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Lower‐than‐expected CH 4 emissions from rice paddies with rising CO 2 concentrations
Author(s) -
Qian Haoyu,
Huang Shan,
Chen Jin,
Wang Ling,
Hungate Bruce A.,
Kessel Chris,
Zhang Jun,
Deng Aixing,
Jiang Yu,
Groenigen Kees Jan,
Zhang Weijian
Publication year - 2020
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.14984
Subject(s) - paddy field , methane , environmental science , straw , agriculture , soil water , greenhouse gas , agronomy , rice straw , carbon dioxide , microorganism , environmental chemistry , chemistry , soil science , ecology , biology , genetics , bacteria
Elevated atmospheric CO 2 (eCO 2 ) generally increases carbon input in rice paddy soils and stimulates the growth of methane‐producing microorganisms. Therefore, eCO 2 is widely expected to increase methane (CH 4 ) emissions from rice agriculture, a major source of anthropogenic CH 4 . Agricultural practices strongly affect CH 4 emissions from rice paddies as well, but whether these practices modulate effects of eCO 2 is unclear. Here we show, by combining a series of experiments and meta‐analyses, that whereas eCO 2 strongly increased CH 4 emissions from paddies without straw incorporation, it tended to reduce CH 4 emissions from paddy soils with straw incorporation. Our experiments also identified the microbial processes underlying these results: eCO 2 increased methane‐consuming microorganisms more strongly in soils with straw incorporation than in soils without straw, with the opposite pattern for methane‐producing microorganisms. Accounting for the interaction between CO 2 and straw management, we estimate that eCO 2 increases global CH 4 emissions from rice paddies by 3.7%, an order of magnitude lower than previous estimates. Our results suggest that the effect of eCO 2 on CH 4 emissions from rice paddies is smaller than previously thought and underline the need for judicious agricultural management to curb future CH 4 emissions.