Dissolved Organic Matter (DOM) affects the fundamental biogeochemical processes in soil including circulation and distribution of carbon and nutrients. Likewise, soils are hotspots of microbial diversity, supporting their ability to provide key soil functions and ecosystem services. Detailed understanding of the interaction between DOM chemical diversity and soil microbial community is essential to predict the direction of C in soil after vegetation restoration. In this study we have characterized the chemical diversity of soil DOM, evaluated the associated changes of the soil microbial community composition and determined the specific relationship between DOM and microbial community composition. The results indicated that the unsaturated degree, obstinacy, oxidation degree, and average molecular mass of soil DOM increased with the duration of vegetation restoration. DOM with low double-bond equivalents (DBE) was less stable and was more likely to undergo transformation reactions to produce persistent organic materials with high carbon and high double-bond equivalents. The relative abundance of soil bacteria and fungi showed different trends in response to vegetation restoration efforts which may be related to the change of soil chemical composition as suggested by redundancy analysis. In addition, network analysis identified complex connectivity and strong interaction between the soil microbial community and DOM. Overall, this study has important guiding and prediction significance for the relationship between DOM and soil microbial community during vegetation restoration. Moreover, it provides a theoretical basis for the quantitative evaluation of the ecological restoration effect to alleviate soil and water loss on the Loess Plateau.

溶解有机物 (DOM) 影响土壤中的基本生物地球化学过程，包括碳和养分的循环和分布。同样，土壤是微生物多样性的热点，支持它们提供关键土壤功能和生态系统服务的能力。详细了解 DOM 化学多样性与土壤微生物群落之间的相互作用对于预测植被恢复后土壤中 C 的方向至关重要。在本研究中，我们表征了土壤 DOM 的化学多样性，评估了土壤微生物群落组成的相关变化，并确定了 DOM 与微生物群落组成之间的具体关系。结果表明，不饱和度、固结度、氧化度、土壤DOM的平均分子质量随着植被恢复时间的延长而增加。具有低双键当量 (DBE) 的 DOM 稳定性较差，更有可能发生转化反应以产生具有高碳和高双键当量的持久性有机材料。土壤细菌和真菌的相对丰度对植被恢复工作的响应表现出不同的趋势，这可能与冗余分析表明的土壤化学成分的变化有关。此外，网络分析确定了土壤微生物群落和 DOM 之间复杂的连通性和强相互作用。总体而言，本研究对植被恢复过程中DOM与土壤微生物群落的关系具有重要的指导和预测意义。而且，