McMillan: Aim high on seeding density, canola expert says

Seeding is now active across most of the Prairies, but is running one to three weeks behind normal, leaving farmers eager to get seed in the ground as soon as possible.

It pays to ensure the job is done right the first time. Autumn Holmes-Saltzman, agronomy specialist with the Canola Council of Canada, says “Take the time now, in springtime, to set yourself up for success over the rest of the season.”

Her message was clear: the impact of poorly-established canola crops lingers throughout the rest of the season.

The first goal to achieving the highest yield possible is ensuring a uniform and strong plant stand. The recommended number of plants per square foot varies anywhere from five to 15. The Canola Council of Canada recommends targeting 10 plants/sq.ft., because that stand density resulted in yields within 10 per cent of the top yield potential.

Holmes-Saltzman recommends to growers, “Aim high. Targeting a high plant density leaves you room for environmental, pest, mechanical and operator error.”

If growers target 10 plants/sq.ft., even if some individual plants are lost, the remaining plants can compensate, resulting in yields that are close to their potential. Canola adapts by changing the number or size of branches per plant, or pods per branch.

The ability of plants to compensate, of course, has limits. Although some growers have had decent results from as low as two plants/sq.ft., that normally only occurs under very favourable circumstances.

Holmes-Saltzman cautions growers, “Don’t cut seeding rates under any circumstance. Reduced rates add a lot of risk to your operation.”

Lower plant populations mature later, increasing the risk of frost. They can be more variable in development and maturation. This makes sclerotinia management more challenging and increases the amount of green and small seeds.

Seeding depth is one of the other crucial considerations. Since canola seeds are small, they cannot push to the soil surface from the same depths that larger cereals can. The deeper the seed, the colder the soil, which also slows germination and increases the risk of diseases infecting the seedling.

Seeding from half an inch to one inch depth is ideal, depending on moisture and seed bed conditions. Holmes-Saltzman said it is important to check seedling depth after the first 100 feet or walk over the previous pass to get an accurate measurement of depth when travelling at full speed.

Inaccuracies

With the push to get acres sown, farmers may be tempted to seed faster than normal. Seeding speed is a function of equipment efficacy — and increased speed can lead to inaccuracies of seed placement.

In some situations, this may simply lead to variations in emergence timing. When side-banding with fertilizer, canola seed can be placed too close, causing fertilizer burn. Increased speed can also lead to more soil disturbance causing buried rows. Faster seeding also means faster fan speed, causing cracked or damaged seeds.

“There is not one best speed of seeding, but in general the faster you seed the more inaccurate seed placement will be,” Holmes-Saltzman says.

Even with the pressure to get acres sown as fast as possible, ensuring the right steps are taken at the start of the season is crucial to avoiding later problems.

“Getting canola off to a strong start in the springtime by targeting a thick plant stand is one of the most important steps to guarding a high yield potential,” Holmes-Saltzman says.

— Stuart McMillan writes from Winnipeg on weather and agronomic issues affecting Prairie farmers.

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