A mammoth summer storm this week whipped up winds in excess of 100 MPH, flattening corn from western Iowa, through the central Corn Belt, into Michigan and north into Canada. Thousands of acres were affected, sources say. See how some fields were affected and what kind of yield losses can be expected.
Jon Edler stands in one of his corn fields damaged by the storm. Edler estimates about half of his corn suffered greensnap after high winds blew through.
Here's another view of Edler's snapped-off corn. "Corn is most susceptible to greensnap prior to tasseling, when it is rapidly growing," says Iowa State University Extension agronomist Roger Elmore. "We've learned from previous greensnap events in Iowa and Nebraska that yield loss is directly related to the amount of stalk breakage that occurred. In other words, yield loss from broken plants is directly related to stand loss."
Some hybrids handle greensnap better than others, Elmore adds. "Several companies provide growers with greensnap ratings that may prove useful in selecting less susceptible hybrids. Stage of growth affects breakage too as mentioned above. Factors that increase early season growth tend to increase breakage susceptibility, such as high N, P and K rates; spring-applied N; tillage; and high organic matter,” he says.
Edler's bins weren't the only ones damaged by the storm. This bin sits just outside Marshalltown in Marshall County, Iowa.
"I never thought I'd live to see a storm that rivals the 1998 storm that had 100 MPH winds in a 20-mile-plus swath over 100 miles long," says ISU Extension field agronomist in Iowa City, Iowa, Jim Fawcett. He estimates 100,000 acres of corn were affected in half a dozen Iowa counties.
One difference in this year's storm is the timing: The 1998 storm hit in late June when corn plants were more susceptible to greensnap damage. "Most of the corn is in the V14-V18 stage now, so less subject to green snap. The heavy downpours that occurred at the same time may have also helped by saturating the topsoil and allowing roots to shift rather than breaking stalks," Fawcett says.
Yield losses in affected fields, like this one in north-central Illinois, will probably end up around 20%, Fawcett says. The biggest thing to do if you were affected now is to check to see if your insurance policy will cover the damage you incurred. "Many policies do not cover wind, or if they do, it is only covered if there is greensnap," he says.
If you have a multi-peril crop insurance policy, you are likely covered. "However, the potential loss in one or several corn fields will not likely be known until harvest," says ISU Extension farm management specialist Steve Johnson.
Will the markets take note of the losses? "In the real scheme of things, the wind storm has little effect on things," says Agriculture.com Marketing Talk member frankne.