Recalcitrant components accumulation in dissolved organic matter decreases microbial metabolic quotient of red soil under long-term manuring

文献类型： 外文期刊

第一作者： Yang, Xiao

作者： Yang, Xiao;Zhang, Shuai;Wu, Dong;Huang, Yaping;Zhang, Lu;Zhang, Wenju;Yang, Xiao;Guo, Shengli;Zhang, Lu;Liu, Kailou;Wu, Huiqiao

作者机构：

关键词： Chemodiversity; Manure amendment; Soil pH; Fluorescence spectroscopy

期刊名称：SCIENCE OF THE TOTAL ENVIRONMENT （ 影响因子：8.2； 五年影响因子：8.6 ）

ISSN： 0048-9697

年卷期： 2024 年 934 卷

页码：

收录情况： SCI

摘要： Microbial metabolism is closely related to soil carbon dioxide emissions, which in turn is related to environmental issues such as global warming. Dissolved organic matter (DOM) affects many fundamental biogeochemical processes such as microbial metabolism involved in soil carbon cycle, not only directly by its availability, but also indirectly by its chemodiversity. However, the association between the DOM chemodiversity and bioavailability remains unclear. To address this knowledge gap, soils from two agro-ecological experimental sites subjected to various long-term fertilizations in subtropical area was collected. The chemodiversity of DOM was detected by multi -spectroscopic techniques including ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy and excitation emission matrices fluorescence spectroscopy. Results showed that long-term manure amendments significantly decreased microbial metabolic quotient (qCO2) by up to 57%. We also observed that long-term manure amendments significantly increased recalcitrant components of DOM (indicated by the aromaticity, humification index, the ratio of aromatic carbon to aliphatic carbon, and the relative abundances of humic-like components) and decreased labile components of DOM. Negatively correlation between the qCO2 and the proportion of recalcitrant components of DOM supported that accumulation in recalcitrant components of DOM increased microbial carbon utilization efficiency. Random forest models also showed the highest contribution of the relative abundances of humic-like components and the aromaticity of DOM in affecting qCO2. Both of the redundancy analysis and structural equation modeling further indicated the decisive role of soil pH in influencing the DOM chemodiversity. Soil pH explained 56.7% of the variation in the chemodiversity of DOM. The accumulation of recalcitrant components in DOM with increasing soil pH might be attributed to the accelerated microbial consumption of bioavailability components and/or to the negative impact on the solubility of bioavailability components. Overall, this research highlights the significance of long-term manure amendments in regulating qCO2 by altering the chemodiversity of soil DOM.

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