Cutting up can be fun, but not when it comes to your fields. This fall harvest left most farmers little choice but to harvest in wet conditions. Now what? Do you wish for snow so you don't have to look at the mess all winter?
Iowa State University agricultural engineer Mark Hanna feels your pain. About three-fourths of combine mass and virtually all of loaded grain tank weights are carried on the combine's front axle, he reports. "With good yields, grain tank extensions, and a 12-row head, front axle load can be 18 to 20 tons,” he notes.
Compacted soils beneath the rut may interfere with subsequent crop rooting. Hanna says ruts deeper than about two inches can interfere with maintaining seed depth during planter operations next spring unless they are leveled.
But here's where your patience comes into play. Hanna says loosening soil by tillage to relieve compaction requires soil be dry enough so that soil shattering is effective. Because soil moisture has re-filled the top 12 to 24 inches of the soil profile in many areas, deep tillage with a chisel plow or subsoiler this fall or next spring will use fuel and time, but is unlikely to loosen soil effectively between soil effectively between tillage shanks.
Here's the good news—the full soil moisture profile in the upper layers will aid freeze and thaw cycles and help loosen soil during winter, depending on air temperatures and snow cover.
Hanna says ruts deeper than planting depth will definitely need to be leveled before planter operation. "A good strategy may be to wait until a week or two before planting next spring and use a light tillage pass such as with a field cultivator, light disk, harrow or soil finisher,” he says. "If only a portion of the field is rutted, consider tilling only that area to avoid re-compacting subsoil in other parts of the field.
Waiting until warmer weather next spring allows potential for some drying of the top two or three inches of soil and avoids further compaction of wet, plastic soil on the surface that would result from a tillage pass this fall. If compaction effects are observed during the 2010 growing season and soil is dry after harvest, tillage next fall (2010) may be considered deep enough to break through the compacted layer.
No-till farmers that have rutted fields may have to bite the bullet and do a little tillage, Hanna adds. "I would wait until spring and carefully evaluate field conditions,” he advises. "Obvious visible ruts more than a couple of inches deep will be too big of a challenge for the planter and will require some light tillage with a harrow, field cultivator or lightweight disk to level the ruts. I would till no larger area than is required though,” he adds.
Farmers with large wet spots in the field need to consider those areas too. If loose residue has washed into these areas and is more than an inch thick, Hanna recommends moving the build up or incorporating into the soil with some tillage before attempting to plant.