Minnesota's grain harvest is in full swing, but it's not too late to review on-farm grain storage principles. There are four simple steps to maintain post-harvest quality: sanitation, loading, aeration and monitoring the grain.
Sanitation. Be sure that the storage structure and grain-handling equipment (conveyors, wagons, trucks, elevators) are clean and keep outside areas clean. A common rule-of-thumb is, "If you can tell what has previously been in the bin, it is not clean." Debris and grain spills outside the bin encourage rodents and insects. Keep weeds from growing around bin areas--these sites are ideal for pests to hide.
Combining and loading into storage. Grain harvested with a clean and properly adjusted combine should also be run through a grain cleaner to further remove fine materials, which make life easier for molds and insects. In addition, a grain distributor is extremely helpful--it spreads fine material uniformly across the grain mass.
When loading, you want to create a grain mass that's clean, dry and uniform--without foreign material. Immediately after the bin is filled and the grain is level, apply an approved grain protectant to help control insects that enter through roof openings. Use a grain protectant if storing grain for one year or more.
Aeration. In the fall, and with any bin that holds more 2,000 to 3,000 bushels, aerate to cool the stored grain and create a better storage environment. Those who grow field crops should be able to cool grain to temperatures below 50 degrees F by gradually cooling through the fall. Insect activity is reduced at this temperature. Keep grain temperature lower than 50 degrees F at all times of the year. Aerate to cool grain to 20 to 30 degrees F for winter storage.
When aerating dry grain, about 0.1 cubic feet of air per minute per bushel of grain is recommended. When natural-air drying grain, allow four to six weeks, depending on the weather and initial crop moisture. For more detailed information, see the Extension publication "Grain Storage Tips" at www.extension.umn.edu/distribution/cropsystems/M1080-FS.pdf.
Monitoring. Check stored grain regularly for temperature, moisture, insects and molds. Inspect stored grain every seven to 14 days when either outdoor or grain temperatures are higher than 50 degrees F. If the grain is in good condition and has been cooled to less than 30 degrees, you can increase the inspection interval to once every three to four weeks during cold weather.
- Dave Nicolai is a crops educator with University of Minnesota Extension.