1. Methane and nitrous oxide emissions under no-till farming in China: a meta-analysis.
- Author
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Zhao, Xin, Liu, Sheng ‐ Li, Pu, Chao, Zhang, Xiang ‐ Qian, Xue, Jian ‐ Fu, Zhang, Ran, Wang, Yu ‐ Qiao, Lal, Rattan, Zhang, Hai ‐ Lin, and Chen, Fu
- Subjects
METHANE & the environment ,NO-tillage ,CLIMATE change mitigation ,CARBON sequestration ,CLIMATE change research - Abstract
No-till ( NT) practices are among promising options toward adaptation and mitigation of climate change. However, the mitigation effectiveness of NT depends not only on its carbon sequestration potential but also on soil-derived CH
4 and N2 O emissions. A meta-analysis was conducted, using a dataset involving 136 comparisons from 39 studies in China, to identify site-specific factors which influence CH4 emission, CH4 uptake, and N2 O emission under NT. Comparative treatments involved NT without residue retention ( NT0), NT with residue retention ( NTR), compared to plow tillage ( PT) with residue removed ( PT0). Overall, NT0 significantly decreased CH4 emission by ~30% ( P < 0.05) compared to PT0 with an average emission 218.8 kg ha−1 for rice paddies. However, the increase in N2 O emission could partly offset the benefits of the decrease in CH4 emission under NT compared to PT0. NTR significantly enhanced N2 O emission by 82.1%, 25.5%, and 20.8% ( P < 0.05) compared to PT0 for rice paddies, acid soils, and the first 5 years of the experiments, respectively. The results from categorical meta-analysis indicated that the higher N2 O emission could be mitigated by adopting NT within alkaline soils, for long-term duration, and with less N fertilization input when compared to PT0. In addition, the natural log (lnR) of response ratio of CH4 and N2 O emissions under NT correlated positively (enhancing emission) with climate factors (temperature and precipitation) and negatively (reducing emission) with experimental duration, suggesting that avoiding excess soil wetness and using NT for a long term could enhance the benefits of NT. Therefore, a thorough understanding of the conditions favoring greenhouse gas(es) reductions is essential to achieving climate change mitigation and advancing food security in China. [ABSTRACT FROM AUTHOR]- Published
- 2016
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