Pedosphere 33(5): 776--787, 2023
ISSN 1002-0160/CN 32-1315/P
©2023 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Five-year warming does not change soil organic carbon stock but alters its chemical composition in an alpine peatland
Jingcong QIU1, Minghua SONG2, Chunmei WANG1, Xiaomin DOU1, Fangfang LIU1, Jiaxin WANG1, Chenying ZHU1, Shiqi WANG1
1 College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083(China);
2 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101(China)
      Climate warming may promote soil organic carbon (SOC) decomposition and alter SOC stocks in terrestrial ecosystems, which would in turn affect climate warming. We manipulated a warming experiment using open-top chambers to investigate the effect of warming on SOC stock and chemical composition in an alpine peatland in Zoigê on the eastern Tibetan Plateau, China. Results showed that 5 years of warming soil temperatures enhanced ecosystem respiration during the growing season, promoted above- and belowground plant biomass, but did not alter the SOC stock. However, labile O-alkyl C and relatively recalcitrant aromatic C contents decreased, and alkyl C content increased. Warming also increased the amount of SOC stored in the silt-clay fraction (< 0.053 mm), but this was offset by warming-induced decreases in the SOC stored within micro- and macroaggregates (0.053-0.25 and > 0.25 mm, respectively). These changes in labile and recalcitrant C were largely associated with warming-induced increases in soil microbial biomass C, fungal diversity, enzyme activity, and functional gene abundance related to the decomposition of labile and recalcitrant C compounds. The warming-induced accumulation of SOC stored in the silt-clay fraction could increase SOC persistence in alpine peatland ecosystems. Our findings suggest that mechanisms mediated by soil microbes account for the changes in SOC chemical composition and SOC in different aggregate size fractions, which is of great significance when evaluating SOC stability under climate warming conditions.
Key Words:  functional gene,nuclear magnetic resonance,simulated global warming,soil carbon components,soil enzymes,soil microbial diversity
Citation: Qiu J C, Song M H, Wang C M, Dou X M, Liu F F, Wang J X, Zhu C Y, Wang S Q. 2023. Five-year warming does not change soil organic carbon stock but alters its chemical composition in an alpine peatland. Pedosphere. 33(5): 776-787.
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