Controlled irrigation mitigates the annual integrative global warming potential of methane and nitrous oxide from the rice–winter wheat rotation systems in Southeast China.

Abstract Irrigation mode is an important factor in regulating CH 4 and N 2 O emissions from croplands. However, there are no studies on the effects of irrigation mode practiced during the rice season on the annual integrative global warming potential (GWP) of CH 4 and N 2 O in the rice–winter wheat rotation systems. Thus, a field experiment was designed to study the effects of controlled irrigation (CI) during the rice season on the annual integrative GWP of CH 4 and N 2 O emissions from the rice–winter wheat rotation systems, with traditional irrigation (TI) as the control. A notable trade-off relationship between CH 4 and N 2 O emissions was observed in the rice–wheat rotation systems under both CI and TI of rice. CI during the rice season had obvious subsequent effects on CH 4 and N 2 O emissions from the following winter wheat season. Over the whole annual cycle, CI significantly reduced the cumulative CH 4 emission (13.27 kg ha −1 ) by 80.6% than that from the TI fields ( p 2 O emission ( p  > 0.05). The integrative GWP of CH 4 and N 2 O on a 100-year horizon for the CI rotation systems was 2720.35 kg CO 2  ha −1 , which was 41.1% lower than that for the TI fields ( p p  > 0.05). This is the first study to investigate the effects of CI during the rice season on the annual integrative GWP of CH 4 and N 2 O in a rice–winter wheat rotation system. Our results suggest that CI can significantly mitigate the annual integrative greenhouse effect caused by CH 4 and N 2 O from the rice–winter wheat rotation systems, while ensuring the crop yields.