Integrated effects of aerobic tillage and controlled irrigation on rice yield and greenhouse gas emissions in a high-latitude rice growing region

Rice is a major food crop in China, and paddy fields are an important agricultural source of greenhouse gas (GHG) emissions. Achieving high yields while reducing GHG emissions is essential for national food security and agricultural carbon mitigation. Water-management during the rice season is widely used to reduce methane (CH₄) emissions; however, evidence of its effectiveness, particularly with respect to yield responses and CH₄ emissions before and after transplanting, remains inconsistent. To address this gap, we evaluated two tillage practices before transplanting and two irrigation regimes during the early tillering stage: aerobic tillage with controlled irrigation (AC), aerobic tillage with flooding (AF), conventional tillage with controlled irrigation (CC), and conventional tillage with flooding (CF, control). Field experiments were conducted in a high-latitude rice-growing region in China in 2024 and 2025. Across the two years of study, aerobic tillage significantly increased average rice yield by 6.3%, whereas controlled irrigation caused a slight decline. Compared with the CF, the AC treatment markedly reduced the peak dissolved CH₄ flux after the first drainage event by 66.4%–71.2% and lowered cumulative CH₄ emissions by 42.1%–51.7%. Consequently, AC achieved the lowest area-scaled GHG emissions (GHG_A) and yield-scaled GHG emissions (GHG_Y). These reductions were associated with a significantly greater abundance of methanotrophic genes under AC. In addition, aerobic tillage reduced average soil dissolved organic carbon (DOC) during the tillering stage by 11.8% across two study years. Overall, integrating aerobic tillage with controlled irrigation during the tillering stage provides an effective strategy for reducing CH₄ emissions while maintaining high yield and improving water-use efficiency in rice production.