Testing a Hydraulic Down-Pressure System
With about 500 acres of corn and soybeans divided between the Missouri River bottom near Percival, Iowa, and the rolling hills north of Sidney, Randy Grudle and his son, Erik, deal with a wide range of soil types and planting conditions. While the Loess Hills near their home farm consist of light soils that were deposited by the wind over several million years, the river-bottom fields some 10 miles away are table-top flat and consist of heavy, black soil. Adding to the challenge are the dozens of terraces the Grudles have installed on hillside fields to conserve topsoil.
Fortunately, the Grudles essentially leveled the playing field in early 2013, when they field tested a new hydraulic downforce system from Ag Leader on their 16-row John Deere planter. This past spring, they swapped out that system for the newest edition that has since gone on the market.
As Randy explains, he and Erik had already opted for a factory-installed pneumatic down-pressure system when they purchased the planter four years ago.
“I’m not sure the air bags really worked any better than down-pressure springs,” he admits. “The biggest problem is with corn-on-corn, which accounts for about 200 acres. Soybeans are pretty forgiving. Even if the depth isn’t consistent when planting into corn stubble, as long as the seeds make contact with moisture, the crop will come up.”
But corn isn’t like that. “You’ve got to get it in the ground; and that’s why we switched to the hydraulic system. It’s not as much of a challenge when planting corn into soybean stubble, but corn-on-corn can be a challenge due to the residue and root balls on the surface,” he notes.
Even though the air bags could be adjusted from the cab, Grudle says it was hard to know where to set them. Since there was no individual or paired-row adjustment, there also was no variation across the width of the planter.
“With this system, I don’t know as I’ve ever found corn laying on the surface,” Erik adds. “In fact, it’s a rare occasion to find corn seed that’s not right there at 2 inches. The emergence is tremendous. Virtually all of it comes up at the same time.”
Randy admits that even though he has heard good things about some of the aftermarket pneumatic downforce systems, one of the things that appealed most about the hydraulic system was the fact that it used the same Ag Leader monitor he already had in the cab for satellite-assisted guidance.
As the one who most often does the planting, Erik says the thing that surprised him the most was the amount of variation across the width of the planter bar.
“Sometimes I saw the center section reading 300 pounds when the outside ends were at 80,” he recalls. “Other times, it would be under 100 all the way across. I think 385 was as high as I ever saw it go, and 80 was about as low as it ever went. But it was almost always the center section, where the tires ran, that required the most down pressure.”