Closing in on the Seed

February 7, 2011 06:15 AM
Closing in on the Seed

The final contact that your planter makes with the seed every spring can hold the secret to taking yields to the next level.

"Furrow management plays a bigger role in uniform emergence than most farmers realize," says Farm Journal Field Agronomist Ken Ferrie. "The closing assembly’s job is to make sure every seed has uniform contact with the soil and to firm the soil enough to keep the seed environment from drying out," he explains.

Ferrie encourages farmers to build the foundation for higher yields with picket-fence stands and photocopy ears. He leads the Farm Journal Test Plots crew to the field with new equipment designed to tackle the production challenges of today.

The decision of which style of closing wheel to outfit your planter with is driven by tillage system, soil texture, field conditions and weather.

Manufacturers have responded to today’s production practices with a spectrum of closing assembly designs.

"There are two trends that are increasing the challenges when selecting the correct closing wheel: variability within a field and variability from one field to the next," Ferrie says.

Particularly for those working in no-till and strip-till fields, when it comes to the planting pass, most farmers have to deal with balancing the optimum planting date and optimum planting conditions.

In tough no-till conditions, it can be easier to smear the sidewall and not have good seed-to-soil contact. If there is an open slot or sidewall smearing, it will be harder to get water into the seed for germination.

If you do tillage before the planter, it’s easier to get even soil moisture across the field. In no-till fields, it’s more challenging to find that balance. Even if 80% of a field is fit to plant, it’s the other 20% that is still too wet where it can be difficult to keep the furrow closed.

"If you’ve no-tilled corn for long, you know that the bushels lost can be dramatic when you’re unable to close the slot," Ferrie says. "Ten years ago, a farmer was much more likely to use one method to manage soils across all acres. Today, it’s common to use no-till, strip-till and conventional tillage depending on soil conditions."

New-style closing assemblies have been added to the available rubber and solid cast-iron options. To evaluate these options in a demonstration plot this past spring, we outfitted one planter with 10 different closing wheel styles. They included: Great Plains Spider Wheel; Kinze solid cast iron; Kinze rubber; Martin Dimple; Martin Spader; S.I. Distributing Close-N-Till; S.I. Distributing Finger Till; Yetter Close-Till; Yetter 6200 Firming Wheel; and Yetter Spiked Wheel with Scraper.

The field used for our demonstration has been in continuous no-till corn-soybean rotation. Planting conditions were fair, with 80% of the field fit to plant and 20% marginal.

From the bottom up. The process of properly closing the seed trench includes closing the furrow from the bottom up. When planting in marginal conditions, firming from the bottom up can be hard to achieve.

"When forced to plant later in the season, many no-till farmers have found that using spiked closing wheels allows them to move forward and plant in moist conditions," Ferrie says.

The wheels we tested range in their aggressiveness for closing and firming the furrow.

"At all costs, the furrow must be closed," Ferrie says. "Soil textures and moisture dictate the aggressiveness demanded to shut the slot, which means that tough no-till fields need an aggressive closing wheel."

While rubber closing wheels are adequate for conventional tillage or coarse soils in no-till, they may run up against their limitations in no-till fields with clay-structured soils.

Solid cast-iron closing wheels, however, are somewhat more universal.

"They can do a good job in conventional tillage without too much tail pressure, and they can be quite effective in no-till with more down pressure," Ferrie says. "But they too can meet limitations in the toughest soil and field conditions with high moisture and high clay content."

Ferrie recommends that farmers run rubber and cast closing wheels in a staggered position on the planter to better close the furrow. A seed firmer is an asset to any planter, he says, and it plays an important role when running spiked closing wheels to tuck the seed into moisture.

If you’re switching between conventional tillage and no-till in a season, you can mix and match a combination of spiked wheels that give more firming action. If you don’t want to make changes to your closing wheel assembly, consider adding a drag chain or firming wheel behind each row.

Ferrie notes that many farmers have taken to running a drag chain behind their closing wheels to help smooth the final seedbed. While spiked wheels can fracture sidewalls that were smeared by the disk opener and close the furrow over the seed, in tough conditions they can also leave air pockets that lead to soil drying out around the seed. Dragging a chain behind the spiked wheels can help fill in some of the air pockets and reduces the chance of the seed drying out.

"Dragging a chain behind all closing wheels isn’t a bad idea," Ferrie says. "It leaves behind a level seedbed."

The packing action provided by the Yetter firming wheel was similar to that of the chain in leveling the furrow; but at the same time, it firmed the soil and removed air pockets.

"The combination of this firming wheel with spiked wheel assembly is a unique combination for farmers who want to plant in no-till and conventional tillage conditions with a single setup," Ferrie explains.

Dig to check. The best way to check closing wheel performance is to do some digging behind the planter.

"We dig a cross-section of the row and work until we can find the seed and observe how it was placed in the soil," Ferrie explains. "In ideal conditions, you want to see the seed at the bottom with enough firm soil over the top of it to keep the seed area from drying out."

Eliminating air in the furrow will encourage even emergence.

"Spiked closing wheels can create a uniform microenvironment for the seed, but closer to the surface it can be loose," Ferrie says.

Firming the soil evenly across the surface with either a drag chain or a firming wheel will ensure good crown root development if the weather turns dry after the plant emerges.

Comparing Wheels

GreatPlains BlackGreat Plains Spider Wheel

This wheel pulls the soil back over the row with its angled spoked feet and clears away heavy residue. It provides good seed-to-soil contact as it crushes the sidewall.


cast Kinze Cast Iron

Solid cast-iron wheels feature an increased weight and sharp cutting edge that provides a more universal fit for conventional tillage and no-till with adequate closing and firming.


RubberKinze Rubber

Rubber closing wheels are best suited for conventional tillage. These lightweight wheels can close the furrow from the bottom up with enough firmness to keep soils from drying out.


Martin DimpleMartin Dimple

These less aggressive wheels with a dimpled diameter are designed for lighter soils, such as sands. They can be used in no-till but are best for conventional tillage and strip-till.


Martin SpaderMartin Spader

Two spader wheels are recommended in no-till to break up both sidewalls of the furrow. In conventional tillage and strip-till, the planter can be outfitted with one spader and one solid wheel.


SI closentillS.I. Distributing Close-N-Till

As another alternative to solid cast iron, these wheels squeeze the slot together without causing it to dry out. Fins on the side are designed to break clods and refine the top layer of soil.


SI fingertillS.I. Distributing Finger Till

Compared with solid cast-iron wheels, these are lighter weight but more aggressive for hard no-till conditions. The wheels feature fins for firming and spikes on the outer diameter.


Yetter CloseTillYetter Close-Till

The depth ring is built into the casting of this wheel to control depth so the spikes do not interfere with seed placement. Its 15" diameter allows it to be run one per row, opposite a solid wheel.


Yetter FirmingWheelYetter Firming Wheel

This packer wheel features spring tension and can be adjusted for weight. Designed for use with spiked wheels, it ensures a closed trench and no air pockets.


Yetter spikescraperYetter Spiked Wheel with Scraper

This wheel’s teeth lift and fracture soil. A depth band controls spike depth and prevents seed dis-turbance. The scraper cleans the wheel as the spike exits the soil.


Thank You to Our Test Plot Partners

Each Farm Journal Test Plot is a cooperative effort. Thanks go to: Yetter Manufacturing, Pat Whalen, Susan Wherley and Scott Cale; Great Plains Manufacturing, Tom Evans and Doug Jennings; Kinze Manufacturing, Susanne Veatch, Laura Blomme and Mike Feldman; Martin Industries, John Martin and Ronnie Hoult; S.I. Distributing and Dave Burgei; AutoFarm; McCormick USA, Doug Rehor and Kurt Schneick; Precision Planting and Gregg Sauder; Rod Wilson; Crop-Tech Consulting, Brad Beutke, Isaac Ferrie and Jason Keinast. 

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