不同种植方式下土壤中重金属分布的研究及评价

[目的]了解不同种植模式下土壤重金属的分布特征。[方法]通过对北京郊区大田和蔬菜用地不同耕层的土壤进行分析,探讨不同种植模式下土壤重金属的分布特征。[结果]大田上层土壤中Cu、Pb、Zn含量明显高于下层,温室菜地上层土壤中Cu、Cd、Zn含量有明显增高趋势。除Cd外其他元素在大田土壤中变异较小,同一土层中各元素的分布相对均一。菜地中Cu、Zn、Cd的变异系数大,Pb、Cr、Fe、Mn在上下土层中的变异很小。大田和蔬菜用地的土壤单因素污染指数和综合污染指数均小于0.7,但蔬菜种植区的综合污染指数明显高于大田。[结论]菜地的土壤环境质量不如大田,但尚符合土壤环境质量二级标准。

Research and Evaluation on the Distribution of Heavy Metals in Soil under Different Planting Models

[Objective] The aim was to know about the distribution characteristics of heavy metals in soil under different planting models.[Method] Through analyzing the soil in different arable layers in farmland and vegetable field in Beijing suburb,the distribution characteristics of heavy metals in soil under different planting models were discussed.[Result] In the soil in upper layer in farmland,the contents of Cu,Pb and Zn were significantly higher than that in lower layer and the contents of Cu,Cd and Zn in upper layer in vegetable field in greenhouse had significantly increasing trend.Except for Cd,the other elements varied less in the soil in farmland and the distribution of various elements in the same soil layer was relatively even.The variation coefficients of Cu,Zn and Cd in vegetable field were big and the variations of Pb,Cr,Fe and Mn in upper and lower soil layers were very little.The single-factor pollution index and comprehensive pollution index of soil in farmland and vegetable field were smaller than 0.7,but the comprehensive pollution index in the planting area of vegetable was significantly higher than that in farmland.[Conclusion] The soil environment quality in vegetable field was worse than that in farmland,but yet accorded with the secondary standard of soil environment quality.