探究不同植物残体还田条件下微生物关键种如何影响木质素酚的浓度（木质素酚与土壤有机碳的比值），旨在为不同有机物料还田培肥土壤提供理论和技术依据。本研究以河西绿洲灌区的灌漠土作为研究对象，开展了30 a以施加绿肥（GM）、小麦秸秆（SW）、氮肥（N）、绿肥配施氮肥（GMN）、小麦秸秆配施氮肥（SWN）以及不施肥（CK）6种不同施肥处理的培肥试验。结果表明：GM和SW处理的土壤有机碳含量显著高于其他处理；有小麦秸秆参与还田的处理显著提高了总木质素酚浓度以及3种木质素酚类单体的浓度，其中总木质素酚浓度在SW处理中分别比CK、GM、N、GMN和SWN处理高了109%、122%、115%、164%和57%；对比不施肥和施化肥处理，植物残体还田显著提高了微生物关键种F3（盘菌纲，Pezizomycetes）、F26（被孢霉菌纲，Mortierellomycetes）、F173（粪壳菌纲，Sordariomycetes）、B74（阿尔法变形菌纲，Alphaproteobacteria）和B87（放线菌纲，Actinobacteria）的相对丰度。本研究共鉴定出15个关键种，其中关键种B831（属阿尔法变形菌纲）与木质素酚浓度呈显著的正相关关系，并且在SW处理下显著富集。本研究为农业生态系统不同培肥方式下微生物关键种如何影响植物衍生的木质素酚提供了科学参考，为深入了解植物残体还田对土壤有机碳周转的影响提供了理论依据。

In order to provide theoretical and technical basis for returning different organic materials to field and fertilizing soil, soil samples from a 30 a long-term experiment were used to explore how the microbial keystone species affect the contribution of plant-derived lignin phenols to soil organic carbon (SOC) under different plant residue amendment conditions, in which, irrigated desert soils in Hexi oasis irrigation area selected as the research object under different treatments, including green manure (GM), wheat straw (SW), nitrogen fertilizer (N), green manure with nitrogen fertilizer (GMN), wheat straw with nitrogen fertilizer (SWN) and no fertilizer (CK). The results showed that SOC concentrations of GM and SW were significantly higher than those of other treatments. The treatments with wheat straw significantly increased the concentrations of total lignin phenols and three lignin phenol monomers. The total lignin phenol concentration in SW was 109%, 122%, 115%, 164%, and 57% higher than in CK, GM, N, GMN, and SWN, respectively. Compared to non-fertilization and chemical fertilizer treatment, plant residue amendment significantly increased relative abundance of keystone species F3 (Pezizomycetes), F26 (Mortierellomycetes), F173 (Sordariomycetes), B74 (Alphaproteobacteria) and B87 (Actinobacteria). A total of 15 keystone species were identified, of which key species B831 (belonging to Alphaproteobacteria) showed a significant positive correlation with the contribution of lignin phenols to SOC, and was significantly enriched under SW. This study provides a scientific reference for how microbial keystone species affect the contribution of plant-derived lignin phenols to SOC in future agricultural ecosystems under different fertilization methods, and also provides theoretical basis for understanding the impact of plant residue return on SOC turnover.

S154.36

国家现代农业产业技术体系资助项目（CARS-22，CARS-52）和南京土壤研究所创新基金项目（ISSASIP2211）资助。