Small Grain Silage Harvest Can Cause Soil Compaction

Harvesting cover crop silage can create soil compaction if wet conditions exist. ( Farm Journal, Inc. )

Farmers need to be aware that harvesting small grains as silage in late spring, especially if soils are wet, can cause soil compaction that can then lower or limit subsequent corn silage yields that is double cropped.

“Soil is most sensitive to compaction when it is in the ‘plastic’ state—that is when soil particles easily slide over each other leading to a denser soil with fewer pores,” says Sjoerd Duiker, a Penn State Extension soils specialist. “If, by molding a handful of soil, you can easily form a ball, the soil is in the plastic state.”

When compaction occurs, large soil pores are compressed, which leads to reduced aeration, water percolation and increased penetration resistance. That, in turn, makes it harder for corn roots to establish themselves.

Waiting until soils dry is not always an option because small grains have a narrow harvest window to optimize quality. And the longer corn planting is delayed, the greater chance of poorer corn yields as well.

To avoid compaction, consider lowering axle load to below 10 tons by decreasing load or increasing the number of axles. Reducing contact pressure below 35 psi and increasing equipment footprint by using tracks or flotation tires at low pressure also will help. If ruts are created, it’s often tempting to perform tillage to smooth soils ahead of planting. “You always have to remember that tillage makes your soil more susceptible to recompaction in the future,” says Duiker.

For more tips on reducing spring soil compaction, click here.