As the average number of acres individual farmers have to seed in a year continues to grow, there is real pressure to cover ground as quickly as possible. But according to agronomists and machinery engineers, the old expression “haste makes waste” is something to keep in mind. The care and accuracy — or lack of it — that went into seeding operations will ultimately be reflected in a crop’s yield.
Even though most producers have likely heard it before, ensuring seeding equipment settings are checked prior to hitting the fields is an absolutely essential requirement. Despite that, agronomists say improper seed placement remains a common problem limiting yield — and profit. When it comes to seeding accuracy, there are some real benefits to getting it right. “The first step is to check the machines,” says Patrick Mooleki, a soil nutrient management specialist with Saskatchewan’s Ministry of Agriculture.
What you’re looking for depends on the type of seeder used. When the opener depth is controlled by the seeder’s frame, the first thing to do is ensure it sits level when attached to the tractor. “In some cases they are not balanced,” says Mooleki. If so, getting accurate and even seed placement will be nearly impossible.
Garth Massie, a corporate agronomist for air seeder manufacturer Morris Industries, says start the process of leveling a seeder’s frame by picking a level section of field, then seed a short distance at no more than four miles per hour. Use a straight edge about four to six feet in length and lay it across the seed rows. Dig down to find the seed then measure the distance up to the straight edge. Do this across the width of the seeder. If the measurements are consistent, the frame is level.
This process will also reveal any differences along each wing section compared to the main frame. After making these measurements, check the differences between the depth of seed placed by front rows compared to the rear. If there is any, the frame isn’t level from front to back.
For seeders with independently linked openers, the process is a little different. “Check for seeding depth by removing the packed soil until the seed placement zone is found,” says Massie. After finding it, measure up to the top of the packed soil. Going through that procedure for every opener is the only way to get an accurate picture. Adjustments can then be made to each opener individually to even things out.
It might seem like a lot of work, but Mooleki says it’s important to check every seed row, no matter what type of drill you are using. That way it’s possible to identify a problem with a particular opener that may not be immediately obvious.
CHECK EVERY FIELD
Once you’ve finished all this, there is still some work to do. Soil conditions can greatly affect seed placement, so it may be necessary to fine tune those initial settings to each specific field. “Depending on how soft the soil is, that (original depth measurement) may not be where the seed is placed,” says Mooleki. Checking placement accuracy in each field is the only way to be sure it remains consistent. “Soil conditions are going to change (from place to place),” he adds.
Blaine Metzger, a project manager at the Alberta Ag Tech Centre at Lethbridge agrees. “You should check your depth in every field,” he says. Growers need to pay particular attention to placement accuracy in the first few rounds. After manually checking placement a few times during those initial passes, an operator should have a good idea of how well things are working.
Metzger says varying soil moisture levels and even the different
check seeding depth accuracy for maximum yields
types of crop stubble will cause variations in placement, which is part of the reason he recommends checking it in every field.
SLOW AND STEADY
There are other factors that affect seeding depth as well, and ground speed is one of the most important.
Increasing field speed makes it harder for any style of seeder to penetrate the soil. “The faster you go, the more it tends to ride out,” says Metzger. “The trip mechanism on the shank has a problem keeping the opener in the ground.” That can cause shallow seed and fertilizer placement.
Further aggravating the problem is openers cause more soil disturbance at high ground speeds. “The faster you go the more the opener throws soil. It has less time to flow around the opener,” adds Metzger. And that leads to a reduction in the amount left behind to pack on top of the seed row, causing seed depth and seed-to-soil contact to vary considerably. On top of that, soil can be thrown onto furrows left by adjacent openers, causing even more depth variations.
High travel speed also means seed and fertilizer coming out of the knife will tend to roll and
The photo on the left demonstrates good, uniform canola emergence, in part due to proper depth. The photo on the right shows the impact of seeding too deep.
bounce, which can increase the likelihood of mixing on double-shoot applications, leading to increased seed mortality and reduced germination.
According to Doug Moisey, an agronomy specialist with the Canola Council of Canada, a series of trials sponsored by provincial canola grower organizations and Agriculture and Agri-Food Canada has demonstrated that incorrect seeding depth can be a major limiting factor for canola yields. “Seeding too deep results in variable and lower emergence rates. Low plant populations combined with poor emergence and variable staging can result in a 17 to 20 per cent yield loss or more compared to uniform stands with adequate plant populations,” he says. The trials also showed weather influenced those numbers. “That (yield loss) can vary depending on the year,” he adds.
Moisey says the variable emergence associated with placing seed too deep can create other problems for producers during harvest. It creates a wide variation in plant maturity across a field, so deciding when to swath can be problematic.
The only way to avoid all these problems is for producers to get down on their knees a few times in the spring to find out exactly what is going on behind a seeder.
“You’re going to have to get dirty,” says Metzger.
Scott Garvey is machinery editor for Grainews. He also runs a cow-calf operation at Moosomin, Sask. Email him at scott. [email protected]