基于空间差异度的不同插值方法土壤属性制图效果及影响因素分析——以新乡县为例

Influence Factors and Effects of Different Interpolation Methods for Soil Properties Mapping Based on Spatial Difference Degree-A Case Study of Xinxiang County

利用从2008年河南省新乡县测土配方施肥项目2 694个农化样中随机抽取的1 347个样点数据,选取有效磷和缓效钾为研究对象,通过Kriging、IDW、PRP 3种插值方法对其进行制图,以空间差异度为评价标准,比较不同插值方法的制图效果及影响因素,以期为土壤属性空间预测提供理论依据。结果表明:从制图结果空间差异度统计特征值及其各等级面积百分比来看,制图效果优劣程度为Kriging法>IDW法>PRP法;从空间差异度各等级所包含的样点数来看,不同插值方法制图结果受样点分布影响,空间差异度小的区域内包含样点数较多,而空间差异度大的区域内包含样点数较少;另外,制图结果还受土壤属性自身空间变异性的影响,因此,对于空间随机性变异的土壤属性应在变异较大的区域内增大采样密度,确保制图结果空间表达的准确性。

Kriging ,inverse distance weight method（IDW） and polygon value represented by point value method（PRP） were used for mapping of available phosphorus and slow-release potassium , and the influence factors and effects of these interpolation methods for soil properties mapping based on spatial difference degree were analyzed with 1 347 sample data from 2 694 soil samples collected from Xinxiang county of Henan province in 2008 .The results showed that the effect of mapping was the best using Kriging method ,IDW method was worse ,and PRP method was the worst ;the effects of mapping with these interpolation methods were influenced by the space dis-tribution of samples ,more samples were included in the region with lower spatial difference de-gree ,and the other region included fewer samples ;due to the impact of soil properties themselves spatial variability on mapping ,for the soil properties with spatially random variation sampling density should be increased in severe variation region to ensure the mapping results accuracy .