Pioneering Experiments Testing Effects Of Greenhouse Gases On Crops

"When you consider the importance of the Midwest in terms of global food security, it is important to do this research here," said Stephen P. Long, a photosynthesis expert and the Robert Emerson Professor of Plant Biology at the UI. "Up to now, experiments related to global warming on many crops have been done in locations on the periphery of major food production areas."

Researchers want to know how soybeans may be affected, and what scientists might do to assure the integrity of yields and quality as the climate changes. By 2050, carbon dioxide levels are expected to be about 1.5 times greater than the current 370 parts per million, while daytime ozone levels during the growing season could peak on average at 80 parts per billion (now 60 parts per billion).

SoyFACE (Free Air gas Concentration Enrichment) is the first test of crop growth in the presence of both increased carbon dioxide and ozone. Five UI departments, the USDA-ARS and Illinois State Water Survey, as well as researchers from four other nations and two other U.S. universities are participating this summer.

Four control and four experimental 70-foot-diameter rings currently surround 24 varieties of soybeans. The experimental rings have ABS plastic pipes that deliver at crop level a precisely regulated flow of carbon dioxide, based on wind speed and direction, pumped from a 50-ton solar-powered tank.

Next summer, soybeans will grow on an adjacent 40 acres dotted with 24 of the octagon-shaped rings. Four rings will pump carbon dioxide, four will provide just ozone and four will provide ozone and carbon dioxide. Natural conditions will exist in an equal number of control rings for each test. Also next summer, eight more rings, including four experimental rings delivering carbon dioxide, will be placed among corn, which will be rotated into the 40 acres being used this year for soybeans.

Soybeans are sensitive to ozone. In August 1999, for instance, levels in central Illinois exceeded the crop threshold for damage on 28 days. Greenhouse experiments suggest a 50 percent loss in crop yield under constant 2050 levels. Greenhouse work has shown increases in yields under elevated carbon dioxide. This experiment, Long said, will provide insight as to what happens in real field conditions. Long, crop scientist Donald R. Ort and plant biologist Evan H. DeLucia head the project. Tim Mies, a research engineer in crop sciences who led the SoyFACE construction, is site manager. Tai Tran, an undergraduate student, designed the ozone system with a grant from the UI Environmental Council, a program that coordinates and supports environment-based research, teaching and public service.

The Illinois Council for Food and Agricultural Research, Archer Daniels Midland Co., USDA-ARS and the U.S. Department of Energy provided initial funding for the work.