Mitigating methane emission from paddy soil with rice-straw biochar amendment under projected climate change

Elevated global temperatures and increased concentrations of carbon dioxide (CO(2)) in the atmosphere associated with climate change will exert profound effects on rice cropping systems, particularly on their greenhouse gas emitting potential. Incorporating biochar into paddy soil has been shown previously to reduce methane (CH(4)) emission from paddy rice under ambient temperature and CO(2.) We examined the ability of rice straw-derived biochar to reduce CH(4) emission from paddy soil under elevated temperature and CO(2) concentrations expected in the future. Adding biochar to paddy soil reduced CH(4) emission under ambient conditions and significantly reduced emissions by 39.5% (ranging from 185.4 mg kg(−1) dry weight soil, dws season(−1) to 112.2 mg kg(−1) dws season(−1)) under simultaneously elevated temperature and CO(2). Reduced CH(4) release was mainly attributable to the decreased activity of methanogens along with the increased CH(4) oxidation activity and pmoA gene abundance of methanotrophs. Our findings highlight the valuable services of biochar amendment for CH(4) control from paddy soil in a future that will be shaped by climate change.