There’s no question about the value of grain drill calibration, since drills meter by volume rather than by individual seeds. Planting more than the recommended seed rate obviously wastes resources and money. Just as bad, planting too little seed can result in thin stands that don’t produce to the field’s full yield potential. Plus, the thin stand makes the crop more susceptible to weed pressure, which can hurt yields even more.
Unfortunately, the normal procedure for grain drill calibration takes time plus a handful of tools that include everything from a hydraulic jack and a postal scale to sandwich bags and a tape measure. The goal is to count the number of seeds dropped over a certain area by rotating the drive wheel or pulling the drill a specified distance. Moreover, the process should be repeated for each new variety or seed size.
It’s little wonder that many producers simply use the seed chart that was supplied with their grain drill as a basis for setting the seed meters.
Calibrate from the cab
On the other hand, equipping the drill with a scale system allows you to go straight to the field and calibrate the unit the entire time you’re seeding.
Consider this from Nick Von Muenster, our President here at Scale-Tec. “The standard procedure for calibrating a grain drill prior to planting generally consists of collecting seed in a tarp or sandwich bags attached to the drop tubes over a given distance,” he says. “Next, you need to weigh the seed and then calculate the population based on seeds per pound.” (Every container of bagged or bulk seed, including soybeans, includes a seeds-per-pound listing.) “Of course, checking the rate in the field means getting out of the cab, doing a little bit of digging and counting the number of seeds within a certain area.
“Yet, a scale system on the drill can tell you the same thing so much faster and easier,” he continues. “With a scale on the grain drill or air seeder, you simply plant a known amount of acres, look at how much weight you’ve distributed over that number of acres and do a simple calculation to see if you’re on rate, above rate or below rate. Then you can make a quick adjustment. Just as important, you can check the calibration at any time throughout the field as conditions change.”
Adjust quickly to manage variables
As most university extension specialists are quick to point out when giving calibration advice, a number of variables affect seeding rate, including differences in seed size, seed coatings and seed treatments. As an example, one Nebraska winter wheat variety evaluation revealed that the number of winter wheat seeds in one pound can range from more than 20,000 to less than 10,000, depending on the variety and the year it was produced. Similarly, seed coatings and treatments can slow the movement of seed through a grain drill or air seeder and affect rates in a way that isn’t always measured using standard calibration procedures.
Finally, it’s generally recommended that small grain seeding rates should be increased once the optimum planting dates have passed in order to offset the loss of tillers and ultimately reduced yield potential caused by the delay. In every case, it’s important to recalibrate your drill. Yet, how many producers take the time to recalibrate when planting is already running behind?
Producers may also lose confidence as they move from bagged seed to bulk seed. When using bagged soybean seed, for example, producers can count the number of bags used in a specific field area, but without a scale it is more difficult to judge seed usage when filling from a bulk container.
“Regardless of the challenge, a scale system on the drill or air seeder makes it fast and easy to set and/or verify calibration,” Von Muenster concludes. “We know that there are a lot of factors that affect seeding rate and seed flow through the seed meter and seed delivery tubes. So, having a scale on the machine simply allows you to monitor those situations and adjust to them in the field rather than just once or twice before you go out to the field.”