目前土壤属性的曲面建模面临两大问题,一是缺乏足够多的采样点进行模拟,二是采样点的土壤属性与环境变量间存在非线性关系。高精度曲面建模(HASM)方法在如何融合地学信息对土壤属性进行空间插值,尚需深入研究。本文提出高精度曲面建模与地学信息相结合的土壤属性空间插值方法(High accuracy surface modeling for soil properties,HASM-SP),分别基于研究区的土壤类型、土地利用类型和母岩类型,模拟了江西省典型红壤丘陵区土壤的速效磷(AP)、锂(Li)、pH、碱解氮(AN)、全钾(K)和铬(Cr)6种土壤属性的空间分布。将HASM-SP与普通克立格(OK)、OK与地学信息相结合的方法(OK-Geo)和分层克立格(SK)相对比,结果表明:结合地学信息可以使插值方法(HASM-SP和OK-Geo)模拟结果的平均误差更趋近于0;相对于其他3种方法,HASM-SP具有较小的平均绝对误差和均方根误差。从模拟的空间分布图上来看,HASM-SP获得了由于地学要素类型突变导致的土壤属性空间变异的细节信息。因此,基于地学信息的土壤属性高精度曲面建模方法(HASM-SP)与传统插值方法相比,不仅提高了土壤属性空间分布的模拟精度,还能更好地刻画突变边界处土壤属性的空间变异,使土壤属性分布图更好地符合地学规律和实际情况。HASM-SP的提出对于丰富土壤属性的高精度曲面建模理论具有重要意义,并为土壤管理、精准农业的实施以及区域环境规划等提供科学依据。
There are two main limitations in surface modeling of soil property.One is the small number of available observations,and the other is the nonlinearity of the relationship between environmental variables and soil properties.It is still needed to research how high accuracy surface modeling(HASM)is combined with geographical information in soil property interpolation.This paper presented the method of HASM combined geographical information for soil property interpolation(HASM-SP).Based on types of soil,land use and parent rocks,we simulated the spatial distribution of soil properties of soil available P,Li, pH,alkali-hydrolyzable N,total K and Cr in a typical red soil hilly region.We compared the performance of HASM-SP,ordinary kriging(OK),ordinary kriging combined geographical information(OK-Geo)and stratified kriging(SK).The results showed that the methods combined with geographical information(HASM-SP and OK-Geo)obtained a lower estimation bias.Compared with the other three methods(OK-Geo,OK and SK),HASM-SP showed less MAEs and RMSEs.From the interpolation maps,much more details were presented in the HASM-SP maps of soil properties due to the abrupt boundary from spatial variation of geographical information.Therefore,HASM-SP can not only improve the interpolation accuracy but also characterize the spatial variation of soil property surface in the abrupt boundary,which can make the map consistent with the true geographical information. HASM-SP has great significance for enriching the theory of high accuracy surface modeling of soil property,and providing scientific evidence for the application of the soil management, precision agriculture and regional environment planning.