What were the canola yield robbers in 2020?

Some farmers benefited from the environmental conditions while others were ready to put 2020 behind them

In 2020, canola fell more than 11 bushels short of the 52 bushels per acre yield target the Canola Council of Canada (CCC) hopes Canadian farmers can achieve by 2025. Though a handful of major factors held yield back last season, hot and dry conditions bit into the most acres, said CCC agronomy specialist Justine Cornelsen.

Speaking at the Canola Discovery Forum held during CCC’s Canola Week last December, Cornelsen said the 2020 season looked entirely different in three distinct areas of the Prairies.

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Highly diverse conditions across the Prairies

In southern Alberta, weather played in producers’ favour. For the most part, rain fell when and where it was needed throughout the season, translating to above-average yields. For Alberta’s dryland farmers, timely rain was an unusual but extremely welcome surprise.

Unfortunately, none of the rest of the Prairies had such producer-friendly conditions.

In northern and central Alberta and northwestern Saskatchewan, the season ended before it began. Spring flooding, together with significant carryover of crops from the year prior, made seeding nearly impossible from Red Deer right up into the Peace region.

“There were a lot of things not working in those farmers’ favour in 2020,” said Cornelsen in a follow-up conversation. “Many farmers there were simply not able to establish a crop and had a complete crop failure.”

The rest of Saskatchewan and most of Manitoba faced an entirely different set of challenging weather conditions. Seeding across those regions was delayed but, once the season got underway, emergence looked good. Unfortunately, conditions degraded as hot and dry weather set in. Particularly, hot weather hit just as canola flowered, compromising seed set.

While July was a hot, hot month across almost the entire Prairies, proximity to the Rockies brought cooler nighttime temperatures to most of Alberta, decreasing heat-related yield losses. Much of Manitoba, on the other hand, suffered through consecutive days over 30 C with nighttime temperatures exceeding 20 C.

“Flowering is the worst time for a heat wave,” says Cornelsen. “Anything over 29.5 C as a daytime high is going to cause stress in the plant. Where we get into trouble is when it doesn’t cool off at night. If it stays above 15 to 16 C, that keeps the plant in an elevated state of stress. What happens then is the plant directs its resources to survival instead of toward seed set.”

Most of Manitoba’s and Saskatchewan’s fields were further challenged by dry conditions.

“The heat would’ve been okay if we had some moisture to decrease plant stress, but that wasn’t the case,” says Cornelsen. “In Manitoba, areas received 15 inches of rain at the beginning of July and then the taps turned off.”

With the exception of Manitoba’s intense, early, July rain event, little precipitation fell across either province through the summer months.

The dry was particularly problematic because the season had started fairly well from a moisture perspective. Though winter snowpack was low across Saskatchewan and Manitoba leading into the 2020 season, carryover from the rain and snow that fell during harvest 2019 improved seeding conditions. That, together with some early-season rain, meant seedlings got up and out of the ground well.

However, fairly easy access to early-season moisture meant plants didn’t need to root particularly deep. The shallow roots not only worsened plants’ abilities to withstand the later-season dryness, they also translated to decreased seed production.

“Wet then dry means roots are not there when they’re needed,” says Cornelsen. “That shift in energy — pushing roots down further rather than investing resources into reproduction — can really cost producers yield.”

Extreme winds

In addition to hot and dry conditions costing yield, extreme winds compromised crops across large swaths of the Prairies, especially northeastern Saskatchewan and northern Manitoba. In Manitoba, Cornelsen says more than 250,000 acres were reseeded due to emergence issues, including wind damage.

“In northern Manitoba, it was really bad. It almost looked like something from the Dust Bowl. It was just a wave of wind — days of 50-kilometre-plus winds with no break. That’s not normal for that area,” says Cornelsen.

The winds caused secondary issues. Farmers who were unable to apply timely herbicides lost yield to weed competition. Also, the wind pushed flea beetles lower into the crop where they caused more-than-typical damage when they shifted to stem feeding.

Less disease pressure with some exceptions

On the plus side, hot and dry conditions meant there was less disease pressure than usual.

Clubroot would have been more of an issue in higher moisture, but it wasn’t able to get established in many areas. Sclerotinia was also really low due to the dry conditions during flowering,” says Cornelsen.

Still, some disease factors did cut into yield. Blackleg managed to get going because of the spring moisture, rebounding in Manitoba. Verticillium stripe was found in more areas, though some suspected cases turned out to be other disease vectors when analyzed. Root rots proliferated in some fields.

While southern Alberta producers are likely to look back on 2020’s growing season with satisfaction, most of the rest of the country is ready to put 2020 behind them and look forward to 2021.

“Mother Nature definitely threw her wild cards at some areas in 2020,” says Cornelsen. “But every year we have our challenges, and we continue to prove how resilient of a crop canola is.”

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