After years of field cultivation and disc ripping on his family’s corn and soybean operation, Ben Pederson believed he was improving soil tilth. But visual indicators on his farm near Lake Mills, Iowa, began to leave him less convinced that full-width tillage was worthwhile.
“We’d see some fluffed up soil on top, but beneath that was a hard smear layer that wasn’t conducive to strong root growth,” Pederson says. “Less obvious was the long-term effects that leveling off the soil with a field cultivator in spring would have on future yields. Even though we couldn’t see it year to year, that valuable black topsoil my grandfather farmed was eroding away.”
Rather than leave potential problems to the next generation, Pederson moved to 100% strip-tilled corn and soybeans 3 years ago on his own farm, with the goals of improving soil health, reducing fuel consumption and being more efficient with fertilizer applications.
“Most of our fields are in the 2% to 4% range for organic matter,” Pederson says. “Anything we can do to increase those levels is an objective, and in a perfect world, it would be nice to get up to 6% or better.”
Pederson admits it will take time to see measurable improvement in soil health, but they’ve been able to reduce fuel usage by 1½-gallons per acre over conventional-tillage practices and better target fertilizer through banded applications with their eight-row SoilWarrior strip-till unit from Environmental Tillage Systems.
With highly variable soils and unpredictable fall and spring weather cycles, Pederson wanted a flexible strip-till system. He prefers making two passes for corn — one in fall to build strips with the SoilWarrior — and then a secondary pass in spring, primarily for nitrogen application. For strip-tilled soybeans, he make a single fall pass to build strips.
TWO-PASS FLEXIBILITY. Lake Mills, Iowa, strip-tiller Ben Pederson says he’s not been completely satisfied with strip-tilling only in fall or spring and his philosophy is to take advantage of whatever window Mother Nature opens to get strips built.
Pederson says he’s not been completely satisfied with strip-tilling only in fall or spring and his philosophy is to take advantage of whatever window Mother Nature opens to get strips built.
“In fall, I use a single large coulter on the row unit, which goes about 8 inches wide and 10 inches deep, and we apply our phosphorus and potassium behind it in the strip, which has time to mellow during the winter,” Pederson says. “Then in spring, we’re coming back with two smaller, wavy coulters which only go 3 to 4 inches deep.
“We’re looking to smooth out the strips, dice up some of the remaining residue and incorporate our fertilizer.”
The only other features on the row units are gauge wheels and containment coulters — a simple setup Pederson prefers because it minimizes plugging issues. Although they strip-till corn-on-corn, Pederson hasn’t felt the need for row cleaners on the strip-till unit.
However, he does have row cleaners on his 16-row John Deere planter and this past fall, Pederson used chopping corn heads on their John Deere combine to size heavy residue into smaller pieces, which more easily degrade and break down. He also uses stalk-crushing devices that bend the stalks and reduce tire wear.
“Corn-on-corn is a challenge, and one of the other options we may look at in the future is selection a hybrid for smaller corn plants,” he says. “Having that smaller stalk could be a way to manage that corn-on-corn residue build-up.”
EFFICIENT APPLICATION. One of the biggest benefits Pederson sees with his two-pass strip-till system is the ability to band nutrients below the soil surface on multiple occasions. He’s cutting back about 25% to 30% with overall fertilizer application and yields haven’t suffered.
Pederson tried no-tilling soybeans, but preferred strip-till to incorporate a fertilizer application when building fall strips. He’s seen better early season growth with strip-tilled soybeans, compared to no-till.
“We live in a pretty cold climate and a little bit of tillage gives me an edge early in spring,” he says. “I’m getting a little bit drier and warmer seedbed, and can avoid early-season stunting. I also think I’m getting more height and more pods.”
Pederson is pleased with the two-pass system, but has yet to identify any yield benefits with strip-tilled corn or soybeans, largely because of severe drought the first year, and excessive moisture the following season. This year has also been variable, with heavy rains early in the growing season and dry conditions later in summer.
While Pederson isn’t expecting 2014 yields to top averages for a typical year — 50-plus bushels per acre for soybeans and 190 bushels per acre for corn — he is hoping for his best strip-till harvest to date.
“We’ve seen some increased water-holding capacity, better water infiltration, which has helped reduce erosion, somewhat minimize ponding and helped in droughty conditions,” he says. “I expect we’ll have better yields than the past 2 years, but I’m anxious to see what our strip-till yields would be in a normal year.”
More Efficient Fertility
One of the biggest benefits Pederson sees with his two-pass strip-till system is the ability to band nutrients below the soil surface on multiple occasions. In fall, he variable-rate applies potash and monoammonium phosphate (MAP), with plans to incorporate smaller amounts of sulfur for strip-tilled corn and soybeans.
CUTTING THROUGH CORN. In fall, Pederson uses a single large coulter on the row unit, which goes about 8 inches wide and 10 inches deep and applies phosphorus and potassium behind it in the strip. Then in spring, he comes back with two smaller, wavy coulters which only go 3 to 4 inches deep.
With the secondary strip-till pass in spring, Pederson bands about 90 pounds per acre of 32% nitrogen as urea ammonium nitrate (UAN) and ammonium thiosulfate 3 to 4 inches deep in the strip for corn.
“This past spring, we went to a liquid kit on the strip-till unit, where we have a narrow fan spraying into the mixture of soil that’s suspended in the air and it’s worked really well,” Pederson says. “We had applied dry urea the first 2 years, but I like the ease of handling and the ability to mix in other products.
“One of my concerns with urea was that it converts to ammonium and microbes feed on that in a matter of days, whereas with UAN I have some nitrates there that the microbes leave alone and the crops can access those nutrients early on.”
Pederson broadcast applies an additional 30 pounds per acre of 32% and then sidedresses the balance. The only application he makes with his 16-row John Deere planter is 4 to 5 gallons of pop-up fertilizer in-furrow for corn.
While he’s still fine-tuning his fertility program for strip-till, Pederson says banding nutrients has reduced fertilizer use.
“We’re cutting back about 25% to 30% in our overall fertilizer application and yields haven’t suffered,” he says. “I think this year we’ll try to push the limits of efficiency even more to take advantage of the banding efficiency, especially with commodity prices down and fertilizer prices going up.”