How Will Early Planting Affect Your Corn Yield?

May 21, 2015 12:00 PM
How Will Early Planting Affect Your Corn Yield?

With 85% of the corn planted as of last Monday’s USDA Crop Progress report, this spring’s planting is running ahead of schedule for many farmers.

“Crops here are in good shape for now,” says one farmer in Chicot Country, Ark., with “corn knee-high to waist high.”

Growers who escaped the rains are also in good shape. “Corn (is) all in and most up,” reports a farmer in Pottawattamie County, Iowa.

Power Hour Noon Logo

But will all this early planting translate into bigger yields this fall?

Yes, according to University of Illinois researchers Scott Irwin, Darrel Good and John Newton. “Agronomic research at the farm-level clearly shows that early planting of corn, all else constant, results in higher yields,” they write. “However, the same research shows that the penalty for late planting is much larger than the benefit of early planting.”

Here are the dates that appear to affect yield for better or worse:

  • If you planted your corn before April 25, that results in the highest yield.
  • If you planted your corn between April 25 and May 15, that will result in “modest yield penalties.”
  • If you planted your corn after May 15, that may result in “more severe yield penalties” for your crop.

That May 15 date is a key one, both for your own farm and USDA’s numbers. According to the agency’s early-season corn yield projections approach, “the model produces an estimate that the U.S. average corn yield is increased by 0.289 bushels per acre for each percentage of the crop that is planted by May 15.”

Based on that number, the USDA estimates a yield of 166.8 bushels, just a shade less than the U of I’s calculation of 166.9 bushels.

Of course, summer weather still matters. “July temperature and precipitation are typically the most important factors influencing the U.S. average corn yield,” the researchers say. 

How is your planting season going? Share your observations and photos with AgWeb's Crop Comments section




Back to news



Spell Check

Tucker Hamilton
Hemingford, NE
5/26/2015 09:37 AM

  I agree with the other comments in that it depends on so many different variables but I will defend this article. In order to aggregate the data into 1 supply and demand report, you have to make very broad generalizations on weather, soil conditions, planting practices, etc. Doing this allows some inkling of an idea of production that is better than a wild guess.

Greensburg, IN
5/22/2015 07:55 AM

  There are exceptions to every rule, in fact, the past two years my latest planted corn did as good if not better than my earlier planted. It all depends on conditions when you plant, the growing season temps/precip and how soon frost comes. But I understand the general perception that early corn may avoid the extreme heat of mid-july at pollination. However to draw a simple conclusion I don't agree with. Heck the U.S. hasn't plant all that further ahead compare to most years. In fact as of the first week of May there were 9 out of the 15 years "prior" corn planting was above the 55% this year. I'll put more weight on what happens after planting especially near pollination. We need to remember the U.S. planted 56% between 4th week of April & 2nd week of May. That puts a heavy concentration of acres in same pollination window. So it's a flip of a coin for now what may or may not happen.

Loren Seaman
Hugoton, KS
5/22/2015 12:16 PM

  As a 37 yr crop consultant, I agree . All of these "research result opinions" need to qualified to the area you are farming. I am always surprised that a lot of the ag info that is offered on national web seems meant to be taken as gospel for the whole country.


Corn College TV Education Series


Get nearly 8 hours of educational video with Farm Journal's top agronomists. Produced in the field and neatly organized by topic, from spring prep to post-harvest. Order now!


Market Data provided by
Brought to you by Beyer