Effects of elevated ozone concentration on methane emission from a rice paddy in Yangtze River Delta, China

• Published in: Global change biology 2011-02, Vol.17 (2), p.898-910
• Main Authors: ZHENG, FEIXIANG, WANG, XIAOKE, LU, FEI, HOU, PEIQIANG, ZHANG, WEIWEI, DUAN, XIAONAN, ZHOU, XIAOPING, AI, YONGPING, ZHENG, HUA, OUYANG, ZHIYUN, FENG, ZONGWEI
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Atmospheric sciences; Biological and medical sciences; biomass; CH4 emission; Climate change; Fundamental and applied biological sciences. Psychology; General aspects; Methane; Oryza sativa; Ozone; Rice; rice paddy; Yangtze River Delta; yield
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/j.1365-2486.2010.02258.x

Few investigations have been made on the impact of elevated ozone (O₃) concentration on methane (CH₄) emission from rice paddies. Using open-top chambers in situ with different O₃ treatments, CH₄ emissions were measured in a rice paddy in Yangtze River Delta, China in 2007 and 2008. There were four treatments applied: charcoal-filtered air (CF), nonfiltered air (NF), and charcoal-filtered air with different O₃ additions (O₃-1 and O₃-2). The mean O₃ concentrations during the O₃ fumigation were 19.7, 22.6, 69.6 and 118.6 ppb in 2007 and 7.0, 17.4, 82.2 and 138.3 ppb in 2008 for treatments CF, NF, O₃-1 and O₃-2, respectively. The rice yields, as compared with CF, were reduced by 32.8% and 37.1%, 58.3% and 52.1% in treatments O₃-1 and O₃-2 in 2007 and 2008, respectively. The diurnal patterns of CH₄ emission varied temporally with treatments and there was inconsistence in diurnal variations in CH₄ emissions from the paddy field. The daily mean CH₄ emissions were significantly lower in treatments O₃-1 and O₃-2 than those in treatments CF and NF. Compared with CF treatment, CH₄ emissions from the paddy field were decreased to 46.5% and 38.3%, 50.6% and 46.8% under treatments O₃-1 and O₃-2 in the whole growing seasons of 2007 and 2008, respectively. The seasonal mean CH₄ emissions were negatively related with AOT40 (accumulative O₃ concentration above 40 ppb; P < 0.01 in both years), but positively related to the relative rice yield (reference to CF; P < 0.01 in 2007 and P < 0.001 in 2008), aboveground biomass (P < 0.01 in both years) and underground biomass (P < 0.01 in 2007 and P < 0.05 in 2008). The decreased CH₄ emission from the rice paddy due to an increased O₃ exposure might partially mitigate the global warming potential induced by soil carbon loss under elevated O₃ concentrations.