Weed pressure usually isn’t too serious of a problem for most western Canadian crops in March or even early April, especially if there is still snow on the ground, but it’s a topic on many farmers’ radars as they plan for the coming growing season.
For several producers in Western Canada, talking about weed control in mid-March was field work still several weeks away, while in other parts of the Prairies, part of the spring herbicide program had already been completed.
All producers contacted for this April 6 farmer panel were committed to applying a timely weed control program to deal with that first flush of weeds in the spring. In all cases, glyphosate factored into the pre-seed or pre-emergence weed control program, but whether tank mixes were used depended on the weed spectrum and other management factors.
Most producers also pay attention to a post-harvest weed control program as needed. And that, combined with a timely burndown of weeds in the spring, gives crops the best chance of getting off to a vigorous start.
Here’s what producers in Western Canada, along with one expatriate now in southern Montana, had to say about weed control at seeding.
Josh Fankhauser aims to have the first round of spring weed control applied on his southern Alberta farm by early March. That involves a broadcast application of Edge and Fortress granular herbicides on about 20 per cent of his farm acres.
About 10 per cent of the farm at Claresholm, an hour northwest of Lethbridge, is seeded to a pea-canola intercrop mix and those fields will be treated with Edge. Fortress is applied to another 10 per cent of the farm, which will be seeded to cereals.
With a no-till operation, Fankhauser relies on snow and rain rather than tillage to move the herbicides into the soil profile.
“We have been experimenting with the intercrop for about six years,” he says. “And, certainly, for the past two years, we no longer seed a pulse as a monocrop. But by seeding peas and canola together, you lose in-crop herbicide options, so we use the granular products.”
Acres treated with the granular herbicides will later be treated with straight glyphosate about three to six days before crops are seeded. The rest of spring-seeded acres will receive a pre-seed application of glyphosate tank mixed with another product.
“There are many good herbicides out there we can use with glyphosate, so the tank mix depends on the weed spectrum,” he says. He might apply a pre-emergence burndown in a year when a crop is seeded quite early before most weeds have appeared, but he prefers what he considers the more effective pre-seed treatment.
Fankhauser’s crop rotation includes about 20 per cent of the farm seeded to winter wheat, along with spring wheat, some barley that might be cut for silage for the beef herd as needed, the pea-canola intercrop, flax and straight canola. Also, about 30 per cent of the farm is seeded to forages, producing pasture and hay for the cow herd.
And when he looks at the overall weed control program, he considers the most important treatment of the year is the post-harvest, fall glyphosate application. “If someone said I could only do one treatment in a year, it would be the fall-applied glyphosate,” says Fankhauser. “It is the best time to control some of your most troublesome weeds.”
Smoky Lake, Alta.
In north-central Alberta, Robert Semeniuk says he pretty well sticks to a pre-seed glyphosate burndown, unless there is some unusual circumstance that requires a pre-emergence herbicide treatment after seeding.
“We did do more pre-emergence applications in peas at one time,” says Semeniuk, who farms with family members near Smoky Lake, about 90 minutes northeast of Edmonton. “But they’ve developed some improved products that work well ahead of peas, so we plan on a pre-seeding burn down.”
Along with peas, Semeniuk grows canola, malt barley and CPS wheat, and he is working to include more oats in rotation.
Ahead of all crops, he applies a pre-seed application of glyphosate usually tank mixed with another herbicide to provide more effective weed control. “We have pretty good records and monitor weeds, so there usually aren’t too many surprises when it comes to weeds,” he says. “We tank mix the glyphosate with a second herbicide depending on the weed spectrum.”
And depending on the field, he is more inclined to use glyphosate alone on canola fields because with InVigor and Roundup Ready varieties, he has the opportunity to use glufosinate (Liberty) and glyphosate (Roundup) herbicides for effective in-crop weed control.
Semeniuk says he hopes to include a post-harvest herbicide application in his plans, but over the past few years with late and horrendous harvest conditions, fall field work just wasn’t an option.
Dustin Williams will pull out any guns needed to help control specific weed infestations, but for most acres on his southwest Manitoba farm, a straight glyphosate pre-seed burndown provides effective weed control.
Williams, who grows grains, oilseeds and pulse crops near Souris, usually applies a good-quality glyphosate product enhanced with LI 700, a non-ionic penetrating surfactant that improves the effectiveness of the herbicide.
Developed by Loveland Products Canada, LI 700 has a unique formulation, which lowers the pH of spray solutions. It reduces chemical drift potential by producing a more uniform spray pattern with larger droplets. That helps reduce spray drift from glyphosate products during the pre-seed burndown.
“If we do have a field that has a particular problem with kochia or volunteer canola, then I will use another add-in herbicide with the glyphosate,” he says. “But over most of the farm, a high-end glyphosate with LI 700 does an excellent job.”
Williams says he has occasionally needed to apply a pre-emergence herbicide treatment, but generally he finds it is less effective in controlling weeds. He seeds with a disk drill which can kick up dust that coats weeds, and sometimes the drill will just bury weeds that keep on growing. The dust reduces the effectiveness of the contact herbicide.
Another effective weed control measure is to scout fields in the fall, particularly looking for problem perennial weed patches such as quackgrass, Canada thistle or foxtail barley.
“If we start to see some of those weed patches developing, we apply spot treatment with glyphosate to provide control and occasionally, if needed, we may need to tank mix with another product, but that is rare,” he says. “Usually the spot treatment with glyphosate is effective.”
With seeding and the first herbicide application of the year likely still about two months away, at the time of the mid-March interview, Larry Pratt says his family farm sticks mainly to a pre-seed burndown ahead of seeding, usually in the second week of May.
If weather and harvest co-operate, he does favour a post-harvest weed control application, but in recent years that hasn’t always been possible. “If harvest is a bit delayed, we might no sooner get done with it and have to deal with the cow herd, hopefully before the weather gets miserable,” he says. “So that post-harvest treatment isn’t always an option.”
Otherwise, a pre-seed burndown with a multi-action product, such as PrePass or CleanStart, is carried out ahead of seeding.
“We make a point of scouting fields before seeding to see what is out there and then we can get the right product for the weed spectrum,” he says. And along with proper timing, it is important to use products at the proper rate for the most effective weed control, he adds.
The farm rotation this year will include wheat, barley, oats, canola and fababeans. Fababeans have been grown on the farm for the past four years. “It seems to be well suited in our area,” Pratt says. “It seems to do better than soybeans. Fababean is the first crop seeded and the last to be harvested.”
Three Forks, Mont.
It was a year ago in mid-March that the Groeneweg family of east-central Saskatchewan, moved lock, stock and barrel to a dryland farming operation in southern Montana, just in time for a dry growing season.
The area around Three Forks, just northwest of Bozeman, only gets about 12 inches of precipitation most years during the growing season. In 2020, the area received about 60 per cent of what’s considered normal.
“It was a bit of a downer for our first crop, but that’s farming,” says Franck Groeneweg, who along with his wife, Kari, and their four children, moved to Montana after 18 years of farming at Edgeley, Sask.
As Groeneweg prepares to seed his second crop, including spring wheat, chickpeas, winter canola and some flax, he plans to apply a pre-seed burnoff ahead of the wheat. Options are still open but it could include glyphosate, likely tank mixed with 2,4-D, or he may apply a Fortress-type product that includes dicamba and tribenuron. “A lot will depend on the weed spectrum,” says Groeneweg. “And then you also have to think about the crop you might seed next year and consider if there might be any residual herbicide activity.”
The pre-seed treatment will be applied with cereals, while with pulse crops he’ll plan for pre-emergent weed control. “Pulses can be slower to get started and there aren’t as many in-crop herbicide options,” he says. “I’ll hold off a bit after seeding to let weeds get growing and then apply a herbicide before the crop emerges.”
Groeneweg says it was surprising to learn that even if a crop has only a slight growth advantage on weeds, it really benefits its competition factor. “For example, I’m not sure how many farmers know this, but even if your wheat plants have only one more leaf than a wild oat, the risk of yield loss is considerably less.”
Winter canola, which so far hasn’t been adapted well to Western Canada, can do quite well in southern Montana. Seeded around August 1, Groeneweg laughs when he says there isn’t much to look at this spring as the snow melts. “It looks like canola in mid-June that got sprayed with 2,4-D,” he says. “There is nothing there, it looks dead. But if you look closer, there are growth points and the plants also have deep taproots, so it will come along.”
Winter canola works well with the Montana climate, he says. It will be growing and can take advantage of spring moisture during the higher-rainfall month of May, and it should be done flowering and avoid the heat blast temperatures of early summer.
“There are some newer winter canola varieties that grow quite well,” says Groeneweg. They are available in Roundup Ready and Clearfield systems, but, so far, none are available for LibertyLink.
As the family settled on the 15,000-acre grain farm, there have been a number of learning curve moments. One on the farming side is a return to a crop-summerfallow rotation. About two-thirds of the Groeneweg’s farm is cropped while one-third sits fallow to conserve moisture. He’d like to move that closer to 75 per cent crop and 25 per cent fallow, but then he also has to respect how the local, long-time farmers have managed their farms even with 50-50 crop-fallow rotations and “appreciate they may know what they’re doing.”
While it was shaping up in Manitoba’s Interlake District to be a spring with decent moisture for seeding, Eric Fridfinnson, who farms near Arborg, says he will be applying his usual weed control program to get all crops off to a good start.
Fridfinnson follows a bit of a longer crop rotation that includes wheat, soybeans, canola, flax, some barley and oats, and there is usually some forage seed production that includes alfalfa and grass seed.
Weed control at seeding usually includes a combination of pre-seed burndown or pre-emergence burndown, depending on crops and weed spectrum.
“Like most farmers these days, we are well aware of the challenge to avoid herbicide resistance in weeds and the need to rotate herbicides,” he says. A pre-seed burndown includes glyphosate tank mixed with products such as Aim, Heat or BlackHawk, all of which help to increase weed control efforts with different active ingredients and modes of action.
“With some of these products, like a tank mix of glyphosate and Authority, it also provides some residual herbicide activity in the soil,” he says. “That is really a benefit to crops such as flax and soybeans. They can be a bit slow to get started, so the longer herbicide activity gives them a chance to grow ahead of the weeds and then they can compete.”
Again, depending on the crop, seeding depth, growing season conditions and weed pressure, he often applies a pre-emergent herbicide to catch that later flush of weeds before the crop comes out of the ground.
“You have to pay attention to timing, but it is a great tool,” he says. “Especially in situations that are a little more weedy, if your timing is right, the crop is coming up just as the weeds are removed. The crop can get off to an excellent start.”
Fridfinnson says he has even done pre-seed and pre-emergent burndowns on the same field in the same year. The field is sprayed just before seeding, and if there is a weather interruption that delays seeding, once the crop is seeded, “we come back with a pre-emergence treatment to control weeds before the crop emerges,” he says.
“With either treatment, it is important to remember the value of early weed control to help increase the competitiveness of the crop,” he says.