Demonstration plots to examine new closing systems
At planting, you want to leave the corn field with the confidence that you have a fighting chance for a picket fence stand that produces photocopy ears. Setting the stage for that goal includes proper seedbed preparation and planter setup, but the closing wheels seal the deal as the final contact in the planter pass.
Knowing that closing the furrow is a critical step in setting the seed for success, many manufacturers have released new closing systems. The attachments provide features that are not offered by the standard solid rubber and cast closing wheels.
In 2010, the Farm Journal Test Plots conducted its first year of a demonstration plot that put nearly a dozen closing wheel designs through the paces in a no-till field. Expanding the demonstration to two fields in 2011, Farm Journal Field Agronomist Ken Ferrie and his crew examined how the new-style wheels are designed to run in varying field conditions.
The plot itself is different from many of the studies that Ferrie conducts.
"We do this as a microplot. Every test row is next to standard rubber or cast wheels so we can compare side-by-side results," he explains. "To set up this plot, we had to keep in mind that closing wheel performance is tied to the unique conditions of the field. We focused on measuring emergence rather than taking it to yield, like we do in our other plots."
The crew returned to the plots to do 50' stand counts. This data was recorded to measure the difference in plants emerged at several 48-hour intervals.
"Uniformity in emergence affects ear count," Ferrie says. "The goal is for all the corn plants to germinate within a 48-hour window."
The closing wheel should securely seal the furrow and firm the soil in order to remove any air pockets, which reduces seed-to-soil contact and delays germination.
In this way, closing wheels are designed for specific soil conditions. For example, the rubber closing system is designed for mellow conventional tillage conditions. The cast wheel works in tougher field conditions, such as no-till. Many consider the staggered cast-iron closing wheel plus a drag chain to be the universal unit for ensuring that the seed trench is closed.
"Anyone who no-tills knows that the worst thing to do is to leave the slot open," Ferrie says. "The alternative styles of wheels with spikes, teeth or angled feet aim to provide the proper closing even in the toughest conditions."
The closers. Our demonstration plot included three solid wheels (Kinze cast, Kinze rubber and S.I. Distributing Close-N-Till); five spiked wheels (S.I. Distributing Finger-Till, Yetter Close-Till, Yetter Cast Spike, Martin Spader and Exapta Thompson); and three swept-back wheels (Great Plains Spider, Schaffert Mohawk and Yetter Paddle).
The solid wheels are designed to close and firm the seed furrow but have trouble crushing the sidewall in tough conditions.
The spiked wheels eliminate sidewall smearing in tougher conditions. While they can close the seed slot and ensure that it won’t crack back open, they are not designed to provide as much firming action for the soil around the seed.
The swept-back wheels firm with their footed design but might not be able to crush the sidewall around the seed in the toughest conditions.
The two test fields in 2011 had very different seedbeds. The first field was in-line ripped in the fall, had a burndown applied and then was hit with a vertical tillage harrow. "It was an ideal vertical tillage seedbed," Ferrie says.
The second field was no-till sod, the toughest conditions these wheels could be run in, Ferrie adds.
The two fields provided a spot where each wheel could be operated in the environment it is designed for as well as conditions that are outside of its recommendation. This allowed the plot team to see a wide range of performance and develop a better understanding of each system.
We also added accessories: a drag chain or the Yetter 6200 Firming Wheel to serve as equalizers for the closing wheels. "The drag chain can level the furrow and pull soil into air pockets left by the closing system," Ferrie says. "The firming wheel makes the setup a two-part closing system, similar to that of the Case IH row unit. The spiked closing wheel can break sidewall compaction and firm air pockets out of the furrow."
The crew also looked at the Exapta wedge, which can be added to the bolt that secures the closing wheel to the tail section. The wedge is an angled piece of iron that changes the pitch of the closing wheels to make them more aggressive at taking out sidewall compaction.
Overall, in the vertical tillage field with the burndown application, the staggered cast-iron wheel with a chain was tough to beat.
"The swept-back wheels provided some firming, but when we added the drag chain, the results with those wheels were right in line with the cast wheels," Ferrie says. "The spike wheels are more aggressive, and when we added the firming wheel those performed as strongly as the swept-back and cast wheel. Even the rubber wheels, when staggered and run with a chain, did surprisingly well, but those were outdone by the cast wheels."
The no-till sod field was intentionally chosen for some of the toughest conditions a planter would ever face.
"In this field, every wheel beat the solid rubber wheel," Ferrie says. "As they are designed, in these tough conditions the spike wheels did perform well. The swept-back wheels and the solid cast wheels needed the help of the wedge to make them aggressive enough to close the slot. However, by adding a wedge to the spike wheels, which are more aggressive to begin with, we could really take out the sidewall compaction. In the most aggressive setting, we can throw out the chunks of sod that stuck to the seed."
Ferrie tells farmers to make their field conditions paramount in a closing wheel decision and ask manufacturers about recommended field operations.
"The biggest challenge for farmers when trying to understand today’s options for closing wheels is that they take them for granted," he explains. "They might switch their seedbed preparation on some or all of their acres and not look at how that affects the process of closing the furrow and firming the soil around the seed."
In the spring, farmers need to stay on top of their planting conditions as the environment changes.
"Remember, the closing wheel can provide two functions: closing the furrow and firming it up so the soil doesn’t dry out. In typical no-till conditions, with a seed firmer, you should have plenty of moisture to work with, and getting the slot closed over the seed is the most important thing to accomplish," Ferrie says. "When you are worried about having enough moisture, the most important thing is to firm around the seed so it doesn’t dry out."
Smearing the sidewall is one of the worst things that can occur during planting. That leaves the slot open, which can lead to rootless corn, hatchet roots and uneven emergence—all of which undermine high yields.
Even so, Ferrie recognizes that planting conditions aren’t always ideal and that farmers have to deal with what Mother Nature delivers.
"Farmers need to consider their options if they have to keep planting in tough conditions when the timing window is slipping away," Ferrie says. "Most likely, 80% is ready to plant and 20% is not. In conventional conditions, you’d make a tillage pass; in no-till or vertical tillage, you can readjust the closing system to keep the 80% happy but close the furrow in those tougher conditions as well."