Effect of vegetation restoration on the soil water stable aggregate in the limestone mountains of China

In order to elucidate the effect of vegetation restoration on the soil physical characteristic and soil water stable aggregate in the limestone mountains of northern Anhui Province, soil samples were collected from land under different vegetation restoration regimes. The content of soil water aggregate was measured by high vacuum slow wetting. The results indicate that the highest content of aggregate size of 0.50~0.25 mm and lowest values of bulk density were found in the soil under Setaria glauca and Vitex negundo var. cannabifolia restoration, which indicated that the restoration of grass-shrub improved the formation of <1 mm aggregates, thereby improving the soil structure underneath. The highest value of mean weight diameter (MWD, 0.47 mm) and geometrical mean weight (GMD, 0.61 mm) were found, respectively, in the soils under grass-shrubs S. glauca and V. negundo var. cannabifolia, and the shrubs Ziziphus jujuba var. spinosa and Vitex negundo var. cannabifolia. These results indicate that there was a difference in the distribution, as well as in the stability, of soil water stable aggregates among the four vegetation restoration measures. The results from the present study will provide a reference for evaluating the benefits of ecological restoration and soil quality in the region of the limestone mountain.