土壤环境监测点位最优网格研究--以南阳盆地农耕区土壤镉元素为例

Study on optimal grid of soil environmental monitoring sites:taking soil Cd element farming area of Nanyang Basin for example

以河南省南阳盆地农耕区为研究区,利用1∶25万土地质量调查表层土壤数据,选择镉元素为研究对象,利用Moran指数,检测研究区域内土壤镉元素空间自相关的指标;采用随机抽样法,分别形成4 km×4 km、8 km×8 km、16 km×16 km和32 km×32 km等4种尺度的网格,分别通过半方差分析、交叉验证,对不同采样尺度下的土壤镉元素的空间变异进行分析及预测精度;最后以普通克里格插值方法为例,探讨采样点数量对土壤质量指数空间分布表征的影响,研究了土壤环境监测点位的最优布设网格。通过对南阳盆地农耕区土壤数据研究发现,土壤环境监测点位采用16 km×16 km尺度的网格比较适宜。

In this paper,the farming area of Nanyang basin in Henan Province was taken as the studying area,based on the surface soil data of 1∶250000 Land Quality Survey,the Cd element was selected as the research object.Using the Moran index,the spatial autocorrelation index of Cd element in the studied area was detected by Moran index,random sampling method was used to form 4 km×4 km,8 km×8 km,16 km×16 km and 32 km×32 km grids.The spatial variability of Cd element in soils with different sampling scales was analyzed and predicted by semi-variance analysis and cross-validation.Finally,the effect of the number of sampling points on the spatial distribution of soil quality index was studied by using Kriger interpolation method.The optimal grid layout of soil Environmental monitoring was studied.Based on the soil data of the farming area in Nanyang Basin,it was found that 16 km×16 km grid is suitable for the environmental monitoring point.