NDSU Extension - Ramsey County


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November 1 Agriculture Column


The weather turned out better than expected however we received more than any of us wanted. When ever they talk about up to 10 inches of snow possible makes me quiver.  So, we can be thankful for what we received in the immediate lake region.  I have heard unofficial reports of near three inches in the Edmore area and that is really just what they needed, just kidding.  We are really getting Devils Lake set up for a big rise next spring, depending on snow amounts over the winter.  The harvest had been going very well and even with that said we are around one half done with the corn maybe a little better.  The corn looks very good this year, what a treat compared to other years.  Talking about corn I have included some storage issues with outside storage of corn from Ken Hellevang.

Storage Management for 16-20% Moisture Corn


Corn harvested at moisture contents up to 20 percent moisture can be safely stored over winter with aeration. Corn at 20 percent moisture has an allowable storage time of about 25 days at 60 degrees, 50 days at 50 degrees, 90 days at 40 degrees and over 300 days at 30 degrees.


Even corn at 16 percent moisture should to be cooled as soon as possible to enhance storage life. Corn at 16 percent moisture has an allowable storage time of about 70 days and 70 degrees, 120 days at 60 degrees and 230 days at 50 degrees.


To enhance the storage life of the corn, cool it as soon as is possible. Allowable storage time charts are available at http://www.ag.ndsu.nodak.edu/abeng/postharvest.htm


Running the fan 24 hours per day will cool the corn to roughly the average outdoor air temperature. If the daily high is 60 degrees and the low is 35 degrees, the average is about 48 degrees. Running the fan just during the coolest 15 hours of the day will permit cooling the corn to a lower temperature, but will take longer. The final temperature operating the fan from about 7 p.m. until about 10 a.m. might be about 42 degrees, assuming a high of 50 and a low of about 35 degrees during the fan operation. Even though this difference seems small, a ten-degree decrease in grain temperature will roughly double the allowable storage time.


The time required to cool the corn can be estimated by dividing 15 by the airflow rate. For example, an airflow rate of 0.2 cubic feet per minute per bushel (cfm/bu) will cool the corn in about 75 hours, 15/0.2. This could be during 5 nights operating the fan 15 hours per night or during 3 days operating the fan 24-hours per day.


Once the corn has been cooled, the fan can be turned off until the next cooling cycle. Corn should be cooled to about 20 to 25 degrees for winter storage.


Without aeration corn should be placed into storage at 60 degrees or cooler and the temperature monitored closely. Respiration heating and solar heat gain on the bin may cause the grain temperature to increase. Allowable storage time is based on the kernel temperature and is reduced by about 50 percent for each 10-degree increase in kernel temperature. The allowable storage time for 17 percent moisture corn at 60 degrees is about 75 days and 18 percent corn is about 50 days at 60 degrees.


Moisture migration will occur when the grain temperature is more than 20 degrees warmer than outdoor air temperature, so is more of a problem in bins without aeration for cooling the grain. Convection currents will flow down the bin wall and up through the center of the bin causing moisture increase in the top center of the stored grain.  Be prepared to move the grain if problems develop.


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