Remote Sensing of Sulfur Dioxide Effects on Vegetation: Spectral Reflectance of Soybeans and Winter Wheat Exposed to Sulfur Dioxide in Experimental Plots

摘要

Remote measurements of the spectral reflectance of experimental, 0.40 ha plots of soybeans (Glycine max (L.) Merr. var Essex) and winter wheat (Triticum aestivum (L.) var Coker 68-15) were made after the plants were given controlled exposures of sulfur dioxide (SO sub 2 ) and the foliar effects were observed and recorded. The plots were divided into subplots, each of which was treated with a specific dose of the pollutant; the 2-hour average concentrations ranged from zero to 10480 mu g/m exp 3 to simulate acute exposures that might occur in agricultural areas near large, coal-fired power plants. Then the subplots were scanned systematically with a spectroradiometer. Spectral scanning as performed on these subplots can provide guidance for selecting appropriate films and optical filters for aerial multiband cameras and optimal channel combinations for airborne multispectral scanners to be used for detecting and mapping SO exp 2 effects on sensitive crops. It is concluded that although some statistically significant relationships exist between reflectance and foliar injury, they show up only when the level of injury is relatively severe. The very light to moderate effects that might be encountered in agricultural fields near large, coal-fired power plants probably cannot be consistently detected with airborne remote sensors because of the masking effects of variables such as weediness, canopy density, and moisture stress. In these experiments it was much easier to detect the SO sub 2 effects on wheat than on soybeans. (ERA citation 07:048245)