Selecting ozone exposure statistics for determining crop yield loss from air pollutants

Area of Science:

• Agricultural Science
• Environmental Science
• Atmospheric Chemistry

Background:

• Ambient ozone is a significant abiotic stressor affecting crop productivity.
• Previous studies have utilized various ozone exposure metrics to assess crop damage.
• Understanding the relationship between ozone exposure and crop yield is crucial for agricultural management.

Purpose of the Study:

• To evaluate the effectiveness of numerous ozone exposure statistics in predicting crop yield loss.
• To identify the most suitable ozone metrics for different crop species.
• To inform agricultural practices regarding ozone pollution impacts.

Main Methods:

• Calculated 163 ozone exposure statistics from hourly ozone data in a California ambient ozone gradient.
• Utilized polynomial regression to correlate ozone statistics with crop yield for alfalfa, tomatoes, cotton, and dry beans.
• Assessed statistic performance using residual mean square (RMS) values.

Main Results:

• No single ozone statistic was optimal for all tested crop species.
• Ozone statistics incorporating threshold levels generally performed well, with optimal thresholds varying by crop.
• Daily hours of exposure above a high-concentration threshold correlated well with yield for alfalfa, market tomatoes, and dry beans.
• The average of daily peak ozone concentrations best predicted cotton yield.

Conclusions:

• The selection of ozone exposure statistics for crop yield assessment should be crop-specific.
• Ozone statistics with threshold levels are valuable, but the optimal threshold is species-dependent.
• When statistical performance is similar, biologically relevant ozone metrics should be prioritized.