Seed survival: Are you at 60%?

May 17, 2017 - Issue 8

The seeding rate calculator at canolacalculator.ca defaults to 60% seed survival, which is fairly typical for canola in Western Canada.

If choosing the default isn’t your style, the best way to find out the typical seed mortality in your system is to start doing your own stand counts and cross-referencing that with your actual seeding rate in seeds per square foot. 

The following can also help to figure out what influences survival…

You might be at 70% or more if: Seed goes into warm, moist soil in mid May. The drill’s ground speed is slow enough to improve consistency of depth for each row. You use a low rate of seed-placed fertilizer.

You might be at 50% or less if: Canola goes into cool soils. This reduces survival but also greatly expands the germination period and reduces stand uniformity. Seed goes into dry soil. In dry conditions, seeding deeper to reach moisture might be a good strategy to at least get some seeds germinating, but this will keep survival low. High rates of seed-placed fertilizer will also reduce survival, especially in dry soils.

Also use the calculator to set seeding rates (lb./ac.) based on seed size. For example, large seed with a thousand seed weight of 6.6 grams, a target stand of 6 plants per square foot and 60% seed survival will require a seeding rate of 6.3 lb./ac.

A couple of things might jump at you in that paragraph, including:
1. The target of 6 plants per square foot sounds low. Doesn’t the Canola Council of Canada recommend 7 to 10 plants per square foot. We did. But new analysis of modern hybrid performance combined with current price per pound of seed led to a reevaluation of recommended target stands.
2. 6.3 lb./ac. may still seem too high, even with a lower target stand. If warm, moist soil conditions this time of year suggest a higher seed survival rate, enter 70% and watch the recommended rate drop to 5.4 lb./ac.

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