WASHINGTON – U.S. farmers can grow more corn than ever before thanks to genetic modifications and improved planting techniques, but the crops are also increasingly vulnerable to drought, researchers recently said.
The study in the journal Science found that “densely planted corn appears to be unexpectedly more sensitive to water scarcity,” raising concerns about future food supply as the planet warms.
The United States is the largest exporter of corn in the world, shipping about 40 percent of the world’s corn.
In recent years, most commercially produced corn has been modified with new traits that make roots better able to access water and build in pest resistance.
That has allowed farmers to plant more corn and set the plants more closely together than they could in the past, resulting in higher yields.
However, the plants have also become more susceptible to dry spells over the past two decades, which is a concern because most corn crops in the United States rely on natural rain, not irrigation.
If predictions for future climate in the midwestern U.S. — known as the Corn Belt — are correct, then corn yields could fall 15 to 30 percent over the next half century, scientists said.
“Recent yield progress is overall a good news story. But because farm yields are improving fastest in favorable weather, the stakes for having such weather are rising,” said David Lobel of Stanford University who led the study. “In other words, the negative impacts of hot and dry weather are rising at the same time that climate change is expected to bring more such weather.”