Consider Seeding Depth, Soil Moisture and Soil Temperature
Across the Canadian Prairies, soil moisture reserves are much lower than normal, thanks to a drier autumn and less snowfall than usual this past winter.
You may be tempted to seed deeper to find moisture, especially if you’re seeding into ground that’s extremely dry. But as agronomists like Justine Cornelsen will tell you, if you’re betting on this high risk/reward strategy to pay off with a bumper crop this season, the odds are stacked against you.
Seeding Deeper Means Higher Risk
Cornelsen, who’s an Agronomy Specialist with the Canola Council of Canada, recommends a seeding depth of ½" to 1". Any deeper than that, and it’s likely the seed will struggle to germinate and make it out of the ground.
“People do push it sometimes, but you need everything in your favour to get those seeds up,” Cornelsen says. “Otherwise, your risk is going to be much higher for losing plants.”
Cornelsen explains that because canola seeds are so small, they have a limited amount of energy available to successfully germinate and emerge. When seeds are too deep in the soil, that energy is used up before the seedling can make it to the surface.
Seeding Depth for BrettYoung Canola
Rene Mabon, Agronomic Services Manager for BrettYoung, also recommends a ½" to 1" seeding depth for BrettYoung’s TruFlex™, Roundup Ready® and Clearfield® canola varieties, since that’s shown to lead to the most reliable stand establishment.
Mabon says seeding deeper than that not only risks creating issues with seedling survival, but it can also make the young plant more prone to seedling diseases, like damping off.
“Seed too deep, and you will lose seedlings. Seed shallow (in the dust), and you don’t get enough moisture to start germination – so you are in the same place,” says Mabon. “I’m a risk-taker, so I would tend toward seeding a bit deeper to find moisture this spring, and I’d up my seeding rate a bit to compensate for the likely losses.”
Watch the Weather
As Cornelsen and Mabon both point out, there’s also some risk if you don’t plant deep enough. When moisture reserves are low, as they are now, and the soil is dry and dusty, strong winds can blow soil and exposed seeds away. That’s why Cornelsen recommends keeping an eye on the weather and holding off on seeding if the forecast is for high winds, like the 80 km/hr winds we saw in late March this year.
Canola does require some soil moisture to germinate, so she also recommends getting your canola fields planted just before a rain event this spring if your fields are dry, an option producers have this year with the open spring.
Seed-to-Soil Contact Essential
Cornelsen notes canola needs good seed-to-soil contact so it can access soil moisture. Given the current situation, with low soil moisture reserves, she recommends avoiding spring tillage and trying to direct-seed if you can.
“It doesn't take a lot of moisture, but there has to be some for the seeds to start germinating. That’s why seed-to-soil contact is so important,” she says, adding that you can play around with packing pressure while planting this year as a way to increase seed-to-soil contact.
“The soil might be really dry, but if you can pack the seed firmly so it’s surrounded by whatever available moisture that’s there, that's going to increase its odds of going up this spring.”
Recommended Soil Temperature
Soil temperature will be another important consideration for you this spring. According to the Canola Council, a good starting point for seeding canola is when the three-day average in the seed zone is 4-5°C – around the temperature when biological activity usually begins.
Mabon also recommends having a soil temperature of at least 5°C when planting canola. “I’d say 7-10°C is probably better for faster emergence, but lots of evidence supports the yield benefits of seeding early, so starting at 5°C makes sense,” he says. We see these yield benefits with earlier spring-sown crops because the flowering window avoids the hot conditions in late July. But this doesn’t mean planting at the beginning of April. Many early seeded canola crops become at risk for spring frosts and extreme flea beetle feeding. Early to mid-May is classified as early seeding.
If you would like more information or support with determining the proper seeding depth for your farm this spring, contact your BrettYoung Regional Account Manager.