Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2003
Publication Date: N/A
Technical Abstract: The effects of increased atmospheric concentrations of CO2 and of ozone on soybean evapotransporation, ET, were determined using an energy balance approach. Plots of soybean were exposed to either a 180 µmol mol-1 increase in CO2 concentration (elevated [CO2]), a 25% increase in ambient ozone concentrations (elevated ozone), or both (elevated CO2 X ozone). Data for the elevated CO2 and elevated ozone treatments were collected throughout the 2002 and 2003 growing seasons and the elevated CO2 X ozone treatment was added in 2003. Measurements were recorded in 10 second intervals from emergence to canopy senescence. Measurements included net radiation, soil heat flux, air and soil temperatures, canopy temperature, and wind speed. Sensible heat flux was calculated from the wind and temperature measurements. ET was determined as a residual in the energy balance from net radiation, sensible heat flux, and soil heat flux.