Corn yields in the United States could soon be greatly reduced by global climate change, according to researchers from North Carolina State University.
More frequent droughts in the Midwest of the United States could reduce corn yields by 10 to 15 percent in coming years, according to a report announcing the findings.
Corn is especially sensitive to environmental stresses like droughts, according to the new study. During 18 years between 1995 and 2012, crops in Indiana, Illinois and Iowa suffered from the effects of droughts in those areas.
Researchers modeled temperature and precipitation on a scale called vapor pressure deficit (VPD). While numbers too high or low on the scale represent unfavorable conditions for crops, a number near the middle represents desirable climates.
The study examined dozens of climate models, and 29 of these predict the VPD will rise, as droughts become more common.
Soy beans could also be affected by rising temperatures, according to the study. The effect on these crops is not expected to be as severe as damage to corn.
"Yield increases are getting smaller in bad conditions. Agronomic and genetic crop improvements over the years help a lot when growing conditions are good, but have little effect when growing conditions are poor, like during droughts," Roderick Rejesus, co-author of the study from North Carolina State, said.
Researchers looked at the way crops were planted, and suggest that corn fields on commercial farms may be too dense. When plants are placed close together, large numbers can often be affected by environmental stresses. Most corn fields in the United States are not irrigated, and depend on rain to thrive.
"The Corn Belt is phenomenally productive. 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," David Lobell of Stanford University, who led the research said.
The United States produces 35 to 40 percent of the world's supply of corn and soybeans, giving the country the distinction of being the world's top exporter of corn. Most of this grain is grown in Midwest states. Because of this, droughts in these areas can have significant consequences for both domestic and international food supplies.
Beyond the year 2050, droughts could cause an even-greater reduction in the amount of corn and soybeans harvested. The only long-term solution to the problem is reducing climate change, the researchers stated.
Investigation of the role of rising temperatures on decreasing corn yields was published in the journal Science.
