吉林省德惠市土壤速效钾的空间分异及不同插值方法的比较

Spatial Heterogeneity and Comparison of Different Methods of Interpolation of Soil Available K in Dehui City, Jilin Province

基于地统计学和地理信息系统,采用区变量的半变异理论定量研究了土壤速效钾的空间变异特征,分析比较了不同空间插值方法的插值精度,并利用最优Kriging法插值生成了研究区土壤速效钾的分布格局图。结果表明:研究区土壤速效钾具有中等强度的空间自相关,步长为108.5km;块金效应显著,C0/sill值为0.43。所有插值方法中,球面多项式插值的RMSE最大,平常克吕格的指数模型插值精度最高。IDW虽然也常常被用来进行土壤属性特征的插值分析,但它只与距离有关,对于区域性的较大差异或存在多因子影响时,Kriging方法有其明显的优势;土壤速效钾的分布以中部饮马河为线,东西差异较大,总体自东北向西南呈有规律地逐渐增大的趋势。

Based on statistics and GIS, spatial heterogeneity of soil K was studied using semivariogram, the results of different interpolation methods were analyzed and compared, and the distribution map of available K in studied area was made used optimized Kriging method. The results show that available K in studied area belongs to middle class in respect of spatial autocorrelation, lag and c_o/sill were 108.5 km and 0.43 respectively and nugget effect is obvious. Among all the interpolation methods, the RMSE of GPI is the highest, and that of exponential model of ordinary Kriging is the lowest. Though, IDW is usually used as soil interpolation method together with Kriging, Kriging has obvious advantage over IDW when there are great differences or there are a lot of influence factors. Taking the Yingma river as borderline, the distribution of soil available K in studied area is very different in west part and east part. On the whole, the value is increasing gradually from northeast to southwest regularly.