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<p>Rice paddies are a major anthropogenic source of atmospheric methane (CH₄), yet the spatial pattern and underlying mechanism of CH₄ emissions from rice paddies across climatic gradients remain poorly understood. We collected and incubated 30 flooded paddy soils spanning tropical to temperate regions of China, quantified CH₄ emissions and explored their soil and microbial drivers. We discovered that cumulative CH₄ emissions exhibited pronounced geographical variability, with higher emissions in tropical soils (0.18–10.75&#xa0;mg kg<sup>−1</sup>) than in temperate soils (0.07–0.17&#xa0;mg kg<sup>−1</sup>), and were primarily regulated by dissolved organic carbon (DOC), DOC accounted for 36.0% of the variance in cumulative CH₄ emissions. Peak CH₄ emission rates were jointly influenced by DOC and microbial biomass carbon, together they explained 24.4% of the variance in peak CH₄ emission rates. The timing of peak emissions was governed by the slow degradation of particulate organic carbon (POC), POC accounted for 13.8% of the variance in the timing of peak emissions. Structural equation modeling (SEM) further revealed that soil pH and mean annual temperature (MAT) could indirectly regulate cumulative CH₄ emissions through affecting the accumulation of labile carbon and nitrogen pool, the model explained 63% of the spatial variation in cumulative CH₄ emissions in total. The indirect effect of MAT was 0.20, and the indirect effect of soil pH was − 0.26. These results highlight the critical role of climate–soil-microbe interactions in shaping regional patterns of methane emissions from rice paddies and provide mechanistic insights for improving CH₄ emission predictions under future climate change.</p>

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Methane emissions from rice paddies are regulated by carbon availability and soil pH along a mean annual temperature gradient

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年3月19日

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  • Dai Yusong,
  • Cao Jiawei,
  • Li Huabin,
  • Hu Jinli,
  • Liu Guangcheng,
  • Su Ronglin,
  • Wu Xian,
  • Wang Yan,
  • Hu Ronggui

摘要

Rice paddies are a major anthropogenic source of atmospheric methane (CH₄), yet the spatial pattern and underlying mechanism of CH₄ emissions from rice paddies across climatic gradients remain poorly understood. We collected and incubated 30 flooded paddy soils spanning tropical to temperate regions of China, quantified CH₄ emissions and explored their soil and microbial drivers. We discovered that cumulative CH₄ emissions exhibited pronounced geographical variability, with higher emissions in tropical soils (0.18–10.75 mg kg−1) than in temperate soils (0.07–0.17 mg kg−1), and were primarily regulated by dissolved organic carbon (DOC), DOC accounted for 36.0% of the variance in cumulative CH₄ emissions. Peak CH₄ emission rates were jointly influenced by DOC and microbial biomass carbon, together they explained 24.4% of the variance in peak CH₄ emission rates. The timing of peak emissions was governed by the slow degradation of particulate organic carbon (POC), POC accounted for 13.8% of the variance in the timing of peak emissions. Structural equation modeling (SEM) further revealed that soil pH and mean annual temperature (MAT) could indirectly regulate cumulative CH₄ emissions through affecting the accumulation of labile carbon and nitrogen pool, the model explained 63% of the spatial variation in cumulative CH₄ emissions in total. The indirect effect of MAT was 0.20, and the indirect effect of soil pH was − 0.26. These results highlight the critical role of climate–soil-microbe interactions in shaping regional patterns of methane emissions from rice paddies and provide mechanistic insights for improving CH₄ emission predictions under future climate change.