区域土壤Cd和Cr空间分布的影响因素研究

以种粮大县肇源为研究区,对土壤表层Cd、Cr两种元素水平空间变异及分布特征的影响因素进行深入探讨。结果表明:(1)肇源县土壤表层重金属Cd和Cr的平均含量分别为0.078、46.006 mg/kg,略高于松嫩平原土壤背景值。表层土壤Cd的块金效应为0.432,具有中等程度的空间自相关性;表层土壤Cr的块金效应为0.227,存在强烈的空间自相关性。Cd、Cr元素的空间自相关表现出较为明显的各向异性,均在45°(东北-西南)和135°(东南-西北)方向上空间自相关最强烈。(2)表层土壤和成土母质中Cd和Cr元素含量相关分析结果显示,相关系数分别为0.167、0.639,在P0.01水平上显著相关;不同成土母质类型区域表层土壤中Cd和Cr元素含量的方差分析结果显示,方差齐性检验显著性分别为0.627和0.975,表明成土母质是表层土壤重金属元素Cd和Cr水平空间分布的主要影响因素。(3)研究区内表层土壤Cd和Cr元素的空间分布还受土壤类型、pH、土地利用及覆被类型的影响。

Influential Factors of Spatial Distribution of Cd and Cr in Regional Soils

Influential factors of spatial variabilities and distributions of Cd and Cr were analyzed in topsoils of Zhaoyuan County, a major agricultural county. The results showed that the average concentrations of Cd and Cr in topsoils were 0.078 mg/kg and 46.006 mg/kg, respectively, slightly higher than those of the Songnen Plain; the ratios of nugget/sill were 0.432 for Cd and 0.227 for Cr, respectively, indicating a moderate spatial autocorrelation for Cd and a strong one for Cr. Anisotropy analyses suggested that the spatial autocorrelation of Cd and Cr were dependent on the direction, and there were the most obvious spatial autocorrelation in 45°(northeast-southwest) and 135°(southeast-northwest) direction. Correlation coefficients of Cd and Cr between topsoil and parental material were 0.167 and 0.639, respectively (P<0.01). Variance analyses of Cd and Cr in topsoils under different parent materials showed that F values were 0.627 and 0.975, respectively, indicated that the spatial distributions of Cd and Cr were dominated by parent material, while also affected by soil type and pH value, land use type and cover type.