内蒙古河套平原小麦产区土壤元素生物有效性研究

Research on Biological Availability of Soil Elements in Wheat-growing Regions in Hetao Plain,Inner Mongolia

采集内蒙古河套平原小麦产区土壤样品,分析元素形态分布及有效态含量特征。结果表明:不同元素在该地区土壤中的主要赋存形态存在差异,Cd元素主要以碳酸盐结合态为主,易被作物吸收,生物毒性较大,Hg元素主要为强有机结合态,在强氧化条件下可被作物吸收,Cr、Cu、Ni、Pb、Zn、As等元素主要赋存形态为残渣态,不易迁移转化,生物活性较低;不同元素有效态含量的区域分布特征有很大差异;以有效系数来评价元素的生物活性,S、Ca和Mo的生物活性最高,Cu和Pb中等,Zn、Fe、Mn等7种元素生物活性不高;各元素有效态含量在垂向上的分布也存在差异。本研究对探讨河套地区农业土壤营养元素和有害元素的环境效应及其迁移转化规律具有重要意义。

With collection of soil samples from wheat-growing area in Hetao Plain of Inner Mongolia, this research analyzes the distribution of element speciation and content characteristics of available state. The result shows that occurrence states of elements in soil are various. Cd is usually in carbonate--bounded state and can be absorbed easily by crops,but its biological toxicity is strong; Hg is usually in strong organ- ic-bounded state and can be absorbed by crops under the strong oxidizing conditions;Cr,Cu,Ni,Pb,Zn,As and other elements are usually in residual state, can hardly be transported and transformed, and are inactive biologically. There are obvious diversities among regional characteristics of availability of different ele- ments. By evaluating biological activities of elements,it is found that S,Ca and Mo rank the top,Cu and Pb are in the middle, and seven other elements like Zu, Fe, Mn and so on are at the lowest. There is also differ- ence in the vertical distribution of elements; availability. This research is of great significance for exploring the environmental effects, transportation and transformation of positive and negative agricultural soil ele- ments in Hetao Plain.