Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract only
Publication Acceptance Date: 2/15/2004
Publication Date: 8/15/2004
Citation: Leakey, A., Bernacchi, C.J., Below, F., Bordigno, R., Mies, T., Morgan, P., Nelson, R.L., Ort, D.R., Uribellarea, M., Long, S. 2004. The heart project: determining how the major agricultural ecosystem of the U.S. will respond to atmospheric change in 2050 [abstract]. Plant Biology Annual Meeting. Interpretive Summary:
Technical Abstract: Our atmosphere is changing. Concentrations of both carbon dioxide ([CO2]) and ozone ([O3]) in the atmosphere have increased and will continue to do so. This may dramatically affect the Corn Belt, with important economic and climatic consequences. The 'Heartland Ecosystem and its Adaptation, Responses and feedbacks To global atmospheric change' project (HEART) at the University of Illinois, Champaign, IL grows fields of soybean and corn under the atmospheric conditions predicted for 2050 (+50% [CO2] and +20% [O3] compared to today). This is done with Free-Air Concentration Enrichment (FACE) technology, which uses natural wind patterns to carry the gases through the crop canopy from a ring of release pipes surrounding the experimental plots. This open-air laboratory allows the crops to grow in the atmosphere of 2050 under the normal field conditions of Central Illinois. Photosynthetic assimilation of [CO2] produces carbohydrates that are used by plants as an energy source as well as for energy storage in seeds and tubers. Whereas more [CO2] in the atmosphere was predicted to increase crop growth and yield, ozone is toxic and greater concentrations in the atmosphere were expected to reduce crop yield. In our 2002 experiment, elevated [CO2] increased corn yield by 20% and soybean yield by 15%, but elevated [O3] depressed soybean yield by 14%. The seed quality of the soybeans also changed, with altered fatty acid and mineral composition. In 2003, the soybean crop was grown under simultaneously elevated [CO2] and elevated [O3]. The presence of elevated [CO2] protected soybeans from [O3] damage and the yield enhancement by [CO2] was maintained. Soybeans were discovered to use less water under the atmospheric conditions of 2050 and were therefore more drought tolerant. But changes in crop water use are likely to be especially important for regional climate. Soybean-corn is the largest ecosystem in the US, occupying 153 million acres or 9% of the area of the contiguous states. It covers more than half of some of the Midwest states. Evaporation from this ecosystem cools the land in summer and provides water to the atmosphere to feed subsequent rainfall. The HEART Project also tests different varieties of soybean and corn to determine those which will respond most favorably to elevated CO2 and be most tolerant to O3. These results will provide critical information for land management decisions and assist the U.S. Corn Belt community in adapting to atmospheric change.