Cool Weather Limiting Crop Maturity

Half of Iowa corn crop is running 11 days or more behind normal; frost threat is concern.

Cool temperatures across Iowa this past week, especially at night, has limited corn and soybean progress toward maturity. Most of the state received rainfall, but amounts varied considerably with only a small area getting a good soaking. Dairy farmers began chopping corn for silage and seed corn harvest got underway this past week.

That's the summary from the weekly weather and crop conditions report, released September 8 by Iowa Ag Statistics Service, the Iowa field office for USDA's National Ag Statistics Service.

Half of crop is two weeks behind

The report says the 2008 corn crop's condition in Iowa is 61% good or better, and soybeans are 60% good or better. That's down a couple of percent from the last few weeks. But the concern isn't crop condition as much as it is the crop progress toward reaching maturity.

This year's late-planted fields need a normal or a later than normal date for the first killing frost to occur, so the crops can reach maturity and escape yield loss.

About 50% of Iowa's corn crop has reached dent stage by September 8, 2008--more than two weeks behind last year's 87% and 11 days behind the 5-year average of 82%. About 5% of the 2008 Iowa soybean crop is now dropping leaves, compared with 20% last year and 18% normally shedding leaves by September 8.

No frost in 10-day forecast

The third cutting of alfalfa is 61% complete, 9 days behind last year's 81% pace and more than two weeks behind the 5-year average of 87%.

Iowa's slow developing 2008 corn and soybean crops dodged a bullet—it didn't frost in Iowa during the early morning hours of September 9. The weather forecast had predicted cool temperatures, says Harry Hillaker, state climatologist for the Iowa Department of Agriculture. Temperature in Des Moines at 6 a.m. Sept. 9 was 45 degrees F. In areas of far northern Iowa, the low dipped to around 35 to 37 degrees F.

The good news is the 10-day weather forecast from the National Weather Service shows no frost expected for Iowa and the Upper Midwest's main corn and bean growing area during the next week or so.

TAGS: Soybean USDA
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