Chlorophyll Content of Soybean Foliage in Relation to Seed Yield and Ambient Ozone Pollution

A field test was conducted to determine if ozone pollution adversely affected the chlorophyll content and seed yield of soybean. Eight soybean cultivars were grown to maturity in test plots in central New Jersey; one-half of the plots was treated with an antioxidant (ethylenediurea) to protect the plants from the effects of ambient ozone and one-half was left untreated. Periodic chlorophyll measurements revealed no significant difference between EDU-treated and untreated plots during the major part of plant growth. The absence of a yield effect predicated on the normal chlorophyll content was corroborated by actual total seed measurement. Our results did not support predictive models that forecast a significant yield reduction from a 7-h seasonal mean of 0.058 ppm 0₃, but agreed with results obtained previously in Maryland and Georgia.