表征不同地貌土壤有机质空间变异的方法研究——以龙海市为例

Methods to characterize spatial variability of soil organic matters in different terrains——Taking Longhai City as a case

以龙海市为研究区,在沿海平原区与丘陵山地区分别采用4种格网密度(0.5 km×0.5 km、1 km×1 km、2 km×2 km与3 km×3 km)与4种不同样点分类方式的组合,研究不同地貌区高效表征土壤有机质空间变异的采样点布设方式。结果表明,在不同格网密度下,沿海平原区按土壤类型进行采样的土壤有机质均方根误差均较其他方式低,为精度最高的样点布设方式;丘陵山地区以土地利用方式结合土壤类型为高效的样点布设方式。在样点密度布设方面,沿海平原区0.5 km×0.5 km、1 km×1 km与2 km×2 km三种格网密度的土壤有机质均方根误差差值均在35%以内,而2 km×2 km格网密度下的样点数量仅为0.5 km×0.5 km的15.21%,因此,在精度要求不高的情况下,为节约成本,可采用2 km×2 km格网密度下进行采样。同理,丘陵山地区宜采用2 km×2 km格网密度,按土地利用类型结合土壤类型的分类方式进行样点布设。

In order to study sampling points allocation methods for spatial variability of soil organic matters in different terrains , Longhai City was chosen an object as a research area .and the combination of four grid densities （0.5 km ×0.5 km, 1 km ×1 km, 2 km ×2 km and 3 km ×3 km） and four classification methods in coastal plain and hilly regions was adopted .At the same time the spatial interpolation methods to predict and compare the accuracy of soil organic matter contents were applied .The results showed as follows.In coastal plain , under different grid densities , sampling point layout according to soil types , the root mean square error of soil organic matters was lower compared with other methods .In this sampling points allocation method its accuracy was the highest . Meanwhile in hilly and mountainous region , sampling point layout based on the land use patterns and soil types was a more efficient way.On the sampling point density layout , in coastal plain , the value differences of root mean square error all were within 35%in 0.5 km ×0.5 km、1 km ×1 km and 2 km ×2 km grid densities.While in 2 km ×2 km grid density, the amount of the sampling points was only 15.21%of that in 0.5 km ×0.5 km grid density.That is to say if there is no need of a high accuracy , using 2 km ×2 km grid density to allocate the sampling points is a better choice to save the cost .It showed the same result to allocate the sampling points in 2 km ×2 km grid density based on the land use patterns and soil types in the hilly and mountainous region .