Planting corn | Don’t ignore tube errors, says seeding expert
PORTAGE la PRAIRIE, Man. — People new to the nuances often assume that singulation and uniform spacing go hand in hand.
“Not true,” corn planter guru Bill Lehmkuhl told a corn planter school sponsored by Pioneer Seeds earlier this spring.
“Singulation and uniform spacing are two totally different issues,” he said. “The word singulation refers only to the way the meter takes one seed at a time off the disc and drops it down the seed tube.”
Lehmkuhl said growers often have perfect singulation but terrible spacing. People have to draw a clear distinction between the two definitions, he added.
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“Spacing refers only to the distance between the plants in the row,” he said.
“Singulation will always affect spacing if the singulation is bad, but even when singulation is good, the plant spacing is affected by what happens once the seed falls out of the meter into the seed tube.”
Lehmkuhl said seed problems within the tube fall into the category he calls seed tube error. It can start just as the seed is ready to be released from the metering disc.
“A little bit of static electricity might hold one seed just a fraction of a second too long. When the next seed comes along and they go down the tube together, obviously you’ll end up with a skip followed by a double.”
He said row unit bounce caused by tractor speed is a major factor contributing to poor spacing and is always one of the first things to examine when trouble shooting poor plant spacing.
“Even if singulation coming off the disc is perfect, a bouncing row unit causes the seed to ricochet and bounce around inside the seed tube, eating up precious time.”
He said it’s a two-pronged problem: higher ground speed creates the problem in the first place and exacerbates it by making the gap longer.
As the seed wastes time in the tube, the tractor’s faster forward speed means the planter covers more distance before the seed is dropped.
Seeding one m.p.h. slower will likely eliminate seed ricochet or poor spacing within the row.
The exact geometry of the backward arch of the seed tube helps the seed fall into the trench without bouncing on the tube walls.
“Theoretically, the seed should drop out the bottom of the tube with no acceleration forward or backward. Zero miles per hour.”
Lehmkuhl said the well tested design is “pretty well universal throughout the planter industry. Dickey John builds them for just about all planter manufacturers.”
For more information, contact Lehmkuhl at blehmkuhl@precisionagriservices.com.
