Canada
April 15, 2013
Canola stand establishment benefits from a shallow seeding depth of between half an inch and one inch. The question is whether the drill can achieve this depth consistently from row to row.
“For some drills, the overall average depth may be an inch, but some runs could skim the surface while others are down two inches,” says Shawn Senko, Canola Council of Canada (CCC) agronomy specialist. “Even if those very shallow and very deep seeds do emerge to form plants — and many of them won’t — the wide range of emergence dates will present challenges all season long for pest management and harvest timing.”
A first step is to inspect openers, trips and tires. Replace openers worn to the point where soil penetration, seed placement and fertilizer-seed separation are compromised. Worn trips will result in poor penetration and may inconsistently trip in and out of the ground, affecting depth. Worn tires or tires that won’t maintain air pressure can also influence seed depth consistency.
Next, level the drill from side to side and front to back. This can improve any drill — old or new. Find a flat, ideally concrete, surface and check that each opener sits at the same depth. Check the manual or with the manufacturer for tips to level the drill and, if necessary, make adjustments to individual rows. “Growers who get drills leveled are sometimes surprised at the differences from row to row,” Senko says.
While doing the pre-season inspection, check shank bushings, disk bearings, meter rollers, packers and packer bearings for wear. Also check hoses, tank gaskets and manifolds. Replace any parts worn beyond recommendations. These parts will not influence opener operating depth, but may influence seed placement and packing performance — factors in uniform emergence.
After the drill is ready to go, check a number of runs again in the field as seeding depth consistency can change under draft pressure. To check seed depth in the field, start at least 150 feet behind where the drill stopped or walk over to the previously seeded pass. “You want to check seed depth at a spot where the drill would have been moving at full speed. That way, the seed depth measurement will accurately reflect what the drill is doing,” Senko says.
Use a seed depth tool to carefully dig to the bottom of the seed row furrow or to where the opener normally places the seed. Check a few rows to make sure depth is consistent and on target. Adjust air velocity if seed bounce is evident. Seeding speed may also be a factor.
“Find a speed that balances consistent seed placement with your need to get the job done in a timely fashion,” Senko says. “At higher speeds, rear openers tend throw more soil over the front rows, which delays and reduces emergence rates for seed in those front rows.”
While looking at seed depth, check that packer wheel, gauge wheel and down pressure settings are appropriate for soil type and moisture conditions. Heavy packing in moist conditions, for example, can increase crusting in some soils.
Residue can also be a factor in seed depth. Inconsistent spread of residue at harvest can influence seed placement in no-till situations — especially when seeding shallow. “It is important to know how your drill penetrates through that thatch layer to achieve the soil contact seed needs,” Senko says.
Independent link opener systems and some disc drills provide advances in seed depth management from row to row, but it is worth checking seed placement with these drills as well.
“Seed depth is always important for canola,” Senko says, “but if we have a late spring in 2013, shallow and consistent seeding depth across the width of the drill will provide the uniform and rapid pop up your crop may need to mature in time to maintain high quality at harvest.”
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