Dry conditions at seeding followed by plenty of rain left some canola growers in Western Canada wondering if their canola had enough nitrogen to reach its yield potential.

As a result, there was increased interest in top-dressing N on canola this growing season.

As Jack Payne, regional agronomist with Farmers Edge, explains in this Canola School episode from CanolaPalooza in Lacombe, the decision to apply a rescue treatment of N must be made early — it should be done before the crop starts bolting.

“When you’re looking at top-dressing, you have to make that decision fairly soon,” he says, noting canola’s largest uptake of N is in the first six to eight weeks of development.

You also have to keep in mind it’s not immediately available to the crop and could take 10-14 days to be taken up by the plant, he notes.

Ultimately, as canola yield targets have climbed from 40 to 70-plus bushels/acre, so have the nitrogen requirements for the crop, forcing growers to look at alternatives for applying N. As Payne explains, each bushel requires 2.8 to 3-plus pounds of N.

“If we look at a 70 bushel crop of canola, it’s going to require 200 pounds-plus of nitrogen to meet that yield,” he says. “We can’t put all that physical product through the air-seeder.”

That might mean more top-dressing in the future, or applying prior to seeding, either by broadcast or banding.

“We have to sometimes think outside the traditional one-pass system,” says Payne.

Related: Canola School: N Sensing Tech in the Palm of Your Hand

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