Paying attention to soil conditions, making timely adjustments and minimizing air pockets while strip-tilling in the fall will pay off with better corn roots, stands and yields, says Kevin Kimberley, owner of Kimberley Ag Consulting in Maxwell, Iowa.
After years of consulting with strip-tillers throughout the U.S., Kimberley has a wealth of firsthand, practical experience to share.
Here are 8 tips from Kimberley for strip-tillers to consider:
1. Strip-tilling Requires Management
"Some people think that strip-tilling means that they can just plant and everything will be OK," Kimberley says. "Strip-till is a different tillage system and it's married to the planting system. If you mess up strip-tilling, you can have a disaster."
Soil conditions change, so be willing to make adjustments when strip-tilling in the fall and/or the spring, he says.
2. Air Pockets Can Wreak Havoc
If corn struggled to emerge, had a poor root system and an uneven stand, growers should think back to what happened when strip-tilling last fall, Kimberley says.
"I like to run a coulter 1 inch deeper than the knife," he says. "This applies for knives that are straight, or mole knives that don't have a toe. With knives that have a toe, watch out for ones that angle down too much because of the soil they explode, causing more air pockets."
All mole knives have a shoe. Kimberley urges strip-tillers to use mole knives that have a narrow width: He cuts most mole knives down with a plasma cutter to 0.75 to 1 inch wide.
"Soil structure is crucial to even emergence and uniform stands of corn," he says. "It's worse to have soil that's too loose than soil that's too tight. Plants won't do well in extremely loose soil, but you can see that corn plants will emerge and grow well between the dual tracks from the tractor."
CUTTING EDGE. Kevin Kimberley cuts down wide mole knives with a plasma cutter so they are 0.75 to 1 inch wide. (Kimberley photo.)
When roots hit loose soil and air pockets, the plant expends more energy staying upright, Kimberley says, and emergence will be uneven.
Whether you strip-till in the fall or spring — or both — stop periodically and dig out a section of the strips with using a spade and a shovel.
"Start by pushing the spade down into the slot," Kimberley says. "Then use another shovel and dig behind the spade and dig up to it. The spade should come free and you can examine the slot. Look for air pockets."
3. Don't Worry If Berms Are 3 To 4 Inches High
By spring, the soil from berms should be almost level with the surrounding soil.
"Big berms require digging up lots of soil, which create air pockets and loose soil," he says. "Depending on the soil type and field conditions, the berms might be taller than 3 or 4 inches. That's OK."
4. Keep Strip-Tilled Soil Within The Row
Catch all of the dirt that flows behind the mole knife with the closers.
"Move the closers forward so they run beside the knife and catch the dirt," Kimberley says. "You want to capture all of the soil for the berm over the strip. You don't want to lose the dirt because it came out of the slot.
"If you lose some of this dirt, the berm could invert by spring."
5. Don't Wait Until Harvest Is Over To Begin Strip-Tilling
Wet, cold and mucky soils make strip-tilling difficult and result in more air pockets and soil that doesn't flow.
"Depending on where you farm, the earlier you strip-till, the more microbial activity will be happening in the soil because of the warmer temperatures," Kimberley says.
Some strip-tillers make strips in the fall and come back later that season and inject anhydrous. Other clients of Kimberley apply anhydrous in the spring.
"Some of the strip-tillers I work with also put down their phosphate and potash in the fall," he says. "Other strip-tillers wait until the spring and then put down liquid 28% nitrogen. I've got clients who are doing everything."
Strip-tillers need to adjust to weather conditions and keep their options open.
"We have some customers who start building strips late in the summer, after harvesting wheat," Kimberley says. "Then they come back in the fall when the soil temperatures are right for applying anhydrous ammonia, which they place in these strips."
6. Use Trash Wheels
"I really like the Yetter Shark Tooth trash wheels for moving all kinds of trash," Kimberley says. "I put them on the strip-till rigs of all of my clients. The Yetter Shark Tooth floats and it works well."
7. Pair Three Coulters With A Mole Knife
DO THE MATH. Setting the coulter to run an inch deeper than the knife on a strip-till rig helps prevent the dirt from exploding, says Kevin Kimberley, owner of Kimberley Ag Consulting. (Kimberley photo.)
Kimberley urges strip-tillers who have mole knives on their strip-till rigs to use three coulters for each row to manage the soil tilled by the knife.
"Place one coulter in front of the mole knife to size the dirt," he says. "This helps the knife from blowing out big chunks of soil. If there's a problem with this, I cut the mole knife down so it's 0.75 to 1 inch wide, depending on soil conditions."
Set the coulter so it runs 1 inch deeper than the mole knife and place the other two coulters ahead of the knife, Kimberley says.
"The two coulters ahead of the knife need to be off center by 3 to 5 inches, depending on soil conditions," he says. "Stagger these coulters instead of running them side by side with the mole knife.
"Staggering them keeps the dirt from plugging up between the coulters when the soil is wet."
Set these two sizing coulters so they run about half the depth of the mole knife, Kimberley adds.
"If the knife runs 8 inches deep, set the coulters for 4 inches," he says. "Most of the time, the coulters should be set for 3 to 4 inches deep. That keeps us out of trouble."
Kimberley likes to run a 20-inch-diameter Great Plains Turbo-Till coulter in front of the mole knife, in the center of the row. The coulter goes into the ground straight, but it turns and pulls soil loose. Even though it loosens soil, the coulter doesn't throw soil out of the row, he says.
Kimberley prefers to use a ripple coulter on either side of the mole knife. He likes 22-inch coulters best, but says 20-inch coulters will work, too.
Improving the flow of the soil, and keeping the knife from digging up big chunks of soil will pay off with better seed placement and uniform emergence and stands for corn, Kimberley says.
"You will have a wider area to plant into next spring and you'll get better crown roots, too," he says. "Even with RTK auto-steer, wider strips are more forgiving."
8. Fall Strip-Tillers Should Consider A Spring Pass
Last spring, some strip-tillers Kimberley works with ran a Turbo-Till coulter on their strip-till rigs. But most of his clients used the ripple coulter and narrow knife from Wako to go through strips that were built in the fall of 2010.
People who were spring strip-tilling also used the plow coulter and Wako knife, which is 1½ inches longer than standard knives, Kimberley says. The narrow Wako knife minimizes the amount of dirt and residue that may plug up where the knife bolts onto the shank.
Kimberley recommends spring strip-tilliers use just one coulter — the narrow ripple coulter — along with the narrow knife. Set the knife to run about 4 inches deep and the coulter about 5 inches deep.
However, there are times when Kimberley recommends that spring strip-tillers use three coulters per row along with narrow knife.
Running through the fall strip in the spring helps the soil warm up more quickly.
"This aerates the soil so it dries out more quickly and you can plant the next day," Kimberley says. "This faster warmup will result in corn and soybeans that emerge more quickly and potentially yield more.
"If you wait for that strip to warm up, you may wait to get into your field until after your neighbor who cultivates."
Some strip-tillers wonder why they should strip-till again in the spring in strips they already made in the fall.
"I tell them, 'Being willing to make adjustments is where you make your money,'" Kimberley says. "Be willing to change."