Potential risk assessment of ground-level ozone on rice yield under climate change scenarios

The adverse effects of surface ozone on crop yieldhave been widely concerned by scholarsover the years, and it was necessary to conductan accurate ozone risk assessment for crop production. Using the measured ozone concentration over the rice-growing season during 2013~2015, the variations of ozone concentration and AOT40 were analyzed in this study. In addition, the stomatal conductance model for rice was revised by combining with the meteorological data and stomatal conductance. Moreover, the stomatal ozone absorption flux for rice was calculated, and the rice yield losses caused by ozone exposure under current and future climate change scenarioswere evaluated in this study. The main results were as follows: Ozone mean concentrations overthe rice-growing seasonduring 2013~2015 were 35.8nL/L, 42.0nL/L and 47.9nL/L, respectively, and the AOT40 values were 5.33μL/L•h, 9.03μL/L•h and 11.25μL/L•h, respectively. The revised model could be used to simulate the stomatal conductance of rice, the stomatal ozone fluxes AFst 02during 2013~2015were 2.02mmol/m2, 6.42mmol/m2 and 7.79mmol/m2, respectively. The estimatedaverage relative yield losses of rice caused by ozoneduring 2013~2015were 4.9%, 11.7% and 14.3%, respectively. In the future climate change scenario, the stress effect of ozone on rice would be reduced if ozone concentration was not consideredin the model. If future ozone concentrationswereconsidered,the relative yield losses of rice caused by ozonewould beincreased by 4.7~5.7%. © 2020, Editorial Board of China Environmental Science. All right reserved.