Jason Koberstein and his father, Dan, of Holyoke, Colo., rely on spring strip-tilling to help manage the heavy, black ground where they grow irrigated corn.
“This year, we strip-tilled about 1,300 acres,” Jason says. “We went to the Sunflower 7600 strip-till rig because it had more clearance and could go through more residue. With its wavy closing discs and the baskets on the back, the Sunflower system for closing works better for us.
“We like the bigger coulters, so we can cut deeper into the soil, as well as the finger-style trash whippers that move more trash without moving as much dirt. We also like the mole knife shank, which is easier to replace.”
The Kobersteins started strip-tilling about 7 years ago. They grow corn, winter wheat and some sugarbeets on 4,500 irrigated and dryland acres, about 170 miles northeast of Denver. They also run about 200 cows, grow some alfalfa hay and have three trucks for commercial hauling.
After discing all of their corn ground last spring, they strip-tilled their irrigated-corn ground, strip-tilled their sugarbeets and no-tilled the dryland corn. Strip-tilling corn ground helps the soil warm up faster vs. no-tilled and conventional-tilled ground for corn, Koberstein says.
“Strip-till just creates a better seed bed altogether,” Jason says. “It loosens the soil and then firms it up. It’s not cloddy.”
Jason graduated from high school in 1999, went to junior college in Sterling, Colo., and has been farming full-time with his father for the past 10 years.
The past few springs have been wet, which kept the Kobersteins from doing deep tillage with a chisel plow. And like many farmers last fall, the Kobersteins faced wet conditions in their fields.
“Corn harvest last year was very wet and we tracked up a lot of the field,” Jason says. “We also had a lot of trash to get through, so we decided to work all of the corn ground with a disc. Disced ground seems to dry out quicker and warm up faster, so we could go planting a little quicker.”
Most of the land the Kobersteins farm consists of pretty heavy, black soils, while they also have lighter, sandy soils. Annual precipitation averages 17.74 inches per year with 12.76 inches from April to September, according to the Western Regional Climate Center.
Yield on irrigated corn — which had a lot of corn stalks — averaged 220 bushels per acre in 2009. Dryland corn yields run about 100-plus bushels per acre, while winter wheat yields average 50 to 60 bushels per acre.
“Getting organic matter into the soil is beneficial,” Jason says. “We put down nitrogen, phosphate and a little sulfur in the row this year with the Sunflower strip-till machine. It was set up to make a strip 8 to 9 inches deep, where we put down 50 to 100 pounds of liquid fertilizer per acre.”
Putting the nitrogen, phosphate and sulfur down while strip-tilling and applying more phosphate and sulfur when planting corn worked nicely this year, he says.
They also sidedressed irrigated corn in 2009, applying the fertilizer with the irrigation system. Last year, they went back to sidedressing dryland corn.
“In the sandy soils, we no-till the corn-on-corn,” he says. “We go back in with a really thin knife and apply anhydrous,” Jason says. “When we were in the drought, that dried it out too much. Now that we’re getting moisture, we may try strip-tilling dryland corn.”
The Kobersteins faced rainstorms last spring.
“We went and disced when we could,” he says. “Sometimes we disced right before we strip-tilled. Other times, it was about a month before strip-tilling. We disced the fields 3 to 4 inches deep, so we didn’t loosen the soil up too much. We went far enough down to cut the trash.”
Discing the fields allowed the soil to breathe and dry out before strip-tilling. The Kobersteins wanted to plant all of their irrigated corn by May 10, but it was a little later than that this year.
“It was so cool this spring and it took forever for the corn to come up anyway,” Jason says. “We had a good stand for the most part, with a final stand of 31,000 plants per acre. Because of the cool ground temperatures around here, no one gets a full stand.”
Jason recommends that would-be strip-tillers spend enough time evaluating strip-till rigs before buying one.
“We didn’t look around enough at strip-till machines when we bought the first one,” he says. “Then we went with Sunflower because we wanted equipment that would work in ground that had been disced. It’s important that strip-tillers find a rig that fits their operation.”