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Limited potential of harvest index improvement to reduce methane emissions from rice paddies
Author(s) -
Jiang Yu,
Qian Haoyu,
Wang Ling,
Feng Jinfei,
Huang Shan,
Hungate Bruce A.,
van Kessel Chris,
Horwath William R.,
Zhang Xingyue,
Qin Xiaobo,
Li Yue,
Feng Xiaomin,
Zhang Jun,
Deng Aixing,
Zheng Chenyan,
Song Zhenwei,
Hu Shuijin,
van Groenigen Kees Jan,
Zhang Weijian
Publication year - 2019
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.14529
Subject(s) - environmental science , paddy field , agronomy , agriculture , irrigation , greenhouse gas , population , leaf area index , methane , staple food , biology , ecology , demography , sociology
Rice is a staple food for nearly half of the world's population, but rice paddies constitute a major source of anthropogenic CH 4 emissions. Root exudates from growing rice plants are an important substrate for methane‐producing microorganisms. Therefore, breeding efforts optimizing rice plant photosynthate allocation to grains, i.e., increasing harvest index (HI), are widely expected to reduce CH 4 emissions with higher yield. Here we show, by combining a series of experiments, meta‐analyses and an expert survey, that the potential of CH 4 mitigation from rice paddies through HI improvement is in fact small. Whereas HI improvement reduced CH 4 emissions under continuously flooded (CF) irrigation, it did not affect CH 4 emissions in systems with intermittent irrigation (II). We estimate that future plant breeding efforts aimed at HI improvement to the theoretical maximum value will reduce CH 4 emissions in CF systems by 4.4%. However, CF systems currently make up only a small fraction of the total rice growing area (i.e., 27% of the Chinese rice paddy area). Thus, to achieve substantial CH 4 mitigation from rice agriculture, alternative plant breeding strategies may be needed, along with alternative management.