Take Stock of Tillage

The benefits of vertical tillage may not be immediately apparent at field level. To see the beneficial impact, you need to explore the soil beneath the surface. 

By: Rhonda Brooks

Missy Inline Ripper editRemember how you were told as a kid to not judge a book by its cover? That same advice applies to evaluating vertical tillage. When you first implement this system, don’t look for big changes on the surface of your fields; it’s what’s happening inside your soils that truly counts.

Mentally grasping that fact was one of the more challenging things Weston Wiler says he had to work on when he adopted a vertical tillage system four years ago on his farm near Hillsdale, Mich. Unlike conventional tillage, which moves soil sideways and turns it over to show off the dark, rich dirt underneath, Wiler says vertical tillage doesn’t provide that kind of eye candy.

"Initially, I had to have a little faith to believe it was working," Wiler recalls.

That’s because true vertical tillage works below the field surface, between 2" and 14" deep, to take out soil density layers. Such layers occur when the air space between soil particles is reduced. That’s a problem because air space is critical to good corn root growth. Corn roots naturally grow into the ground at a 35° to 40° angle, but if there is an abrupt change in soil density, the roots will turn and grow horizontally, says Farm Journal Associate Field Agronomist Missy Bauer, who spoke on vertical tillage at the 2013 Farm Journal Corn College Fundamentals program.

To further explain, Bauer offers this scenario. "Think about a 5-gal. bucket of golf balls and how much air is in between them versus a bucket of peas. If the corn roots are growing in a bucket of golf balls and suddenly hit peas, they will turn sideways because they can’t handle the sudden change in density."

Weston Wiler vertical photo edit

The value of true vertical tillage takes time to see, but be patient, says Weston Wiler. The benefits will show up in ear count and yield.

Horizontal tillage tools such as a disk, cultivator or moldboard plow can create abrupt changes in soil density. When a density layer occurs, you need to use a vertical tillage tool that can reach a couple of inches beneath the layer to fracture it—what Bauer describes as shattering the soil profile. The process of achieving good shatter helps create uniform soil density and, ultimately, prepare a good seedbed for planting.

If your fields contain few or minimal soil density layers, your corn crop will quickly benefit from a vertical tillage system. If you have deep density layers or compaction, which destroys the physical structure of the soil by compressing the soil particles, you will need to implement vertical tillage practices for years. That’s why Bauer refers to vertical tillage as a system and not a one-time practice or simply a tool.

Types of tools. There is a wide range of tools you can use to accomplish a vertical tillage system. Primary vertical tillage tools include chisel plows, disk rippers and inline rippers. Other tools are better suited to leveling fields, such as harrows, coulters and rolling choppers, which prepare the final seedbed. Consider your soil surface residue needs and how deep your density layers run before making your equipment selections.

Jay Reed says the vertical tillage system is worth the time commitment and the investment in equipment he and his brother, Mike, have made.

The Reeds began using the system eight years ago on their Wabash, Ind., farm. Among the benefits they’ve gained: Water no longer ponds in their fields because the horizontal layers that used to hold back moisture are gone. They spend less time and less money on fuel because they make fewer trips across fields. They are able to get their fields level in the fall, which provides a smooth seedbed for planting each spring.

The only downside to the system, Jay says, is a bit more weed pressure.

"You won’t rip out weeds like you would with a field cultivator, so you might need to change up your weed control program," he notes.

Wiler says a vertical tillage system promotes good corn stand establishment.

"I was having issues with my ground being too wet and cold in the spring, and this opens up the ground just a little so it warms a bit faster," he says.

Bauer says in wet soils you can usually run a vertical tillage leveling tool before you can a field cultivator. Because you’re only tilling the soil a couple of inches deep in the spring, you won’t bring up a lot of wet soil to the surface.

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Check your primary tillage for adequate shatter between the shanks by digging behind the machine, advises Missy Bauer, Farm Journal Associate Field Agronomist.

Horsepower needs. There are some factors you’ll want to take into consideration before you commit to a vertical tillage system. Equipment costs are the obvious factor. What you might not be thinking about, though, is whether you have adequate horsepower to pull and run the tools, particularly the leveling tools, at a high-enough rate of speed.

"Speed is a big function of a vertical tillage leveling tool’s ability," Bauer explains. "If the manufacturer says to run it at 10 mph and you can only run it at 7 mph, then you’re probably not going to get the action you want."

Wiler says he experienced that challenge when he started using vertical tillage. The first tillage tool he purchased was a 20'-wide shallow vertical-tillage harrow, and he had a tractor with 150 hp to run it. He quickly found out the tractor was insufficient even for that small of a tool. He now runs much wider vertical tillage tools, using tractors with up to 550 hp.  

"You’re trying to make a vertical line down in the ground," Wiler says. "If you go slow, you can’t get that fissure. You have to hit the ground hard and fast to get the shatter you need."

The other caveat Wiler offers about implementing vertical tillage is based on appearance. Your neighbors might wonder what’s going on when they see you running a leveling tool across fields at high speeds. "It looks kind of crazy," Wiler says. "But that’s part of the biology of the system."