不同采样尺度下土壤重金属的空间变异特征

Spatial Variability of the Soil Heavy Metal with Different Sampling Scales

为研究不同采样尺度对土壤重金属元素空间变异结构的影响,本文利用地统计学方法探讨了两个取样尺度下,浙江省慈溪市表层土壤中重金属含量的空间变异性特征。研究结果表明:不同尺度下,土壤重金属在含量变化存在一定差异,但七种土壤重金属元素的变异系数大小均符合相同的规律;不同尺度下土壤重金属含量均存在较好的空间结构,但土壤重金属空间相关距离有一定差异,大尺度下的空间相关性要稍优于小尺度下采样的空间相关性。两种采样尺度下,除Hg元素外,土壤中重金属元素含量可以被较为准确地估计,但大尺度下的采样点元素被低估的可能性要大于小尺度下采样的可能性。

To study about the spatial variability of the soil heavy metal affected by the different samples scale, geostatistics were used for the analysis of the spatial variability of soil heavy metal in top soil of Cixi city in Zhejiang province with two sampling scales. The result showed that there was different range in the soil heavy metal content change of two sample scales, but the coefficient of variation of seven heavy metal content in soil of two sample scales was in the same orders. There was good spatial variability structure of the soil heavy metal content of the two sample scales, hut the spatial correlation distance was different and the spatial correlation degree of the big sample scales was better than the small sample scales. The content of heavy metal in soil can be exactly estimated except of Hg but the feasibility of the heavy metal content in small sample scales was underestimated than the big scales.