Submitted to: The Earth's Changing Land Global Change and Terrestrial Ecosystems and Land
Publication Type: Abstract Only
Publication Acceptance Date: May 26, 1998
Publication Date: N/A
Beginning in 1992 the Free-Air Carbon Dioxide Enrichment (FACE) facility at Maricopa, AZ, has provided realistic insight into how elevated CO2 will affect growth, development, and final yield of spring wheat (Triticum aestivum L., cv Yecora Rojo) in large-scale production environments. Treatments provided exposure to ambient and elevated CO2(~550 umol/mol or a nominal 200 umol/mol above ambient). Main plots were split to test the interactive effects of either water or nutrient stresses with CO2. Treatments were replicated 4 times. Results showed that elevated CO2 stimulated biomass and green leaf area index during early- and mid-season. This effect was amplified under deficit irrigation and lower soil fertility levels, presumably because plants developed a more extensive rooting system and exploited available soil resources more completely. Developmental rates were accelerated by water and nutrient stress but appeared minimally affected by elevated CO2. When grown under optimum water and nutrient conditions, final grain yields were increased significantly (+16%) at elevated CO2 concentrations compared with control treatments. The response to CO2 was increased further (21% to 25%) when plants encountered moderate water stress. In contrast, when limited soil nitrogen reduced yields below potential levels, the beneficial effects of CO2 were diminished (+5% to 12%). These data are available in IBSNAT format for crop growth modeling purposes under the auspices of the GCTE Wheat Modeling Network.