Drought-Stress Corn Concerns
URBANA, ILL.
Illinois and other major areas in the Midwest
are watching thousands of acres of corn that
are experiencing severe drought-stress. Livestock
managers are planning strategies if timely
rain does not arrive.
Corn plants are firing (drying) from the roots
up the stalk of the corn plant. Some corn has
tasseled which may not pollinate resulting in
barren corn stalks (no ears). Other cornfields
are in various stage of grow from three to six feet
in height.
The following strategies can be considered.
• If corn plants have green active tissue, the
plant may recover and produce more plant dry
matter or yield per acre if rain arrives. Do not
harvest too early.
• Immature drought-stressed can appear dry
and dead, but may contain over 70 percent
moisture in the stalk. For optimal fermentation,
ensile when the chopped material ranges from
30 to 38 percent dry matter depending on type
of storage (in a bag, bunker, and piles can be
wetter while upright storage must be drier).
• If the corn plant has not pollinated, the quality
of the corn silage will be reduced, but the
plant may continue to store nutrients if green.
• Drought stressed corn can be high in nitrates.
Field values as high as 17000 ppm (1.7
percent) has been measured in commercial Illinois
labs. Levels over 4400 ppm (parts per million)
require feeding adjustments. Values over
17600 ppm (in the total ration dry matter)
should not be fed to dairy cattle.
• Fermenting corn as silage can reduce nitrate
levels by 25 to 40 percent. Ensiling corn silage
is a recommended practice, but green chopping
or pasturing can be risky. Baling corn silage as
hay or baleage will similar to grass hay quality
when the plants are immature. No nitrate
changes will occur when produced dry hay.
• Adding a silage inoculant is recommended to
improve fermentation as natural occurring bacteria
may be low. Do not add urea or limestone
as it can slow down fermentation.
Drought stress corn silage can contain 60 to
80 percent of corn silage nutrient value depending
on the stage of maturity. One guideline
is each foot of corn plant may yield one ton of
dry matter (varies depending on stage of maturity.
Testing the harvested drought-stressed
corn silage after ensiling can measure nutrient
content and nitrate levels. Livestock producers
may be able to purchase drought-stress corn locally
as it has little value for grain or hog producers.
Similar to livestock producers the
southwest areas of the U.S. last summer, dairy
managers are asking what will be available and
affordable for their dairy cattle this fall and winter?
Drought-stress corn silage may be an alternative
locally.
Consumers will share in the cost of droughtstressed
corn this summer as corn yields may
be quite low raising food prices and ethanol
costs. Δ
DR. MIKE HUTJENS: Professor of Animal Sciences
Emeritus, University of Illinois