MECHANISTIC PROCESS-LEVEL CROP SIMULATION MODELS FOR ASSESSMENT OF AGRICULTURAL SYSTEMS
Location: Crop Systems & Global Change
Title: Effect of elevated carbon dioxide and water stress on gas exchange and water use efficiency in corn
Submitted to: Agricultural and Forest Meteorology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 27, 2010
Publication Date: January 14, 2011
Citation: Chun, J.A., Wang, Q., Timlin, D.J., Fleisher, D.H., Reddy, V. 2011. Effect of elevated carbon dioxide and water stress on gas exchange and water use efficiency in corn. Agricultural and Forest Meteorology. 151:378-384.
Interpretive Summary: Little is known on how the water use of corn will be affected at high atmospheric carbon dioxide (CO2) concentrations. In this study we investigated the relationship between plant growth and water use by a corn crop in sun-lit growth chambers with soilbins at two CO2 concentrations. Soil water contents observed under elevated CO2 were higher than those grown under ambient CO2 concentrations even though less irrigation water was applied. The corn grown at high CO2 used 25 to 30% less water for the same amount of biomass production than corn grown at ambient CO2 concentration under well watered and water stressed conditions. This study suggests that less water will be required under high-carbon dioxide environment in the future than at present. These results can be used to provide efficient water management strategies for crops under the high-carbon dioxide environment in the future. Agronomists, water conservation practitioners, agricultural engineers and agricultural extension specialists will benefit from this research.
[CO2] has been predicted to increase in the future, and thus leading to possible changes in precipitation patterns. The objectives of this study were to investigate water use and canopy level photosynthesis of corn plants, and to quantify water use efficiency in corn plants under two different [CO2] levels. Corn plants were planted in sunlit plant growth chambers from sowing with optimum water and nutrient conditions and temperature (28/18 °C) conditions. From 21 days after emergence (DAE), the eight treatments including two levels carbon dioxide concentrations (400 and 800 ppm) and four levels of water stress (well-watered control, “mild”, “moderate”, and “severe” water stress) treatments at each [CO2] level were imposed. Soil water contents were monitored by a Time Domain Reflectometry (TDR) system (15 probes per chamber). Approximately 20 to 49% less water was applied for elevated [CO2] treatments than for ambient [CO2] from 21 DAE. However, higher soil water contents were recorded under elevated [CO2] than under ambient. The higher soil water contents resulted mainly from less water use in elevated [CO2] than in ambient and contributed to higher water use efficiency under elevated [CO2] conditions. However, corn growth such as height, leaf area, and biomass accumulation was not significantly different in [CO2] or water stressed treatments. The “breaking points” (changes from high to low rates of soil water loss) were observed in the bottom of soil depth for the water stressed conditions, and the “breaking points” under ambient CO2 appeared 6 to 9 days earlier than under elevated [CO2]. This study suggests that less water will be required for corn under high-[CO2] environment in the future than at present.