Abstract:

In recent years, land desertification has become one of the most important and pressing ecological environmental issues globally, biological soil crusts can form protective layers with a certain coverage, thickness, and well-developed structure, which is conducive to the ecological restoration of desertified land. However, the impact of biological-chemical composite crusts on desertified land remains unclear. This study selected sandy soil from the Hetian region of Xinjiang, constructed soil crust layers by adding SJP organic materials combined with different types and concentrations of mosses (Fissidens sp., Plagiomnium sp., Bryum sp.) and algae (Anabaena azollae, Oscillatoria sp., Trebouxia sp.), and selected the optimal configuration scheme based on soil nutrient content, enzyme activity, and microbial community structure characteristics. The results showed that the contents of soil organic carbon, available potassium, available phosphorus, total nitrogen, total phosphorus, and pH increased continuously with the increase of treatment time under different types and concentrations of treatments. Soil enzyme activity was generally improved compared to the blank control group. The soil crust layers significantly affected soil microbial diversity, with dominant species belonging to Proteobacteria, Cyanobacteria and Firmicutes. The study on microbial diversity showed that each treatment group had a significant impact on soil bacterial diversity, and the bacterial communities of the signature species differed at the genus level. Based on principal component analysis, the optimal soil crust scheme was determined to be 30 g/m² Fissidens sp. + 10 g/m² Anabaena azollae, this study provided certain technical support for the ecological restoration of desertified land.

Key words: SJP-modified organic materials, biological soil crusts, soil nutrients, soil enzyme activity, soil microorganisms