More often than not, harvest will yield field ruts in addition to grain, especially after Iowa’s record-setting September rains. Before managing these ruts with tillage, farmers should consider several factors, advises Barb Stewart, state agronomist for USDA’s Natural Resources Conservation Service (NRCS) in Iowa.

Before performing any tillage, first double-check if the tillage operation would still meet the conservation compliance requirements for highly erodible land. “When in doubt, always visit your local NRCS office,” says Stewart.

Wait until soil dry is enough before doing any type of tillage

DON’T MAKE IT WORSE: With wet ground at harvest this fall, combines, tractors and wagons are cutting ruts in fields. If you plan to use tillage to remedy the ruts, think it through ahead of time so you avoid doing damage to soil structure and creating more compaction.

Second, wait as long as possible to start tillage operations, so the soil can dry out as much as possible. Perform tillage operations when the soil that’s at or just above the tillage operating depth is dry enough to prevent soil smearing and compaction. Iowa State University Extension ag engineer Mark Hanna recommends the following method for assessing soil moisture conditions.

* Collect a handful of soil from an area between ruts and 2 inches above the operating depth of the tillage tool and form it into a ball. Then throw the ball of soil as if throwing a runner out at first base. If the ball stays mostly intact until it hits the ground, the soil is too wet to till.

* Next, take a similar soil sample in your hand and squeeze the soil in your fist and use your thumb and forefinger to form a ribbon of soil. If the ribbon extends beyond 2 to 3 inches before breaking off, the soil is too wet to till.

Watch depth of tillage, and target your tillage to fill in ruts

If you are going to perform tillage to get rid of ruts, you need to consider tillage depth. “Deeper tillage and more aggressive tillage operations are likely to damage soil structure, ultimately leaving soil susceptible to further compaction,” says Stewart. On sandier soils, tillage should be 6 to 8 inches deep to fill in the ruts. On heavier soils, tillage should be as shallow as possible.

 Also, you need to target your tillage. If ruts are uniformly distributed across the whole field, some type of tillage may need to be done on the whole field. In many cases, however, ruts are localized and only need localized repair.

Consider planting cover crops after doing this fall tillage

Last, but not least, consider planting cover crops after doing the tillage. “The living root of the cover crop will start rebuilding soil structure,” says Stewart. “This will help you get a head start on preventing future issues with soil compaction.”

Remember, the best defense is a good offense, she adds. While fall tillage can help alleviate the negative impacts of field ruts, the best defense is building soil health and soil aggregate stability. Soil can better resist compaction by eliminating tillage, increasing organic matter content, and maintaining a living root system in the soil for as much time as possible.

For more information about fighting compaction with improved soil health or planting cover crops, visit ia.nrcs.usda.gov online or visit your local NRCS field office.