Location: Soil and Water Management Research
Title: Carbon dioxide control in an open system that measures canopy gas exchanges Authors
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 15, 2014
Publication Date: N/A
Technical Abstract: Atmospheric carbon dioxide concentration affects both C3 carbon net assimilation as well as crop water use. Methods for measuring whole canopy gas exchange responses under carbon dioxide enrichment are needed for breeding programs aiming to develop crop cultivars resistant to stresses like drought in a future higher carbon dioxide world. Previously we developed and tested a portable, open transparent chamber system for measuring canopy gas exchanges. Here we describe further development of this system by adding the capability of controlling carbon dioxide concentration. Pure carbon dioxide injection into the system was accomplished with a data logger operated mass flow controller attached to a high pressure carbon dioxide gas cylinder. Across the full range of chamber air flow rates, carbon dioxide concentration enrichment controls were within ± 12 µmol per mol of the desired set point. Following an abrupt user-selected change in chamber air flow rate, carbon dioxide concentration enrichment controls were re-established within 3 to 5 min.