环渤海低平原土壤盐化特征及基于DEM的Co-Kriging插值研究

Spatial Variability of Soil Salinity and Its Esti mation by Co-Kriging Based on DEM in the Low Plain Around the Bohai Sea

针对环渤海低平原土壤盐化特征,通过选取0～20cm深度内的127个代表性土样进行土壤全盐量测定,结合DEM,综合运用地质统计学方法与GIS技术研究土壤盐分的空间分布状况。结果表明,土壤盐分空间变异强度属于中等,土壤盐分单变量和交互变量的空间相关程度均属于中等,空间自相关距离分别为40.60km和135.60km。环渤海低平原土壤盐分含量在不同高程上存在分布差异,并随着高程的降低土壤盐分含量呈增加的趋势。自内陆平原向东部滨海平原土壤盐分含量逐渐增加,盐分含量较高的地区出现在唐山-天津-沧州-东营-滨州一线。非盐化土以内陆平原为主,分布在保定-衡水-邢台-邯郸一线。通过协同克立格插值的均方根误差与普通克立格插值相比减少了0.29%,而预测值与实测值的相关系数提高了20.58%。

Takinginto account salinization existingin the low plain around the Bohai Sea at present ,soil samples from0 to 20 cm were collected from 127 sitesinthe plain ,and soil salinity was analyzed .In additional ,the digital elevation model （DEM） of the study area was also considered . Geostatistical method combined with GIS was used to analyze spatial variability of soil salinity . Results showed that ：spatial variability belonged to moderate degree with CV=0.91 .Spatial correlation of single variable and cross variable belonged to moderate degree ,spatial correlation distance was 40.60 kmand 135.60 kmrespectively .Soil salinity spatial distribution difference existedin different altitude as the altitude falling soil salinity rising .Soil salinity content showed anincreasing trend frominland plain （Baoding-Hengshui-Xingtai-Handan） to the east coastal plain （Tangshan-Tianjin-Cangzhou-Dongying-Binzhou）.Compared with the ordinary Kriging under the same sampling numbers ,the root-mean-square error produced by Co-Kriging decrease by 0.29%, while the correlation coefficient between the predicted value and the measured value increased by 20.85%.