An Overview of High Accuracy Surface Modeling of Soil Properties

AbstractHigh accuracy surface modeling (HASM) of soil properties is regarded as an important topic for the fields of pedometrics and “digital soil”. The HASM method, constructed by Yue et al., is a spatial interpolation technique based on the fundamental theorem of surfaces. In this paper, we will give an overview of high accuracy surface modeling of soil properties. Soil properties for the interpolation were measured on 150 samples of topsoil (0–20cm) in a red soil region of Jiangxi Province, China. Predicted and measured values were compared using the mean error (ME), mean absolute error (MAE) and root mean square error (RMSE). First, HASM has more accuracy than the classical interpolator including kriging, inverse distance weighting (IDW) and splines. Second, in order to improve the calculation speed for HASM applied in soil interpolation, multigrid has been combined in HASM (HASM-MG). HASM-MG can be considered as an accurate method for interpolating soil properties on the premise of improving the calculation speed, and it advances the practicability of HASM applied in soil property interpolation. Third, modified HASM method based on the incorporation of ancillary variables was developed for improving interpolation of soil properties (HASM-SP). To evaluate the performance of HASM-SP, it was compared with ordinary kriging (OK), ordinary kriging combined geographical information (OK-Geo) and stratified kriging (SK). HASM-SP not only showed less MAEs and RMSEs, but also presented much more details due to the abrupt boundary from spatial variation of geographical information. Therefore, HASM can be considered not only as an alternative, accurate and high speed method for interpolating soil properties, but also can make the map more consistent with the true geographical information