The closing wheels were evaluated with replicated 50' stand counts that were taken every 48 hours after first emergence.
Three-year study examines closing wheel designs
To answer questions about the options available for closing systems, Farm Journal Field Agronomist Ken Ferrie organized a multiyear test plot to look at the various planter closing wheel designs.
"One reason why there are so many options available is that farmers are planting into a variety of seedbed conditions," Ferrie says. "The field conditions are what drive the type of closing system for your planter."
Today, Ferrie groups the closing systems into the following three categories: solid wheels, spiked wheels and firming spiked wheels.
"The purpose of the closing wheel system is to crush the sidewall, close the furrow from the bottom up and firm the soil over the seed to prevent it from drying out," he says. "Solid rubber closing wheels are designed to do this in conventional tillage. As farmers transition to reduced tillage or no-till, the rubber wheel will come up short, and the slot is left open, which is a disaster for corn stands. We have to focus on closing the slot."
To gain in-field experience, Ferrie outfitted an 8-row Kinze planter with several closing system combinations. The center four rows had solid rubber wheels on two rows and solid cast wheels on two rows. The outer two rows on each side had the following closing wheels: Copperhead Furrow Cruiser; Exapta Thompson; Great Plains Spider; Martin Spader; Pro-Stitch; Schaffert Mohawk; S.I. Distributing Close-N-Till; S.I. Distributing Finger-Till; Yetter Close-Till; Yetter Cast Spike; and Yetter Paddle.
The alternative wheels to the solid rubber and solid cast are primarily designed for tough conditions to condition the sidewall and adequately close the furrow. To understand how the wheels perform in a range of conditions, Ferrie included varying seedbeds in the three-year study ranging from no-till sod to vertical tillage with a spring harrow pass.
"In a conventional seedbed, the primary concern is that the soil will dry out, causing poor germination or poor crown root development, which sets us up for rootless corn," Ferrie says.
"Alternatively, in no-till it’s harder to get the slot closed above the seed. For example, the rubber tire does a good job of firming in conventional tillage, but it will have trouble crushing and closing the sidewall from the bottom up in no-till."
Unlike other Farm Journal Test Plots, this effort was not evaluated based on yield results. Instead 50' stand counts were taken at first emergence and every 48 hours until the counts didn’t continue to increase. The stand counts were located in multiple management zones of the field for each closing wheel.
"We know it’s important for a field to emerge uniformly, to establish photocopy plants, which leads to photocopy ears, which leads to more yield," Ferrie says. "To that effect the closing system has the job of securely closing the furrow and eliminating air pockets to improve the chance of even emergence."
The right one. The closing wheel designs are categorized by the type of action they provide. Solid wheels pinch the furrow closed from the bottom up. Spiked wheels are designed to crush the sidewall. The firming spiked wheels are designed to provide both crushing action of the sidewall and firming above the seed.
"One challenge with the spiked wheels is that on their way out of the furrow, they can bring soil with them," Ferrie says. "But our study will tell you that straight tines do a better job of crushing the sidewall then curved tines or solid wheels in the tough planting conditions like wet no-till or sod fields."
At the end of the three years, Ferrie concluded that in the tougher conditions the solid cast iron wheels in a staggered position were tough to beat. In the more mellow conditions, the solid rubber wheels performed well. However, in the toughest no-till conditions there were times the solid cast wheels did not close the slot and it was a disaster. That is where the alternative styles can get the job done better.
- Mid February 2013