New Research Finds Some U.S. Soybean Yield Losses Caused by Weather Variations

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COLUMBUS, Ohio – Researchers have determined that precipitation and temperature variations over the past 20 years have suppressed the U.S. average soybean yield gain — how much it improves every year — by around 30 percent, contributing to an industry loss of $11 billion nationwide.

In Ohio alone, that soybean yield suppression is estimated to have cost some $2.9 billion during the past 20 years, according to a new study co-authored by a field crops expert in the College of Food, Agricultural, and Environmental Sciences at The Ohio State University.

Global annual temperatures have increased by 0.4 C (0.72 F) since 1980, with several regions exhibiting even greater increases, said Laura Lindsey, a soybean and small grains specialist with Ohio State University Extension and a co-author of the study. OSU Extension is the college’s outreach arm.

And for every 1 C (1.8 F) rise in temperature during the growing season, soybean yields fell by about 2.4 percent, the study found.

In Ohio, that translates into about a third of a bushel per acre per year yield loss, Lindsey said.

“During the past 20 years, temperature and precipitation have been changing, and that change is associated with yield reductions and economic loss that is region-specific,” she said. “States including Ohio, Illinois, Kentucky, Indiana, Arkansas, Missouri, Iowa and North Dakota have experienced negative impacts on yield due to weather variables.

“Missouri suffered the most negative impact with an estimated loss of $5 billion during the past 20 years, while Ohio had the next highest loss, at $2.9 billion.”

The study, which appears in the February 2015 journal Nature Plants, was co-authored by James E. Specht, researcher with  the University of Nebraska; and Spyridon Mourtzinis, Francisco J. Arriaga and Shawn P. Conley, all researchers with the University of Wisconsin-Madison.

The study is based on data gleaned from 12 states, including data from Ohio State researchers’ Ohio Soybean Performance Trials, which document temperatures, changes in cultural practices, soybean varieties and technology in soybean production from 1970 to the present, Lindsey said.

The U.S. is one of the world’s largest soybean exporters, with some 80 percent of its soybeans being grown in the upper Midwest. Since most of that production is not irrigated, soybean production in the region is highly affected by weather conditions during the growing season, according to the study.

While more state-specific research is needed to help mitigate some of the weather variability, according to the study, some crop management strategies could help limit the potential negative impacts of weather variations on crop yields.

“Strategies include the development of new cultivars and hybrids, the use of altered maturity groups, changes in planting dates, the use of cover crops, and greater management of crop residues from the previous year,” Lindsey said. “If we don’t develop strategies to mitigate weather variability, it could have a long-term impact on soybean farmers, the soybean industry, trade policy, consumer food prices, food security and the economy.”

The study’s other contributors and co-authors include William J. Wiebold,  University of Missouri; Jeremy Ross,  University of Arkansas; Emerson D. Nafziger,  University of Illinois; Herman J. Kandel,  North Dakota State University; Nathan Mueller,  South Dakota State University; and Philip L. Devillez, with Purdue University.

Tracy Turner
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Laura Lindsey