If current climate and crop-improvement trends continue into the future, Midwestern corn growers who today rely on rainfall to water their crops will need to irrigate their fields, a new study finds. This could draw down aquifers, disrupt streams and rivers, and set up conflicts between agricultural and other human and ecological needs for water, scientists say.

The study, reported in the journal Ecosphere, calculated the extent to which hotter conditions expected by midcentury will draw more moisture out of corn plants, said University of Illinois plant biology professor Evan DeLucia, who led the study.

“As the atmosphere warms, it dries, and so the draw for water to go from plants to the atmosphere increases,” DeLucia said. “The ability of the atmosphere to draw water from plants is determined by its ‘vapor pressure deficit.’

“If you add to this the decades-old trend toward bigger, more productive corn plants, you see an overall increase in water use and water loss through plant leaves – without comparable increases in rainfall to counter the deficit,” he said.