Farmers are eager to harvest soybeans and corn, but fields are soggy after significant snow and rainfall over the past week. Sjoerd Duiker says the compaction threat is therefore very considerable.

As a minimum, a farmer should wait to access fields until no significant ruts are formed, the Penn State University soils specialist says. However, he says it may be impractical to wait for some low-lying wet spots to dry out before venturing into harvest.

"If ruts are formed in these spots, it may be necessary to do some limited tillage to smooth the soil in the spring prior to planting," Duiker says. "It's probably not a good idea to do tillage this fall prior to cover crop establishment due to suboptimal soil conditions for tillage."

Duiker says rut formation is significantly reduced by using flotation tires or tracks due to their bigger footprint. He suggests growers inflate flotation tires to their lowest permitted pressure to carry the load, as Ohio State research shows that inflation pressure basically controls the benefit of flotation tires.

"Typically, rut formation is much more severe in tilled fields than in long-term no-till fields," Duiker says. "This is due to the fact that the tilled soil has a loose consistency, while the no-till soil has a firm matrix interspersed with macropores. It is these macropores that explain the high water infiltration rates of no-till soils."

For growers wondering if tillage will be needed next spring after harvest operations on no-till soils this fall, Penn State research has shown that, except if ruts are formed, there seems to be little benefit to tilling these fields.

Localized tillage may be needed where ruts are formed, but Duiker says it's usually disadvantageous to till the whole field because of the expense involved and the destruction of the no-till history of the field.

"Finally, make sure you use designated traffic lanes to haul the grain out of the field to limit the impact you have on the most precious and amazing resource you have — the soil," he adds.