An optimal drainage timing maximizes methane emission reduction in rice fields

Abstract:

Rice fields are important contributors to the global methane (CH4) budget. While rice production must increase to meet the demand from a growing population, there is a need to mitigate CH₄ emissions through the employment of sustainable management strategies. Field drainage is a popular practice that mitigates CH₄ emissions by shortening the period of time the field spends in anaerobic conditions. However, it is still unclear how the time at which the field is drained regulates CH₄ emission reduction. Here we combine data from 22 field experiments with a CH₄ emission model to analyze the drainage timing on the temporal evolution of methane emissions and identify the drainage timing that maximizes CH₄ emission reduction. We show how these ‘optimal’ drainage timings vary depending on whether the field is organically amended or not and estimate the maximum achievable emission reduction. Overall, the analysis suggests that the emission reduction can be doubled by simply adjusting drainage timing.