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Compaction can be costly

The decision to till this fall or at any time needs to be carefully considered.

When soil conditions are near field capacity, soil aggregates are "lubricated" by water and readily reposition themselves through the air spaces, especially when heavy harvest or tillage equipment is used. In addition, equipment operators need to remember that soil compaction can occur during the application of manure or anhydrous as well when soil moisture exceeds field capacity (maximum amount of moisture retained by the soil).

Under wet conditions, the use of heavy equipment, such as tractors, grain carts, and combines, can significantly change soil structure and cause soil compaction. Operating in wet conditions and especially doing extra tillage will increase fuel use per acre as well.

Compaction near the surface, within the top three to six inches of the soil, is generally associated with the amount of surface pressure. Compaction below that is primarily associated with axle weight. For example, if soil a foot below the surface is at field capacity and the tractor's axle load is seven to eight tons or greater, compaction can occur at this depth, despite lower surface pressures. This is true especially at this time of the year, when significant amount of tillage preformed around the state.

Although it's tempting to consider tillage to loosen up soil that may have been compacted by fall harvest traffic, soil below the surface couple of inches in most cases is still holding significant amounts of moisture from mid-October rainfall. Living plant roots are not present to remove infiltrated rainfall and soil moisture is at or near field capacity, making it too wet for good soil fracture from tillage operations.

The potential damages to soil, such as side wall compaction, potential soil erosion, loss of organic matter, etc., exceed the perceived benefits of deep ripping or any conventional tillage system. Tillage studies have shown deep ripping or any other conventional tillage systems typically have no economic return advantages in both corn and soybean performance in these types of conditions. The cost associated with conventional tillage over no-till ranged between $25 to $35 per acre.

Before rushing to till their fields farmers should ask the following question, what the objective for tilling my field is. The decision should be based on field performance and sound economic returns considering the input cost for the tillage operation.

The decision to till this fall or at any time needs to be carefully considered.

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