By Matthew Wilde
Prescriptive tillage is growing in popularity as farmers strive to boost agronomic, economic and environmental performance.
Farmers can prescriptively vary the depth and intensity of tillage equipment on-the-go based on field and agronomic conditions, much like variable rate seeding. Case IH and John Deere offer the automated technology.
Tillage prescriptions are written by farmers or their trusted advisers and uploaded to a tractor's computer. The prescription automictically adjusts a tillage tool's settings such as the depth of shanks and disks, the gang angle of disks and down pressure of wings and rolling baskets as it moves across the field.
A prescription could call for aggressive settings in areas of a field to alleviate compaction, slice and dice and incorporate residue, eradicate weeds and level ruts. In light, highly erodible soil, the prescription could adjust the tillage implement to be less aggressive or not engaged to keep as much residue on the surface and prevent erosion.
Though not widely used yet, tillage experts expect that to change.
"Once farmers see the benefits and power of this technology, they will adopt it," said Andrew Klopfenstein, a senior research associate engineer in Ohio State University's (OSU) Department of Food, Agricultural and Biological Engineering. "They will want it for all their tillage tools."
PRESCRIPTIVE TILLAGE STUDY
Klopfenstein has conducted prescriptive tillage research for about five years, roughly the same time manufacturers started offering it as an option. This includes a 2018 study on Dug Radcliff's farm near Circleville, Ohio, in conjunction with Case IH. It helped the company perfect its recently released AFS (Advanced Farming Systems) Soil Command prescription tillage technology.
Radcliff was so pleased with prescriptive tillage results he plans to join a growing trend of farmers who've adopted the practice. The technology is designed to increase productivity and revenue while protecting the environment.
"I wish we had this (prescription tillage) 30 years ago ... it's exciting," Radcliff said. "I saw a (yield) increase that was enough to say 'wow, this is good.'
"We need to make money, but I intend to take care of the land we own and rent," he continued. "Prescription tillage is another important tool in the toolbox (to do that)."
Radcliff and OSU teamed up to see how prescription tillage could help one of his highly variable fields with compaction problems that limited yields. It is nearly 60 acres of highly erodible, light and heavy soils with side hills and buried rocks. Radcliff wouldn't deep till the parcel to break up compaction due to erosion fears and bringing up rocks, which would cause even more problems. But he was willing to give variable-depth and variable-intensity tillage a try.
Even though Case IH was still working on automated, prescriptive tillage at the time of the study, the company wanted to see how it could affect agronomic performance. Klopfenstein, working with OSU Ph.D. student Brittany Schroeder, used yield, soil and topography maps to write a tillage prescription for the field that was previously planted to corn.
The data was used to establish presets in AFS Soil Command, which made adjustments to a Case IH Ecolo-Tiger 875 disk ripper pulled by a Case IH Steiger 580 Quadtrac tractor supplied by the company. Klopfenstein operated the equipment and manually hit presets to mimic automated prescription technology at work, based on location within the field using a GPS and mapping technology.
Here's the prescription:
- Shank depth was set at 12, 8 or 4 inches. Shanks penetrated deeper in heavier, flatter ground with more residue and shallowed up in lighter, rocky ground with less residue and steeper slopes.
- Front disk depth was set at 6, 3 or 0 inches. Disks dug in more in relatively flat, heavy soil with high residue, shallowed up in steeper, rocky areas with less residue. Disks didn't penetrate highly erodible soil with less than 50% residue cover and slopes ranging from 2.5 to more than 5%.
- Rear leveling disk depth was set at 5, 2.5 and 0 inches. The leveler disks adjusted for similar reasons as the front disks.
- Down pressure on the rear crumbling basket was set at 200, 100 and 0 pounds. The most pressure was applied in flat, heavy soils with 50 to more than 75% crop residue. Pressure lessened in lighter, hillier and rockier ground with less residue. No pressure was applied in highly erodible soil.
"We have extremely variable farms that go from peat moss to black soil to gravel all in one pass," Radcliff said. "We can be more aggressive where we need to be to manage residue and reduce compaction and less aggressive where it's not needed to prevent erosion."
RESULTS
Prescriptive tillage shattered compaction to promote better root development and water infiltration to reduce ponding in the test field, according to Radcliff. There was no noticeable soil loss or rock concerns.
Soybeans yields in 2019 averaged 69 bushels per acre (bpa) for the field that never topped 60 bpa in the past. The field was planted to corn in 2020. It averaged 205 bpa, which Radcliff said is exceptional considering the challenging growing season. If compaction wasn't remedied, he added yields would have easily been 10 to 15 bpa less.
Klopfenstein says prescriptive tillage uses less fuel than traditional tillage because the tractor doesn't work as hard all the time. Past research indicates a 5-10% savings per acre, on average, depending on field conditions.
"You are doing the right things to the right areas of a field to maximize productivity, agronomics and yield," said Chris Lursen, Case IH tillage marketing manager.
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