Desertification has become an important issue for the sustainable development of human society at global scale and has led to the changes in soil properties and vegetation cover. Biocrusts and litter crusts play roles in improving the soil microhabitat of sandy ecosystems. Soil microbial communities mediate ecosystem functions in various ecosystems, e.g., soil biogeochemical processes. However, limited information is available about how the underlying processes of bio-crusts/litter crusts restoration are driven by soil bacterial communities in sandy land. Here, we investigated the changes in soil bacteria from three groups (sandy land, bio-crusts, and litter crusts) and three soil layers (0–2 cm, 2–5 cm, 5–10 cm) with nine replicates each collected in July 2019 utilized high-throughput pyrosequencing of the V4-V5 rRNA gene region. Most soil nutrients (SOM, AP, AK, and TN) and enzyme activities (BG and DHA) had differences among the three groups and three soil layers. OTU richness and diversity of bacteria were positively correlated with most soil variables. The constructed co-occurrence networks between soil variables and bacterial communities, and within bacterial communities showed that bacterial taxa had closer relationships with all soil variables in crusts than sandy land and varied among the three sand groups (sandy land, bio-crusts, and litter crusts). The result showed that the composition of bacterial community was regulated mainly by soil variables and crust types. Compared with sandy land, more predictors in nutrient cycling were found in crust types. They played major roles in nutrient cycling in desert ecosystem restoration on the basis of random forest modeling. Our findings indicate some bacterial taxa may played the predominant roles in connecting with soil variables and other bacterial taxa across crusts types, and litter crusts and bio-crusts drive the nutrient cycling by mediating the restoration of bacterial taxa in sandy ecosystems.

荒漠化已成为人类社会在全球范围内可持续发展的重要问题，并导致了土壤特性和植被覆盖度的变化。生物结皮和垃圾结皮在改善沙质生态系统的土壤微生境方面发挥了作用。土壤微生物群落介导各种生态系统中的生态系统功能，例如土壤生物地球化学过程。然而，关于沙地土壤细菌群落如何驱动生物结壳/凋落物结壳恢复的基本过程的信息有限。在这里，我们调查了三类土壤（沙地，生物结皮和垃圾结皮）和三层土壤层（0–2 cm，2–5 cm，5–10 cm）中土壤细菌的变化，每个阶段收集了9个重复样本2019年7月利用了V4-V5 rRNA基因区域的高通量焦磷酸测序。三组和三层土壤之间大多数土壤养分（SOM，AP，AK和TN）和酶活（BG和DHA）都有差异。OTU丰富度和细菌多样性与大多数土壤变量呈正相关。在土壤变量和细菌群落之间以及细菌群落之间建立的共现网络表明，细菌分类群与地壳中的所有土壤变量之间的关系比沙质土地更紧密，并且在三个沙类（沙地，生物结皮和凋落物）之间变化地壳）。结果表明，细菌群落的组成主要受土壤变量和地壳类型的调节。与沙地相比，地壳类型中养分循环的预测因子更多。在随机森林模型的基础上，他们在沙漠生态系统恢复中的养分循环中发挥了重要作用。我们的发现表明，某些细菌类群可能在与不同地壳类型的土壤变量和其他细菌类群相关联方面起主要作用，而凋落的外壳和生物外壳通过介导沙质生态系统中细菌类群的恢复来驱动营养循环。