SOYBEAN YIELD IN NEW-JERSEY RELATIVE TO OZONE POLLUTION AND ANTIOXIDANT APPLICATION

The yield of two commercial soybean cultivars, Williams and Cutler 71, was compared in ethylenediurea-treated and untreated test plots in New Brunswick, NJ; over a 3-yr period. No statistically significant (P = 0.05) difference between treatments was found for the cultivars although the National Ambient Air Quality Standard (NAAQS) of 0.12 ppm ozone was exceeded for as many as 72 hr per growing season and the 7-hr daily mean equaled 0.062 ppm. On this basis, it was concluded that Williams and Cutler 71 do not sustain a yield loss attributable to ozone pollution in New Jersey. This is contrary to predictions based on the National Crop Loss Assessment Network (NCLAN) models relating yield loss to the 7-hr ozone mean during the growing season. The open-top chamber method on which the models are based do not reflect the episodic nature of ozone pollution or some of the more important environmental conditions that influence plant growth in the field.