Source: Alberta Agriculture and Forestry
Safe storage is a combination of both the temperature of the grain and the moisture level at which it is stored.
It has been a difficult and stuttering harvest this year with short periods of combining between showers and cool temperatures.
“You might breathe a sign of relief when harvesting is complete, but it really isn’t done until the grain ends up at the buyer’s and is paid for,” says Harry Brook, crop specialist at the Alberta Ag-Info Centre. “Maintain vigilance when the crop is in the bin. A lot of this year’s crop is not totally dry and will need aeration or drying before selling. “
He says that storing the crop is also risky, especially with damp grain.
Maximum moisture content levels for straight grade seed
|Seed type||Moisture content|
|Domestic Mustard Seed||10|
*percentage wet weight basis
(Adapted from: Management of cereal grain in storage)
If grain is placed in the bin damp or even wet, safe storage time is limited before it degrades or attracts grain insects.
Brook adds that aeration is best used for reducing crop temperatures to extend that safe storage.
“However, if you are trying to use aeration and supplemental heat, be aware the air requirements to make that work are much higher than for merely reducing the crop temperature.”
Aeration for purposes of cooling only requires an airflow of 0.1 to 0.25 cubic feet per minute per bushel (cfm/bu).
“If you are trying to use supplemental heat, you need to up the airflow to 0.25 to 0.50 cfm/bu. Dryeration – using aeration for drying – takes a long time, taking 200 to 400 hours to drop moisture 1 to 3%. Grain drying uses the highest airflow. To dry up to 4 to 5% moisture from the crop, you need fans to push 0.75 – 1.0 cfb/bu to dry the grain. This can take up to 750 hours.”
He adds that there can be problems when trying to dry grain in the bin, that includes:
- Once the drying front starts moving, it should not be stopped until it passes through the entire bin.
- The bottom of the bin will be over-dry when the top is dry. “Moving the grain will help equalize the moisture, but you don’t want to over-dry grain as that could result in income lost that could be paid for by the grain buyer.”
- Beware of moisture 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 and 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 immature grain to keep it cool. If moisture does move and centralize in the bin, it starts to heat and that attracts grain beetles.”
“Cool, wet harvesting conditions are potential ingredients to cause storage problems,” Brook adds. “You have spent a lot of money and time getting the harvest in the bin. Take the time to monitor the stored grain condition and keep the bins cool. Don’t get an unpleasant surprise when selling the grain with discounts for heated grain or insect problems.”
Connect with the Alberta Ag-Info Centre:
Hours: 8 am to 5 pm (open Monday to Friday, closed statutory holidays)
Toll free: 310-FARM (3276)