July 9, 2010

US research finds soy yields to fall due to climate change

Climate change and pollution may cut yields for soy 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 on Wednesday (July 7). 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% more food by 2050 to feed a rising population, the UN's Food and Agriculture Organisation (UN FAO) said. 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. "How top-producing areas fare with climate change will be very important in determining global food security for the future."

The university studied how soy in open fields grew in higher carbon dioxide and ozone levels, in research funded by the USDA, 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. Rainfall during the Midwest growing season is projected to drop 30% by 2050, Ort said.

Ozone pollution has suppressed soy yields in Indiana, Illinois and Iowa by 15%, the University of Illinois said, citing research at its Soy Free Air Concentration Enrichment facility, known as SoyFACE.

Using the same soy cultivars in 2050 as those being planted now would cut yields by another 20% 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 soy 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 USDA forecasts average soy 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 soy, the US faces a much greater ozone challenge than Brazil."