For some, harvest time is just around the corner, so producers need to prepare their storage bins, according to Ken Hellevang, North Dakota State University Extension Service agricultural engineer.

""Grain quality can be maintained in storage bins if managed properly,"" Hellevang says. ""It is a wise investment of time to spend a few hours maintaining a bin for the $40,000 to $80,000 worth of stored grain in each bin."

He recommends these steps for preparing a bin for storage:

• Repair any holes that may allow water to enter. Look for holes by looking for sunlight coming into the bin. However, do not seal openings intended for aeration.
• Clean the inside of the bin using brooms and/or a vacuum.
• Examine the inside of aeration ducts for debris and insects.
• Service the aeration ducts, fans and vents to ensure proper operation.
• Clean around the outside of the bin.

Grain stores best when it is dry, clean and cool. Weed seeds and fine foreign material, which usually are wetter than the grain, will accumulate in the center when loaded into a bin, which can cause storage problems. This material should be removed from the grain by using a grain cleaner or other methods before storage.

Temperature plays an important role in grain storage. The optimum temperature for insects is between 70 and 90 degrees, so grain should not be stored at this temperature. Cooling below 70 degrees reduces insect reproduction and feeding activity. Cooling below 50 degrees causes the insects to become dormant.

The optimum temperature for mold growth is about 80 degrees. Mold growth is extremely slow below 30 to 40 degrees. The expected grain allowable storage time is approximately doubled for each 10 degrees that the grain is cooled.

Aeration should be used to cool the grain whenever outdoor temperatures are at 10 to 15 degrees cooler than the grain. For winter storage, it should be cooled to a temperature of about 20 degrees in northern states and 30 to 40 degrees in southern states.

""The time required to cool grain weighing 56 to 60 pounds per bushel using aeration can be estimated by dividing 15 by the airflow rate,"" Hellevang says. ""For example, the grain will cool in about 75 hours using an airflow rate of 0.2 cubic feet per minute per bushel. Air takes the path of least resistance, so cooling times will vary. Measure grain temperature at several locations to ensure that all the grain has been cooled."

Stored grain must be monitored, so insect infestations or grain spoilage can be detected before serious losses occur. Check stored grain biweekly during the critical fall and spring months, when outside air temperatures change rapidly, and during the summer. After the grain has been cooled to winter storage temperature, check the grain at least monthly. Check and record the grain temperature and condition at several locations.

The 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.

""Bring a grain sample indoors if the grain temperature is below 50 degrees and allow it to warm to room temperature,"" Hellevang says. ""Place the grain on a white surface and examine for any insect activity. Fumigation is not recommended when grain is stored at temperatures below 60 degrees. However, most storage problems can be controlled during the winter by cooling the grain."

More information about dry grain aeration, handling and storage is available at http://www.ag.ndsu.nodak.edu/abeng/postharvest.htm.

Additional information is also available in The ""Dry Grain Aeration Systems Design Handbook"" and ""Grain Drying, Handling and Storage Handbook"" which can be purchased through the MidWest Plan Service. These publications can be purchased separately or as a set, along with ""Managing Dry Grain in Storage"" and ""Low Temperature and Solar Grain Drying Handbook,"" for $40. For more information, go to http://www.mwps.org, e-mail mwps@iastate.edu or call (800) 562-3618.

NDSU Agriculture Communication