Iron amendment decreases methane emissions from subtropical paddies by altering soil microbial communities

This study clarified the effects of Fe amendment on CH₄ emissions from subtropical paddy fields under various N fertilization rates through a 4-year <i>in situ</i> field experiment. We found that the Fe amendment combined with reduced N fertilization rates decreased CH₄ emissions, in particular under the 60% of conventional N fertilization rate. Furthermore, the Fe amendment lowered the <i>mcrA</i>/<i>pmoA</i> ratio. Moreover, the Fe amendment increased connectivity while reducing modularity in co-occurrence networks of methanogen communities. Soil Fe²⁺ content and methanogen community structure were key drivers of CH₄ emissions. The findings provide an insight into the microbial mechanisms of mitigating CH₄ emission from flooded paddy soils through the Fe amendment.