With conditions across the prairies bringing a lot more moisture than normal, it is a great time to review practices for Broadcasting Canola.
Published on June 16, 2022 in the Western Producer, here are some key takeaways:
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.
2. 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.
Floaters and Valmar applicators have a 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.
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.
5. 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.
6. 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.
7. 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.
8. 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.”