Corn growth is behind schedule in many parts of the Midwest due to late plantings and cool temperatures. Adnan Akyuz, North Dakota's state climatologist and a North Dakota State University climatologist, says corn in his state is about 150 growing degree units behind what the level should be on July 30.
"North Dakota is currently between 5 and 100 growing degree units behind last year," Akyuz says. "Compared with 2004, one of the worst corn years that farmers can remember, this year started to catch up with 2004. In fact, southwestern North Dakota started to fall behind 2004 records by about 20 growing degree units."
While doing research to see if and when corn would reach maturity and whether it would have enough time to dry to its acceptable moisture level, Akyuz found that if the weather during the rest of the growing season progresses on the average, the corn with 90-day maturity that requires at least 2,150 growing degree units would reach maturity on Oct. 1.
"At this time, corn would have 30% moisture," says Joel Ransom, NDSU Extension agronomist. He adds that cool weather is not necessarily bad news for corn yield. It's the excessive moisture at the end of the season that is the problem.
Akyuz says based on the assumption that corn with 90-day maturity reaches maturity Oct. 1, the estimated corn moisture content would be 25% on Oct. 15 and 23.4% moisture on Oct. 25.
Corn will continue to dry after the growing degree units reach zero. But how much corn will dry after that point depends on the air temperature and relative humidity, according to Ken Hellevang, NDSU Extension Service grain drying expert.
"It is a hopeful assumption to think the temperatures will be near average for the remainder of the growing season," Akyuz says. "If the temperatures are only 1 degree below average every day for the remainder of the growing season, it would push the maturity day to Oct. 16 and the driest corn moisture for the season to 25%, barely dry enough to be able to combine."
Corn needs to be at 14% moisture for long-term storage, Ransom says.
"If the temperatures are 1 degree above normal every day on the average during the remainder of the growing season, Sept. 24 is when this type of corn would reach maturity," Akyuz says. "It would then dry down to 21.8% moisture content on Oct. 25."