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Grain Management Vital this Fall

University of Minnesota Extension, Stearns County News
November 11, 2015         
Source:  Dan Martens, Extension Educator
University of Minnesota Extension
Stearns, Benton & Morrison Counties

Grain Management Vital this Fall
By Dan Martens, University of Minnesota Extension

FOLEY, Minn. (11/10/15) Managing stored grain can be a little more challenging with abnormal weather patterns. It’s important to understand the concepts, consider current weather trends and patterns, practice good observation skills, consider past experience, and apply some common sense. 

North Dakota State University Extension Service agricultural engineer Ken Hellevang recommends producers check the moisture content of the grain at a few locations in the bin because this will determine the management steps they need to take to preserve the stored grain. Dr. Hellevang recommends the following management practices:

Producers should follow the moisture meter manufacturer's recommendations to obtain an accurate reading. They can verify the meter's reading by warming the grain sample to room temperature in a sealed plastic bag or other sealed container before measuring the moisture content.

Here are other grain management suggestions from Hellevang:

• Check the grain temperature. Warm grain creates conditions conducive for insect infestations. Reducing the grain temperature reduces insect activity; insects in stored grain become dormant below about 50° F. In addition, the allowable storage time, which is related to mold growth, is approximately doubled for each 10 degrees the grain is cooled. For example, cereal grains such as corn at 16% moisture content can be stored about 70 days if maintained at 70° F and about 230 days at 50° F.

• Cool stored grain to near the average outdoor temperature during the fall using aeration. This minimizes migration and condensation in the grain. Grain temperature should be cooled to within about 20 degrees of the coldest average monthly temperature or at least below 40° F for winter storage. To estimate the cooling time of 56 pounds-per-bushel grain, divide 15 by the airflow rate. For example, about 75 hours of fan time is required to cool the grain using an airflow rate of 0.2 cubic feet per minute per bushel (cfm/bu).

• Check stored grain biweekly until it has been cooled to the winter storage temperature. Check and record the grain's temperature and condition at several locations. Temperature history can be used to detect grain warming, which may indicate storage problems. Look for indications of problems, such as condensation on the roof or crusting of the grain surface. Probe to examine grain below the surface.

Temperature cables are an excellent tool to measure the grain temperature, but they only measure the temperature of the grain next to the sensor. Grain is a very good insulator, so warm or hot grain just a few feet from the sensor may not be detected.

Open or unlatch the grain bin's fill or access cover during fan operation to serve as a pressure relief valve. Bin vents may become blocked by frost or ice if fans run when the outdoor air temperature is near or below freezing. The resulting air pressure may damage the bin roof. Cover the aeration fan when it is not operating to prevent pests and moisture like snow, fog and rain from entering the bin.

Hellevang says corn moisture content may be an issue this year. Corn at moisture contents up to 20% was harvested and placed in bins with natural-air drying fans sized to provide an airflow rate of at least 1.0 cfm/bu. Even though the outdoor temperature and relative humidity were conducive for drying during October, the drying zone may not have moved through all the grain. The estimated drying time for corn with a moisture content up to 20% is 30 to 40 days with an average air temperature of about 50° F, about 50 to 60 days at 40° F and at least 70 days when the air temperature is near 30° F.

The moisture-holding capacity of the air at temperatures below 35° to 40° F is small, so drying becomes inefficient using natural-air/low-temperature drying. Drying time also is related to the airflow rate, so at an airflow rate of 0.75 cfm/bu drying time is about 53 days rather than the 40 days at 1.0 cfm/bu (40 divided by 0.75).

Warming the air by about 5 degrees will allow producers to continue drying corn with the typically higher air humidity level that occurs in November if the outdoor air temperature is averaging at least 35° to 40° F, Hellevang says. Adding more heat causes grain in the bottom of the bin to dry to a lower-than-desired moisture content.

AND ALWAYS make SAFETY a priority in all grain handling and management work.


Daniel Martens
Extension Educator, Ag Production Systems
(320) 968-5077
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