When hard ground bends and breaks equipment on strip-till rigs, and ripple and fluted coulters won’t go in the dirt, try a straight coulter, says Iowa tillage and planting consultant Kevin Kimberley.
“A straight coulter, along with a narrow knife, will get into the ground if you adjust the down pressure,” says Kimberley, who works with strip-tillers in the Corn Belt and Great Plains. “But the straight coulter also tends to blow apart the dry, hard dirt. If you get 0.04 or 0.05 of an inch or rain, that may be enough moisture to let you go back to a ripple or a turbo coulter.
“You need to watch carefully how the soil is working and be willing to change coulters, if needed,” Kimberley says. “There’s more resistance when a curve in a turbo or ripple coulter tries to push into the ground vs. a straight coulter,” he adds. “These curved coulters will break away dirt from the sides, while a straight coulters slices through the ground.”
Options Pay Off
Kimberley acknowledges that having another set of coulters to use in different conditions takes money and time, but he believes strip-tilling fields in the fall, with the best equipment available, creates better seedbeds to plant into the following spring.
“Having options is everything and it’s a key for better stands, yields and profits,” Kimberley says. “So, even if you don’t want to make the switch from one set of coulters to another, ask yourself what the cost and the benefit will be. It may be a hassle to remove and install different coulters this fall, but the payoff comes at harvest.”
One of the easiest ways to see which coulter to run in the fall is to install a ripple, a turbo and a straight coulter on a toolbar and run it in a field and see which one performs the best — doing what the ground tells you, Kimberley says.
If the soil is blown when farmers are strip-tilling, they can create air pockets and fist size clods, he says. In many places in the Corn Belt, it will take 8 or 10 inches of rain in a single event to bring the soil back together.
One of the benefits of using a turbo or a ripple coulter vs. a straight coulter is that coulters with curves create a wider tilled strip, Kimberley says.
“The wider strip gives more room for the crown root of the corn to grow out,” he says. “It’s simple. The wider the tilled strip, the wider and larger the crown roots can become. In a narrower strip or slot, the roots will be confined. Crown roots are important because they play a big role in feeding water to the plant.”
Vertical Tillage Helps
If there’s a growing trend among strip-tillers, it’s running a vertical tillage tool about an inch deep after corn has been harvsted and before fall strip-tilling.
“A strip-tiller I work with in Nebraska’s done this the past 3 years and vertical tillage works fantastic,” he says. “We become creature of habit and we need to be open minded to see what field conditions tell us to do.
“Vertical tillage knocks the root balls loose and flattens the corn stalks so they flow better through the strip-till toolbar. Flattening the trash into the dirt accelerates their breakdown.”
Kimberley continues to see a yield advantage for strip-tilled corn. For some strip-tillers Kimberley works with, their 2012 strip-tilled corn yielded 30 to 35 bushels per acre more than that of no-tilled corn grown by neighbors. That totals out to $210 to $245 per acre.
“Their strip-till corn yielded more and it was drier, too,” Kimberley says. “Corn no-tilled a week before the strip-tilled corn was green, while the strip-tiller was able to combine his corn and haul it to town without having to dry it.
“The strip-tilled corn was drier because it gets out of the ground sooner in the spring and dries down sooner in the fall than no-tilled corn.”
Kimberley says it all goes back to strip-tillers being able to plant corn into the tilled strip vs. planting no-till corn with the “V” in the soil.
“In no-till, water goes down into that “V” and it sits there. That chills the corn and it can set back its growth.”
All in all, Kimberley says making adjustments now in dry, hard soils can and does definitely pay off with a better seedbed, stands and yields.
“If you don’t strip-till in the fall — where you then have the chance for the winter weather to freeze and thaw and mellow out the soil — then in the spring you may have problems if the soil is dry or if it is wet,” he says. “If it’s dry, you’re making clods that don’t come together.
“The air gets in between the clods and the dirt doesn’t warm up as fast. But if the soil is really wet, then strip-tilling smears the soil.”-