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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCED SYSTEM MODELS AND DECISION SUPPORT TOOLS TO OPTIMIZE WATER LIMITED AGRICULTURE

Location: Agricultural Systems Research Unit

Title: Simulation of free air CO2 enriched wheat growth and interaction with water, nitrogen, and temperature

Authors
item Ko, Jonghan
item Ahuja, Lajpat
item Kimball, Bruce
item Anapalli, Saseendran -
item Ma, Liwang
item Green, Timothy
item Ruane, Alex -
item Wall, Gerard
item Pinter Jr, Paul
item Bader, Daniel -

Submitted to: Agricultural and Forest Meteorology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 11, 2010
Publication Date: August 20, 2010
Citation: Ko, J., Ahuja, L.R., Kimball, B.A., Anapalli, S., Ma, L., Green, T.R., Ruane, A., Wall, G.W., Pinter Jr, P.J., Bader, D. 2010. Simulation of free air CO2 enriched wheat growth and interaction with water, nitrogen, and temperature. Agricultural and Forest Meteorology. 150:1331-1346.

Interpretive Summary: In this study, CERES-Wheat4.0 in RZWQM2 was calibrated and validated for simulations of spring wheat grown in the Free Air CO2 Enrichment (FACE) experiments at Maricopa, Arizona, USA. Soil moisture and plant growth were simulated with reasonable accuracy. The effects of water and N treatments were higher than those of CO2, and the model reasonably simulated these effects. We also presented sensitivity of wheat to individual climate change variables for future model application as well as simulation with projections from 16 GCMs that include increased temperature and precipitation changes along with CO2 for 2050. The beneficial effects of CO2 on yield were cancelled by negative effects of temperature increases, where precipitation changes had negligible effects. The irrigation and N effects were much higher than climate change effects. The CERES-wheat 4.0 module in the RZWQM2 model responded satisfactorily to the climate change deriving factors including CO2, temperature, and precipitation. The results demonstrate the promise of the model for simulating climate change impacts on wheat production and soil water availability.

Technical Abstract: Agricultural system simulation models are key tools for assessment of possible impacts of climate change on crop production and environmental quality. In this study, the CERES-wheat 4.0 module in the RZWQM2 model was calibrated and validated for simulating spring wheat grown under elevated CO2 conditions in the FACE (Free Air CO2 Enrichment) experiments conducted at Maricopa, Arizona, USA from 1992 to 1997. The validated model was then used to simulate the possible impacts of climate change on the crop for a 16 year period centered on 2050 with a projected atmospheric CO2 concentration of 550 ppm. Sixteen General Circulation Model (GCM) projections of climate in response to this CO2 concentration were used for this purpose. In the FACE experiment, the crops were grown under ambient (365-370 ppm) and elevated (~ 550 ppm) CO2 concentrations with two irrigation treatments (wet and dry) in 1992-93 and 1993-94, and two nitrogen (N) treatments (high and low N) in 1995-96 and 1996-97 crop seasons. The model simulated crop growth and grain yield, and soil water responses to CO2 reasonably well, reproducing variations due to the treatments. Under ambient CO2 in 1992-93 and 1995-96, biomass was simulated better in the dry and low N treatments with root mean square difference (RMSD) of 181 kg ha-1 and 161 kg ha-1, respectively, compared to the wet and high N treatments with RMSD of 259 kg ha-1 and 268 kg ha-1, respectively. The effects of water and N treatments were higher than those of CO2, and the model reproduced these effects well. Elevated CO2 effects on crop growth were counter-balanced by temperature effects, and projected precipitation had little effect on the simulated crop. The model results provide reasonable confidence for simulations of possible impacts of projected climate change on wheat crop growth in the region, within normal field data uncertainties.

Last Modified: 7/10/2014
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