Researchers find corn yields more sensitive to drought, climate change

May 5, 2014
Researchers find corn yields more sensitive to drought, climate change
Corn in Hawaii. Image courtesy CTAHR LIFE program.

A new analysis of corn production in the American Midwest has determined that today's crop yields are more sensitive than ever to bad weather, and especially to drought conditions anticipated under likely climate change scenarios.

The study published in May in the journal Science was led by a Stanford University earth scientist and co-authored by Associate Professor of Economics Michael J. Roberts in the College of Social Sciences at the University of Hawai'i at Mānoa.

"The Corn Belt is phenomenally productive," said David Lobell, an associate professor of environmental Earth system science at Stanford University. "But in the past two decades we saw very small yield gains in non-irrigated corn under the hottest conditions. This suggests farmers may be pushing the limits of what's possible under these conditions."

"A lot of agricultural research has been designed, at least in part, to improve performance during ," said UH Mānoa's Roberts. "However, even as individual plants may become more drought tolerant, that doesn't tell you what happens at a larger scale. Farmers adjust seeding rates and planting times to take advantage of new traits, which can also factor into drought sensitivity."

To conduct their analysis, researchers combined field-level records of soybean and maize (corn) sowing and collected by the U.S. Department of Agriculture with high-resolution daily weather data. They considered four weather variables: minimum and maximum daily temperatures, precipitation, and the daytime vapor pressure deficit or VPD. The study included more than 1 million records for crops grown across Iowa, Illinois and Indiana between 1995 and 2012.

The researchers found that over time, crops have become more vulnerable to changes in VPD, which measures aridity, a key indicator of drought that is closely linked to extreme heat in the Midwest.

The effects were much stronger for corn than for soybeans, a result that the authors believe may be tied to how densely corn is sown. Recent technological advancements have developed corn plants with stronger, more efficient root systems – allowing for tighter sowing – but densely planted corn can suffer higher stress during periods of drought and thus produce lower yields.

The researchers predict that at current levels of temperature sensitivity, crops could lose 15 percent of their yield within 50 years, or as much as 30 percent if crops continue the trend of becoming more sensitive over time.

"In fact, if this trend in drought sensitivity continues the impacts of could be twice as bad as most people predict for this region," Roberts said. "The key thing to recognize is that greater drought tolerance may come at a cost of lower yield potential, possibly giving up some historic productivity gains."

Corn is the primary seed crop grown in Hawai'i, according to the Hawai'i Crop Improvement Association. The United States produces about 40 percent of global corn, and 35 percent of global soy. More than 80 percent of U.S. is grown without special irrigation (rain-fed only).

Explore further: AgriLife Extension expert: Spider mite damage to corn affected by irrigation level

More information: David B. Lobell, Michael J. Roberts, Wolfram Schlenker, Noah Braun, Bertis B. Little, Roderick M. Rejesus, Graeme L. Hammer. "Greater Sensitivity to Drought Accompanies Maize Yield Increase in the U.S. Midwest." Science 2 May 2014: Vol. 344 no. 6183 pp. 516-519. DOI: 10.1126/science.1251423

Related Stories

Signs for optimism as harvest reaches peak in Iowa

September 19, 2012

The latest government crop yield predictions may give grain farmers cause for optimism as the harvest season reaches its crescendo in Iowa, corn and soybean experts at Iowa State University said this week.  

Expert: Drought-tolerant corn advances beginning to show

December 27, 2012

There's nothing like a couple years of drought to help determine the advances being made in drought-tolerant corn. And Dr. Qingwu Xue, a Texas A&M AgriLife Research scientist, says there are some significant differences starting ...

Recommended for you

Study suggests fish can experience 'emotional fever'

November 25, 2015

(—A small team of researchers from the U.K. and Spain has found via lab study that at least one type of fish is capable of experiencing 'emotional fever,' which suggests it may qualify as a sentient being. In their ...

New gene map reveals cancer's Achilles heel

November 25, 2015

Scientists have mapped out the genes that keep our cells alive, creating a long-awaited foothold for understanding how our genome works and which genes are crucial in disease like cancer.

Insect DNA extracted, sequenced from black widow spider web

November 25, 2015

Scientists extracted DNA from spider webs to identify the web's spider architect and the prey that crossed it, according to this proof-of-concept study published November 25, 2015 in the open-access journal PLOS ONE by Charles ...

How cells in the developing ear 'practice' hearing

November 25, 2015

Before the fluid of the middle ear drains and sound waves penetrate for the first time, the inner ear cells of newborn rodents practice for their big debut. Researchers at Johns Hopkins report they have figured out the molecular ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.