Study indicates double cropping to expand due to climate change

Associate Editor

(June 21, 2016) Could widespread double cropping be a bigger part of the Northeast’s agricultural future?
Maybe not for you. But your children?
Recent climate change science suggests that’s a different story.
Climate change — warmer temperatures and later fall freezes, in this instance — is expanding the amount of land nationally and regionally suitable for double cropping, according to a Stanford University study released last year.
The amount of land suitable to grow winter wheat followed by soybeans could double or triple by the end of the century, the report published in Environmental Research Letters in January 2015 said.
To be “suitable,” the study’s researchers determined the crop’s environment would need at 750 milimeters of rainfall per year and a 75 percent likelihood that both crops would survive the harvest.
Farmers in southern Pennsylvania have already seen some of that, said Andrew Frankenfield, an agricultural educator with the Penn State Extension. Farmers in that area sit roughly along the border where double cropping becomes less feasible, but temperature changes have led to shifts in growing habits over the last decade, he said.
“We’re definitely seeing (corn) farmers shortening their day lengths,” he said.
The report, by then-doctoral student Christopher Seifert and professor David Lobell, found that between 1988 and 2012, suitable land for double cropping grew by 28 percent due to warmer temperatures and later fall freezes. Their prediction models mirrored those numbers.
Applying its model to two climate change scenarios, the study said the amount of suitable land would likely grow until 2060, spike sharply between 2060 and 2080 and slow through 2100 as increasing temperatures made the South less hospitable to double cropping due to a lack of cold winter temperatures for winter wheat.
While double cropping would come with increased costs for northern Maryland and southern Pennsylvania farmers, it would most likely be more profitable as well, Frankenfield said. But the study’s authors said the costs of climate change would eventually outweigh the benefits for growers.
“In the United States, double cropping can potentially make agriculture more resilient to climate change by improving overall productivity and by increasing farmers’ annual incomes,” Seifert said in a statement. “But the gains from double cropping will probably not be able to make up for the overall drop in crop yields that we expect to see with future climate change.”