基于地理探测器的封丘县农田土壤重金属分布影响因素研究

以河南省封丘县为研究区，利用反距离加权插值法研究了农田土壤重金属Cd、Cu、Cr、Pb、Zn和As的空间分布特征；同时，应用基于地理探测器模型定量研究了8个因子对土壤重金属空间分布的影响。结果表明：研究区土壤Cd、Cr、Pb和Zn含量超过了黄河下游潮土背景值，而Cu和As含量低于黄河下游潮土背景值；其中有极少量样点Cd含量超过农用地土壤污染风险筛选值，而其他均未超标。在空间分布上，Cd、Cr、Pb含量的高值区分别主要分布在研究区中部、西南部和北部，As含量的高值区分布在研究区北部和西南部，Cu和Zn含量的高值区在研究区南北方向呈带状分布。Cd、Pb和As含量的低值区主要分布在研究区南部，Cr、Cu、Zn和As含量的低值区主要分布在研究区中部。地理探测器分析表明，土壤重金属空间分布受到自然因子和人为因子的共同作用，有机质含量是影响较大的自然因子，人口密度是影响较大的人为因子。两因子之间的交互作用均大于单因子的作用，其中有机质含量与各因子的交互作用对重金属空间分布的影响较显著。

Study on Factors Influencing Heavy Metal of Farmland Soils Based on Geographical Detector in Fengqiu County

It is important to analyze soil heavy metal distribution and related influencing factors for heavy metal prevention in cropland and food security in region. In this study, the spatial distribution characteristics of Cd, Cu, Cr, Pb, Zn and As in cropland in Fengqiu county of Henan province were explored based on IDW interpolation method. Simultaneously, the geographical detector model was adopted to illustrate the effects of 8 influencing factors on heavy metal distribution in spatial. The results showed that the average contents of Cd, Cr, Pb and Zn exceeded the soil background value of the fluvo-aquic soil in the lower Yellow River, while Cu and As were lower than the background value. All heavy metal contents in soil fell in the range of allowable value for agricultural land except for Cd from few samples. In spatial, the high-value of Cd, Cr, and Pb were respectively distributed in the middle, southwest and north of the research area, respectively, while As was distributed in the north and southwest of the study area. The high-value of Cu and Zn were showned asin zonal distribution. The low-value areas of Cd, Pb and As were mainly distributed in the southern part of the research area, and the low-value areas of Cr, Cu, Zn and As were mainly distributed in the middle. Cr, Cu, Zn and As showed higher content in the east and west than in the mid part; Cd was higher in the east and lower in the south part; while Pb had a decline trend from north to south in the study area. According to the geo-detector model, the spatial distribution of heavy metals were influenced by both the natural and artificial factors. Soil organic matter content was a dominant factor among the natural, while the population density was the primary one of the artificial factors. The interaction between each two factors was significant, especially the interaction between the soil organic matter and other factors exerted a significant influence on the spatial distribution of heavy metals. The obtained results could provide some references for the management and prevention measure of heavy metal in cropland.