Effect of vegetation restoration on stability of soil aggregates in coal mining subsidence area

In order to identify the soil aggregate composition and stability changes of soil aggregates in different vegetation restoration types in coal mining subsidence areas, and then screen out the best reclaimed forest types. Aiming at the coal mining subsidence land in Shenfu Dongsheng mining area, three forest types of Amygdalus pedunculata, Cerasus humilis, and Xanthoceras sorbifolia were set up in the coal mining subsidence of this area, and the surrounding unreclaimed land was used as a control to explore the response of soil mechanical stability and water stability aggregate composition and stability in 0-20 cm and 20-40 cm soil layers to long-term vegetation reclamation. The results showed that the reclamation of Amygdalus pedunculata, Cerasus humilis, and Xanthoceras sorbifolia increased the content of mechanical stability and water-stable aggregates of 0-20 cm and 20-40 cm soil layers>2 mm and 0.25-2.00 mm, and decreased the content of mechanical stability and water-stable aggregates of 0.053-0.250 mm and<0.053 mm soil layers; the mechanical stability aggregates (DR>0.25) and water stability aggregates (WR>0.25) in different soil layers of different reclaimed forest types increased by 17.86%—33.36% and 12.94%—21.69% respectively compared with the control; the mean weight diameter (MWD) and geometric mean diameter (GMD) increased significantly larger than the control plot, and the number of fractal dimensions (D) decreased compared with the control. The MWD and GMD of Xanthoceras sorbifolia soil aggregates were the largest,, the D value was the smallest, and the stability was the highest; 0.053—0.250 mm and<0.053 mm aggregates were negatively correlated with R>0.25, MWD and GMD. The main conclusion is that different types of vegetation restoration can promote the transformation of aggregates of smaller size to larger size aggregates, especially the aggregate content greater than 0.25 mm, which increases the stability of soil aggregates; Xanthoceras sorbifolia forest has the highest macroaggregate content, the best stability and better vegetation restoration effect.