苏北优势农业区土壤砷含量空间变异性研究

为研究江苏北部优势农业区土壤砷含量的空间变异性并分析引起其空间变异的原因,该文采用经典统计学和地质统计学相结合的方法对土壤中砷含量进行了分析.在对原始数据进行探索性空间分析的基础上,采用加权多项式回归法及交叉验证法,对球形、指数、高斯模型拟合实验半变异函数的结果进行评价,并根据评价结果选择了带块金效应的高斯模型作为实验半变异函数的拟合模型.采用普通克里格法对苏北优势农业区土壤砷含量空间分布情况进行插值计算,结果表明苏北优势农业区土壤砷含量存在明显空间相关性并且实验半变异函数表现为各向同性.区域内土壤砷含量最高的区域在研究区的西北部,而最低值在研究区的中北部.劣质水灌溉是引起这种变异的主要原因.

Spatial variability analysis of soil arsenic content in predominant agricultural area in the north of Jiangsu Province

The spatial variability and the cause of the variability of soil arsenic (As) in north predominant agricultural area, Jiangsu Province were analyzed using mathematical statistics and geostatistic methods. Based on the spatial data analysis of the observed values, polynomial-weighted and cross-validation were adopted to evaluate the semivariogram model fitting results by spherical model, exponential model and Gaussian model. According to the evaluation results, the Gaussian model with sill was suggested to be preferable for fitting the semivariograms. Ordinary kriging were used to estimate soil As distribution in the monitoring area. The results show that soil As in north predominant agricultural area, Jiangsu Province, is autocorrelated and the experimental semivariogram is isotropic. The values of soil As are the highest in the north-west part of the monitoring area and the lowest values are in the middle-north part. Irrigation with poor quality water is the main cause of the variability.