Winter cereals match herbicides in controlling wild oats

Producers might be ‘fairly shocked,’ but study finds winter 
cereals are as effective as herbicides in wild oats control


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Winter cereals control wild oats just as well as herbicides do, suggests a study underway in Lacombe.

“When we had two years of winter cereals — either running or with an early-cut silage in between — we had as good of wild oat control as when we went three years of alfalfa or canola-wheat-canola-wheat with 100 per cent herbicides,” said Neil Harker, research scientist with Agriculture and Agri-Food Canada.

“That’s fairly impressive as to what those crops can do for you in terms of wild oat management without herbicides.”

Concern is mounting about herbicide-resistant wild oats, he added.

“Wild oat, in Alberta at least, is the weed that’s most resistant to the herbicides we use,” said Harker. “In random surveys of farmers’ fields, it’s in over 50 per cent of fields now.”

While most of the resistance is to Group 1 herbicides, wild oats is also a “high risk” for glyphosate (Group 9), resistance, and more than 10 per cent of fields in Alberta are now Group 2 resistant.

During the five-year study, researchers evaluated the effectiveness of novel wild oat control methods by comparing different practices, such as double seeding rates, and different rotations to the canola-wheat rotation that is standard on the Prairies. And so far, the results have shown promise for moving away from herbicides.

“When we combine things like winter cereals with double seeding rates and early-cut silage, we can do as well as a canola-wheat rotation in terms of wild oat management,” he said.

“There’s several plots with no wild oat herbicides for three years running that look as good as canola-wheat with a full herbicide rate.”

Most producers are “fairly shocked” that they could go three years without using a wild oat herbicide and still have effective control, said Harker.

“But you have to be willing to grow a winter cereal, and a lot of people aren’t.”

Craig Shaw, a mixed grain grower near Lacombe, has no such compunctions.

“I love it in the rotation,” said Shaw, who’s been growing winter wheat since 1997.

“When you get hail and end up silaging the crop, it’s a great opportunity to incorporate winter wheat into your rotation.”

With winter wheat — as with any crop, producers need to “look at where the opportunities and advantages are,” he said.

“Generally, we’ve used this crop as an early cash flow and move it off the combine, more times than not in the feed market,” said Shaw.

“If you’re in a year when the crop’s a little short, you can generally gain 50 cents a bushel over what you would get once harvest pressure starts to fall into place.”

But for many growers, it comes down to “straight economics,” said Harker.

“The most economical thing to do right now in the short term is grow canola-wheat-canola-wheat, and in some areas, it’s canola-canola-canola,” he said.

“But the risk of that is, in the long term, you’re going to run into weed, disease, and insect issues that will hurt us.”

In Arkansas, where herbicide-resistant palmer amaranth has devastated cotton crops, they’ve changed their rotations “because they have to,” he said.

“You run it as long as it will run and then that old dog won’t run anymore,” said Harker.

“We may get to the point where we have to do something a little different, too.”

About the author

Reporter

Jennifer Blair

Jennifer Blair is a Red Deer-based reporter with a post-secondary education in professional writing and nearly 10 years of experience in corporate communications, policy development, and journalism. She's spent half of her career telling stories about an industry she loves for an audience she admires--the farmers who work every day to build a better agriculture industry in Alberta.

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