几种土壤交换性酸测定方法的效果比较

为真实地反映酸性土壤交换性酸含量水平,探讨了KCl淋溶法、BaCl_2淋溶法、NaAc淋溶法、KCl-三乙醇胺(Triethanolamine,TEA)提取法和BaCl_2-TEA提取法对紫色土、黄壤、红壤和砖红壤4种土壤的交换性酸测定效果。结果表明:5种方法测得的土壤交换性酸大小关系为:BaCl_2-TEA提取法KCl-TEA提取法NaAc淋溶法BaCl_2淋溶法KCl淋溶法。BaCl_2淋溶法能较为真实地反映出土壤交换性酸水平,其次为KCl淋溶法。受土壤有机酸和铝氧化物的影响,NaAc淋溶法、KCl-TEA提取法和BaCl_2-TEA提取法测得的土壤交换性酸含量偏高。但由于尚无标准方法对测定结果进行验证,因此,还需进一步对土壤交换性酸测定方法及其影响因素开展研究。

Comparison of Soil Exchangeable Acidities by Different Measured Methods

The contents soil exchangeable acidity of purplish soil, yellow earth, red earth and latosol were measured respectively by the methods of KCl leaching, BaCl₂ leaching, NaAc leaching, KCl-TEA (Triethanolamine) extraction and BaCl₂-TEA extraction in order to accurately measure the content of soil exchangeable acidity in acidified soil. The results showed that the measured content of soil exchangeable acidity followed the order of BaCl₂-TEA extraction > KCl-TEA extraction > NaAc leaching > BaCl₂ leaching > KCl leaching. Among the five measurement methods, the methods of BaCl₂ leaching and KCl leaching are the two novel methods which could be used to measure more accurately the content of soil exchangeable acidity of acidified soil. Comparatively, the contents of soil exchangeable acidity measured by BaCl₂-TEA extraction, KCl-TEA extraction and NaAc leaching were a bit higher due to the influence of soil organic acids and Al oxides, however, further studies should be conducted on the measurement of soil exchangeable acidity and its influential factors because of the lack of standard method to verify the current experimental results.