Spatial distribution characteristics of reconstructed soil bulk density of opencast coal-mine in the loess area of China

Abstract

Controlling and adjusting the reconstructed soil bulk density (RSBD) in an artificially disturbed ecosystem is one of the main challenges in land reclamation. Exploring the spatial distribution of RSBD is the best starting point to analyze and improve reclamation technology. This study quantifies the spatial distribution pattern and variation of RSBD on reclaimed land in the loess area of China using geostatistical spatial interpolation and multiple regression analysis. Topography (platform, slope, and slope aspects), vegetation cover, soil particle size distribution, and soil erosion were found to affect the spatial variability of the RSBD. The boundary between the sunny slope and shady slope was considered to be the dividing line for the RSBD, which was generally distributed in stripes and patches. The RSBD was higher on the sunny slope than on the shady slope at 0–10 cm, while the opposite was observed at 20–40 cm. However, the RSBD at the depths of 40–60 cm increased from west to east, and the direction of the strong spatial variability also gradually changed from “ Southwest ↔ Northeast ” to “ West ↔ East ”. The unary quadratic regression equations accurately represent the variation laws of RSBD at different soil depths under different topography and vegetation cover (R2 > 0.90). Measures that utilize engineering and vegetation to improve the RSBD should be adjusted according to the specific landscape and topography. This study provides a theoretical basis for the improvement of the RSBD and the optimization of land reclamation technology used in opencast coal-mine dumps in the loess area.