柳江流域岩溶区土壤元素地球化学特征研究

Study on element geochemistry of Limestone soil in liujiang drainage area

通过野外土壤剖面调查和取样分析,集中典型土壤剖面数据,分析柳江流域石灰岩土壤剖面元素地球化学特征,指出石灰土剖面地球化学特征及可能的影响因素,为认识流域内岩溶区土壤剖面的形成及演化提供地球化学依据。结果表明:(1)石灰土土壤富集Si、Al元素,Na、Mg、Ca元素含量较少,呈弱碱性;Mg、Ca含量与pH值呈正相关关系;Zn、Pb、Cd与pH值呈负相关关系。(2)有机碳、N含量随土壤加深而降低,K、K2O、pH值含量则相反。(3)土中微量元素Zn、Pb、Cd含量显著高于全国土壤含量平均值,但没有超标。(4)不同群落类型的植物影响石灰土壤剖面的有机碳含量和pH值。

Based on field investigations on typical soil profiles and samples, the elements geochemistry and its regularity of limestone soil in Liujiang drainage area were analyzed, and the possible factors were provided, which present the basis of formation and evolution for soil profiles. The results showed that：（1）The contents of silicon and aluminum are taking larger proportion than the Na, Mg and Ca＇s; the limestone soil is weakly alkaline; there is positive correlation between pH value and the content of Ca and Mg, but negative correlation between pH value and the content of microelement.（2）The contents of organic carbon and N decrease with the depth of soil profile, while the K, K20, pH are opposite. （3）The contents of microelements are greatly higher than national average, but safe. （4）Both organic carbon and pH value are affected by vegetation covered above.