Ozone Dosage-Crop Loss Function for Alfalfa: A Standardized Method for Assessing Crop Losses from Air Pollutants

Abstract

Ozone dose-crop loss conversion functions for alfalfa (Medicago sativa, L. var. Moapa 69) yield reduction and defoliation were developed using standardized field plots within an ambient O3 gradient in the South Coast Air Basin. Seasonal yields and defoliation values were tested with O3 dose, average daily maximum temperature, average daily minimum temperature, and average daily relative humidity in regression analyses to determine significant functional relationships. Only the ambient O3 dose variable was found to have a significant effect on alfalfa yield or defoliation (yield, r = –0.827, t-slope = 3.900; defoliation, r = –0.890, t-slope = 5.190). The ozone dose-crop loss conversion functions were calculated by converting the dose-response functions to dose-percent reduction functions. © 1976 Air & Waste Management Association.