Since Marvin Dusanek began strip-tilling 15 years ago, he and his son, Dave, have worked on managing residue. That’s especially the case since the Dusaneks, who farm near Monticello, Iowa, quit growing soybeans and corn in a 50-50 rotation and switched exclusively to continuous corn.
“Our bean yields were going down, down, down and our corn yields were going up, up, up,” Dave Dusanek says.
When they switched to strip-tilling continuous corn about 7 years ago, he thought it would be easy.
“That switch was a slap in the face,” Dusanek says. “Residue decay from these new hybrids is our biggest challenge in corn on corn.”
Bad weather in 2007 and 2008 prevented them from strip-tilling in the fall, which is when Dusanek wants to lay down strips.
Without GPS, they struggled to consistently make new strips directly in between the previous year’s standing stalks and to plant precisely into them. Rocks and residue plagued the first two strip-till machines from doing the job the Dusaneks expected.
“We had to make a switch,” Dusanek says. “Dad built a machine from scratch. It’s a moose.”
Marvin Dusanek spent 18 months designing, fabricating and assembling a 12-row strip-till rig. It’s made from two John Deere cultivator bars that parallel each other — with 4 feet in between — and are welded together for strength.
Marvin Dusanek removed the disc gangs from a chisel plow and replaced the concave discs with straight coulters. The coulter gangs up front on the strip-till rig run straight to size residue before it reaches the row cleaners.
The coulters are on 30-inch spacings and are spring-loaded to handle rocks. The row cleaners have constant down pressure so they are always in contact with the ground.
“You need a clear strip,” Dave Dusanek says. “That’s important in a high-residue environment.”
The row cleaners are followed by John Deere Tru-Depth chisel-plow shanks, which can take up to 1,250 pounds of lateral force before they trip and reset. His father made tips for the shanks with steel from a road-grader blade, but Dusanek says the may use custom-made, 4-inch-wide mole knives when they strip-till this fall.
The closing wheels behind the shanks are infinitely adjustable. “You can customize how wide and high you want to build the strips,” he says.
The Dusaneks started strip-tilling with the custom-made, 12-row rig in the spring of 2009. If they had to do it over, they’d consider making it a 16-row strip-till rig, he says.
The strip-till rig has a 7-ton, dry-fertilizer box mounted behind the two bars with the air-delivery system they used on their previous strip-till machine.
Managing residue, using GPS and making strips in the fall are keys to successfully strip-tilling continuous corn, Dusanek says.
“The biggest thing to prepare yourself for is residue management,” he says. “That’s something we’re still learning about with continuous corn.”
This fall, his parents and hired man will run the harvester and Dusanek will strip-till. He’s going to experiment with several ways to manage residue.
Possibilities include hitting some ground with a tool like a Great Plains Turbo Chopper with coulters and a chopping reel on corn stalks, then strip-tilling.
Some fields might get strip-tilled and then disced. And on others, Dusanek will disc lightly, then strip-till. He says he’s considering all options due to the high amount of residue accumulating in continuous corn.
“I want to get my strip-till done in the fall,” Dusanek says. “I want to use the freezing and thawing action during the winter.
“Strips made in the fall allow some of the fluff to settle out of the mellow strips and regain some soil structure.”
Corn Yields Vary
Since the Dusaneks started strip-tilling continuous corn, their yields seem to be on par with their neighbors who conventionally till.
“Last year was my second-best year in the 10 years I’ve been farming with my Dad for corn yields,” Dusanek says. “We had some early corn — 100-to-102-day corn — in the 190-bushel-per-acre range. Hybrids of 111-to-113-day corn were going 230 bushels per acre and the rest fell in between.
“Last year was the first time we’ve ever seen the yield monitor hit 300 bushels per acre a few times. You see it once and you get a taste of it and you want to see it more. You can’t ever be too satisfied with what you are doing.”
Run With RTK
The Dusaneks struggled for years to make new strips between the old corn rows, avoid rootballs and keep the planter on the strips 100% of the time.
“We tried simply driving between last year’s corn rows and had somewhat decent luck with that,” Dusanek says. “We’d leave standing corn stalks, but we could not stay in between the rows year after year after year without the guess rows becoming inconsistent. Making a few rounds between the old rows is no big deal.
“But trying to consistently stay between them and keep guess rows tolerable across an 80-acre field was tough. At some point, we’d get into the rootballs again.”
Shredding stalks didn’t work well. There was so much fluff they couldn’t see where to make the next pass when strip-tilling.
Discing in the fall and strip-tilling in the spring was OK, but left the ground too rough. Also in the fall, they tried running a stalk chopper that pulled a disc. That had its limitations as well.
The Dusaneks starting planting their first corn fields with RTK GPS in the spring of 2009.
“This spring, we hit it pretty hard,” Dusanek recalls. “We were behind and at one point planted for 40 hours straight when rain was forecasted. We wouldn’t have done it without auto-steer.
“We have Trimble Autopilots in our three main tractors — one for strip-tilling, planting and spraying. That’s been a nice addition.”
David and Marvin Dusanek each bring strengths to the farm. His father is the brains behind anything mechanical, his son says.
“He’s been an innovator in building all kinds of stuff,” Dusanek says. “When he builds something, it doesn’t break.”
Dusanek has a degree in electrical engineering and handles the computers, precision ag equipment and GPS.
“I’m fortunate to have a father who is extremely open-minded to new ideas that I bring to the table,” he says.