How much time would you be willing to spend to protect a $40,000 investment?
Grain producers need to consider that question every fall, said Ted Funk, a University of Illinois Extension agricultural and biological engineer.
"Harvest time will be here before we know it," said Funk, "and producers could be storing anywhere from $20,000 to $40,000 of grain in a 10,000-bushel bin. It's a wise investment of time to prepare the bin and the grain for storage."
Grain quality can be maintained in storage if it's managed properly, said Funk, and he suggested the following steps for preparing a bin for storage:
1) Repair any holes that may allow water to enter. Check for holes by looking for sunlight coming into the bin. However, don't seal openings intended for aeration.
2) Clean the inside of the bin using brooms and/or a vacuum.
3) Examine the inside of aeration ducts for debris and insects.
4) Service the aeration ducts, fans and vents to ensure proper operation.
5) Clean around the outside of the bin.
Grain stores best when it is dry, clean and cool, said Funk.
"Weed seeds and foreign material are usually wetter than the grain, and will accumulate in the center when the grain is loaded into a bin," Funk said. "That material should be removed from the grain. Use a grain cleaner before storage, then unload some grain using a center take-out after the bin has been filled or distribute the material while filling the bin."
Funk said temperature also plays an important role in grain storage.
Insects thrive at temperatures between 70° and 90° F," he noted. "Temperatures below 70 degrees reduce insect reproduction and feeding activity, and below 50° insects become dormant."
Lower temperatures also help control mold growth, said Funk. "Mold grows best at around 80°, but it's extremely slow below 30° and 40°. Allowable storage time is almost doubled for every 10° that the grain is cooled."
To cool the grain, Funk advised using aeration whenever outdoor temperatures are 10-15° cooler than the grain. The time required to cool grain weighing 56 to 60 lbs./bu. can be estimated by dividing 15 by the airflow rate.
For example," said Funk, "the grain will cool in about 75 hours using an airflow rate of 0.2 cu. ft./minute/bu. Air takes the path of least resistance, so cooling times will vary in the storage. You should measure grain temperature at several locations to assure that all the grain has been cooled."
For winter storage, grain should be cooled to a temperature of 20-30° in northern states, and 30-40° in southern states.
Finally, Funk recommends checking stored grain bi-weekly during the critical fall and spring months when outside air temperatures are changing rapidly.
"Monitor your stored grain so that insect infestations or grain spoilage can be detected before serious losses occur," said Funk.
After the grain has been cooled for winter storage, and after a storage history without problems, Funk said you should check and record the grain temperature and condition at several locations during the months when outside temperatures are below 40°.
"The temperature history can be used to detect grain warming, which may indicate storage problems," he said.
Condensation on the roof or crusting of the grain surface can also be indications of a problem, Funk said. In addition, "Probe to examine grain below the surface," he advised. "Bring a sample indoors if the grain temperature is below 50°, warm it to room temperature and then place it on a white surface and examine it for any insect activity."
Funk does not recommend fumigation at grain temperatures below 60°, and he said most storage problems can be controlled during the winter by cooling the grain.
Producers can obtain more information about dry grain aeration and grain handling and storage from the MidWest Plan Service. "Dry Grain Aeration Systems Design Handbook" (MWPS 29) and "Grain Drying, Handling and Storage Handbook" (MWPS 13), are available for purchase separately. Or, you can buy them as part of a package that includes "Managing Dry Grain in Storage" (AED 20) and "Low Temperature and Solar Grain Drying Handbook" (MWPS 22).
The four publications are an excellent reference set, Funk said, and are available for $40. For more information, go to www.MWPS.org, email mwps@iastate.edu or call 800-562-3618.