Monitor grain bins closely this spring for moisture and mold

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.    

Storing dry corn on farm is riskier than normal this year for many farms in west central Michigan, especially if it is to be held into the late spring and summer months. Typically as the weather warms, it is recommended that aeration fans are run periodically to bring the temperature of the grain up. Uniform aeration of grain may be quite difficult in some bins this year.

High grain moisture content during corn harvest made the crop difficult to thresh and resulted in higher levels of broken kernels and fines in threshed grain, especially compared to what has been experienced in the past several years. Because of the increased amount of fines, some grain handling systems – even those that incorporate equipment such as screens to help remove the fines – may not have been able to keep up with the large amounts of fines that were going into the bins with the grain.

Layers of fines in the bin (or concentrated areas of fines) will restrict air flow to areas of the grain. As air moves through the grain, it will always take the path of least resistance going around areas where fines accumulated. This can lead to the potential for hot spots and moisture condensation in those areas that are not properly aerated. In many cases, normal coring of the bins may not have taken enough of these fines out of the bin. Therefore, extra monitoring of your bins this spring is essential for minimizing problems in your stored grain.

Also of concern is the potential for uneven moisture in the grain. As grain was harvested last fall, there was large variation in grain moisture content in parts of the state, sometimes as wide as 10 points from mature to immature grain, in many cases from one area of the field to another. As this grain entered the dryer last fall, the high level of variation caused the drier to adjust more than usual. There’s concern whether the sensors in the dryer were sensitive enough to uniformly dry the corn and whether you were able to effectively aerate the bin to even out any moisture differences. There is a potential that there are areas or pockets of higher than intended moisture grain in the bin. With good air flow through the bin, this would not be a great problem, but coupled with a large amount of fines, grain may not have dried in the bin as expected.

Even the most experienced operators should monitor bins with extra care and caution because of the high number of potential variables with this stored corn crop. It may be impractical in many large bins to try to probe them with a grain sampling probe simply because you’re not getting far enough into the grain. Sampling from the top and bottom access doors doesn’t give you a sample of what is in the middle of the bin, around the walls, etc. Also check the exhaust air coming out of the bin when you first turn on the aeration fans, and while they are running, to monitor for the smell of mold or sour grain.

To help minimize your potential for loss, if you have any doubts about the quality of the corn you are storing, you might consider moving a significant portion of your stored corn to see what you have. If you find the corn is not flowing out of the bin as expected, or if you have areas of caking and crusting, or pockets of mold, you should empty those bins of corn first.

Read about grain bin safety.

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