LINCOLN, Neb. -- With harvest underway across Nebraska, producers need to keep in mind that too much soil compaction this fall can impede the crop's roots next season, a University of Nebraska-Lincoln engineer said.

Farmers should practice controlled traffic and avoid tillage, said Paul Jasa, UNL Extension engineer.

"Eighty to 85 percent of soil compaction damage is done during the first pass of the tires," Jasa said. "Grain carts should be following the same tracks as the combine. A lot of producers think they should spread out compaction, but really they are less likely to have a lot of compaction issues if they keep traffic controlled."

Compaction, which is the loss of pore space between soil particles, occurs when that space is squeezed out of the soil and reappears somewhere else, such as in the form of a rut.

"It's important not to leave a track in the first place," Jasa said.

To reduce compaction, avoid being out in the field when the soil is too wet and avoid tillage. If ruts are formed during harvest, tillage can break up compaction, but the soil must be dry to fracture compaction. However, tilling destroys soil structure and allows more tracks.

"Typically tracks are as deep as you tilled," Jasa said. "Compaction is caused primarily by tillage. It breaks up the existing soil structure and packs the soil below the tillage depth."

He added the best indicator of compaction is to look at the crops' roots.

"They should go downward and outward about 6 to 8 feet in the soil," he said. "If they stop at 6 inches, you know you have a problem."

Farmers also should try to leave as much residue on their fields as possible this fall.

"Residue will catch snow fall and reduce wind erosion," Jasa said. "By leaving that residue standing upright and anchored you will get more uniform soil moisture conditions and more uniform soil temperatures next spring."

Jasa recommends processing and spreading residue as uniformly as possible with the combine this fall so it can decompose evenly this winter.

"Avoiding tillage not only will save money, but conserve soil moisture, residue and energy," he said.

For more information about harvest management, visit Crop Watch, extension's crop production newsletter.

SOURCE: University of Nebraska news release.