[Effects of biological soil crust on soil erodibility in Hilly Loess Plateau region of Northwest China].

Based on the analysis of the effects of biological soil crust (biocrust) in re-vegetated grasslands on soil physical and chemical properties, and by using EPIC estimation model in combining with simulated rainfall trials, this paper studied the effects of biocrust with different biomass and different soil texture on the soil erodibility (K value) in Hilly Loess Plateau Region of Northwest China in different seasons. The results showed biocrust could significantly decrease soil erodibility, with the K value of biocrust soil decreased by about 17%, compared with subsoil. The soil erodibility decreased with the increasing biomass of biocrust. The K value of moss crust soil decreased by 21%, compared with cyanobacteria crust soil. The erodibiliy of biocrust soil differed with different seasons, being significantly higher in rainy season than before or after the rainy season due to the differences in the biological activity of the biocrust organisms. The erodibilty of biocrust soil with different texture also varied significantly, with the K value in the order of sandy loam soil > silt soil > sandy soil. The measurement under simulated rainfall showed that the development of biocrust could decrease the erodibility of biocrust soil by about 90%, compared with that of the subsoil (5-10 cm).