The contribution of CH₄ emissions from paddy soils to greenhouse gas emissions is key in the evaluation of future climate change scenarios. Most studies in this field have investigated the effects of elevated CO₂ concentrations (e[CO₂]s) on CH₄ fluxes and methanogenic communities in paddy soils under constant CO₂ concentrations ([CO₂]s). However, atmospheric [CO₂] is gradually increasing and the relationship between future climate change and CH₄ emissions from paddy fields is poorly understood. This study explored the responses of CH₄ fluxes and methanogenic communities in paddy soils to different e[CO₂]s using open-top chambers. The rice biomass, CH₄ fluxes, methane production potential, and methanogenic characteristics were analyzed under CK (ambient [CO₂]), C₁ (e[CO₂] by 120 µmol mol^–1), and C₂ (e[CO₂] by 200 µmol mol^–1) treatments. The results indicated that the C₁ and C₂ treatments insignificantly increased the CH₄ flux in paddy fields. However, the C₁ treatment significantly increased the CH₄ flux/biomass at the elongation stage, while the C₂ treatment significantly increased the CH₄ flux/biomass at all of the growth stages. The C₁ and C₂ treatments had a positive effect on both methane production potential and methanogenic abundance at all of the growth stages, but this effect was not always significant. In addition, the C₁ and C₂ treatments significantly altered the methanogenic community structure at the elongation stage. Notably, there was a significant linear relationship between the CH₄ flux/biomass and [CO₂] at all of the growth stages; between the methane production potential and [CO₂] at the tillering, elongation, and milk-ripening stages; and between the mcrA gene abundance and [CO₂] at the milk-ripening stage. A linear model based on rice biomass, methane production potential, and soil DOC concentration explained 72.7% of the variation in the CH₄ fluxes. Overall, the linear relationship between CH₄ fluxes and atmospheric [CO₂] levels was controlled by the rice biomass, soil carbon substrate, and methanogenic communities.

_{稻田土壤CH 4}排放对温室气体排放的贡献是评估未来气候变化情景的关键。_{该领域的大多数研究都调查了在CO 2浓度([CO 2} ]s)恒定的情况下，升高的CO ₂浓度(e[CO 2 _] s )对水稻土中CH ₄通量和产甲烷菌群落的影响。然而，大气中的[CO _{2 ]逐渐增加，而未来气候变化与稻田CH 4}排放之间的关系却知之甚少。本研究探讨了水稻土CH _{4通量和产甲烷群落对不同e[CO2} ]使用顶部开口室。_{在CK（环境[CO 2} ]）、C ₁（e[CO ₂ ] by 120 µmol mol ^–1）和C ₂（e[CO 2 ] ）下分析了水稻生物量、CH _{4通量、甲烷生产潜力和产甲烷特征。 2} ] 通过 200 µmol mol ^–1 ) 处理。结果表明，C ₁和C ₂处理对稻田CH _{4通量的增加不显着。}然而，C ₁处理显着增加了伸长阶段的CH _{4通量/生物量，而C 2}处理显着增加了所有生长阶段的CH _{4通量/生物量。}C ₁和C ₂处理对所有生长阶段的甲烷生产潜力和产甲烷丰度都有积极影响，但这种影响并不总是显着。此外，C ₁和C ₂处理显着改变了伸长阶段的产甲烷群落结构。值得注意的是，在所有生长阶段，CH ₄通量/生物量与[CO _{2 ]之间均存在显着的线性关系。}分蘖期、伸长期和乳熟期甲烷生产潜力与[CO _{2 ]之间的关系；}和之间牛奶成熟阶段的mcrA 基因丰度和 [CO _{2 ]。基于水稻生物量、甲烷生产潜力和土壤 DOC 浓度的线性模型解释了 72.7% 的 CH 4}通量变化。_{总体而言，CH 4}通量与大气[CO ₂ ]水平之间的线性关系受水稻生物量、土壤碳底物和产甲烷群落控制。