If you didn’t understand farming, last spring’s planting season would have looked almost serene. In most areas, balmy weather arrived in early April and lasted until corn and soybeans were in the ground. But behind the scene, farmers took desperate measures to get crops planted in the wake of two wet planting and harvest seasons that left soils in an agony of ruts and compaction.
"Getting a seedbed—that was the goal," says Farm Journal Field Agronomist Ken Ferrie. "Often, that meant modest tillage to fill ruts and level fields enough to plant. Some growers switched crops—no-tilling soybeans into rutted fields, for example. Everyone did what they could, but unfortunately that often involved putting in a tillage layer.
"Now is the time to fix soil density problems that have been multiplying for the past two years. An early harvest is a gift of precious time," he adds.
The problems will be different in every field. "The first step is to correct problems that were put in during the 2009 harvest," Ferrie says. "Often, those were compounded by actions you took last spring. For example, if you disked last spring to fill in ruts, you put in a disk pan. But the compaction from wheel tracks that occurred the previous harvest season is still there too."
Ruts on top of ruts. In some cases, new ruts were put in as farmers sidedressed and sprayed their 2010 crop when the weather turned wet following that ideal planting season.
"You may have harvested soybeans and planted in good shape but put in pinch rows if it was wet when you sprayed or sidedressed," Ferrie says. "This is the first year I’ve seen wheel track compaction from a sidedress bar that was severe enough to stunt corn. If you’re rotating to soybeans, that compaction might not have to come out, but if it’s a dry fall and you have time, take the opportunity to fix it."
You probably will need to do tillage to fix the more serious problems. "Your tractor may have cut ruts 8" or 9" deep, while your grain cart cut ruts only 4" or 5" deep. But the grain cart may have created deeper compaction because of its greater weight," Ferrie says. "Your tillage tool has to reach beneath the deepest compaction. And you must cut those wheel tracks at an angle, so till across the tracks."
Many growers also face problems with residue. "Often, old crop residue did not get buried in the fall of 2009 or spring of 2010, so you may need to bury two years’ worth," Ferrie says.
If you have shallow wheel tracks in a field that grew soybeans this year and is going to corn next year, residue probably isn’t a concern. "In that case, you can fix the wheel tracks fairly easily by running an in-line ripper across them," Ferrie says. "But if you have severe wheel tracks in soybean residue, you may need to rip with an in-line ripper in two directions or use an in-line ripper followed by a chisel plow."
In continuous corn, Ferrie says, "you’ll probably need to run a disk ripper deep enough to fix the compaction and also bury the residue. If you don’t have a disk ripper, make two passes—one with an in-line ripper to remove the wheel tracks and one with a disk chisel, shallowly in the opposite direction, to bury residue."
That may sound like a lot of expense for tillage in one season. "But remember, you didn’t get tillage done last year," Ferrie says. "If the soil is dry this fall, go after your problems. You may be able to fix damage in one year instead of two or three."
No-till and strip-till. Some density problems may have been concealed during 2010. "Many no-till farmers who were in corn/soybean rotations got beans harvested on time but struggled with corn harvest," Ferrie says. "If you planted corn into soybean residue, you didn’t have much problem because you didn’t track up the field during harvest. And corn fields that went to no-till soybeans in 2010 did pretty well if the fields only had wheel-track compaction."
The problem of 2009 wheel tracks lies hidden beneath soybeans that were no-tilled in 2010. "Don’t no-till corn into those fields in 2011 without taking a serious look belowground," Ferrie says. "The wheel-track compaction from 2009 is still there. If it’s shallow, you may be able to strip-till and use the bar to get through the tracks.
"Another option is to make one pass with an in-line ripper to lift the wheel tracks. If you do, try to level the field this fall and stay in the vertical tillage format. If the surface is level enough next spring, you can no-till. If it isn’t, make one more leveling pass in the spring before planting."
If you opt to strip-till, make sure your shanks run deep enough to take out the wheel-track compaction. "If a field is rutted or compacted too deep, you may have to get out of strip-till for a season and use tillage to fix the problem," Ferrie says. "If it’s shallow enough to fix with strip-till, and if the soil is dry enough, strip-till as early as possible this fall. You’ll do a better job of taking out compaction, and also build a better strip, if the soil is dry."
Strip-till early. "You may have an opportunity to strip-till earlier than normal. If it’s too early to apply nitrogen, just pull the strip-till bar and take advantage of the dry soil," Ferrie says.
Pay attention to changing conditions. "If certain rows are having trouble with old wheel tracks—fighting the tracks and bringing up huge chunks—park your strip-till bar and do tillage."
Every field is different, Ferrie emphasizes. "You may find that the compaction-correction plan you came up with won’t work in certain fields or portions of fields. And—especially if you mapped rutted areas last harvest season—you may find you only need to till in spots.
"Carry a spade and dig in each field to see how deep the compaction is," Ferrie continues. "Then use a spade and a tile probe after you start tilling, to see if you are accomplishing what you want. If your implement isn’t reaching the target depth, you’ll need to do something different."
Because correcting multiple years of compaction is so important, this may be the year to assign a special tillage team or hire some custom tillage.
Keep your spade handy for the fall of 2011, though. "Many farmers won’t be able to fix all their problems in one year," Ferrie says. "They may have to repeat some of these processes.
"But an early harvest offers a golden opportunity to get headed back to your normal program, whether it’s conventional tillage, no-till or strip-till. Time is of the essence this fall in terms of getting tillage completed."
Don't forget the lime
Tillage wasn’t the only practice that didn’t get completed during the soggy fall of 2009. "A lot of farmers were unable to apply lime," says Farm Journal Field Agronomist Ken Ferrie. "Use any opportunity to apply it this fall, and keep soil from sliding into acidity. If possible, apply the lime ahead of tillage."
You can e-mail Darrell Smith at firstname.lastname@example.org
- October 2010