Abstract: Reseeding the legume Caragana korshinskii, is an effective strategy to restore the vegetation in degraded desert steppe. Here, we explored the responses of soil environment and microbial communities to desert steppe degradation and C. korshinskii reseeding. A typical native-degraded-restored closed-loop system in desert steppe: the natural stage with native C. korshinskii (NC), vegetation degradation stage (bare soil) (BS), both vegetation and soil degradation stage (desertified soil) (DS), and restored stage with reseeding C. korshinskii aged eight years (RC). The results showed that, within this closed-loop system: 1) Compared to BS, soil degradation (DS) resulted in a 199% increase in sand content (P < 0.05), while no difference between RC and NC (P > 0.05), indicating restoration of soil texture. 2) The soil microbial structure of RC was similar to that of NC, but based on changes in abundance, it could be divided into communities that increased with the rise in soil sand content (UTC+SPP), decreased due to vegetation degradation and increased soil sand content (FOC+SEC) (P < 0.05), and unchanged (UC). 3) Microbial networks showed lower average degree and modularity after reseeding C. korshinskii compared to NC. In summary, eight years of vegetation restoration led to the recovery of soil texture and microbial community structure, but not community complexity and stability. The results emphasize the time lag for soil microbiome reconstruction after reseeding C. korshinskii, providing novel insight into plant-soil-microbial interactions during the restoration of degraded desert steppe.

Key words: desert steppe degradation, legume reseeding, soil microbial diversity, soil microbial complexity and stability, soil texure