Effects of Chronic Exposure to Simulated Power Plant Emissions and Ozone in Soybean Production
- Herbert C. Jones,
- J. C. Noggle and
- Charlie McDuffie *
Acute SO2 effects on vegetation are less likely because large point sources comply with ambient air quality standards and emission limits. The remaining concern is for direct effects of SO2, which might occur from exposure to intermittent, subacute dosages. Limited data exist for assessing chronic effects because experimental exposure regimes used in most effect studies on soybean [Glycine max. (L.) Merr.] are from field and laboratory exposure regimes consisting of SO2, NO2, and O3 dosages with a high degree of uncertainty. Chronic exposure of ‘Essex’ soybean to 0.06 µL L−1 (0.06 ppm) O3 for 8 h d−1, 5 d wK+−1, for 18 wk in the greenhouse caused a 34% reduction in yield compared to charcoal-filtered air. Sulfur dioxide in combination with O3 and NO2 caused no additional reduction in yield, but lower dosages of SO2 increased yields compared to the O3 treatment, apparently by retarding O3-induced premature senescence. Emissions from a power plant had no adverse effect on yield on the cultivar Essex during a 3-yr field study (1981–1983).
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