Chicago | Reuters –– Maturing corn and soybeans in the northern U.S. Midwest may see an early freeze this weekend that could damage crops still far behind in development, with agronomists saying this year’s record harvests may be trimmed.
Minnesota, South Dakota and Wisconsin crops are immature after late planting and a cool summer, raising the risk of freeze damage, even though the world’s biggest producer of grains is still on track for record corn and bean harvests.
The U.S. Agriculture Department on Thursday updated monthly production estimates above last month’s record projections, pressuring Chicago grain futures prices, which set new four-year lows on Thursday.
“The risks are high that a fair amount of acres in those three states would certainly be vulnerable to a lethal freeze,” said Bob Nielsen, Purdue University agronomist.
In South Dakota only one per cent of corn had reached maturity by Sunday while no corn in Minnesota or Wisconsin had. That points to a frost risk for 2.6 billion bushels of corn, or about 18 per cent of the projected U.S. crop.
While the outlook for the severity of the freeze has eased since the start of this week, forecasters on Thursday were calling for temperatures to dip to the low 30s F by the weekend for the Dakotas, Minnesota, northern Iowa and western Wisconsin.
Joel Widenor at Commodity Weather Group said Saturday morning would be coldest and temperatures are expected to dip in southeastern Minnesota, central and northeast Iowa and western Wisconsin.
A killing frost is defined as temperatures falling below 28 F for at least a couple of hours. At that point the plants shut down, halting kernel and pod filling.
The first killing frost in Iowa, the top corn state, usually comes in mid-October while the Dakotas, Minnesota and Wisconsin see one a week or two earlier.
“Normally it wouldn’t be a problem but right now we’re behind normal heat units,” said Iowa State University agronomist Mark Licht. “The forecast in the coming week doesn’t give me too much encouragement.”
Soybean development also lags but those plants are sensitive to shorter days and speed up maturation. For soybeans, the bigger concern from any cold is lower quality soybean oil.
Widenor said, however, “The chance of a damaging event still seems very low.”
Most grain traders were skeptical a frost would dent the supply outlook, given bumper crops on the way.
“We will lose some bushels up north; it’s very cold in Wisconsin, North Dakota and Minnesota. But those losses will certainly be offset in Illinois, Iowa, Indiana and Nebraska, where the yields are just huge,” said grains analyst Mark Gold at Top Third Ag Marketing.
“I would expect prices to make their lows maybe in the first week of October and then maybe see a little bit of a rally,” he added, with a prolonged early freeze among “the only reasons to experience a bounce in the market.”
— Christine Stebbins reports on agriculture and ag markets for Reuters from Chicago. Additional reporting for Reuters by Michael Hirtzer.