“Due to how quickly damage can occur, ongoing attention is needed to avoid potential canola storage problems as fall transitions into early winter,” explains Neil Whatley, crop specialist at the Alberta Ag-Info Centre. “Because of its high oil content, canola seed is more susceptible to deterioration in storage than cereal grain.”
Canola is stored at a lower seed moisture level to prevent spoilage. Safe, long-term canola storage is at or below 8% moisture content and cooler than 15 C. Declining outside air temperatures also affects storage safety.
Whatley explains that canola respires or goes through a ‘sweat’ period for up to 6 weeks after being binned. Even if it is initially binned dry, monitoring needs to continue.
“Respiring canola generates additional heat and moisture, creating an unstable condition. It can potentially result in hot spots or mould growth. Mould creates more heat when it forms and that accelerates its spread. Aerating stored canola during its respiration period is important.”
Changing outside air temperatures in the fall and spring cause repeated moisture cycles in a bin, permitting moisture to concentrate in certain bin areas. That could lead to spoilage and heating.
“As outside air temperatures decline during October and November, the grain nearest to the outside bin edges cools first. From there, the cooling system migrates downward along the bin edge, and then upward through the central core,” he adds. “As this cooling system migrates, it gathers moisture and warmth that creates a pocket of humid and warmer air at the top of the central grain core where spoilage and heating can begin.”
“As outside air temperatures decline, aeration fans should be running until canola at the top of the bin is cooled to the average daily temperature. It is wise to aerate repeatedly until the whole bin of canola is between 0 and 5 C. That is why November is an important month to check canola bins again to ensure they are stable going into winter as temperatures drop below 0 C and stay there.”
Another option that Whatley suggests for producers to consider is coring or turning one third of the canola bulk out of a full bin by truck in November.
“Use this method when aeration is not possible, but there are benefits of this method even when aeration is being used. Moving the grain disrupts the moisture cycle created by declining outside temperatures, cooling the grain mass and reducing the risk of spoilage. Even monitoring a bin temperature with sensors may not provide a complete reading of the entire bin. Problems may emerge in pockets away from the sensors.”
“Besides cooling the grain, turning lets producers smell and feel it as they are moving it. They can recognize the first stages of spoilage. If green counts, moisture, weeds or dockage are high, turning the whole bin may be the safest way.”
He adds that producers should be extra attentive when canola is stored in large bins, especially tall and narrow bin types that can reduce aeration air flow due to increased compaction.