Numerical Experiments o Possible Changes in Maize Canopy Climate due to Increasing CO₂ Levels

抄録

The sensitivity of canopy climate to the air's CO₂ level increment is investigated using a canopy flow model based on the mean turbulent field (MTF) closure models. Leaf processes in the model are highly parametrized using the experimental results obtained from the dependence of stomatal diffusion resistance on the CO₂ level. An increase in stomatal resistance with the CO₂-level was greater in C₄ plants (maize) than in C₃ plants (rice), indicating that changes in maize canopy climate are more significant than in rice canopy. In a model maize canopy, daily sensible heat loss increased along with CO₂ levels, with concomitant decreases in daily latentheatloss. Somewhat hotter and drier air conditions within maize canopies at higher CO₂-level are anticipated to be unfavorable for the growth and yield of maize crops.