Alternative Ozone Dose Metrics to Characterize Ozone Impact on Crop Yield Loss

Abstract

AbstractPrevious studies of the National Crop Loss Assessment Network (NCLAN) relating the impact of ozone (O3) on agricultural crops have used the seasonal arithmetic average of O3 for either a 7‐ or 12‐h daily period as the measure of dose in the dose response relationships. This study investigated the use of alternative dose metics that gave differential weighting to hourly O3 concentrations according to level of O3, period of day, or total hourly solar radiation. Data were used from two NCLAN studies in which two different methods of O3 addition were used for 7 h/d. In addition, one study included 12 h/d exposure for one method of O3 addition. The residual sums of squares from fitting a common Weibull response model to each experiment were compared over the range of dose metrics. The results suggested that the dose metrics using equal weighting of peaks and valleys closely reflected plant reaction to O3, but the fit of the dose‐response models improved if relatively little weight was given to the final 5‐h component (1700–2200 h EDT) of the 12‐h exposure period. Weighting by total hourly solar radiation gave results very similar to the best obtained from differential peak‐valley weighting and 7 h:5 h weighting.