Due to the unusually cool growing season during 2009, many farmers left their corn  standing in the field over winter. On Dec. 7, 2009 USDA  reported that about 23% of Wisconsin's corn crop had not been harvested. Shortly after the report, a large snowstorm and sub-zero temperatures brought grain harvest to a standstill. Some harvesting has occurred since early December, but if approximately 15-20% of the acres have not been harvested, it amounts to 440,00-590,000 acres of corn left standing in the field.
This year was the most expensive corn crop ever produced by Wisconsin farmers. In the PEPS Program , cash corn cost $531/acre to produce. Thus, the standing corn left to overwinter in the field represents $234 to $313 million of value.
The 2009 growing season was the coolest of the previous 30 years at the Arlington  and Marshfield Agriculture Research stations . Other years that had low growing degree day accumulation were 1992 and 1993, but unlike those years, 2009 was a record yield year at 153 bu./acre.
Usually corn is left standing in the field because it is either too expensive to dry, or grain dryers cannot keep up so harvest gets behind and eventually farmers are caught by bad weather. Corn drying is expensive when corn is wet. Grain moistures were running 30% or greater for many fields during October which was a cool, wet month. To dry corn from 30% moisture to 15% moisture for storage, it would cost 96¢/bu. using a 1.4% shrink factor and 5¢/point of moisture for each bushel. For a 150-bu. yield level, this amounts to $144/acre just for drying and shrink costs (see calculator ).
We have been monitoring a field of corn planted at Arlington with the objective of determining the grain drydown pattern and yield impact on corn left standing through the winter until spring. The field was planted on May 12 with Pioneer  35F40 (105 day RM, Hx1, LL, RR2). The grain moisture on Oct. 22 was 42%. Today, it was 19.5% moisture. The drydown pattern is similar to 1993 when grain ended up drying to about 15% moisture. So far the hybrid has had good standability and ear retention even though there have been heavy snow and ice events on the field this winter. So far yield has not been affected.
As spring approaches, farmers who left corn standing in the field over winter will be hard pressed to finish last year's grain harvest, prepare fields for 2010 and plant in a timely manner. Everything will need to go right. So the more preparation that can be done from this point forward will pay off for the 2010 growing season.