How Much Corn Can We Plant on a Good Day in Iowa?

May 1, 2011
ICM News

By Roger Elmore, Department of Agronomy

Corn planters are rolling in parts of Iowa. This is good news; the bad news is that only 3 percent of our crop was planted as of April 24. On Monday, April 25, Iowa Secretary of Agriculture Bill Northey commented on the current NASS Iowa Crops and Weather Report and the slow corn planting progress to date. There was only a half-day suitable for fieldwork the previous week so little corn planting progress had been made. 

As I write this on Friday, April 29, although planting has started again in some places, rain is forecast for tonight and tomorrow for parts of Iowa. Secretary Northey on Monday also presented useful historical crop planting information indicating that we can plant up to slightly more than 20 percent of our corn acres in one week,  based on the five-year average. Remember though, the five year average includes one of the fastest planting seasons on record, 2010, and one of the slowest, 2008.

Another way to look at this is to consider how many acres are planted per day suitable for fieldwork. On average, during any week this time of year, fields are suitable for work about 3 ½ days, or half the time.

We can put a lot of corn in the ground quickly! Last year, based on data from the Iowa Crops and Weather Reports, Iowan's planted from 37,000 acres per suitable day to nearly 1.4 million acres (see Table). In 2008 and 2009, over 1.2 million acres were planted per day suitable for field work during the best weeks.

Several factors contribute to our ability to plant rapidly. Modern planters are larger than older models, fields are larger, more fields have improved drainage with tiles, and global positioning systems, improved operating lights, planter monitors and well-equipped tractor cabs all allow farmers to plant longer hours with less fatigue. In addition, the common knowledge that yield penalties generally are less with early planting than late planting has spurred this trend.

It remains to be seen how long it will take to plant our estimated 13.9 million acres this year. Iowa farmers are well-equipped to do it in record time, if the weather cooperates. We just need ten excellent days!

Table.  Iowa corn acres planted per day (that farmers could be in the field), 2008, 2009, and 2010. Data adapted from USDA-NASS.



Roger Elmore is a professor of agronomy with research and extension responsibilities in corn production. He can be contacted by email at or (515) 294-6655.


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