Last year's crop came in cold, wet and late. With cash corn prices struggling to gain strength, much of that crop is still in the bin and as winter drags on, grain quality can begin to suffer. Ken Hellevang from North Dakota State University Extension (NDSUE) notes, "The early snow, cool fall and early cold winter temperatures made 2013 a challenging year for corn and sunflower harvest. Some grain went into storage at higher than recommended moisture contents, and that increases the likelihood of storage problems.”
The first concern is for temperature. Northern states should store grain at 20 to 30°F while parts south must keep grain below 40°F. Insects are dormant below 50°F and maximum storage potential doubles with each ten degrees grain is cooled. However, condensation can form during aeration if corn is cooled below 20°F.
Solar energy can also play a surprising role in the health of stored grain and studies have shown that on February 21 in any given year, the daily total solar energy heating on the south sides of grain bins is more than twice what it is in July. That means grain near bin walls and at the top of the bin could be warmer even than the actual outside air temperature. Grain temperatures should be monitored in those locations, but grain has a high insulation rate and a 'hot pocket' just a few feet away may not show up in a single measurement.
The recommendation is for a number of temperature samples at different spots in the bin.
Grain moisture meters are unreliable at best for grain under 40°F and unless your meter makes adjustments for temperature, samples will have to be warmed before a solid reading can be taken. Corn above 21% moisture must be dried before the end of February to minimize the risk of moisture related problems.
Hellevang continues, "Natural air drying is not efficient until the average outdoor temperature reaches about 40 degrees. The moisture-holding capacity and, therefore the drying capacity, of colder air is so limited that drying at colder temperatures is extremely slow and expensive. When natural air drying, adding supplemental heat primarily reduces the final moisture content of the grain and only slightly reduces drying time."
Do not operate the fan during rain, fog or snow as this may blow more moisture right into the bin. Always cover the aeration fan when it is not in use to keep pests and moisture out.
Remember safety first. Wet stored grain increases the risk of personal injury or death, especially if the grain bridges, is attached to the walls or forms columns, all of which can easily and unexpected collapse, leaving you or your help buried and in a dangerous position.
NDSUE recommends, "Read NDSUE publication “Caught in the Grain!” (available at http://tinyurl.com/caughtingrain) and view one of the online videos on the hazards of grain entrapment for specific information on the dangers and rescue procedures.
Crop returns are much too low to take chances with grain storage. Take stock of your stored grain today while there is still time to correct problems that could make your crop unmarketable. Click here for more from Ken Hellevang and North Dakota State University Extension on winter grain storage considerations and always remember, safety first.