Single Seeds

Singulation is often overlooked, but research shows benefits to corn.

Todd Hesse (far left) of Ziegler Ag Products, shows farmers corn ears with good singulation (top row) and poor singulation. (Progressive Farmer image by Matthew Wilde)

If a student scores 95% on a test, it's an A. That's great in school, but not when planting corn.

Todd Hesse, ag technology, seeding and tillage manager with Ziegler Ag Equipment, told farmers during the 2019 AGCO Crop Tour they are sacrificing yield and money if they settle for a 95% singulation rate.

"That sounds great, but there's still a lot of improvement to be made if you take advantage of technology," Hesse says. "We can almost guarantee 99% singulation or better on our planter (White 9800VE Series) with vDrive and vSet. Anything less than that, and farmers can see a 2- to 6-bushel-per-acre (bpa) yield drop."

The equipment expert made the claim, backed up by company demonstration plot findings, during a Crop Tour field event at the Iowa Lakes Community College (ILCC) farm, near Emmetsburg, Iowa. It was one of five educational events held nationwide last year by AGCO and its dealers, such as Minnesota-based Ziegler, with 27 locations in the Upper Midwest. The tour showcased equipment, technology and agronomic demonstrations.

Singulation -- the measurement of dropping one seed at a time -- is one of four best-planting practices examined by AGCO. The others are downforce, seed depth and planting speed.

All are important, Hesse says, but singulation is often overlooked. Farmers at the Emmetsburg field day were asked their primary concerns during planting, and singulation wasn't a focus.

"I watch singulation somewhat when I plant, but there are so many things to monitor," says Tim Leuer, a local farmer.


If a planter skips a seed drop or plants doubles, yields diminish. A skip means no ear, and two plants too close to each other (a double) overcompete for nutrients, water and sun. One will act more like a weed and curtail growth of the other.

AGCO singulation demonstrations consist of "problem" rows using planter seed discs modified with plugged and extra holes to cause skips and doubles. The average singulation rate for these rows is 93.3%. Control rows were planted with White 9800VE Series planters factory-equipped with Precision Planting vSet meters and vDrive, achieving 99.6% singulation accuracy. The vSet meter features a flat disk with a single vacuum setting and a floating, five-lobed singulator that makes sure no two seeds can occupy the same hole. The vDrive is an electronic drive system that allows row-by-row control of vSet meters.

Control rows with nearly perfect singulation averaged 5 bpa better than poorly singulated rows across more than 6,000 acres of side-by-side Crop Tour corn plots in 17 locations from 2016-18. That's a 0.8 bpa gain for every percentage point improvement in singulation.

"Singulation is the first thing you can control before the seed drops; it's the first step in the (yield potential) pyramid," Hesse says.

Iowa State University hasn't conducted singulation studies yet, Extension cropping systems agronomist Mark Licht says, and he doesn't dispute the AGCO numbers.

"Singulation is an issue with corn," he adds.

Precision Planting, an AGCO subsidiary, conducted a singulation study in 2018 on its research farm in Illinois. A 95% seed singulation rate resulted in a 10.4-bpa yield loss versus the control at 99.5%. At $3.50 per bushel, the economic loss was $36.49 per acre.


Two rows of shucked corn from the 2019 singulation study at the ILCC farm were laid out on a table. Thirty-two consecutive ears were picked from a row with near-perfect singulation and a row with poor singulation.

Jason Lee, AGCO North American agronomist, pointed out the differences to tour attendees.

"One thing I immediately notice is the consistency in ear size," he surmises. "Where you have poor (singulation), you get a lot of nubbins. There are 14 ears not filled out like they should be. The top row (good singulation) only has five."

Lee and Hesse estimated a 3-bpa difference between singulation examples.

"The one take-home message is: If you are not measuring singulation and plant spacing yet, do it," Lee says. "The more variability, the more harm done to yield."

Glenn Young, who farms near Estherville, Iowa, isn't concerned about singulation. But, he wanted to see the consequences of too many skips and doubles.

"I knew they were planning to screw up intentionally, and I wanted to see the effects," Young says. "Singulation is good in my fields; it rarely dips below 95%."

Leuer strives for a 90% singulation rate or better but wants to improve. Future commodity prices will dictate when planter upgrades can be made to do that.

"If you don't have seed in the right place, you won't get the yields," Leuer says. "I would like to (upgrade), but it's expensive. You have to take that into consideration."


Singulation has a direct correlation to yields when planting corn. But, how about soybeans?

"Generally speaking, most farmers aren't concerned about singulation when planting soybeans," says Mark Licht, Iowa State University Extension cropping systems agronomist. "Traditional thought is it doesn't matter since plants compensate so well to having neighbors." That might not be the case in all seeding environments, according to Beck's Hybrids.

The seed company conducted soybean singulation studies last year for the first time after its row-spacing research showed 10-inch rows outyielded 15- and 30-inch rows by 6 and more than 10 bpa, respectively. Jason Gahimer, Beck's Practical Farm Research (PFR) operations manager, says the only noticeable difference was the singulation and seed spacing was better in 10-inch rows, which led to the soybean singulation studies.

"We typically see a lot more branching, which collects more sunlight in narrow-row environments with seed planted several inches apart," Gahimer says. "That leads to more nodes, pods and seeds, and larger seeds, as well. All those things contribute to higher yields."

Soybean singulation studies were conducted at Beck's six PFR sites across the Midwest.

Ten-, 15- and 30-inch rows were planted with seeding populations of 100,000, 140,000 and 180,000 seeds per acre. Individual seed spacing ranged from a little over an inch to more than 6 inches apart. Row width and seed population dictated seed spacing.

For example, seeds were planted 6.27 inches apart in 10-inch rows with a seed population of 100,000. Seeds were 1.16 inches apart in 30-inch rows with a seed population of 180,000. Seed spacing may vary a little due to seed roll once it's dropped in the trench, Gahimer says.

The 2019 data is still being collected and will be published in Beck's annual PFR book this winter.

"For farmers with the ability, we hope the trials show to plant soybeans at the same time as corn and take time to singulate and space seed; do all the little things the like with corn," Gahimer says. "In 10-inch soybean environments, we believe there is an advantage to singulation. Maybe up to 3 bushels better. I think there is more value singulating soybeans in 15-inch rows than 30-inch rows."

Beck's plans to continue soybean singulation research in 2020 through its PFR program.


> Three years of AGCO Crop Tour results are summarized here:

> Follow Matthew Wilde on Twitter: @progressivwilde


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