Extension Ag Update
September/October 2006
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During Harvest, Minimize Soil Compaction

Ellen Phillips, Extension Educator, Countryside Extension Center, 708-352-0109, ephillps@uiuc.edu

In October and November, there are usually more rainy days.  Producers may want to rush harvesting to get done before winter.  However, this can lead to soil compaction.  When fields are wet, consider delaying harvest to avoid excessive soil compaction.  Unless significant harvest loses are possible due to lodging, etc. it is best to wait until the soils dry or freeze enough to support your harvesting equipment.  A recent survey in Ohio showed that farmers tend to over inflate tires, which increases compaction. Having tires properly inflated distributes the load over a wider area and results in less compaction. Other things to consider include emptying the combine more frequently so that it is carrying less weight across the field.  If possible, unload the combine at the ends of rows to avoid taking grain carts or trucks into the field and creating further soil compaction.  If the truck must be driven in the field, then try to drive in the same tracks as the combine wherever possible.  The impact of carts or trucks can be lessened by using as many axles per unit load as possible to reduce the pressure per unit area.  Researchers in Ohio found that the main axle of a combine or 600-bushel grain cart bears up to 20 tons.  On a silty loam clay soil, that 20-ton axle load compacted soils at least 20 inches deep and affected crop growth for five years.