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.
- March 2012