Effect of four native plant species on soil properties in desertified alpine meadow of the Tibetan Plateau

Desertification has already become a serious threat to alpine meadows in southeastern Tibetan Plateau, and to provide scientific evidence for selecting adaptive plant species and a reasonable direction for recovering desertified alpine meadows, the effects of four native plant species, including Rhodiola rosea, Kengyilia rigidula, Elymus nutans, and Salix cupularis, on soil physicochemical properties, soil enzymes, and soil microbial biomass were explored in this study. The results showed that: 1) After five years of vegetation restoration, soil moisture increased significantly (P<0.05), and increased the most (by 357.70%) in the treatment with E. nutans among the four plant species; meanwhile, both soil pH and bulk density decreased at different levels for the different species; 2) Activities of soil enzymes related to carbon, nitrogen, and phosphorus cycles increased significantly (P<0.05), and the activities of cellulase, peroxidase, sucrase, protease, and phosphatase in the treatment with R. rosea, which were 3.19, 1.98, 3.22, 1.87, and 4.59 times that of the control, respectively, exhibited the highest values than the others; 3) Soil microbial biomass carbon (MBC) and nitrogen (MBN) increased significantly (P<0.05), and soil MBC, MBN, and microbial biomass carbon to nitrogen ratio (MBC/MBN), which were 4.39, 3.46, and 1.27 times that of the control, respectively, were the highest in the treatment with R. rosea; 4) The correlations between soil enzyme activity, soil physicochemical properties, and microbial biomass factors were significant in the two treatments with R. rosea and S. cupularis; however, these correlations were not observed in the treatment with E. nutans. The results indicated that R. rosea could embody the best approach to restore desertified alpine meadows among the four native plant species after five years of planting.