Thick residue has always been a thorn in the side of farmers who grow corn-on-corn.
That was particularly true in states like Illinois in 2010. Although many corn yields suffered, corn-on-corn particularly took a hit. One likely reason was above-normal 2009 surface residue had a toxic impact on 2010 corn.
“If I can handle the residue, I can grow continuous corn,” says John Obery, a Metamora, Illinois, farmer. “I want to reverse the toxic effect of old roots and stalks.”
Obery thinks he's found a way to do it with a twist on strip-till. Last fall following harvest, he used a modified Great Plains Turbo-Till unit and/or a modified Blu-Jet SubTiller II tillage tool. These tools slice and dice the residue and leave a planting strip for spring.
He's equipped both units with homemade hillers. “They raise a mound of dirt so it dries out and warms up in the spring,” Obery says. “I also get mixing of residue in the top few inches of the soil.”
The system doesn't meet the definition of strip-till for the National Corn Growers Association (NCGA) yield contest. No more than one third of the row width can be disturbed, according to NCGA. In Obery's system, the entire field is lightly tilled.
Still, it works. “I can handle lots of residue,” says Obery.
The strips he makes in the fall enable plants to push through and grow in mellow, dry, and warm soils.
The tillage combination used hinges on soil compaction levels. On compacted soils and on end rows, Obery first makes a fall pass with the Turbo-Till followed by the SubTiller II. The Turbo-Till sizes the residue and lightly tills the soil surface. The SubTiller II's shanks run at 12 to 14 inches deep to remove compaction.
On less compacted fields, Obery makes two passes with the Turbo-Till. Two gangs of blades spaced 10 inches apart act to move soil every 5 inches at a 6-inch depth.
To boost consistent penetration, he added 4,800 pounds of weight on top of the Turbo-Till. This creates more consistent depth and ensures the Turbo-Till stays in the soil rather than jumping out.
The homemade hillers on the back of both units bring a bit of ridge-till to Obery's system. The system isn't technically ridge-till, since ridges are built in fall rather than summer. Still, they enable early planting to occur next spring.
“What I like about my ridges is they don't melt down and become hard to see in the spring,” he says. “If I get heavy rain in the late winter and early spring, I can get erosion from conventional strips. I don't have that with my hillers. The ridges are big enough where they shed water and not invert.”