Influence of varying cover-soil thickness on the restoration of degraded riparian grassland

This experiment tested different options for restoring the damaged environment in the southern segment of the Sangonghe using four levels of cover-soil thickness (0, 8, 12, and 16 cm). Leguminosae and Gramineae local grasses were mixed and sown on bare shoal. The effects of environmental restoration and species diversity were surveyed, and the traits of the plant communities were compared after a six-year restoration period. The results were as follows. 1) In general, the coverage, height and aboveground biomass of the grassland plant community increased with cover-soil thickness. For the 0 and 8 cm cover-soil treatments, all three of the aforementioned traits were lower, compared to those of the 12 and 16 cm cover-soil treatments (P < 0.05). The coverage of grassland plants with 16 cm of cover-soil was significantly greater than those treated with 12 cm of cover-soil (P < 0.05). 2) For the different treatments, the Shannon-Wiener index ranked 16 cm > 8 cm > 12 cm > 0 cm of cover-soil; the Pielou index ranked 16 cm > 12 cm > 8 cm > 0 cm of cover-soil; and the Margalef index ranked 16 cm > 8 cm > 12 cm > 0 cm of cover-soil. No significant differences in plant species diversity was detected between the 8, 12, and 16 cm cover-soil treatments (P > 0.05). 3) There was, however, a significant positive correlation between aboveground biomass and the Shannon-Wiener index of different treatments (P < 0.01). The research showed that under the same sowing conditions, cover-soil can promote the conservation and restoration of grassland ecosystems. Therefore, we suggest that 16 cm of cover-soil is the best option.