Skip to content

Broadcast canola: Desperate times call for desperate measures

Several factors make it a gamble to seed canola.
Broadcast-canola
Some canola growers on the eastern prairies may still be trying to decide if they should broadcast seed or wait for better drying days, or simply write off those acres.

WESTERN PRODUCER — It’s June 7. Seed alone costs $80 per acre; total inputs cost $400 per acre. Is it worthwhile to make a mess of your land? Can you harrow and spray on time? Plus, it’s already a short season.

When you consider all these factors, is it worth the gamble to seed canola?

Some canola growers on the eastern prairies may still be trying to decide if they should broadcast seed or wait for better drying days, or simply write off those acres.

Canola prices will be high in the fall, most inputs may already be in the ground, but with saturated soil, do you have confidence you can harvest a profitable canola crop this fall?

It’s a difficult question and one that some advisers were reluctant to answer on June 3.

But now Canola Council agronomist Angela Brackenreed. She was happy to step up to the plate.

In a phone interview, she said there’s no rule of thumb guiding what to do and there’s no way to predict success.

“I’ve seen broadcast canola crops with survival way under 50 percent,” said Brackenreed, who farms at Justice Man.

“I’ve seen survival of broadcast canola all the way up to 90 and even 100 percent. Every seed dropped on the field germinated and survived. You don’t get that with the best drill.

In this scenario, they broadcast, did a light incorporation then got a light rain and everything was pretty much perfect. We bumped the seeding rate quite a bit because we expected poor survival, so of course that helped also.”

Brackenreed said seed-to- soil contact is essential to achieve any kind of crop with a harrow or shallow cultivation. If you broadcast today, you know that you’re already facing a short growing season. A higher seeding rate helps move that crop along. The same suggestions apply whether you seed with a Valmar, airplane or helicopter.

“The most common setup, and probably the best-case scenario, is a Valmar with a harrow dragged directly behind. Looking at the classifieds this past couple weeks, suddenly there’s a bunch of harrows on the market. People who have a set they don’t need realize there’s a big demand.

“Right now, all we can do is do what we can and hope Mother Nature is kind to us.”

Canola Council agronomy director Clint Jurke said before blowing on the seed, a grower should take a real good look at the numbers.

“If you can’t drill your seed into good soil conditions, than your yield expectations will certainly be impacted. And you also have the additional cost of trying to manage a poor canola stand through the season,” said Jurke in a phone interview.

“With a weak stand, you can count on additional herbicide costs. You’ll have some areas you can harrow and other areas you can’t get close to, so that means maturity will be very uneven. That impacts your fungicide application. At the other end of the season, you can start to get risk of frost and a very tough crop with highly variable moisture content.”

“I wouldn’t say I’m against broadcasting canola. I’d only say that a grower has to set realistic expectations.”

Canola Watch, published by the Canola Council of Canada, has published tips on broadcast seeding of canola. The tips are based on experience, observation and limited research. There has been no concerted broadcast research, so official recommendations do not exist.

The following points have been edited from a Canola Watch posting.

Timing — Manitoba crop insurance data shows canola seeded in the first week of June yields 90 percent of average. If early June broadcast appears to be the best solution, warmer soil should assist rapid germination and establishment of the seedlings with less risk of mortality from cool soils or frost damage.

Seeding rate — Seed germination and seedling survival could be lower than for seed drilled into a moist, packed seedbed, but not necessarily. In the Ultimate Canola Challenge site in

Manitoba in 2013, one team of experts chose to broadcast onto moist, warm soil, with exceptional survival.

With a seeding rate of 10 seeds per sq. foot, low emergence of 20 percent will result in two plants per sq. foot. A related study found an established uniform canola stand with as few as two plants per sq. foot generally had higher economic potential than a thicker stand reseeded late. If emergence is 80 percent, the population will be at the top end of recommended target of five to eight plants per sq. foot. This higher plant population has the benefit of earlier maturity.

Equipment — Floaters and Valmar applicators have a boom 60- or 70-foot boom that can be used to broadcast canola. Some applicators have multiple compartments, each with their own meters, to apply fertilizer and seed at the same time. Another option is a regular air drill with openers lifted out of the ground.

Fertilizer — A good-yielding crop needs fertilizer. Some take a chance and skip fertilizer, hoping to bank on a decent supply from soil reserves, but that hope rarely turns out well.

• Apply the recommended rate of phosphorus. The starter rate of phosphorus is not enough. Use the full recommended rate when broadcasting. Canola with phosphorus often gets off to a quicker start, which can reduce days to maturity.

• Use urease and nitrification inhibitors. Broadcast nitrogen has a higher risk of loss when applied on moist soils. Combination products with urease and nitrification inhibitors are a good choice to protect the nitrogen in this situation.

• Consider a slightly lower than recommended nitrogen rate, 85 to 90 percent of soil test recommendation for canola broadcast in late May or early June. The full rate of nitrogen could extend the required days to maturity.

• Seed soon after blending. When seed and fertilizer are blended days prior to application, fertilizer could reduce canola seed viability

• John Heard tested germination after blending with fertilizer. A day or two showed no significant effect on germination, but ammonium sulphate was particularly damaging when left longer.

• Fertilizer prills are abrasive and can remove some canola seed treatment. Ammonium sulphate blended with canola seed will often take on a blue tint, indicating a high rate of abrasion. Ammonium sulphate also has an affinity for moisture and can increase plugging in humid conditions. One benefit of blending phosphorus or urea with canola is that it bulks up the canola, thus making application less finicky.

• Consider a split fertilizer application. Broadcast seed first, then top up with appropriate nitrogen and sulphur if the crop establishes. Early access to nutrient is important for optimal yields, so top-dressing applications should be made as soon as possible after emergence.

• Broadcast nitrogen and sulphur first, then drill your seed. If the key barrier to using the drill is getting stuck pulling a fully-loaded cart, growers can broadcast nitrogen and sulphur, and use the drill just for seed and phosphorus. They won’t have to fill the seeder tank right full, which allows the drill into a field without getting stuck.

• Ammonium sulphate is particularly hard on canola seed germination when mixed and left for three or more days.

Residue risk — Broadcast seeding requires good seed-to-soil contact. A thick layer of thatch prevents seed and fertilizer from getting down to the soil surface. Cultivating ahead of broadcasting can create large clods and crusted soil surface.

Cultivate or harrow after seeding — Shallow cultivation or harrowing improves seed-to-soil contact. The ideal harrowing pass will run on a right angle to the floater pass. Therefore, harrow after the floater leaves the field, rather than chase the floater around the field.

Airplane or helicopter — If a field is too wet for a floater, it’s too wet for harrows and sprayers. Fields should be harrowed after broadcast seeding to loosen the soil surface and provide seed to soil contact, especially for seed broadcast onto stubble. Canola seed is very light and does not embed into the soil, even if dropped from an airplane at high speed. Aerial seeding also requires ground-based fertilizer application. The critical time for fertilizer application is within five weeks of crop emergence.

Weed control caution — Seeds on the soil surface are vulnerable to herbicide damage. Do not apply post-seed/pre-emergence glyphosate on Liberty Link and Clearfield seeds that have been broadcast and remain on the soil surface. Roundup Ready varieties can tolerate glyphosate at this early stage.

Yield expectations — Experience from 2010 and 2011 in wet conditions in the eastern Prairies has shown that growers who tried broadcast or aerial methods had issues all season with thin stands, uneven maturity, weed control, low fertility and poor yields. Best results were on fields that were fertilized early and harrowed to improve seed-to-soil contact. If field conditions allow for follow-up passes to harrow and apply fertilizer, it means the fields could also soon be ready to seed with the drill.

Regis Karamanos compared broadcast and row-seeded canola at six sites from 1997 to 1999. He concluded row-seeding had a significant yield advantage up to 0.58 tonnes per hectare in four of the six experiments and no significant difference at the other two. The yield advantage for row-seeded canola at the four sites was from three to 10 bu. per acre based on canola yielding around 50 bu. per acre. A 1977 study compared broadcast and drilled canola head-to-head. Drilled canola had a yield advantage, but broadcast results were still pretty good.

Contact [email protected]