||Assessing the Impacts of Soil Moisture Stress on Regional Soybean Yield and Its Sensitivity to Ozone (Journal Version).
King, D. A. ;
Nelson, W. L. ;
||Portland Univ., OR. Dept. of Physical and Life Sciences. ;Doane Publishing, St. Louis, MO.;Corvallis Environmental Research Lab., OR.
Soybean plants ;
Plant physiology ;
Regional analysis ;
Soil water ;
Mathematical models ;
Air pollution effects(Plants) ;
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Plants that experience moisture stress show less ozone-caused injury than non-stressed plants exposed to similar levels of ozone. To evaluate the interaction of moisture stress and ozone for soybean grown in the U.S.A., relative yields were simulated with a model to compute a general relationship between moisture stress effects on yield and crop sensitivity to ozone. In 1980 a 25% reduction in ozone would have increased mean yield by 6.0% for adequately watered soybeans, but only a 4.6% increase was predicted when moisture stress was included. This shift represents a 23% decline in sensitivity to ozone caused by moisture stress. The mean predicted ozone impact on soybean yield for 1979-1983 was reduced 19% by moisture stress. These predictions agree with drought-induced reductions in ozone sensitivity observed in pot-grown soybeans, but results from field experiments involving moisture stress are less certain.