Straight-cut canola’s storage impact studied

PAMI employees sift a sample of straw and canola seed at the research site in Portage la Prairie, Man. A sample of canola seed is collected during trials on swathing and straight cutting, including different desiccants, to determine if harvest methods change seed physiology and affect storage of canola seed.  |  PAMI photo

Straight cutting of canola has gone from a fringe activity to a common practice on the Prairies over the last five years.

Agronomists and growers have many theories on swathing versus straight cutting and how the harvest methods affect things like seed size, yield and oil content.

Another factor to consider is storage. Does straight cutting change the characteristics of the seed and how canola reacts when stored?

“If there is a higher risk (with) one of these methods, we want to make sure that producers know about it so they can react appropriately,” said Avery Simundsson, project leader with the Prairie Agricultural Machinery Institute.

“There’s a thought if you’re spraying a desiccant or letting it naturally ripen … it might almost affect oil content, the potential for bacteria growth, dockage and everything else that effects your safe storage,” she said.

“We want to see if there are any higher risks from any of your harvest choices, if it makes a difference at all.”

To evaluate the risks, Simundsson and her PAMI colleagues at Portage la Prairie, Man., studied five harvest scenarios to measure the impact on seed physiology.

They looked at swathing, natural ripening, straight cutting and desiccation with Reglone, desiccation with Heat and glyphosate and just glyphosate.

Following harvest, they sent seed samples to researchers at the University of Manitoba to analyze any differences in seed physiology, including things like seed moisture, oil content and respiration. Those properties may affect how moulds develop on canola seed. Mould growth is a primary cause of seed spoilage in the bin.

Simundsson doesn’t know yet if harvest methods affect canola seed physiology and how the canola stores because results of the seed analysis won’t be finalized for a couple of months.

However, observations from the trial suggest there could be differences.

“(With) natural ripening we noticed last year we did have a lot of weeds in there when we were cutting, so there’s a potential for higher dockage, perhaps,” Simundsson said.

Weed seeds can contain more moisture than canola seeds, particularly if they are green, which can cause problems in the bin.

“These high-moisture seeds may not be enough to elevate overall grain moisture tests, but if these weed seeds congregate in pockets in the bin, they can create localized hot spots for spoilage to begin,” the Canola Council of Canada says on its website.

The PAMI research was a one year study, which was part of a larger project evaluating straight cutting and various pre-harvest aids. PAMI is also assessing swathing, straight cutting with different types of desiccants and how those methods affect yield, seed size, bushels per hour, bushels per litre of fuel and threshing losses.

The study on seed physiology and safe storage may continue next year, depending on funding.

“There’s a lot of interest in safe storage of canola right now,” Simundsson said.

“Part of the push behind safe storage of canola is that bins are getting bigger, which makes it harder to cool properly or force air through it just as efficiently.”

For more information on the PAMI research on canola harvest methods, visit

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