Yield Reduction of Soybean Due to Exposure to Sulfur Dioxide and Nitrogen Dioxide in Combination1
- Robert G. Amundson2
Two soybean [Glycine max (L.) Merr.] cultivars, ‘Beeson’ and ‘Hark,’ were grown in the field and exposed to SO2 alone and in combination with NO2 in open-top chambers supplied with charcoal-filtered air to remove ambient O3. The exposures were for 56 midday hours during the pod-filling period at concentrations of approximately 481 or 1335 µg m−3 SO2 with or without 115 µg m−3 NO2.3 Visible injury was produced only on plants exposed to the higher SO2 concentration, but senescence was accelerated in several treatments (i.e., control about the same as low SO2 < low SO2 + NO2 < high SO2 < high SO2 + NO2. The treatments of high SO2 alone reduced the yields of Hark 26% and Beeson 9%; NO2 with high SO2 reduced the yields 35% for Hark and 31% for Beeson. The lower concentration of SO2 alone reduced the yields of Hark 20% and Beeson 6%; the presence of NO2 at the lower SO2 concentration did not increase the effect on yield reduction in either cultivar. These results suggest that (in the absence of ambient O3) NO2 in combination with SO2 can reduce soybean yield more if the SO2 dose is above a threshold value.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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