Soybean Yields to Drop on Climate, Ozone, U.S. Researcher Says

Climate change and pollution may cut yields for soybeans and other crops by 2050 unless plants are adapted, the University of Illinois said, citing research.

Tests showed crops grown in open fields benefitted less than expected from higher levels of carbon dioxide in the air, the university said in a report published yesterday. The yield increase was only half of that assumed by the United Nations’ climate-change panel to predict world food supply in 2050, according to the report.

The world must grow 70 percent more food by 2050 to feed a rising population, the UN’s Food and Agriculture Organization says. One assumed positive aspect to climate change has been that higher carbon dioxide levels in the atmosphere will stimulate photosynthesis and boost yields, the researchers said.

“More research in these areas is critical,” Don Ort, professor of crop science at the University of Illinois, said in a statement. “How top-producing areas fare with climate change will be very important in determining global food security for the future.”

The university studied how soybeans in open fields grew in higher carbon dioxide and ozone levels, in research funded by the U.S. Department of Agriculture, Department of Energy and the Illinois Council on Food and Agriculture Research.

Rising carbon dioxide levels are creating a global warming effect that changes precipitation patterns, and rainfall during the Midwest growing season is projected to drop 30 percent by 2050, Ort said.

Ozone pollution has suppressed soybean yields in Indiana, Illinois and Iowa by 15 percent, the university said, citing research at its Soybean Free Air Concentration Enrichment facility, known as SoyFACE.

‘Significant Sensitivity’

Using the same soybean cultivars in 2050 as those being planted now would cut yields by another 20 percent because of the expected rise in ozone levels by the middle of the century, according to Ort.

“If pollution from Chicago blows out of the city into agricultural areas, it can interact with sunlight to produce ozone and cause plant yields to suffer,” Ort said. “We are applying for funding to examine corn’s sensitivity to ozone at SoyFACE, but historical analysis indicates a significant sensitivity and yield loss.”

Research at SoyFACE and data from the past 10 years indicates that soybean yields decrease by 1.5 bushels per acre for every additional one-part-per-billion of ozone in the atmosphere, according to the researcher. The U.S. Department of Agriculture forecasts average soybean yields of 42.9 bushels an acre this year, from a record 44 bushels an acre in 2009.

“Agricultural areas located near industrial areas will face the greatest challenges,” the university said. “Of the world’s two top-growing areas for soybean, the U.S. faces a much greater ozone challenge than Brazil.”

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