Originally published September 11, 2017 on Alberta Agriculture and Forestry
A little preparation prior to harvesting can ensure worry-free winter crop storage.
“Warm or wet conditions at harvest and multi-staged crops are potential ingredients for storage problems,” says Harry Brook, crop specialist, Alberta Ag-Info Centre. “You’ve spent a lot of money and time getting the harvest in the bin. Take the time to monitor the stored grain’s condition and cool those bins down. Don’t get an unpleasant surprise when selling the grain with discounts or by being rejected for heated grain or insect problems.”
Brook says producers should clean up spilled grain from around their bins to prevent them from becoming breeding sites for beetles. “Most empty grain bins will have some form of insect of mites feeding on the cereal crop residue. These bins need to be swept or vacuumed out with the debris being either burned or buried.
“Malathion can be sprayed into a bin to control insects in the nooks and crannies feeding on crop debris, but only in those bins that will be used to store cereals. It’s forbidden to use malathion in bins used to store oilseeds. Empty bins can also be treated with diatomaceous earth prior to storing all crops. Diatomaceous earth can also be added to the crop as the bin is filling as a preventative measure.”
Storing the crop is also risky, especially with hot or damp grain, says Brook. “Safe storage is a combination of both the temperature of the grain and the moisture level it’s stored at. Here is a list of crops and the maximum moisture content they are considered to be ‘dry’ at and safe to store.”
Hot grain also acts as a beacon to cereal grain insects. “Rusty grain beetles are good fliers and they home in on hot grain, infiltrating the bin and starting to breed in the high moisture zone.”
This chart shows approximately how long damp grain can be stored safely and estimates the amount of time for safe storage. “Be warned that deterioration can start to occur before the time expires,” says Brook. “It still has to be either dried or aerated. Grain aeration is best used in the fall to cool the crop temperatures down, allowing crop to be safely stored over the winter.”
Drying via aeration requires warmer temperatures and low humidity, which are often lacking in the fall. “Fall temperatures will continue to drop, lengthening the time it takes to bring moisture levels down. Even dry, hot grain placed in a bin creates moisture migration. It takes time for grain to stop respiring and moisture to equalize in the bin. The hot grain or oilseed creates circulation in the bin. Cold air outside will cool the grain against the bin sides and moisture will move down the outsides of the bin the come up the middle. If there is any place for the moisture to accumulate, it will be just below the top, middle of the bin. Green seed or immature seed in the bin may also contain more moisture and add to the problem. This is why it is imperative when harvesting hot grain to cool it quickly. Aeration under hot harvest temperatures is important to get the grain or oilseed temperature down to a safe storage level.”