Prairie Farmer ◆ August 2006
31
Estimate corn yield before harvest
By TOM J. BECHMAN
N
OW is the time to plan for handling corn efficiently this fall.
Planning would be more effective if you knew how many bushels to
expect.
Here’s a time-tested method that
should get you in the ballpark.
You may not be dead-on with your
estimate, but you should be close
enough for planning purposes. That’s
Key Points
in Purdue University’s “Corn & Soybean
Field Guide” on page 56.
■ Getting a handle on how many bushels to
expect at harvest aids in efficiency.
■ Late-season corn yield estimates are
fairly accurate.
■ Repeat checks in several locations for
better results.
Step 1. Mark off one one-thousandth of
an acre at each yield-check spot. For 30inch rows, that’s 17 feet, 5 inches. In 20inch rows, mark off 26 feet, 2 inches.
assuming you check yield at several
spots per field. You can find this formula
Step 2. Count harvestable ears per one
one-thousandth of an acre.
fifth ear. Count the number of complete
kernel rows around the ear, and the
number of kernels per row. Multiply the
number of rows by the number of kernels to determine the number of kernels
per ear.
Step 4. Calculate the average number of
kernels per ear by adding the numbers
for all sampled ears and dividing by the
number of ears sampled.
Step 3. Pull back the husks on every
Step 5. Estimate yield with this formula:
First multiply number of ears per one
one-thousandth of an acre by the average number of kernels per ear to get
total kernel count. Divide that by 90, a
conversion factor based on the average
number of kernels per bushel. The
result is the estimated yield per acre.
Step 6. Repeat yield checks at as many
locations as is practical for you.
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BAD TIMING: A hailstorm hit this
once-beautiful corn in late June, at the
11- to 12-leaf stage.
Midseason hail
wrecks potential
T
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HE farmer who owns this cornfield probably won’t feel like trying
corn-yield-estimate formulas later this
month. A late June hailstorm wrecked
his once-high yield potential.
Actually, he was in a “what can
you do but laugh about it?” mood a
few days after the storm, joking that
he should hold a pool and let people
guess yield. If wagering was legal,
it might help him recoup some input
costs.
Hail at a crucial time simply devastated his hopes of good yields.
Seedsmen checking after the storm
estimated the farmer’s corn still might
make 70 bushels per acre.
Shown several stalks from the
field, Bob Nielsen, Purdue University
Extension corn specialist, had this to
say: “If it was just leaf damage alone,
it might still make 70 bushels or more.
But big bruises below the growing
point concern me. There’s lots of
damage to stalk tissue. We’ll have to
wait and see how that impacts growth
and development.”
Science. Yield. Success.™
www.herculex.net ®™Herculex, the Herculex Shield Logo and “Science. Yield. Success.” are trademarks of Dow AgroSciences LLC.
YieldGard and Roundup Ready are registered trademarks of Monsanto Company. ®LibertyLink is a registered trademark of Bayer CropScience.
B35-208-001 (6/06) BR 010-16297 530-M2-180-06 #63004
®
Herculex Insect Protection technology by Dow AgroSciences and Pioneer Hi-Bred.
DEEP BRUISES: Stalk tissue damage
could prove as troublesome as leaf
damage to this corn hit by hail.