沟谷地不同植被下土壤重金属纵向分异研究

Longitudinal Variation of Heavy Metals Contents in Topsoil Covered with Different Vegetation in Gully Area

研究了长春市君子兰公园孟家河沟谷地纵向剖面不同植被（乔木、灌木、菜地和裸地）下土壤重金属的分异规律．沿沟谷地纵向剖面自上游向下游方向，在距离沟边2m处的谷地坡面上，采集不同植被覆盖下的土壤样方，通过对各样点的土壤表层重金属（Zn、Pb、Cu）的全量分析，得出沟谷地不同植被类型下土壤重金属的分异特征．结果显示，在不同的植被类型覆盖下，土壤重金属含量值有明显差异，Zn的变化范围在70．3～290．9mg·kg^-1，Pb在39．8～79．3mg·kg^-1，Cu在20．3～63．4mg·kg^-1，Zn、Pb、Cu全量具有裸地高于菜地土壤、菜地土壤高于乔木土壤、乔木土壤高于灌木土壤的特征．不同植被下土壤重金属实测平均值与吉林省土壤背景值的对比表明，沟谷地不同植被下土壤中Zn、Pb、Cu的含量均高于吉林省土壤背景值，土壤重金属含量有不断富集的趋势．

This paper, taking the Mengjia River gully area of Junzilan Park in Changchun City of Jilin Province as an example, studied the longitudinal differentiation regularity of heavy metals in topsoil covered with different vegetation in gully area. The soil samples were collected from the gully slope, 2 m away from the gully bank, covered with arbor, shrub, vegetable and barren land along longitudinal profile in parallel with the flow direction, which was used to analyze the contents of Zn, Pb and Cu in the topsoil. The results indicate that the contents of these heavy metals have obvious difference. The content of Zn ranges from 70.3 mg· kg^-1 to 290.9 mg· kg^-1, the content of Pb from 39.8 mg· kg^-1 to 79.3 mg·kg^-1, and the content of Cu from 20.3 mg·kg^-1 to 63.4 mg·kg^-1. They all follow the declined order： barren, vegetable, arbor, and shrub. Moreover, the contents of these heavy metals were higher than their soil background values respectively. Thus, it can be assumed that they have accumulation tendency.