大气臭氧浓度升高对农作物产量的影响

大气O₃浓度升高对农作物产量的影响是评估大气O₃造成农作物减产及经济损失的基础. 分别在北京和广东东莞建立OTC(田间开顶式气室)系统,开展大气O₃对大田冬小麦和水稻的影响研究,在整个生长期对作物进行O₃熏蒸,计算O₃暴露量,获得冬小麦和水稻产量与O₃暴露量之间的响应关系. 结果表明:东莞水稻临界水平(以AOT40计,AOT40为大于40nL/L的小时平均φ(O₃)与40nL/L差值的累计值)为4.95μL/(L·h),而北京冬小麦为2.44μL/(L·h). 根据我国已有农作物O₃暴露量-产量响应关系计算可知,我国水稻和冬小麦的AOT40分别为4.950~9.506和2.280~3.858μL/(L·h),水稻对O₃的敏感性从我国北方到南方呈逐渐增加态势,但冬小麦对O₃敏感性并无明显的地域变化规律. 在大田环境大气φ(O₃)条件下,东莞水稻相对产量损失为2.70%〔AOT40=2.68μL/(L·h)〕,北京冬小麦的相对产量损失为12.85%〔AOT40=6.72μL/(L·h)〕. 我国农作物生长环境多样,作物种类繁多,需要继续开展试验研究来建立本地化O₃暴露量-产量响应关系,用于合理评估区域农作物产量损失. 

Study on the Impact of Elevated Atmospheric Ozone on Crop Yield

Understanding the impact of elevated ozone (O₃) on crop yield is helpful for evaluating the yield loss and economic loss induced from atmospheric O_3pollution. Open Top Chamber (OTC) systems, established in Beijing and Dongguan, Guangdong Province, were implemented to study the impact of different concentrations of O_3on the winter wheat and rice, respectively. The crops were fumigated with O_3during their whole growth period. The exposure indices were calculated, and the response relationship between the exposed quantity of O_3and the yield of rice or winter wheat were obtained. The results showed that the critical level (based on AOT40, AOT40is the hourly meanozone concentration accumulated over a threshold ozone concentration of 40nL/L) of the rice were 4.95μL/(L·h) in Dongguan and 2.44μL/(L·h) for winter wheat for Beijing. Critical levels for crop in China were calculated based on the relationship between the exposed quantity of O_3and the yield of crops in previous studies. The critical levels were 4.950-9.506μL/(L·h) and 2.280-3.858μL/(L·h) for the rice and winter wheat in China, respectively. The sensitivity of rice to the atmospheric O_3increased from the North to the South of China, while that of winter wheat not significantly changed between different regions. Under the current environmental φ(O₃) condition, the relative yield loss was 2.70% (AOT40=2.68μL/(L·h)) for the rice in Dongguan and 12.85% (AOT40=6.72μL/(L·h)) for the winter wheat in Beijing. There are various crop growing environments and numerous crop categories in China, thus more studies should be conducted to establish O_3local exposed quantity-yield response relationships and further to reasonably assess the loss of regional crop yield.