Getting the crop in the bin is only the first part of the harvest – safe storage is the rest of the story.
“Safe storage of the crop depends on two main variables, the temperature of the crops going into the bin and the moisture content of the crop,” says Harry Brook, crop specialist with Alberta Agriculture and Rural Development.
“Chaff and crop residues can also affect the safe storage by preventing air flow or, if they contain more moisture than the grain, creating hot pockets.”
The hotter the grain or the higher the moisture content, the less time it can be safely stored.
Aeration can bring grain temperature down to storable levels but won’t effectively dry the grain. Aeration with added heat can remove a small amount of moisture, but grain drying is the better choice.
“High-moisture cereals and oilseeds need to be dealt with in one of three ways: sell quickly as tough; put it through a grain dryer to bring the moisture down; or, use aeration under warm weather to remove some of the excess moisture, or, under cool conditions, bring the temperature down until it can be sold or dried,” says Brook.
Binned grain goes through a process of moisture migration in the fall and spring. In the fall, with cold temperatures and warm grain, there is a flow of cold air that moves down the outside of the bin, hits the bottom, and flows up the middle of the bin. The air picks up moisture and deposits it in the top middle part of the bin. If the grain goes out of condition it will be in this middle, upper part of the bin.
In the spring, there is a reversal of air flow. With a cool bin and warm outside air, the cold air flows down the centre then moves up along the outside of the bin. This leads to moisture accumulating in the middle and bottom of the bin. Using bin temperature monitors, or even using a metal rod to check the bin on a regular basis, Brook advises.
“When grain goes out of condition due to excess moisture or heat you almost always have to deal with grain beetles,” he adds. “Grain buyers, other than feedlots, will not buy any grain containing live insects. Grain beetles are attracted to heat from heating grain and they are very good at detecting heating grain.
“Treatment to control grain insects usually requires the application of aluminum phosphide pellets, which is a very toxic substance. Another treatment method requires bringing the grain temperatures down to -20 C for a week.”
Other problems which occur with damp and heating grain are fungus and moulds.
“Regardless of the problems, treating them requires expenses and time which can interfere with the marketing and value of your crop,” says Brook. “It’s much better to avoid storage problems by storing grain safely and keeping it in good condition until it is marketed.”