设施菜地重金属的剖面分布特征

Distribution characteristics of heavy metals in soil profile of facility vegetable fields.

以山东省寿光市种植1～12年的蔬菜大棚及相邻的小麦地为对象,研究了设施菜地中As、Cd、Cu、Zn、Cr、Ni 6种重金属在土壤剖面中的分布特征.结果表明:在0～150 cm土层内,随着土层深度的增加,设施菜地与小麦地中6种重金属含量均呈下降趋势;与小麦地相比,相同土层设施菜地中6种重金属的含量均明显较高,设施菜地0～20 cm土层中As、Cd、Cu、Zn、Cr、Ni的含量分别比小麦地相同土层高出35.0%、146.2%、65.6%、36.4%、21.5%和14.0%,120～150 cm土层分别高出10.6%、178.5%、19.4%、20.2%、15.2%和9.3%,20～120 cm各土层中的含量亦高于小麦地.设施菜地0～20 cm土层中,Cd、Cu、Zn含量与种植年限呈显著正相关,随着种植年限的增加,其累积速率分别为0.027、1.153和2.830 mg.kg-1.a-1;设施菜地中6种重金属的含量与土壤有机碳、全氮含量呈正相关,除Ni和As外的4种重金属含量亦与土壤全磷含量呈极显著相关,有机肥等的施用可能在一定程度上导致设施菜地中重金属的累积.

Taking the facility vegetable fields having been planted for 1-12 years and the adjacent wheat land in Shouguang City of Shandong Province as test objects,this paper studied the distribution characteristics of arsenic（As）,cadmium（Cd）,copper（Cu）,zinc（Zn）,chromium（Cr）,and nickel（Ni） in their soil profiles（0-150 cm）.With the increase of soil depth,the test heavy metals contents in the soil profiles all had a decreasing trend,and in the same soil layers, the contents were obviously higher in facility vegetable fields than in wheat land.Comparing with those in the same soil layers of wheat land,the average contents of As,Cd,Cu,Zn,Cr,and Ni in 0-20 and 120-150 cm soil layers of facility vegetable fields were 35.0%,146.2%,65.6%,36.4%,and 21.5%,and 10.6%,178.5%,19.4%,20.2%,15.2%,and 9.3% higher,respectively,and the average contents of the heavy metals in 20-120 cm soil layer of facility vegetable fields were also higher in some degree.In the 0-20 cm soil layer of facility vegetable fields,the Cd,Cu,and Zn contents had significant positive correlations with planting years（P0.05）,with the accumulation rates of Cd,Cu,and Zn being 0.027,1.153,and 2.830 mg·kg-1·a-1,respectively.In facility vegetable fields,the test six heavy metals contents were significantly positively correlated with the contents of soil organic carbon and total nitrogen,and the Cd,Cu,Zn,and Cr contents were significantly correlated with the content of soil total phosphorus（P0.01）.Applying organic fertilizer could induce the heavy metals accumulation in the soils of facility vegetable fields to some extent.