Will VT cure what ails you?
In the ag world, vertical tillage is hot. If it were Hollywood, this up-and-coming piece of iron would be akin to the latest power couple’s forbidden romance. Everyone is talking about it.
John McGillicuddy, an eastern Iowa agronomist with McGillicuddy Corrigan Agronomics, says VT is hot for a couple of reasons. First, more folks are growing a higher percentage of corn on corn. As a result, they’ve got a lot of residue to deal with. Second, the past few springs have been fairly wet, and planting has gone late. A tool that promises to warm the soil a little more quickly is enticing.
• Most identify seedbed prep and residue incorporation as primary VT goals.
• Others are utilizing VT to reduce compaction and level the soil in spring.
• Could water availability, not tillage, be the cause of poor root systems?
Two primary goals
Listen to folks discuss vertical tillage and you may wonder if they’re talking about the same concept. It seems there are a lot of different ways to run a VT implement. In fact, McGillicuddy remarks, “Nobody’s written an actual definition for vertical tillage.”
However, agronomists tend to agree there are several big-ticket items producers are trying to accomplish with VT. The actual goal depends on the individual farm.
According to Bill Preller, Case IH director of sales and marketing, crop production business, most farmers turn to VT for two reasons: residue management and seedbed prep.
“In corn-on-corn situations where you have a lot of residue, a lot of folks will use vertical tillage to cut and size residue in the fall,” Preller notes.
A quick 7 to 10 mph pass in the fall typically provides cutting and “fluffing” action on corn residue. Preller says this provides more soil-to-residue contact, which results in better breakdown over the winter months.
In the spring, Preller says it’s popular to run the VT implement ahead of the planter to again fluff residue. In the process, it also helps bring soil to the top, providing good seed-to-soil contact.
Another benefit of running in the spring pops up when trying to plant soybeans. McGillicuddy says VT can warm the soil significantly earlier. In some instances, a spring VT pass can make a soybean crop advance as if it were planted seven to 10 days earlier.
McGillicuddy notes spring vertically tilled soybean fields also typically have better, more even emergence.
In addition, a lot of folks run in the spring to create a more level seedbed. Preller says this really separates the various pieces of VT iron. Some VT implements provide some leveling aspect, while others do not.
“Leveling really depends on the tool,” he notes. “Running only straight coulters will not level the seedbed. You’ve got to have something that moves soil laterally.”
Along with seedbed prep and residue management, McGillicuddy says many farmers are looking to solve a third problem with VT: spring compaction caused by a disk harrow or field cultivator. On some soil types, either of these implements can create a compaction layer, especially if they are run too early. McGillicuddy says sometimes VT can accomplish the same tillage goals without causing this compaction layer. It may be possible to modify a field cultivator for the same results, he adds.
Not for everyone
Emerson Nafziger, a University of Illinois Extension professor, agrees a VT implement can work well in a variety of situations. However, he’s not ready to say it will cure all tillage woes.
First off, he questions whether it’s proper to blame tillage-caused compaction for reduced root growth. In his experience, root depth is often limited as much by soil moisture as by soil strength. He points out that compaction doesn’t limit growth as much in moist soils versus dry soils.
“Roots follow the water, so if the surface dries out, the roots will grow deeper,” Nafziger adds. “But if it’s really wet, lack of oxygen limits roots more than compacted soils.”
In addition, he says if a farmer runs too early, before the soil has dried out, the equipment’s weight will cause compaction, regardless of the implement.
Nafziger does see a viable reason to make a VT pass if it helps better prepare the seedbed. “Anything you can do to improve those top few inches of soil to improve the seedbed is a good thing.”
Specifically, he thinks VT does a good job of prepping the seedbed in after-corn situations. Following soybeans, he says a field cultivator is tough to beat.
Looking at the big picture, Nafziger says VT implements do what they’re supposed to do — accomplish just enough tillage for specific planting scenarios. “They do less tillage a lot quicker,” he concludes. “In many cases, less tillage is enough to get the job done.”
This article published in the June, 2010 edition of PRAIRIE FARMER.