The US Corn Belt is in ‘uncharted territory’ as experts focus on 2 key weather factors

Farmers in the United States kept hoping and waiting for dry stretches and warmer weather that would make up for the rain and flooding that delayed planting for so long earlier this season. The last things they want now are a colder-than-normal September and an on-time or, even early, frost.

After a cool week this week, AccuWeather meteorologists forecast temperatures to be near normal for early September and slightly above normal for the rest of the month, with rainfall totals normal or slightly below normal throughout.

However …

“The Crop Progress reports suggest corn and soybean crops over much of the Midwest continue to run on average one to two weeks behind schedule and are running out of time to catch up before the cooler air of autumn sets in,” said AccuWeather senior meteorologist Jason Nicholls. “This makes them more vulnerable to frost and even an on-time frost could cause at least a little damage to both crops this year.”

AccuWeather asked several experts throughout the industry about frost and its possible impacts on crops in this difficult season.

“Corn and soybeans are both susceptible to frost,” David Dyson wrote to AccuWeather. He’s the agronomist for The Andersons, Inc., an agriculture-related company involved in commodity training, among other operations. “While traveling around and talking to producers this year, 1974 keeps coming up. That year, we had a late spring and an early frost resulting in a wet and light test weight corn crop.

“When soybeans encounter an early frost, they just stop growing and their seed will start to dry down,” Dyson continued. “This results in significantly smaller soybean seeds … which can lead to a 20-bushel-per-acre reduction in yield.”

AccuWeather meteorologists believe the risk of an on-time frost this year is a little greater than normal. The first frost normally arrives in the Dakotas and western Minnesota in late September, in southern Iowa through southern Wisconsin in early October and in central Illinois by the middle of October.

“We’re in uncharted territory with so much of the corn and nearly all of the soybeans planted in late May or sometime in June,” Emerson Nafziger, professor emeritus of crop sciences at the University of Illinois, wrote to AccuWeather. “Best case [scenario] is that it will be warmer than normal during September and not frost before October 29, which would allow the majority of the corn crop to reach maturity. If temperatures are normal from now on and frost isn’t early, most of the crop will get to – or close to – maturity.”

Nebraska farmer Edwin C. Brummels, in the agricultural industry since 1981, has seen the damage frost can cause. “Frost can be variable in intensity and results,” Brummels wrote to AccuWeather. “A light frost typically isn’t as devastating as if we would get several hours of below 30 degrees. I believe it is 4 hours at 28 degrees usually means game over. So, it’s dependent on severity – it can be just some top leaves dying off prematurely to the plant shutting down completely.

“Yield losses on corn are dependent on the stage of maturity,” Brummels added. “There could be anywhere from 5 to 25% yield loss if we have a frost the second or third week of September…. Soybeans have to finish to achieve optimal yield. A frost the second or third week of September could result in 10 to 30% yield losses, dependent on variety and planting date. It’s hard to say which is more at risk, as probably there are many acres of both that will have reduced yields unless we don’t see a killing frost until approximately October 10.”

AccuWeather estimates corn production will be 13.28 billion bushels and soybean production will be 3.8 billion bushels.

The U.S. Department of Agriculture (USDA) World Agricultural Supply and Demand Estimates (WASDE) report has corn production at 13.90 billion bushels and soybeans at 3.68 billion bushels.

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