Worry Free Crop Storage

Worry Free Crop Storage

“Warm or wet conditions at harvest and multi-staged crops are potential ingredients for storage problems,” says Harry Brook, crop specialist at the Alberta Ag-Info Centre. “You have 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 those piles from becoming breeding sites for beetles.

“Most empty grain bins will have some form of insect or mites feeding on the cereal crop residue.  ese 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 is 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 risky, especially with hot or damp grain, says Brook. “Safe storage is a combination of both the temperature of the grain and its moisture level when stored. Figure 1 shows the relationship between percent moisture, grain temperature and days of safe storage for oats. All cereals show similar relationships between temperature, moisture and safe storage. Figure 2 is for canola.

Figure 1 Oats

Figure 2 Canola

“Be warned that deterioration can start to occur before the time expires,” he says. “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.”

It should be stressed that the average moisture content throughout the grain bin does not determine how long cereal grains can be stored. Spoilage may occur at isolated locations in the bin where grain moisture is high. Grain stored in a bin at a relatively low average moisture conter of 13%, but with the moisture content ranging between 10% and 16%, is not safe for long-term storage because of the excessive moisture content (16%) of part of the grain.

More dried grain goes out of condition because grain temperatures are not controlled than for any other reason. Improper control of the temperature inside the bin causes moisture to move or migrate from one part of the grain mass to another, where the moisture can accumulate and cause grain spoilage problems. 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,” he explains. “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 then 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.”

Figure 3 Moisture Migration in Cold

Figure 4 Moisture Migration in Warm

The quality of grain cannot be improved during storage. Grain improperly harvested and dried will remain of low quality no matter how well it is stored. In cereal grains loss in quality and quantity during storage is caused by fungi, insects, rodents and mites. Respiration may, in certain cases, contribute to a loss of dry matter during grain storage. However, the losses due to respiration are minor compared to those caused by living organisms.

Fungi (molds) are the major cause of spoilage in grain. Losses caused by fungi in cereal grains are related to (1) a decrease in germination, (2) discoloration of the seed, (3) heating and mustiness, (4) biochemical changes, (5) possible production of toxins, and (6) loss in dry matter. All these changes may occur without the mold becoming visible to the naked eye.

Insect infestations in storage can come from grain residues in combines, handling equipment, and from old grain le in storage. Correctly drying, aerating and managing stored grain will minimize the risk of insect infestation and damage. Insect activity goes with moisture accumulation and grain heating.

Figure 5 Cool Grain to Prevent Storage Problems

Most dry grain will form a peak at an angle of 16° - 20° when centre filling without a distributor. Although it is tempting to store those extra bushels, keep in mind they interfere with uniform aeration and add to the moisture migration problem.

Peaking also makes it difficult and dangerous to enter the bin for observation. Because of dust and high temperatures during the summer, never enter the small space between roof and grain. Shifting grain may block the exit.

If the grain has peaked when filling the bins at harvest, remove the grain in the peak immediately for long-term storage. Lowering the centre cone of the bin improves air flow through the centre, and probing and sampling are made easier and safer.

Installing temperature sensors in bins are a well accepted practice and can accurately monitor grain in storage, but as with all mechanical options, they have been known to fail. They are no replacement for periodical checking of the grain bins.

Harvest is late this year so the pressure will be on to get the crop off the field and into the bins. Paying close attention to the quality, and condition of the crop will give you clues as to the issues you may encounter this year with your stored crops. Keep records and representative samples of the grain in each bin. Not only will this help with assessing the bins that are at the most risk of losing crop quality in storage but it will also give you a sample to use for marketing purposes.

excerpts from Agdex 736-13, Ohio State University Extension, Canadian Grain Commission, North Dakota State University Agriculture and University Extension, Penn State University Extension.