生育期麦田土壤进行了土壤有效S的浸提,同时对不同区域土壤的有效S、全S和小麦不同生育期植株的含S量进行了测定。结果表明,在土壤有效S与植株含S量的相关性中,4种方法都达到显著或极显著的水平。采用电感耦合等离子体原子发射光谱法(ICP-AES)和BaSO₄比浊法对Ca(H₂PO₄)2浸提的土壤有效S进行测定,二者的结果具有极显著的相关性,r值达0.867**。二者测定的土壤有效S与植株含S量的相关性也达到了极显著水平,r值分别为0.794**和0.684**,说明了两种方法都适用于对土壤有效S的测定,但ICP-AES法的结果相对更稳定。4种浸提剂测定重复结果间的变异系数以Ca(H₂PO₄)2平均最小,只有5.3%,NaHCO₃最高,达8.3%。根据浸提剂的性质、土壤有效S与小麦植株含S量的相关性、测定结果重复间的变异系数得出,Ca(H₂PO₄)2浸提与离子色谱测定是判定土壤有效S最稳定的一种方法。

Several soil samples from different areas of China were extracted for plant available sulfur (S) with four extractants, CaCl₂、Ca(H₂PO₄)₂ (pH=4.0)、KH₂PO₄、and NaHCO₃ (pH=8.5). The total and available S in soils, and S contents in winter wheat in it's different growth stages were determined. The results showed that the available S in the soilwas significantly related to the contents of S in plants in all of four treatments. The results of using the inductively coupled plasma emission spectrometry (ICP-AES) and turbidimetry to determine soil available S showed extremely significant correlationship between the methods with correction coefficient being 0.867**. The contents of available S in soil determined by these two methods also had a significant correlationship with the contents of S in wheat, with correlation coefficients being 0.794**and 0.684**, respectively, indicating that both turbidimetry and ICP-AES were applicable to determination of available S in soils. But ICP-AES was better than the turbidimetry in stability. Using the Ca(H₂PO₄)₂ as extractant, the average variation coefficient of the results was 5.3%, the least in the four extractants, while using NaHCO₃, 8.3%, the largest.. Based on the characters of the extractants, the correlation of available S in soils with the S contents in wheat and the variation coefficient, it could be concluded that the Ca(H₂PO₄)₂ extractant and ICP-AES testing method were the best ones to determine the available S in soils.

国家自然基金资助项目(39870134)。