Two Iowa State University Extension corn agronomists summarize the 2008 Iowa corn growing season by comparing it to the Shakespeare play "All's Well That Ends Well," a tragicomedy. "The 2008 growing season was like the play, you didn't know whether to laugh or cry during it, but realized at the end that things came out pretty well," said Roger Elmore, extension agronomist.
Elmore and Extension Agronomist Lori Abendroth recap a year where much of Iowa's corn was planted in less than ideal conditions and silking dates were so late that yield predictions normally would have been low - but in the end, the 2008 crop finished with the third best yield expectations in Iowa history. USDA-NASS November estimates indicated 172 bushels per acre which is only a bushel under that of 2005 and nine bushels under the all-time high in 2004.
In May, planting dates were running two weeks later than normal and the crop was still being planted in soil that was too cold and too wet. "In an average year, planting in April and May into cold, wet soil would create problems and almost always ensure lower yields," said Elmore during an interview with Doug Cooper, ISU Extension communications specialist. "This year's growing season was ideal for those poor decisions, but that doesn't mean I will be recommending the practices in 2009 simply because of how well 2008 ended! I will continue to recommend not planting in cold, wet soils." The complete interview is available as the Crop and Weather Update at http://129.186.193/radio/index.php.
Another rule of thumb that was broken according to Elmore and Abendroth was the one associated with late silking dates. Silking is the most critical growth stage for corn with late silking dates typically causing greater yield reductions. Again, 2008 went against this rule.
This leads the agronomists to question the late-silking date rule-of-thumb that generally correlates late silking to lower yields. The time the crop silks, is a useful tool in approximating grain fill time period. Although 2008 went against conventional wisdom, this is because the weather conditions that followed silking, including a late frost, had a great influence on yield potential.
In 2008, sunlight (solar radiation) after silking and rainfall were similar to those of the best possible year, according to the agronomists. Temperatures after silking were also cooler which resulted in slow heat unit accumulation, slow crop development, and subsequently a longer grain-fill period. "Without a late frost though, this all would have been for naught," said Elmore. "The crop season finished well, better than we could have ever hoped."
The late harvest and cool fall did contribute to high grain moisture, an increase in grain molds and in some cases low test weights - which means the 2008 season isn't over yet for some producers and grain handlers. "It will be very important for producers to give extra attention to handling wet grain this winter," said Elmore. "Wet corn should be checked weekly, and monitored for temperature increases."
A full summary of the 2008 Iowa corn season, authored by Elmore and Abendroth, is available through Iowa State University Extension's Integrated Crop Management online newsletter www.extension.iastate.edu/CropNews/.