Global warming may harm crop growth more than originally predicted, according to research being conducted at the University.

A study published by crop sciences professor Stephen Long and colleagues in the latest edition of the New Phytologist journal, shows that the predicted 23 percent increase in surface ozone by 2050 will decrease soybean yield by 20 percent.

Researchers are exploring future effects of global warming on crops with a project called SoyFACE. FACE, short for Free Air Concentration Enrichment, is the world’s first method for growing crops outdoors under the atmospheric conditions predicted for year 2050. These conditions include higher ozone and carbon dioxide levels.

“Global warming is very threatening to crop growth,” said Lisa Ainsworth, a United States Department of Agriculture agricultural research service scientist and an assistant professor of plant biology.

The extent of this threat is being studied at FACE facilities located in China, Japan, Europe and America. The largest FACE facility in the world is at the University, on 80 acres of farmland south of campus at the intersection of Airport and First streets.

“SoyFACE is unique because the crops are grown in the open field rather than a glasshouse – this way is much more realistic,” said Andrew Leakey, a research fellow at the Institute for Genomic Biology.

The facility consists of corn and soybean fields surrounded by pipes that release either CO2 or ozone through small holes. The pipes release gas according to wind speed and direction, and are adjusted with crop growth to remain 10 centimeters above the crops. A computer measures and continuously adjusts CO2 levels.

“For the most part, CO2 is a good thing for the crops but ozone is a bad thing,” Ainsworth said.

Since ozone is toxic to plants, Long said, increased levels decrease crop yields. On the other hand, increased carbon dioxide levels increase crop yields, because plants use carbon dioxide during photosynthesis.

The Intergovernmental Panel on Climate Change concluded in their most recent assessment for the United Nations General Assembly that the worldwide food supply will not be affected much by the predicted atmospheric changes. They believe that the benefits of elevated CO2 should balance out the harm inflicted by the elevated ozone, rising temperature and decreased soil moisture caused by global warming. The results from SoyFACE predict otherwise.

“It will be worse than they suggest,” Long said.

Elevated CO2 levels confer less of a benefit in the open field than predicted by experiments conducted in greenhouses. In fact, except during a drought, high atmospheric levels of CO2 do not affect the yield of corn, according to a study published by Andrew Leakey and colleagues in the “Plant Physiology” journal in February.

“An agrichemical company would never sell a product without testing it in an open field first, but we’re making predictions about future crop growth before doing so,” Long said. “Globally, we need a lot more experiments like SoyFACE if we are going to have any certainty about our future.”

Serious problems may lie in the future of crop growth because elevated CO2 has less of a benefit than predicted and ozone has a negative effect, Long said.

Ongoing research at the SoyFACE facility is being conducted to better understand the crop’s responses to atmospheric changes and to breed for improved responses.

“We want to find a way to make crops more responsive to CO2 and more resistant to ozone,” Long said.