How Long Will It Take To Plant Iowa's 2014 Corn Crop?

How Long Will It Take To Plant Iowa's 2014 Corn Crop?

Last spring when weather finally allowed planters to roll, farmers planted 48% of Iowa's corn crop in a week.

When soil conditions allow and things are working well, farmers can get a lot of corn planted in a short period of time. A 24-row planter running at 5 mph can cover 37 acres per hour. Last spring 48% of Iowa's 2013 corn acreage was planted in one week.

Last week Iowa had on average across the state only three suitable days for planting. That's according to USDA's weekly survey, based on results gathered as of April 27. In those three days last week, Iowa corn planting progressed from 2% to 15% complete. Or, expressed in terms of acreage, corn planting went from 280,000 acres to 1.82 million acres.

CORN PLANTING DELAYS: Some Iowa areas are wetter than others and patience will be needed as the calendar enters May. ISU agronomists say not to wait too long for soil temperatures to rebound, but they warn against planting if soils are wet and not yet ready.

With wet weather and planting delays this spring, Iowa's planting pace has been relatively slow. Slightly over 600,000 acres of corn were planted per day last week, points out Mark Licht, an Iowa State University Extension agronomist. At that pace it will take about 20 days to plant the rest of Iowa's 2014 corn crop. In past years, the peak corn planting pace has been near 1 million acres per day. If this were to happen it drops the need for suitable days down to 12 days.

Planting progress is still slightly ahead of last spring
As cool weather and wet soil conditions continue this week, Iowa's planting progress is behind average, but is still running slightly ahead of last spring.

The USDA/NASS crop and weather report for the week ending April 27 indicates Iowa's corn planting progress is 18% behind the 5-year average but 13% ahead of 2013. ISU's Mark Licht reminds us: "Remember, it was wet last spring too. Progress is incremental and we'll just have to wait for some drier weather to come. Maybe next week."

How to manage this delayed planting situation
What can farmers do to help manage the delayed planting situation this spring? What can you expect or do for the remainder of the 2014 planting season?


As the table accompanying this article indicates, "ISU research shows corn yield potential remains greater than 90% for corn planted in early to mid-May," says Licht. "Even corn planted in late May has pretty good yield expectations. One thing to remember when you are looking charts or research data that show planting date yield potential—the growing season can greatly influence the final outcome. For example, last year I had some corn planted on June 18 that escaped fall frost before maturing and it yielded nearly 170 bushels per acre compared to 200 bushels per acre in 2012. That's a 15% yield loss."

Planting date versus yield potential


Relative Yield Potential

April 20-May 5


May 5-May 15


May 15-May 25


May 25-June 5


June 5-June 15


This table is from ISU Extension and Outreach publication Corn Field Guide, CSI 0001

"Don't get in too big of a hurry. Make thoughtful decisions. Patience will be the key moving forward this planting season," says Licht. "I'd likely not wait too long for soil temperatures to rebound but I would exercise caution against going ahead and planting in wet, mucky soil conditions. I've previously talked about the consequences for planting when soils are too wet. That creates compaction and a host of other related problems that the corn would have to contend with."

Don't be too quick about switching hybrid maturities
Licht adds another caution: "I'd also be cautious if you are thinking about switching corn hybrid maturities. In Iowa, the longer, fuller season corn hybrids have the greatest yield potential. There is no evidence that would support switching to an earlier maturing hybrid until late May or early June. It's really not a matter of yield at this point; it's a matter of the corn reaching maturity before the frost hits in the fall."


In the next week or two, as you are making planting decisions, keep an eye on the calendar and weather forecasts, he advises. "If wet soil conditions look to delay corn planting past mid-May, then you need to start having a conversation with your seed dealers to see what might be available for earlier maturing hybrids. The rule of thumb I use is to shift 5 to 7 days earlier in terms of hybrid maturity for planting corn after May 25 and then cut another 5 to 7 days for planting after June 15."

Rainfall amounts vary considerably in Iowa this spring
The following table gives a good picture of why the percent planted acres varies as much as it does in Iowa this spring. Mark Johnson, ISU Extension field agronomist in central Iowa, looked up the rainfall data prior to the wave of rain that fell on Sunday April 27. He prepared this table showing rainfall for April 1-26, 2014 compared to normal for the same period.

Precipitation for April 1-26 at Iowa locations

Site                 This year (inches)              Normal (inches)

Northwood                5.48                               2.61

Mason City                5.08                              2.66

Humboldt                  3.46                              2.66

Clarion                      4.34                              2.52

Hampton                   5.20                              2.73

Rockwell City             2.88                              2.54

Ft. Dodge                  3.46                              2.68

Webster City              2.46                              2.52

Iowa Falls                  4.39                              2.68

Carroll                       1.93                               2.54

Jefferson                   2.39                               2.54

Boone                       3.01                               2.87

Ames                        3.01                               2.83

Marshalltown             4.60                               2.76

Perry                         2.32                              2.57

Ankeny                      1.28                              2.49

Newton                      3.20                              2.64

Indianola                    4.54                              2.91

"You can see normal rainfall does not vary all that much across these counties, but this year's rainfall has," says Johnson. "The more western counties have been dryer and the more eastern counties have been wetter. The central counties have been somewhere in between, with Wright and Warren being heavier than the other central Iowa counties."

Johnson adds, "I placed the city in the site column to represent its east-west location relative to the group. In Ankeny we had rain off and on Sunday, Sunday night and Monday. I dumped 3.2 inches from my gauge at 6 p.m. on Monday. We've had only a trace since then."

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