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| Comparison of synthetic fertilizer N-induced direct nitrous oxide emissions from croplands between China and India during 1980-2010 |
| Received:January 30, 2016 |
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| KeyWord:N2O emissions;wheat;maize;rice;China;India |
| Author Name | Affiliation | E-mail | | JIANG Guang-fu | State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
China University of Chinese Academy of Sciences, Beijing 100049, China | | | ZHANG Wen | LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 | | | LI Xin | State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
China University of Chinese Academy of Sciences, Beijing 100049, China | | | SUN Wen-juan | State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China | sunwj@ibcas.ac.cn |
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| Abstract: |
| Synthetic fertilizer N-induced direct N2O emissions from wheat, maize, and rice fields in China and India during 1980 to 2010 were estimated using a precipitation-rectified N2O emission factor. A comparison of temporal and spatial variations of the estimated N2O emissions was made between two countries. Results indicated that the direct N2O emission fluxes in China were averaged 1.75 kg N2O-N·hm-2·a-1 for wheat, 1.60 kg N2O-N·hm-2·a-1 for maize, and 0.42 kg N2O-N·hm-2·a-1 for rice over the 30-year period, which were respectively 1.3-, 2.4- and 2.0- times that in India. The spatial distribution of the N2O emissions from wheat and maize fields was characterized by higher fluxes in southeast and south China than in west and north China. By contrast, the east and southwest India showed higher N2O emission fluxes than other areas. The averages of the direct N2O emissions were 98.6 Gg N2O-N in China and 47.8 Gg N2O-N in India over the 30-year period. Wheat and maize fields contributed approximate 90% to the total emissions from these three crops in China, while wheat field accounted for about 70% of the total emissions in India. Over the period 1980-2000, the direct N2O emissions in both countries increased, with the increasing rate in order of wheat > maize > rice. The annual increasing rate was 3.7% for these three crops in China, much lower than that in India(10.4%). A further investigation indicated that the emission intensity(N2O emission per unit crop yield) and its increase rate in China were lower than those in India, though the direct N2O emissions were higher in China than in India. |
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