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Milestone: Popular FACE (Free-air CO2 Enrichment) Dataset Made Publically Accessible.

As the concentration of carbon dioxide (CO2) in the atmosphere increases from burning of fossil fuels and other processes, researchers have consistently found an increase in crop growth and yield, which is attributed to the stimulatory effect of CO2 on photosynthesis. Furthermore, the magnitude of crop responses to CO2 varies with crops and production conditions, especially water availability. From December, 1992 through May, 1997, four free-air CO2 enrichment (FACE) experiments were conducted on wheat at Maricopa, Arizona. The first two were conducted at ample and limited supplies of water, and second two at ample and limited supplies of fertilizer nitrogen. More than 50 scientists participated, and they collected a large and varied set of data on plant, soil, and microclimatic responses to the elevated CO2 and its interactions with the water and N treatments. The dataset has been popular with wheat growth modelers who have utilized the growth, yield, and other data to validate their models, which get used to predict likely future wheat productivity with projected global change.

More than 50 papers have been published based on the results of these experiments, In June, the dataset itself was published and made readily available for anyone to download and conduct further analyses. Published in the Open Data Journal for Agricultural Research (, the whole dataset consists of 23 separate files covering management, soils, weather, physiology, phenology, biomass growth, leaf area, yield, quality, canopy temperatures, energy balance, soil moisture, nitrogen assimilation, and other data. The citation is: Kimball, B.A., P.J. Pinter, Jr., R.L. LaMorte, S.W. Leavitt, D.J. Hunsaker, G.W. Wall, F. Wechsung, G. Wechsung, A.J. Bloom, and J.W. White. 2017. Data from the Arizona FACE (free-air CO2 enrichment) experiments on wheat at ample and limiting levels of water and nitrogen. Open Data Journal for Agricultural Research 3:29-38. (PDF)

We anticipate that the dataset will continue attract users as researchers improve their models and wish to conduct targeted tests with “real world” data. Ultimately, such work should improve our ability to understand possible impacts further increases in atmospheric CO2.


/ARSUserFiles/20200500/images/FACE Wheat photo by Bruce Kimball on USDA web site d2563-1.jpg