Taking farmland soils in Beijing plain as the research object, selecting different functional zones, different planting patterns and different types of parent material,the study systematically analyzed the horizontal and vertical distribution and influencing factors of heavy metal Cr in different soil depths(0~25 cm,25~50 cm)from the point and the area based on the classical statistics and Empirical Bayesian kriging interpolation.The results showed that there was a certain difference in the Cr contents in different soil depths on the whole,with the highest average content of Haidian District and Fengtai District.In the spatial distribution,the Cr content in different soil depths was basically consistent in horizontal pattern, and gradually decreased outwardly with the urban area as the center. From the single factor evaluation method,the area within the warning line accounted for only 19.16%(0~25 cm)and 14.81%(25~50 cm)of the overall study area,showing obvious enrichment. The contents of heavy metal Cr in different functional zone were ranked in different soil depths:urban living zone>agricultural security zone>water source protection zone,and there was a significant effect on heavy metal Cr content in different soil depths. Different planting patterns and different parent material types had no significant effect on the Cr content in different soil depths, with no significant difference between groups.The research results may provide a scientific basis for the further treatment and management of heavy metal pollution in farmland soils.%以北京市平原区农田土壤为研究对象,针对不同功能区、不同种植模式及不同母质类型等因素,基于经典统计学、经验贝叶斯克里格插值法,从点与区域两个方面对不同土壤深度(0~25、25~50 cm)重金属Cr含量的水平和垂直分布及影响因素作了系统分析.结果表明:从整体看,不同土壤深度重金属Cr含量存在一定差异,不同区域比较以海淀和丰台平均含量为最高;空间分布上,不同土壤深度(0~25、25~50 cm)Cr含量水平分布格局基本一致,其分布以城区为中心向外逐渐降低.从单因子评价看,处于警戒线以内的区域面积仅占研究区总体的19.16%(0~25 cm)和14.81%(25~50 cm),存在明显富集现象.不同功能区重金属Cr含量在不同土壤深度中排序均为都市生活区>农业保障区>水源保护区,且对不同土壤深度Cr含量存在显著性影响;种植模式及母质类型对不同土壤深度Cr含量无显著影响,且组间无显著性差异.该研究成果可为农田土壤重金属污染进一步治理和管护提供科学依据.
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