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Testing CERES–Wheat with Free‐Air Carbon Dioxide Enrichment (FACE) Experiment Data: CO2 and Water Interactions
Author(s) -
Tubiello Francesco N.,
Rosenzweig Cynthia,
Kimball Bruce A.,
Pinter Paul J.,
Wall Gerald W.,
Hunsaker Douglas J.,
LaMorte Robert L.,
Garcia Richard L.
Publication year - 1999
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1999.00021962009100020012x
Subject(s) - phenology , evapotranspiration , carbon dioxide , environmental science , agronomy , carbon dioxide in earth's atmosphere , canopy , crop , irrigation , field experiment , atmospheric sciences , chemistry , botany , ecology , biology , organic chemistry , geology
Dynamic crop‐growth models are used to project the effects of rising atmospheric CO 2 concentration and associated climate change on crop yields. Such model predictions are largely untested in the field, for lack of experimental data. We tested the CERES‐Wheat model, modified to include leaf‐level photosynthesis response to elevated CO 2 , using field data from 2 yr of Free‐Air Carbon Dioxide Enrichment (FACE) experiments with spring wheat ( Triticum aestivum L. cv. Yecora Rojo) in Maricopa, AZ. Two irrigation treatments (well‐watered, WW; water‐deficit stressed, WS) and two atmospheric CO 2 concentrations (ambient, 350 (μmol mol −1 ; elevated, 550 (μmol mol −1 ) were simulated. The model was evaluated using measurements of crop phenology, aboveground dry matter (DM) production, grain yield, and evapotranspiration (ET). Model calculations of crop phenology were within 2 to 3 d of observed values under WW, ambient CO 2 conditions in both years. The model did not simulate the accelerated crop phenology (5–8 d at physiological maturity) observed in the WW and elevated CO 2 treatments, indicating the need to include effects of increased stomatal resistance on canopy temperature. Simulations of DM and grain yield were within 10% of measured values, except for a tendency to overcalculate DM response to CO 2 by 10 to 15% in Year 1 for WS treatments. The model undercalculated cumulative ET under WW conditions by 15%; model sensitivity analyses suggest that simulation of potential evapotranspiration (PET) was too low for this arid site. The model reproduced measured dynamics of CO 2 ‐water interactions. Simulated reductions in water loss due to elevated CO 2 were about 4%, in agreement with measurements. The model simulated larger increases in DM production and yield due to elevated CO 2 under WS than under WW conditions. In Year 1, simulated crop response to CO 2 was 2% larger (measured: 3%) under WS than under WW conditions; in Year 2, it was 11% larger (measured: 9%). The ability to simulate CO 2 ‐water interactions, though it needs to be further evaluated with additional experimental datasets, is an important attribute of models used to project crop yields under elevated CO 2 and climate change.