Study Of Surface Ozone Pollution And Its Effects On Winter Wheat Yield By Field Experiments And Modeling

Ozone (O3) is one of the near surface layer of air pollutants, and its negative effects on vegetation and crops has become one of the hot areas of research at home and abroad. To carry out the surface layer of ozone on crop yield loss assessment techniques has important scientific value and practical significance for food security and air pollution control countermeasures. Funded by the National Natural Science Foundation, the research group has accumulated four consecutive years of ozone on winter wheat impact studies Daejeon open-top chamber experiment data, and the same period in surface ozone observations and meteorological data. On this basis, the detailed analysis of variation of the concentration of surface ozone and of the relationship with meteorological factors had been presented in the paper. On the basis of stomatal conductance model, the ozone damage threshold had been determined, the ozone absorption flux model had been improved and the model of the ozone cumulative absorption of the effective dose and the yield loss of winter wheat had been established. The main conclusions are as follows:(1)Analysis of the variation of ozone concentration and meteorological factors had been presented. The analysis showed that there was asignificant synchronization between the peak of daily ozone concentration, AOT40and daily average temperature, daily average relative humidity, daily average vapor pressure deficit, daily precipitation and daily total radiation in the spring of2009-2010. Between ozone concentration and AOT40peak air temperature, VPD and daily total radiation exists significant positive correlation, while there is a significant negative correlation between relative humidity and precipitation.(2)Variation of ozone injury threshold during the entire ozone fumigation had been cleared, the ozone absorption flux damage threshold showed the trend of first and then decreased and peaked in the period of flowering to grain filling. In the early stage of growing period, the ozone absorption flux damage rised because of enzyme activities in vivo anti-oxidation system of winter wheat was growing by ozone stress to stimulate. It resisted damage by ozone on winter wheat to a certain extent caused; But in the end of growing period, with the ozone concentration continued to accumulate more than a certain limit, vivo antioxidant system of winter wheat was destructed gradually and the enzyme activity in the antioxidant system weakened constantly. Then the peroxidation of ozone on winter wheat intensified which resulting in the damage threshold Y gradually decreased.(3)Ozone cumulative absorption flux (Ozone absorption of the effective dose) during the entire ozone fumigation in four years had been obtained. The variation characteristics of ozone absorption flux in2008-2011showed that the ozone absorption flux ozone in150nL-L(?) fumigation was more than which in100nL·L-1fumigation and CK fumigation in the early stage of ozone fumigation and was least in the end of ozone fumigation.(4)The relationship model between the ozone accumulated uptake flux and the panicle weight and the yield of winter wheat had been established. The relationship model between the ozone accumulated uptake flux and the panicle weight of winter wheat showed that the panicle weight would loss5.2percent with the ozone accumulated uptake flux was added to lmmolO3m-2comparing with control (CK). The relationship model between the ozone accumulated uptake flux and the accumulated dry matter weight of winter wheat of winter wheat showed that the accumulated dry matter weight would loss5.3percent with the ozone accumulated uptake flux was added to lmmolO3m-2comparing with control (CK).The relationship model between the ozone accumulated uptake flux and the yield of winter wheat of winter wheat showed that the yield would loss2.8percent with the ozone accumulated uptake flux was added to1mmolO3m-2comparing with control (CK).