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Higher yields and lower methane emissions with new rice cultivars

Jiang, Yu, van Groenigen, Kees Jan, Huang, Shan, Hungate, Bruce A., van Kessel, Chris, Hu, Shuijin, Zhang, Jun, Wu, Lianhai, Yan, Xiaojun, Wang, Lili, Chen, Jin, Hang, Xiaoning, Zhang, Yi, Horwath, William R., Ye, Rongzhong, Linquist, Bruce A., Song, Zhenwei, Zheng, Chengyan, Deng, Aixing, Zhang, Weijian
Global change biology 2017 v.23 no.11 pp. 4728-4738
biomass, breeding, carbon, climate change, greenhouse gas emissions, greenhouse gases, high-yielding varieties, meta-analysis, methane, methane production, microorganisms, oxidation, oxygen, paddies, paddy soils, porosity, rice, root systems, China
Breeding high‐yielding rice cultivars through increasing biomass is a key strategy to meet rising global food demands. Yet, increasing rice growth can stimulate methane (CH₄) emissions, exacerbating global climate change, as rice cultivation is a major source of this powerful greenhouse gas. Here, we show in a series of experiments that high‐yielding rice cultivars actually reduce CH₄ emissions from typical paddy soils. Averaged across 33 rice cultivars, a biomass increase of 10% resulted in a 10.3% decrease in CH₄ emissions in a soil with a high carbon (C) content. Compared to a low‐yielding cultivar, a high‐yielding cultivar significantly increased root porosity and the abundance of methane‐consuming microorganisms, suggesting that the larger and more porous root systems of high‐yielding cultivars facilitated CH₄ oxidation by promoting O₂ transport to soils. Our results were further supported by a meta‐analysis, showing that high‐yielding rice cultivars strongly decrease CH₄ emissions from paddy soils with high organic C contents. Based on our results, increasing rice biomass by 10% could reduce annual CH₄ emissions from Chinese rice agriculture by 7.1%. Our findings suggest that modern rice breeding strategies for high‐yielding cultivars can substantially mitigate paddy CH₄ emission in China and other rice growing regions.