Remember to keep corn in bins cool as it starts to warm up outside, says Ken Hellevang, NDSU Extension agricultural engineer.
He says rising outdoor temperatures and solar radiation can quickly warm stored corn,
"Keep corn temperatures near or below 30 degrees by aerating the corn periodically when outdoor temperatures are below 30 degrees to enhance storability," he advises.
Don't rely on air temperature to determine when to aerate corn. Warming of the grain normally will be limited to a couple of feet near the bin wall and a few feet at the top of the bin. Hellevang recommends monitoring grain temperature in these locations to determine when to operate the aeration fan.
Bin temperature cables help monitor grain temperature but only detect the temperature of the grain next to the cable. Grain has an insulation value of about R-1 per inch, so grain insulates the cable from hot spots just a few feet from the cable.
Other advice on aerating corn:
- Do not operate the fan during rain, fog or snow to minimize blowing moisture into the bin.
- Bin vents may frost or ice over at temperatures near or below freezing, so leave the fill hole or manhole open or unlatched while operating the fan to prevent damage to the bin roof.
- Cover aeration fans when they are not operating to prevent wind from warming the corn. Wind blowing into an uncovered aeration fan or duct will aerate the corn, warming it to temperatures near the daily maximum. This occurs because more wind tends to blow during daylight hours than at night.
- Corn at moisture levels exceeding 21% should be dried in a high-temperature dryer during February or early March to minimize the potential for grain deterioration. Natural air drying is not efficient until the average outdoor temperature reaches about 40 degrees, which normally occurs in early April. The moisture-holding capacity, and therefore the drying capacity, of colder air is so limited that drying at colder temperatures is extremely slow.
For more information about corn drying and storage, do an Internet search for NDSU corn drying or go to the NDSU Web site www.ag.ndsu.nodak.edu/abeng/postharvest.htm.
Source: NDSU Extension Communications