Objective  Exploring the characteristics of nutrient changes in moss crusts and covered soil in karst rocky desertification, and its positive ecological benefits could provide a new theoretical reference for the ecological environment restoration of karst rocky desertification.

  Method  In this paper, soil covered by moss crusts, soils deprived of biocrust-forming mossess (one year later)and bare soils in different levels of rocky desertification (none, light, moderate and severe) in the typical rocky desertification ecosystem –Huajiang rocky desertification area in Guizhou province of China ,were used to investigate the effects of moss crusts on soil enzyme activities, and contents of soil carbon, nitrogen, phosphorus and stoichiometric characteristics of different karst desertification grades (none, light, moderate, and severe) and different soil depths (crust layer, 0-5 cm, and 5-10 cm).

  Result  ① Activities of urease (UE) and β-glucosidase (BG) in moss crust layer increased with the degradation progress of karst desertification. While soil sucrase (SC) and alkaline phosphatase desertification (AKP) did not change significantly. SOC, C/N, C/P, and N/P contents were significantly higher in sample sites of no rocky desertification than those of light, moderate, and sever grades. ② Soil carbon, nitrogen and phosphorus contents and stoichiometric characteristics, enzyme activities (SC, BG, AKP) in crust layer were significantly higher than those in sub-crust layers (0-5 cm and 5-10 cm). ③ Compared with moss crusts, activities of soil SC, AKP, BG and contents of carbon, nitrogen and phosphorus and stoichiometric characteristics decreased significantly one year after crust removal, while did not significantly change compared with bare soil.

  Conclusion  The existence of moss crusts improve soil enzyme activities, and carbon, nitrogen and phosphorus contents, which highlights the important ecological function of moss crusts in degraded karst rocky desertification ecosystems, and its positive ecological benefits could provide a new theoretical reference for the ecological environment restoration of karst rocky desertification.