In the rush to get canola seeded at the optimal time, or even at all, seed placement is often compromised by speed. Yet producers, often under weather and time constraints, sometimes rush through seeding. Doug Moisey of the Canola Council of Canada says that, based on field-scale research he’s done with producers, faster seeding speeds can result in 20 to 30 per cent fewer plants. If faster seeding speeds are combined with lower seeding rates, the total plant count can be less than optimal, which may affect yield.
“It’s just because that seed is deeper and is not coming out of the ground, or is stranded right on the surface,” Moisey explains.
Seeding too quickly can also bounce the seed right out of the furrows or put the seed in the fertilizer row, as the seed shelf won’t be established, Moisey adds. Fast-seeding speeds over uneven ground can make larger drills bounce, creating a wave pattern. All these issues can add up to variable emergence, which causes problems for the rest of the season. Variable emergence makes it hard to know when and where to start controlling weeds, apply fungicides or swath. Ultimately, all these issues can reduce yield.
Moisey says that the optimal seeding speed depends on many factors. “Number one, it’s the soil type. It’s the type of opener you use. It’s the time of year.” He adds that producers seeding into a lot of straw will likely have to slow down more than those seeding into pre-worked soil.
Precise placement more important
However, simply slowing down does not guarantee consistent canola emergence.
“It’s not just slowing down. It’s about seed placement and depth,” says Neil Harker.
Harker and his colleagues at Agriculture and Agri-Food Canada (AAFC) conducted a three-year study on canola emergence at four different sites in Western Canada. Each May, they seeded canola at a rate of 150 seeds per square metre. Seeding depth was set at one or four centimetres and the speed at four or seven miles per hour.
Seeding at seven miles per hour did reduce crop emergence, especially when soil from the back shanks covered front shank rows, burying the seed deeper than intended. However, in AAFC’s trials, seeding depth was an even bigger factor than speed. Canola that was seeded at four centimetres usually had much poorer emergence than canola seeded at one centimetre, no matter what the seeding speed.
Proof is in the placement
These results ring true for Kris Mayerle, who grows canola near Tisdale, Saskatchewan. Mayerle is taking part in a canola trial organized by the Northeast Agricultural Research Foundation. In the spring of 2011, Mayerle seeded 100 acres to canola at speeds ranging from three to seven miles per hour. Plant counts done 10 days and three weeks after seeding showed little difference in emergence.
“We had as many or better plants as our speed increased, which is the opposite of what you’d expect,” says Mayerle. He adds that the other canola producers taking part in the trial are seeing similar results. However, he knows of trials in northwestern Saskatchewan that showed increased seeding speeds led to decreased plant counts.
Producers in the Tisdale area had a lot of unseeded acres in 2010, which may have been a factor in the 2011 research trials.
“In my case, I was seeding into summerfallow that was pre-worked,” says Mayerle. Mayerle has 12-inch spacing on his drill, so he didn’t have as much soil being thrown around as someone with 10-inch spacing. He adds that other co-operators with 10-inch spacing were seeding into standing wheat stubble with firmer soil, which he thinks may have cut down on the amount of soil covering the seed.
The biggest factor in the trials may have been seeding depth. Mayerle says that despite the variation in speed, seeding depth was consistently between a half-inch and three-quarters of an inch.
Both Harker and Moisey suggest that producers get out of their tractors to check the depth they’re actually seeding at. “Most people are unaware of how deep they really are,” says Harker.
“Every field is different, so it’s good to be checking depth at all times,” Moisey says. He explains that soil type can affect seeding depth, and recommends producers check their seeding depth every couple of hours.
Though the Canola Council of Canada never recommends seeding deeper than one inch, producers may be able to chase moisture in the last part of May if the soil in the top inch is warm and dry. Moisey recommends bumping up seeding rates if producers are planning to seed deeper in such a situation. However, he warns that seeding deeper is still a risky strategy.
Harker suggests that producers take into account historical weather patterns in their areas before seeding deeper. For example, despite dry conditions at the Lacombe, Alberta, research site, AAFC still seeded shallow because they knew they would probably get rain later in the spring. However, when they faced dry conditions at Scott, Saskatchewan, they chased the moisture, with good results.
“The recipe of seeding at one depth doesn’t work in a real dry year. You’ll get hurt by leaving it stranded,” says Harker.
Seeding rates also play a role in canola emergence. Though dropping seeding rates may save producers money in the short term, it can cost them later in the season. Moisey says canola producers should aim for six to 16 plants per square foot. Ten plants per square foot is ideal or eight plants per foot of seedrow for producers with wider row spacings.
Despite the time pressures canola producers face in the spring, it’s worth checking seeding rates, depths, and speeds.
“If you set up the crop early in the spring time with a nice, even stand, it sets you up for the rest of the year,” says Moisey. “It’s really important, even if they’re under time crunches, that guys watch what they’re doing and take the time to do it properly with canola. It’s still a very small seed going into a very harsh environment.”
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