Strip-till sets the stage for an optimal seedbed that results in quicker and more even emergence of corn and soybeans, researchers have found. As weather extremes impact Midwest agriculture more each year, strip-till offers even greater solutions like improved soil organic matter, better root establishment and growth, and better water holding capacity – not to mention cooler soils in the summer that won’t fry valuable soil microorganisms.
To examine how strip-till is similar or different to no-till, a research team at University of Illinois spent five years examining the impact in corn and soybeans. Their 2015 study uncovered dramatic improvements in soil conditions offered by strip-till.
How strip-till benefits soil conditions
• 8.6 percent increase in soil organic matter in five years.
• 4 percent reduction in bulk density (more macro- and micro-pores)
• 18 percent reduction in penetration resistance
“I was surprised by how much difference there was,” says Fabian Fernandez, one of the study authors and a soil science researcher/professor at the University of Minnesota. “Soil organic matter is not something that builds very fast. We saw strip-till plants that were able to acquire more nutrients and produce greater yield with less investment in the root. Plants have a way of compensating for stressful conditions. If the plant doesn’t have enough water, or enough nutrients, or has any stress, it will send more resources into root development, to explore more soil volume to get what it needs. Obviously that requires energy expenditure from the plant that is not used for yield.”
Farmers sold on strip-till
Four years ago, Eric Miller had the opportunity to move from his St. Cloud, Minnesota farm and acquire a central Illinois farm near Monticello. Miller used to chisel plow in St. Cloud, but at the new farm he jumped into no-till soybeans/strip-till corn systems, followed by cover crops. The wisdom (and luck) of the choice came home to him last December when his area got six inches of rain in three days. He watched the gullies that some call “tillage mistakes” develop on neighboring fields where minimal crop residue didn’t stand up against the torrent of runoff.
While it took Miller a geographic change to park the chisel plow, Minnesota farmers Tom and Steve Muller cut the tillage cord back in the 1990s. On their 2,800 acres near Windom, they strive for 100 percent no-till soybeans and strip-till corn. They built their own strip-till machine in 1994 after hearing Jim Kinsella, a noted no-till authority at the time. Ten years later their co-op bought its own machine and they’ve done custom fall strip work for the Muller’s ever since. What really makes strip-till work on their farms is GPS-guided equipment and adequate tile drainage.
Tom Muller cites another main reason for not going back – chisel plowing demanded two operations, because it required stalk chopping beforehand. “We didn’t really care for it. It took too much time and fuel,” says Muller, who is a bit mystified by those who insist on continuing with conventional tillage.
Tillage is expensive and time consuming
Talking with other farmers in the area, Muller reports “the reason they don’t do strip-till is for fear of losing a bushel.” It turns out this was literally true in their case—Mullers’ ten year average is 172 bushels of corn per acre, while the Cottonwood County average is 173.
Even in ideal years, strip till provides comparable yields, according to Eric Miller. Though he doesn’t do this well every year, Miller admits he got 250 bu./acre yields in 2015, compared to fantastic 220.5 bu./acre experienced by his neighbors in Piatt County, and 175 bu average yield across Illinois.
According to Wisconsin research, it costs $0.12 less per bushel to strip-till than to chisel plow—fewer passes and less energy intensive work equals much lower expenses for fuel, labor and repairs. Conventional tillage operators in Mullers’ neighborhood may be gaining a bushel per acre, but they are spending an estimated $20.64 dollars per acre to get it.
Not only did Miller park the chisel when he began farming in Illinois, he also changed his rotation: “We follow all crops with covers now. We do a spring burn down. Our rotation is a corn crop, then we drill in cereal rye in the fall, burn that down in the spring and plant no-till soybeans. After soybean harvest, we plant wheat. After wheat harvest the following summer, we plant either clover or tillage radish cover crops. Then it’s back to corn. The soybeans and wheat are no-till and the corn is strip-till.”
With chisel plowing gone, there’s no more wind erosion as cover crops and residue create a snow fence, Miller says. “To improve greater uniformity across fields, we use pattern tile drainage. And by making the strip you create a more uniform seeding environment. When you build strips in the fall, you introduce more air and have less dense soil. Next spring it’ll be warmer and drier in the berm.”
In Eric Miller’s experience, farmers who try strip-till become enthusiastic believers. Case in point is the largest farm in his area of Illinois.
“They started strip-tilling about the same time that we did,” says Miller. “One of the operators told me that they try a new practice on just a small portion of their acres. If it works, they will try to implement it full-scale over a three-year period. When they went with strip-till, they were so pleased with it that they went whole farm right away. They are excellent farmers. I don’t see people trying strip-till and going away from it.”
Banded fertility drives crop, environment success
Both Eric Miller and Tom Muller band P & K and split their nitrogen—Miller does no fall N, while Muller has been steadily reducing fall N. Because there’s no yield penalty, the farmer should feel free to use banding for environmental reasons, according to Fernandez.
“Agronomically, the runoff loss of surface-applied P is minimal, but environmentally, even that small amount can cause trouble,” Fernandez says.
Muller says they are always banding corn. “Occasionally we will broadcast to feed the beans. The university suggests that might be the way to go. Instead of putting all your fertilizer on before the corn and letting your beans get the leftovers, it’s better to separate the operations and feed the beans,” he says. “We place P & K in the band, and we add sulfur and zinc when the soil test shows the need.”
Muller currently split their N application: 60 percent fall nitrogen and 40 percent spring. “After planting, we come in with 28 percent, broadcast over the top, with a herbicide,” he says. “We are seeing really good results with that. The N seems to activate the herbicide a bit. We started doing pre-emerge before waterhemp became an issue, and now it pays big dividends.”
For Miller, he applies a three to four pound pop-up in the furrow at planting time. “Then I apply about 25 to 30 pounds, two inches to the side and two inches deep in the soil. That little bit of nitrogen at planting really helps the corn.” He then sidedresses 150 to 160 pounds when corn reaches the V5 growth stage.
Miller adds that he has eliminated the fall N application, in deference to the nutrient reduction goals Illinois is trying to reach. It’s also made the fall strip work more convenient, because he’s not left waiting for temps to drop below 50 degrees F.
Don’t cook the biology out of your soil
In a conventional tillage system, summer’s frequent light rains only wet the upper two inches of the soil profile, then quickly return to the atmosphere without penetrating deeper, says Jerry Hatfield, who runs the National Laboratory for Agriculture and the Environment (NLAE), a USDA-ARS facility located in Ames, Iowa.
“In a strip-till system, plants can take advantage of a light rainfall. We can dig around in the cooler soil under a strip-till and find roots that are within two inches of the surface and sometimes even closer,” says Hatfield.
That upper two inches is also where a lot of the nutrient cycling and availability takes place. The coolness under the residue preserves biological activity. On any bare soil between rows, surface temps can reach 140 degrees F, and 104 F in the top two inches of the profile.”
“That literally cooks the biology out of the soil,” says Hatfield.