Growers who broadcast canola with a cut rate of fertilizer (or perhaps no fertilizer in the case of aerial seeding) may want to wait for crop insurance to approve the stand before investing in a fertilizer top up. Evaluating the stand will also be necessary to set a reasonable yield target for fertilizer applications.
The window for nitrogen top dress is fairly narrow but you still have time. For canola, maximum rates of nitrogen uptake occur from about the 5-leaf stage to full bloom. Nitrogen must be applied well before that period because rainfall is required to move the fertilizer into the root zone and make it available for uptake. Nitrogen applied later — during peak uptake — will not get to the roots in time to contribute to yield or profit unless it rains immediately after.
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