Zinc, Sulfur Deficiencies Could Cause Yellow Corn Too
COLUMBIA, MO.
Most yellow corn throughout Missouri is
the result of nitrogen deficiency following
heavy precipitation this spring, but zinc
and sulfur deficiency can also cause striping of
corn leaves.
Plant tissue testing is the most accurate way
to diagnose nutrient deficiency symptoms in
corn, says John Lory, nutrient specialist for the
University of Missouri Extension Commercial
Agriculture Program.
In many Missouri cornfields, the wet spring
washed away a lot of the nitrogen applied in the
fall and early spring. Cool, wet soils can also
cause temporary sulfur deficiency by slowing
the release of sulfur from soil organic matter. By
slowing root growth, cool, wet soils can lead to
temporary zinc deficiency as well.
While deficiencies in any or all of these nutrients
can cause yellowing, there are visual differences.
Nitrogen deficiency causes yellowing from the
leaf tip and along the midrib while edges remain
green. Yellowing from sulfur deficiency tends to
be more evenly distributed throughout the
plant. Zinc deficiency can cause yellow to white
bleaching of the tissue between leaf veins. The
bleached area may spread to include the veins,
but the midrib and leaf edges usually stay
green.
Visual symptoms can be confusing, however,
and mild nutrient deficiencies may not produce
obvious visual symptoms, notes David Dunn,
MU Extension associate at the Delta Research
Center’s soil testing laboratory, Portageville.
Tissue testing is the best way to diagnose sulfur
and zinc deficiencies in corn, Dunn says,
particularly when paired samples are taken,
comparing nearby plants that appear to be
healthy with those that exhibit symptoms. He
also recommends testing at different growth
stages.
When submitting samples, remove soil and
foreign matter and place the sample in a clearly
labeled paper bag. Air-dry the sample for 12-24
hours before mailing or dropping off at your
local MU Extension center.
You may also mail samples to the MU Delta
Research Center at P.O. Box 160, Portageville,
MO 63873. Results are returned in about five
working days of receipt. An interpretation of the
results also will be sent.
Maintain records of the sampling date, field location,
submission date and results. Δ