Abstract: The oligotrophic bacteria isolated from the biotic crust in the Gurbantunggut Desert were made into solvent, and two spraying levels were set to compare the effects of oligotrophic bacteria on soil microorganisms, enzyme activities, soil nutrients and formation and regeneration of biotic soil crust. The results are as follows: (1) It could improve the numbers of bacteria, actinomycetes and oligotrophic bacteria at two soil layers (0-2 cm and 2-5 cm in depth) to spray the oligotrophic bacteria, and the numbers of bacteria and actinomycetes at 0-2 cm layer and of oligotrophic bacteria at 2-5 cm layer were more than that without spraying oligotrophic bacteria; (2) The effects of spraying the oligotrophic bacteria on soil nutrients were different, the contents of total P, total K, available N and available P were effectively improved, but the contents of soil organic matter and total N were decreased; (3) There were also the difference in the effects on soil enzyme activities, the catalase and polyphenol oxidase activities were increased, but the sucrase and alkaline phosphatase activities were reduced. The correlation analysis revealed that there was a significant positive correlation between oligotrophic bacteria and actinobacteria, and the correlations between oligotrophic bacteria and other factors were not so significant. Holistically, the original patterns of microorganisms and soil nutrients were changed by spraying the oligotrophic bacteria, and the oligotrophic bacteria were helpful to promote the existence and development of microorganisms and algae crust. Thus, the study results could open a new way for regenerating biotic soil crust and improving the conditions over sand land.  

Key words: oligotrophic bacteria, microorganism, soil nutrition, enzyme activity, sand-fixation, Gurbantunggut Desert