CANOPY REFLECTANCE OF SOYBEAN AS AFFECTED BY CHRONIC DOSES OF OZONE IN OPEN-TOP FIELD CHAMBERS

The relationship between canopy reflectance and ozone (O//3) treatment was investigated in a field experiment with soybean growing in 3-m diameter, 2. 4-m high open-top exposure chambers. The objectives were to develop an understanding of the pattern of reflectance changes induced by this air pollutant and to investigate how these changes might ultimately be related to yield. Correlations were obtained between the reflectance data and visual estimates of non-green leaf area, a widely-used technique for rating pollutant injury. Correlations between the reflectance data and visual estimates of non-green leaf area were high, indicating that rates of senescence could be estimated by either means.