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Tuesday, April 03, 2012

Has Your Stored Grain Spoiled In The Warm Spring Weather?


In the middle of field work and corn planting, have you bothered to check your grain bins?  Oooops.  The warm spring weather, with temperatures in the 80’s across the Cornbelt, may have wreaked havoc with the quality of your grain.  Moisture and temperature are quite dynamic in a grain bin, traveling daily and creating opportunities for spoilage and fostering the growth of molds and insects.  So while you are occupied in the tractor seat, let your aeration system work for you, but you have to give it a kick-start.

If your grain went into the bin last fall at a moisture content that was higher than desirable, or for some reason did not stay cool over the winter, it should probably be at the top of your priority list this spring.  Losing a bin full of grain is financially equivalent to intentionally destroying your planter or a tractor.  North Dakota State University grain storage specialist Ken Hellevang says as the temperature increases, grain moisture content must decrease.  In his recent fact sheet he says corn at only 17% moisture will only survive 20 days of 80º temperatures.  The cooler the temperature the longer the shelf life, but Hellevang says shelf life is cumulative, and some of it was used up last fall, some over the winter, and much more this spring.  He says your goal should be to keep grain at 40º or below.

If it was stored a bit on the high side for moisture last fall, it needs to be monitored and kept cool with aeration fans when the outside air temperature is below 40º until it is dried.  At higher temperatures, air drying will help the grain spoil faster, and putting 70º air on your wet corn will help it spoil faster than it will be able to cool off.  If the air was abnormally warm when your fans were running, keep them running when the temperature is in the 50’s and 60’s.  He says the required airflow rate increase with warmer temperatures and moisture content.

The spring sun on the south side of bin will cause an uneven heating of the grain, but will also cause the airspace at the top of the bin to be warm and heat the top layer of grain.  But he says your objective is to keep the grain cool and below 40º in the spring.  Close monitoring will help detect early problems, including insect infestations.

For summertime storage, corn needs to be 13 to 14% and beans at 11% moisture.  Ensure your moisture tester is properly calibrated and remember that grain temperatures below 40º will not always give proper readings. Corn above 21%should be dried with a high temperature drier, with an airflow of at least one cfm per minute.  He says start drying when the air temperature averages 40º, since it will not dry much below that temperature.

If temped to run the fan only at night.  He says running the fan when the air is warm and shutting it off at night will dry the corn less than desired, “The grain above the drying zone will be warmer if the fan is run just during the warm portion of the day, which will cause the grain to deteriorate faster. And even though the warm air may hold more moisture, the drying time is still almost twice as long because the fan is operating only half of the day.”

A warm spring may have created problems in grain bins, if moisture levels were not as low as they should have been.  Grain has a limited storage time, which is reduced at warmer temperatures and higher moisture levels.  Stored grain temperatures increase in the spring due to rising outside temperatures and should be regularly monitored for mold and insect problems.

Posted by Stu Ellis on 04/03 at 01:30 AM | Permalink

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