Spatial distribution of soil nutrients in reclamation dump sites based on subdivision IDW

Accurately grasping the spatial distribution of soil nutrients is of great significance for evaluating the soil quality of reclamation dumps and formulating corresponding reclamation measures. The general interpolation method of the complex terrain of the dump site has a poor prediction effect. The northern dump of Shengli No.1 open-pit mine in Xilinhot, Inner Mongolia was selected as an example in the paper. The soil nutrients(available nitrogen, available potassium, available phosphorus and organic matter) were spatially interpolated using the inverse distance weighting method based on terrain partitioning, and compared with the conventional inverse distance weighting method and kriging interpolation method. The results show that the cross-validation accuracy obtained by using the partitioned inverse distance weighting method was higher than that of the kriging interpolation method and the inverse distance weighting method. In addition, the R² value of available phosphorus was 0.22, and the R² value of available nitrogen was 0.37. The R² values of available potassium and organic matter were 0.34 and 0.14, respectively. They were also higher than Kriging interpolation and inverse distance weighting. In addition, the partitioned inverse distance interpolation method could accurately estimate the extreme points of the measured points, and could better reflect the details of the spatial distribution of soil nutrients in the dump.