基于GIS和统计学的土壤监测指标时空变化分析

土壤监测对于查清土壤生态质量家底,积极开展土壤污染生态修复与防治,实现可持续土地资源监测与利用有重要指导价值。为了研究江苏省宜兴市土壤监测指标的时空变化,根据宜兴市2004年多目标地球化学调查的426个土壤样本以及2015年1∶5万土地质量地球化学调查的4 458个土壤样本的数据,利用地理信息系统(GIS)和统计学方法研究了该区重要土壤环境参数的变化,通过箱线图和t检验对参数或元素浓度变化进行了检测,利用基于半变异函数的块金值(C0)进行了误差分析,并评估分析了不同的空间变量。结果表明,宜兴市土壤中有机质(OM)、氮、磷、硼等营养元素(指标)在11年间呈增长趋势,土壤pH值呈现明显下降趋势,土壤中镉、铜、铅、锌等重金属元素和硒含量呈上升趋势,砷含量没有明显变化。

An analysis of the temporal and spatial changes in soil monitoring indices based on GIS and statistics

Soil monitoring is of significance for guiding the determination of the ecological quality of soil, the active ecological restoration and prevention of soil pollution, and the sustainable monitoring and utilization of land resources. To investigate the temporal and spatial changes in the soil monitoring indices in Yixing City, Jiangsu Province, this study collected the geochemical data on 426 soil samples taken during the multi-purpose geochemical survey of Yixing City in 2004 and 4 458 soil samples taken during the 1∶50 000 land quality geochemical survey in 2015. Based on these data, this study analyzed the changes in important soil environmental parameters of the study area using the geographic information system (GIS) and statistics. Moreover, it determined the changes in the parameters or element concentrations using box-whisker plots and t-tests, conducted an error analysis using the nugget value (C0) based on the semivariance function, and evaluated and analyzed different spatial variables. The results are as follows. From 2004 to 2015, the organic matter (OM) and nutrient elements such as nitrogen, phosphorus, and boron showed an upward trend; the pH of soil showed a significant downward trend; the contents of selenium and heavy metals such as cadmium, copper, lead, and zinc showed an upward trend, and the arsenic content did not change significantly.