<p>Soil water content (WC) and microbial soil amendments (MSA) can influence methane (CH₄) and carbon dioxide (CO₂) emissions from carbon cycles in paddy fields. However, their individual and interactive effects remain to be elucidated. Thus, this study aimed to explore the individual and interactive effects of WC and MSA on CO₂ and CH₄ emissions and soil chemical properties. WC exerted a more pronounced influence on CH₄ and CO₂ emissions than MSA throughout the experimental period. In the first month, CO₂ emissions primarily contributed to partial global warming potential (pGWP). The cumulative CO₂ emissions under moist and flooded soil treatments were 332.29–353.42 and 240.3–273.17&#xa0;g·m^− 2, respectively. The pGWP in the moist control group significantly increased by 22.61% compared with that in the flooded control group. In the second month, CH₄ emissions accounted for 34.75% and 63.01% of the total pGWP under flooded MSA and control treatments, respectively. Overall, the application of MSA promoted mineralization and nitrification during the aerobic phase of moist soils by stimulating organic matter-decomposing bacteria and nitrifiers, which consequently contributed to the reduction in CH₄ emissions. The experimental results indicate that extending the aerobic phase after MSA application is an effective strategy for reducing pGWP by mitigating CH₄ emissions. Field-scale evaluations are needed to clarify the long-term impacts of MSA on the atmospheric environment in paddy systems.</p>