微生物驱动土壤矿物结合态有机碳的形成  

Microorganisms drive the formation of mineral-associated organic carbon in soils

作　　者：苏兴雷 渠晨晨 康杰 高大鑫 蔡鹏[1,2] 陈雯莉[1,2] 黄巧云[1,2] Xinglei Su;Chenchen Qu;Jie Kang;Daxin Gao;Peng Cai;Wenli Chen;Qiaoyun Huang(National Key Laboratory of Agricultural Microbiology,Huazhong Agricultural University,Wuhan 430070,China;Key Laboratory of Soil Environment and Pollution Remediation in Hubei Province,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]华中农业大学,农业微生物资源发掘与利用全国重点实验室,武汉430070 [2]华中农业大学,土壤环境与污染修复湖北省重点实验室,武汉430070

出　　处：《科学通报》2024年第22期3327-3338,共12页Chinese Science Bulletin

基　　金：国家自然科学基金(41830756,42020104003,42007014)资助。

摘　　要：矿物结合态有机碳(mineral-associated organic carbon,MAOC)是土壤中重要的稳定态有机碳,其含量和动态决定着土壤碳库组成和容量,显著影响全球气候格局.植物和微生物是MAOC形成的两个主要途径,其来源和贡献一直存在很大的争议,特别是在不同生态系统中,植物和微生物对MAOC形成的相对贡献和控制因素可能存在较大的不确定性,对这些问题认知的不足阻碍了土壤可持续管理战略的实施.本研究选取中国区域尺度的旱地(n=24)、水田(n=19)和林地(n=21)表层土壤(0~20 cm),基于矿物结合态有机质(mineral-associated organic matter,MAOM)中的氨基糖和木质素酚的分析,揭示了MAOC中微生物和植物源的贡献及其驱动因子.结果显示,在旱地、水田和林地土壤MAOC中,植物来源碳分别贡献了44.5%、50.1%和49.3%,微生物残体碳分别贡献了44.2%、40.4%和41.0%,其中真菌氨基葡萄糖/细菌胞壁酸比相似(10.6、10.0和11.5,P>0.05).这些结果表明,微生物残体碳在MAOC中具有相似的稳定性,矿物结合改变了土壤有机碳(soil organic carbon,SOC)的组成,可以在很大程度上抵抗土地利用变化对SOC分解的影响.在所有生态系统中,MAOC的形成主要由微生物活动调控.与旱地生态系统相比,水田的环境胁迫导致微生物分解能力受到限制,林地中较高的植物输入量因微生物分解能力有限使植物残留相对富集,土壤稳定碳库以植物源碳为主.高黏粉粒含量和高年平均温度(mean annual temperature,MAT)有利于MAOC中植物源碳的相对富集,而低土壤p H和低MAT使微生物源碳的贡献增加.研究结果对于调整和完善农业土壤管理策略,增加土壤碳储量及减少碳排放,实现土壤碳中和目标具有重要意义.Soil stores the largest amount of carbon in terrestrial ecosystem with~1500 Pg C at the 1m soil depth which plays a crucial role in regulating greenhouse gas emission and global climate change.As the stable organic carbon pool in soils,mineralassociated organic carbon(MAOC)determines the composition,capacity and cycling of soil C.The sources and formation of MAOC,particularly from plants and microorganisms,have long been a subject of debate.Recently,it is widely believed that microbial-derived organic carbon may dominate the preservation of soil organic carbon(SOC)particularly the formation of MAOC.However,a number of evidences have also suggested the important contribution of plant derived organic carbon to MAOC.Plant derived biomolecules such as lipid,lignin and carbohydrate may account for a remarkable proportion of MAOC,making a vital contribution to the accumulation and stabilization of soil organic carbon.However,to date,there is a considerable uncertainty regarding the relative contributions and controlling factors of plant-and microbialderived MAOC across different ecosystems which hinders the implementation of sustainable soil management strategies.In this study,we are the first to provide empirical evidences on the contribution of plant and microbial derived carbon to MAOC in soils of different ecosystems at a large scale.Surface soils(0−20 cm)were collected from uplands(n=24),paddy fields(n=19),and forest soils(n=21)in eastern China ranging from 18°N to 47°N,and the contributions and driving factors of microbial and plant-derived MAOC were scrutinized based on the analysis of amino sugars and lignin phenols.Correlation analysis,random forest(RF)analysis,variance partition analysis(VPA)and structural equation modeling(SEM)were employed to disentangle the environmental factors and soil attributes regulating the formation and accumulation of MAOC and the possible mechanisms.The major scientific hypothesis is that the contribution of plantderived C to MAOC is greater than that of microbial-derived,espe

关 键 词：矿物结合态有机碳 微生物残体碳 植物源碳 氨基糖 木质素酚 

分 类 号：S153.6[农业科学—土壤学]