With spring quickly approaching, farmers' thoughts are on the crop to come. But stored grain might need some attention.
Understanding the causes of storage problems is the first step, says Ken Hellevang, North Dakota State University ag engineer. Typically, he says, trouble comes from a combination of factors: poor initial grain quality, moisture migration, molds and insects.
Grain that went into the bin in less-than-ideal condition needs more intensive management. Broken seeds and damaged seed coats provide a ready avenue for molds and insects.
"If you have grain in bins that wasn't completely dried last fall, you'll need to dry it down to safe storage levels, especially if you plan to keep it stored long term," says Ed Browning, University of Missouri extension ag engineer. "If the grain has been damaged by harvesting or handling, dry it to at least one percentage point below the target levels for safe storage."
"Before the weather warms up much, sample grain to monitor both temperature and moisture content," Hellevang suggests. "Even a 10 degrees difference can affect the condition of grain in storage."
Monitoring moisture in cold grain can be a challenge, he adds. "Most electronic moisture testers are not accurate below about 40 degrees. You may need to pull a sample and bring it inside to warm up, then test the moisture content."
Use a temperature probe to measure variations within the bin and to find hot spots.
"Check the inside of the bin roof for any signs of condensation," says Hellevang. "Look for crusty, wet or frozen grain."
He likes to grab a handful of grain from the surface and another at arm's length in the grain.
"Smell the grain as well as look at it closely," he says. "Check for wet or discolored grain; for moldy or musty odors. If most of the grain in a bin is dry, but spots are wetter than they should be, you can remove that moisture by aerating the grain with natural air.
"If your bin's aeration system has an air-flow rate of about one cubic foot per bushel of wet grain per minute or greater, you can dry grain with natural air. But you need to know the moisture content. If the grain is above the safe storage moisture throughout the bin, you may need to remove the grain and run it through a high-temperature dryer, then recool it."
But for grain that is at or near safe storage moisture, do not use fans any more than necessary to warm the grain slightly and do any needed drying.
"Grain stores better at cooler temperatures, so you don't want to warm the grain too much," he says. "With dry grain, start the fans when the outside temperature gets above freezing and bring the grain back to 40 degrees or so."
There are two reasons for keeping grain as cool as possible:
1) When you run aeration fans, you add moisture with the air - even on low-humidity days.
2) The risk of insect and disease damage increases as grain is warmed above 50 degrees.
Through summer, continue to inspect stored grain regularly.
"Whenever you pull some grain out of a bin, relevel the grain on the surface," says Browning.
"Check again for localized hot spots or molds. You may need to aerate the bin again."