AGRICULTURAL PRODUCTION AND OZONE AIR POLLUTION UNDER 
ENRICHED CARBON DIOXIDE ATMOSPHERE: EFFECTS ON CANOPY 
REFLECTANCE AND PLANT CHARACTERISTICS 
Bernardo F.T. Rudorff 
Charles L. Mulchi 
Craig S.T. Daughtry 
Instituto Nacional de Pesquisas Espaciais - INPE 
Divisào de Meteorologia e Sensoriamento Remoto - D5M 
Caixa Postal 515 
12201-970 - So José dos Campos, SP - Brazil 
ISPRS Commission VII / Working Group 7 
ABSTRACT 
Estimates of future changes in agricultural production in response to changes in concentration of 
atmospheric trace gases are often based on the beneficial physiological effect of carbon dioxide (CO») 
enrichment on plant growth. However, these estimates fail to consider the negative impact of ozone (O3) 
air pollution on crop production. Several field studies with wheat (Triticum aestivum L.) and com (Zea 
mays L.) were conducted using open-top chambers to mimic atmospheric concentrations of CO9 nq O3 
that are predicted to occur during the first half of the 21! century. Canopy reflectance measurements are 
of limited use in air pollution studies, especially for corn. Both, CO» and O4 were found to have a major 
impact on physiological processes that affect photosynthate partioning, especially in wheat, which cannot 
be detected through spectral reflectance measurements. From the experiments carried out in this study it 
is concluded that the CO, enriched environment counteracts the stress caused by O3 air pollution under 
the current climate scenario. 
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