Penn State University: Warming climate to result in reduced corn production; irrigation blunts effect

No matter which of the widely accepted global circulation models ultimately comes closest to predicting the amount of warming caused by climate change, corn production will be reduced, according to a new study by Penn State researchers.

They evaluated the potential impacts of 18 warming scenarios, dictated by various atmospheric greenhouse gas concentrations, to determine the potential effects of future climate change on irrigated and rainfed corn yields from the 2020s through the 2090s. Although the research was focused on the U.S.Great Plains — in the heart of the nation’s top corn-producing region — the results are believed to have global implications.

To estimate yields, researchers employed the AquaCrop model — a crop-growth simulation developed by the Food and Agriculture Organization of the United Nations — to assess the effect of environment and management on crop production, predicting yield response to water. The study site is representative of agricultural management practices in the region and represents the most densely irrigated area in the Central Plains, which is a subregion of the Great Plains.

Corn is susceptible to environmental factors such as increased air temperature, increased radiation, vapor pressure deficit and humidity change, according to lead researcher Suat Irmak, professor and head of the Department of Agricultural and Biological Engineering in the College of Agricultural Sciences. He and his team noted that irrigated yields will be impacted much less than rainfed yields.

“In our study, depending on the atmospheric greenhouse gas concentrations and associated level of warming, we saw declines in rainfed corn yields ranging from 2.2% to 21.5%,” he said. “Under those same greenhouse gas concentrations, the range of declines was lower for irrigated yields — from 3.7% to 15.6%, due to irrigation technologies providing more stable crop growth conditions under water- and temperature-stress.”

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