Abstract:
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.