区域土壤空间抽样方法研究

Study on Regional Soil Spatial Sampling Method

对不同空间抽样方法进行对比研究是寻找具有空间相关性的不同资源和调查对象的最适宜抽样设计方案的重要手段。该文以广东省增城市土壤铬含量为空间要素,分别采用空间简单随机抽样、空间分层抽样和三明治抽样3种方法进行抽样;为便于比较3种方法的抽样精度,设定相同样本容量,采用Kriging插值对抽样结果进行精度评价。结果表明:在较为丰富的先验知识的情况下,三明治空间抽样方法所抽样点在预测土壤重金属含量分布情况时得到的克里格估值误差最小,是一种抽样精度更高、适用范围更广的抽样方案。

The comparative study on different spatial sampling method is an important means to find a spatial correlation of the different resources and survey the most appropriate sampling design. In this paper, the soil Cr content in Zengcheng City in Guangdong Province was taken as spatial elements, three kinds of methods for sampling analysis that respectively were the spa- tial simple random sampling and spatial stratified sampling, spatial Sandwich sampling were discussed. For ease of comparison of three methods of sampling precision, this paper set the same sample size, and then used the Kriging interpolation on the sam- pling accuracy evaluation,and then did cross-validation after Kriging interpolation. In cross-validation process, I MEI value of the Sandwich space sampling method is the most closet to zero, it is 0. 0973, and the value of spatial simple random sampling is the largest. The order of the ｜RMSE-ASE｜ value is：spatial simple random sampling〉spatial stratified sampling〉spatial Sandwich sampling. The results show that, in the case of more rich of prior knowledge, the sample points which gained by Sandwich sampling attain the minimum Kriging estimation error in the case of predicting the distribution of the contents of heavy metals in soil,sandwich sampling has higher sampling precision and wider range of application.