A recent report in the scientific journal Nature said changes in climate are costing U.S. producers $11 billion in lost yield.

The report, titled “Climate-induced reduction in U.S.-wide soybean yields underpinned by region- and in-season specific responses” was developed by a number of university soybean specialists and agronomists across the U.S.

The study’s authors estimated that Minnesota farmers saw a gain of about $1.7 billion over the past 20 years while Missouri farmers experienced smaller yields, reflecting a $5-billion opportunity cost.

“Our data highlight the importance of developing location-specific adaptation strategies for climate change based on early-, mid- and late-growing season climate trends,” the researchers concluded.

Soybean yields have increased across the U.S. the past couple decades, gaining about a third of a bushel a year. But the report suggests the gains would have been 30% greater if high temperatures and changing rainfall patterns had not been so unfavorable to soybean yields. The U.S. experienced a warming trend during the normal summer growing season from 1994 to 2003. Rainfall patterns also changed, with more falling in the spring and fall, but less in June, July and August.

University of Wisconsin researchers Spyridon Mourtzinis and Shawn Conley compared soybean yields in 12 soybean-producing states to month-by-month temperature and rainfall changes. They reported that soybean yields declined about 4.3% for every 1°F rise in average growing-season temperatures. Yields also dropped when May, July and September were wetter than normal and June and August were drier.

So how did climate change impact Illinois producers? According to the study, Illinois producers lost the least, only 1.9 lbs. per acre per year. So over 20 years Illinois producers lost about 40 lbs., or two-thirds of a bushel. Over that same period of time, at a genetic yield rate of gain of two-thirds bushels per year, Illinois producers gained 13 to 14 bushels. So they gained maybe 14 bushels but lost one bushel to climate change.

Our neighbors in Indiana and Iowa lost more, 8 lbs. per acre per year (2.7 bushels over 20 years) and 7.4 lbs. per acre per year (2.5 bushels over 20 years), respectively. While growers in Ohio and Missouri lost 19.7 lbs. and 30 lbs. per acre per, or 6.5 and 10 bushels, respectively. So Illinois is faring very well.

Over the same two-decade period Minnesota gained an additional 4.5 lbs. per acre per year or an additional 1.5 bushels on top of the 13 to 14 bushels added by genetic yield gain. Weather and climate in Minnesota are more favorable to soybean production.

Conley stated “We were able to leverage decades of measured—not estimated—yield data from across the country to account for agronomic and genetic yield advances and to isolate the impact of climate change on soybean yield and yield gain.”

Jim Specht, soybean scientist and professor emeritus at the University of Nebraska added, “This shift is a reflection of the impact of global warming. Due to warmer springs and falls that allow for longer growing seasons in the Dakotas and southern Canada, soybeans now are being grown in places where in the past they could not be grown.”

Agronomist Dr. Daniel Davidson posts blogs on agronomy-related topics. Feel free to contact him at djdavidson@agwrite.com.

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About the Author: Dan Davidson

Soybean agronomist Daniel Davidson, Ph.D., posts blogs on topics related to soybean agronomy. Feel free to contact him at djdavidson@agwrite.com or ring him at 402-649-5919.