典型潮土剖面主要性质和微量金属垂直分布特征

VERTICAL DISTRIBUTION CHARACTERISTICS OF SELECTED SOIL PROPERTIES AND TRACE METALS IN TYPICAL CALCAREOUS FLUVO-AQUIC SOIL PROFILE

对不同利用方式下石灰性潮土剖面主要性质和微量金属元素含量垂直分异规律进行了初步研究。结果表明,长期耕种的菜地和旱地0～15cm表层土壤有机碳含量高于其他土层,pH和CaCO3含量低于下层土壤;表层土壤Cd已明显积累;但Cd、Pb、Cu、Zn含量均未超过国家土壤环境质量二级标准。几种微量金属全量在菜地和旱地表层土壤之间没有显著差异,但菜地表层土壤DTPA可提取态Cd含量显著高于旱地。从微量金属的剖面分布看,石灰性潮土全量Cd和DTPA可提取态Cd、Pb、Cu、Zn均有明显的表聚现象,这种分布与土壤有机碳含量、pH和CaCO3含量显著相关。聚类分析表明,该区域耕作土壤环境分析样品的采集以表层土壤0～15cm多点混合样品为宜。

A preliminary study was carried out on vertical distributions of selected soil properties and trace metals in typical calcareous fluvo-aquic soil profiles under different land use. Results indicate that in vegetable fields and upland soils, the topsoil （0 ~ 15 cm） is higher in organic carbon content, lower in pH and CaCO3 content than the other layers in the soil profiles, and shows significant Cd accumulation, however, the concentrations of Cd, Pb, Cu and Zn have not yet exceeded the second grade criteria of the National Standard for Soil Environment Quality of China. Totals of some trace elements in the top soils do not vary much between vegetable and upland soils, but the concentration of DTPA-extractable Cd in the topsoil is significantly higher in the former than in the latter. In light of distribution of the trace elements in the profiles, surface accumulation is quite obvious of total Cd and DTPA-extractable Cd, Pb, Cu, and Zn in calcareous fluvoaquic soil. This phenomenon is significantly related to content of soil organic matter, soil pH and content of soil CaCO3. Result of cluster analysis shows that it is more advisable to collect mixed muhi-site soil samples from the surface soil layer （0 - 15 cm） for soil environment analysis.