Wet grain causing storage, mold concerns for farmers
The wet conditions of the 2009 corn harvest presented challenges for farmers and those difficulties still have not come to an end.
"Because the harvest was so unique last fall, we were doing things that we hadn't done in a long time," says Purdue University Extension ag engineer Richard Stroshine. "We were harvesting corn a lot later, and at higher moistures and some of it had disease in it. Because of that, there is the potential for some problems to develop."
The higher harvest moisture content and ear rot damage make it likely there is more fine material in grain bins.
"Fine material tends to collect in the center of the bin when the grain is dumped into the bin, even with a centrifugal spreader, and those high concentrations can cause some real problems," Stroshine says in a university report. "Usually farmers want to aerate the grain to control the temperature and take the grain down to a cool temperature for holding it over the winter. Fine materials interfere with that aeration process."
One solution to the issue of fine materials is for farmers to core their bins, or remove the fine materials by opening the center wells of the unloading augers to start pulling corn from the center.
"In bins with flat bottoms, the nature of the flow is such that most of the corn is pulled out from a little column above the unloading auger first, which is right where the fine material is concentrated," Stroshine says. "A lot of farmers already are doing that, but I want to make sure that everyone understands if they haven't done it already, they should do it immediately."
Another issue that can interfere with aeration is having corn peaked in the bins.
"If there's a peak in the bin, it's going to be right above the center core where there is more fine material, so that makes the aeration problem worse," Stroshine says.
Fine materials not only interfere with aeration, however. They also tend to contain more pieces of diseased or moldy kernels.
"If there was ear rot damage to the corn, there are generally higher levels of toxins in the fine materials than in the whole kernels," Stroshine says. "In a year like this, and especially if farmers have problems with ear rot, there is another advantage to getting rid of the fines. By getting rid of them the farmer can often, although not always, reduce levels of mycotoxins in their corn."
Stroshine also reminded farmers that it is essential to check corn in the bins for moisture and mold problems.
"Most farmers probably are checking their corn, but again, I want to remind them that they need to be out there every couple of weeks during the remainder of winter, and when it starts warming up they need to at least be looking inside their bins every week," he says. "Do they smell anything unusual? Do they see any evidence of discolored kernels on the surface of the bins? Is there condensation on the roof or walls? Does anything look out of the ordinary?
"I've already heard of some farmers who have found a layer of moldy corn on the tops of their bins. It's still winter, which means there was a spot of wet corn in the bin. That wet corn starts heating up because of mold activity. Mold activity generates warmth and that warm air rises up to hit the cold roof of the bin. The combination of warm air and cold bin roof causes condensation, which drops back down to the surface of the grain. Since that re-wets the corn on the surface, it starts molding. Sometimes it can happen even if it's cold, because some fungi can grow on wet grain a few degrees below freezing."