Back to the agronomy basics in canola

Experts advise growers to focus on quality seed and nitrogen before less conventional inputs

Blooming rapeseed field at sunset

Canola growers have been asking agronomists questions about promoted products. Do they work? And if so, are they worth the additional cost? Two researchers, Murray Hartman, oilseed specialist with Alberta Agriculture and Forestry, and Neil Harker, research scientist, weed ecology and crop management, Agriculture and Agri-Food Canada, conducted a study to test the inputs that were questioned most. Their conclusions may come as a surprise to some.

“Farmers were concerned that products were being promoted without good independent data to back up their efficacy,” said Hartman in a recent interview. “So it came from the growers, not the scientific community.”

In talking with the Canola Council of Canada’s agronomists, Hartman and Harker were able to put together a list of products that were questioned most. The list included nitrogen (applied at 75, 100 and 125 per cent of best management practice recommendations), foliar stress relievers, boron, a seed primer treatment and a fortified foliar fertilizer supplement. The study also looked at increased seeding rate to see if it would result in increased yields. The seeding rate was 100 seeds per square meter, fertilized according to soil test recommendations, said Hartman.

Planting 100 canola seeds per square meter led to an average plant density of 56 plants per square meter. Where 25 per cent less nitrogen was applied in a sideband at seeding, flowering and maturity time were both slightly decreased. Where 25 per cent more nitrogen was applied as a liquid foliar treatment, yields were greater. Similarly, where 25 per cent less nitrogen was applied in the sideband at seeding, yields were lower. Interestingly, the research showed that canola yields were economically optimized in the BMP treatment with recommended nitrogen rates.

Higher seeding rate didn’t increase yield

What will perhaps surprise some growers is that increasing seeding rate did not increase yield. Increasing seeding rate to 150 seeds per square meter did decrease the percentage of green seed by almost one per cent. “On the Canadian Prairies this decrease in green seed levels has important quality, grading and price implications,” said the final report.

In assessing seed oil concentration, the researchers found that increasing and decreasing nitrogen often increased and decreased concentrations respectively. However, it had the opposite affect on seed protein concentration.

“We weren’t surprised by most of the results,” said Hartman. “But we were a little surprised that we didn’t get an increased yield by increasing seeding rate.”

What about the additional inputs promoted as yield increasers? Hartman said that some growers might be surprised by those results as well. None of the less conventional inputs tested had any impact on canola emergence, days to flowering, days to maturity, yield or quality, said Hartman. While boron seems to have a good market share — Curtis Rempel, vice president of crop production and innovation at the Canola Council of Canada, estimates that a quarter of canola growers have tried a boron product on at least some of their canola acres at some point — its use doesn’t seem to be justified.

“It’s pretty rare to get a boron response,” said Hartman. “I do think because guys are using these products there obviously should be some surprise that we don’t get a general response. And maybe they should rethink their decisions.”

A research report by Nicole Philp, agronomy specialist with the Canola Council of Canada, also concurs with those findings. Her report said that three years of small plot boron trials do not show any consistent benefits to yield or quality in canola. Furthermore, a one-year field-scale trial showed no significant yield difference when boron was applied at various soil pH and organic matter levels.

So what can canola producers do to ensure quality and yield? “We can’t control the weather,” said Hartman. “That’s when the high yields happen, when the weather cooperates.”

Some flexibility, he said, comes from variety choice, but it’s still the standard practices that help ensure quality and yield. “Early and good weed control, and adequate fertility of you macronutrients, so nitrogen, phosphorus and sulphur are the big key [ones],” he said. “If you do that, you’re probably going to maximize yield, especially an economic yield. And the rest of the stuff, it’s unlikely that it’s going to have an excellent response.”

“There’s no magic bullet,” concluded Hartman. “Just well-established agronomy.”

About the author


Melanie Epp

Melanie Epp is a freelance farm writer.



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