It seems logical that straight cutting canola would produce less dockage than combining a swath.
With the combine header higher off the ground, it should pick up fewer weeds growing under the canola canopy and avoid other dockage material.
However, research suggests the logic is flawed.
“I wouldn’t say it (the result) is rock solid, but our field observations for sure did note higher dockage in the straight cut,” said Nathan Gregg, the Prairie Agricultural Machinery Institute’s project manager in Humboldt, Sask.
Read Also
Canada’s plant hardiness zones receive update
The latest update to Canada’s plant hardiness zones and plant hardiness maps was released this summer.
“We have some dockage levels to support that (conclusion).”
Canada’s canola industry needs to figure out how to reduce dockage because China, which bought $2 billion worth of canola from Canada last year, may introduce new regulations on the amount of dockage allowed in imported canola seed.
China plans to lower the dockage allowance to one percent, down from the previous standard of 2.5 percent.
Chinese officials say the action is necessary to prevent the spread of blackleg into China’s rapeseed industry. Blackleg is a soil borne disease commonly found in canola fields.
For the last two years, Gregg and his PAMI colleagues have been studying combine headers and which types work best for straight cutting canola. He also monitored dockage in straight cut canola versus canola combined from a swath.
Dockage is the percentage of foreign material in a sample of grain, such as weed stems, weed seeds and chaff.
Dockage levels for canola, in Western Canada, are typically one to two percent, Gregg said.
The PAMI findings are based on two years of trials at two sites.
Gregg said anecdotal reports cut both ways on dockage. A number of producers swear that straight cutting decreases dockage, while others say it increases dockage.
“Some guys told me they get way less dockage when they’re straight cutting…. And I hear the exact opposite from another producer.”
The Western Producer contacted an agronomist with the Canola Council of Canada and a harvesting expert with the Indian Head Agricultural Research Foundation.
Neither offered an opinion, or evidence, to support either side of the debate.
“My feeling is that there would be a lot of different factors at play and I can think of circumstances where it could go either way,” said Chris Holzapfel, IHARF research manager.
Gregg agreed with that assessment.
“I think it’s really condition dependent…. Some of the conditions we’ve been in with straight cutting have been less than ideal,” he said.
“With higher moisture or a greener crop canopy condition, we do see a greater amount of dockage…. It’s possible in a really well-cured and mature straight-cutting condition, I think you could have minimal dockage.”
The variety of canola and how it grows may also influence the amount of dockage.
“Some varieties have a central stalk and don’t branch until higher up (on the plant),” Gregg said.
“Other varieties branch (lower down)…. That impacts how high you can cut it.”
The PAMI project on combine headers and canola will end this fall. Gregg plans to release a report on the best headers for canola and dockage levels next March.
