Small Town News

Watch for frost damage in corn crops

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This week's freezing temperatures have ended the growing season for most of the Minnesota landscape, according to Dr. Mark Seeley, University of Minnesota Extension cli-matologist. While the outlook does not seem to be critical for crops which have reached maturity, some corn may be affected.

"The majority of the corn in Minnesota is at or beyond the 'half-milk' stage, and most of it in southern Minnesota is at or very close to maturity," Dr. Jeff Coulter, a corn specialist in Extension, stated. "A hard killing frost at the half-milk stage could reduce final grain yield by eight to 12 percent. However, the impact of frost on corn yield decreases as the crop gets closer to maturity. Com is mature when there is no visible milk line and a black layer is present just under the tip of the kernel. For corn that is nearly mature, a killing frost will have little impact on grain yield." 1 Coulter and Seeley agree that corn prematurely killed by a frost will dry in the field at a rate that is similar to com that reaches maturity before a frost.

Seeley added, "The cold may even spur faster field dry down rates so farmers won't have to spend so much money on drying."

On average, we can expect a drying rate of 0.5 to 0.25 percent per day between October 6 and 15, and 0 to 0.33 percent per day between October 16 and 31 in Minnesota.

The grain moisture of com naturally drops as the crop matures, but com grain that is prematurely frozen and at a high moisture level will need sufficient sun and wind to facilitate in-field drying. This is particularly important, as there is a lot of moisture in the cobs of frost-damaged corn. Sometimes the husks on these plants do not loosen as well as normal.

In cases of early frost damage on less mature corn, different management of the crop may need to take place. University of Minnesota Extension has created a website for com and soybean producers who are dealing with frost. The website can be found at www.extension.umn.edu/frost.



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© 2010 Lafayette Nicollet Ledger Lafayette, Minnesota. All Rights Reserved. This content, including derivations, may not be stored or distributed in any manner, disseminated, published, broadcast, rewritten or reproduced without express, written consent from DAS.

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