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Check last year's damp stored corn now

In last fall's mad dash to get the corn crop in the bin, did you store it away a little on the wet side?

If you did, you're not alone. And, you're not out of the woods just yet: The "active period" for grain spoilage is almost upon us, and now's the time to check that stored grain and move it or make other changes if you see signs of spoilage.

"This type of corn has roughly half the storage life of normal corn under the same moisture and temperature conditions," Iowa State University (ISU) Extension ag engineer Charles Hurburgh says of the largely wetter-than-normal corn that was put in storage last fall. Some grain was stored with moisture levels up to 24%, he adds.

Already, the grain's incurred some damage if it wasn't put away under the right conditions. "Corn in bins that were aerated and monitored to stay below 30 degrees Fahrenheit and that had the center cores removed are generally in good condition, while unaerated bins and piles have gone already to 75% to 100% damaged kernels," Hurburgh adds. "Use every opportunity to keep the grain cold. Take some grain out of every bin in the near future; this will indicate if there are problems starting."

Storage times for higher-moisture grain will depend a lot on temperature, according to North Dakota State University (NDSU) Extension ag engineer Ken Hellevang. The lower the temperature, the longer the storage capability.

"For 26% moisture corn, the allowable storage time (AST) for normal corn is about 90 days at 30 degrees, 35 days at 40 degrees and only 12 days at 50 degrees. For 22% moisture corn, the AST is about 190 days at 30 degrees, 60 days at 40 degrees and only 30 days at 50 degrees. For 20% moisture corn, the AST is very long at 30 degrees, is about 90 days at 40 degrees, and 50 days at 50 degrees," Hellevang says. "Immature, cracked and broken corn kernels are more prone to deterioration than good quality corn, so corn this year may be more prone to storage problems."

To get an accurate temperature reading, make sure you're monitoring in the right locations, Hellevang adds. "Warming of the grain will normally be limited to a couple feet near the bin wall and a few feet at the top of the bin. Monitor grain temperature in these locations to determine when to operate the aeration fan," he adds. "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 R1 per inch, so grain insulates the cable from hot spots just a few feet from the cable."

When aerating corn that's on the damp side this time of year, make sure your bin is well-insulated to prevent warmer air from outside during the daytime. That includes aeration fans, Hellevang says.

"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," he says. "This occurs because there tends to be more wind during daylight hours than at night."

Keep your eye on the mercury from now on, Hurburgh advises. Once the temperature of stored grain passes 30 degrees, anything still over 17% moisture will need to be dried or sold.

"Spoilage will happen rapidly," he says. "Natural air will work if the bin has 0.5 CFM/bushel or more of airflow and the moisture is less than 20%. Otherwise, use heated air."

Grain delivery points in areas where a lot of corn was binned on the wet side last fall will be watching for moisture-damaged grain, Hurburgh says. If you deliver to ethanol refiners or livestock feeders keeping your stored grain dry should be a high priority because of the wide spectrum of damage that can render grain unacceptable for either purpose.

"Ethanol plants are sensitive to mold damage; damage interferes with enzymes and fermentation," Hurburgh says. "Livestock feeders should consult nutritionists or veterinarians to screen damaged or blended corn for mycotoxins. Mycotoxins are not normally associated with storage but the combination of corn properties, high moisture, and less drying could create these issues in highly damaged corn."

The same applies if you're delivering to a commercial elevator. There's already a lot of wet, sometimes damaged corn in commercial storage, so blending to improve grain quality may not be as much of an option this year. If you're in an area where there was a lot of wet corn binned last fall, this may affect the timeframe for when you want to deliver your grain to a commercial terminal.

"All users are going to be on the lookout for poor quality grain this year. If you have very high moisture corn still in storage, above 22% moisture, plan to sell or dry it before the end of February," Hurburgh says. "The bottom line is act now to check, move or dry 2008 crop corn. This corn will be difficult to manage for the rest of the year. Damaged corn will be hard to market and will get worse quickly."

In last fall's mad dash to get the corn crop in the bin, did you store it away a little on the wet side?

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