OMAFRA researchers and farmers have been working to better understand the factors that contribute to avoiding winterkill in canola
By Jackie Clark
Canola has been grown for years in Ontario; most acres are spring canola, grown in the northern parts of the province. Recently improved genetics and increased interest has led OMAFRA specialists to investigate best agronomic practices of growing winter canola in southern Ontario.
Farmers in Ontario may be interested in adding winter canola to diversify their rotations for a few reasons.
“Now there’s access to newer genetics and hybrid winter canola varieties,” Meghan Moran, OMAFRA canola and edible bean specialist, told Farms.com. Winter canola now offers an additional option to capture the soil health benefits of having a growing crop present in late fall and early spring.
“When we start talking about cover crops and having a crop there over the winter, growers start to wonder how to make money off of that,” she added.
Canola is a good option for a winter crop because “there’s always a place to sell it,” Moran said. There are two main crush facilities in Ontario that accept canola, so farmers do not have to search for a market.
An additional motivation for adding winter canola to crop rotations in southern Ontario is to mitigate some herbicide-resistance concerns.
“In the more southern parts of Ontario we grow a lot of soybeans and we have a lot of herbicide-resistant weeds, and so a winter-planted crop where you would use different herbicides and at different timings help with weed control. And it’s very competitive so it competes against weeds well,” Moran explained.
However, there are some challenges to growing winter canola; overwintering is near the top of the list. Establishing a uniform crop is important for winter survival.
“Planting date is important” and will vary geographically, Moran said. “We want to make sure we have enough time for the canola to get to the four- to six-leaf stage in the fall.”
Ideal planting time will be about one or two weeks earlier than a farmer would plant winter wheat, she added. Soil conditions and preparation can also promote uniform emergence of canola.
“Canola has a very tiny seed, so we generally want a fairly fine seed bed,” Moran said. “In theory you can no-till canola,” however it isn’t often done because of issues with seed placement and slugs.
Farmers “usually have more success with some tillage or at least moving residue out of the way,” she added.
Additionally, “seeding rate is important in terms of winter survival. The plants need to be spaced out, so they stay snug to the soil surface,” Moran explained. Plants that emerge too close together will compete against each other and grow too tall, increasing risk of winterkill.
Finally, there are fertility considerations. “Canola does require some nitrogen and sulphur in the fall … it’s one of the crops we grow in Ontario that needs the most sulphur,” Moran said.
Researchers have observed that winter weather may play a bit of a factor in winter survival, but soil conditions are more important.
“Some snow cover can help with winter survival, but we don’t have a lot of snow cover in the southern part of the province like in Essex County and (winter canola) seems to do OK there anyway. The biggest thing is drainage. If the field sits wet, that’s a higher risk of winterkill,” Moran explained.
Heavier soils will also heave more with freeze-thaw cycles, and canola plants can end up being heaved right out of the ground, she added.
When judging survival of winter canola and deciding whether to harvest or terminate, patience and careful inspection are critical.
Looking at the leaves in the spring may not be enough to judge stand survival. “In some areas the leaves may actually die off but the plant crown will still be alive,” Moran said.
“Wait long enough that you have some sunshine and some warmer weather and see if you can see some growth,” she explained. “Even if you do see growth, you want to cut a few plants open at the soil surface and check the inside of the stems … if they’re really hollow and brown on the inside then they’ve had damage and you may need to terminate.”
A canola plant with a completely hollow stem may still grow, but has no yield potential, Moran added.
Many growers in Ontario are now testing small fields of winter canola.
Farmers with experience in spring canola “are a little more willing to put in more acres of winter canola if they feel they have the right field for it. It really is about field selection,” Moran explained. A well-drained field is critical for canola success.
“I think we have a good basic understanding of how to manage the crop,” Moran said.
Extension of that knowledge may help more farmers adopt winter canola in their fields. Growers will need to learn how to best set up their equipment and manage their herbicide selection to fit canola into their rotations.
“Some of the herbicides we use in soybeans are injurious to canola,” Moran explained.
Farmers may need a high clearance sprayer to apply fungicide, however most combines should be capable of harvesting the crop.
“If you can harvest soybeans, you can probably harvest canola,” Moran said. Some farmers “like to use a draper head or have knives on the side of that header to cut through the canopy.
“It’s just a matter of perfecting your combine settings for that small seed” to prevent harvest loss, she explained.
“It takes some experience I think to dial it in,” Moran said.
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