OSU
Extension, Darke County
Getting
Your Corn Crop Off to a Good Start in
2013
By Sam Custer
Mistakes
made during crop establishment are
usually irreversible, and can put a "ceiling" on a crop's yield
potential before the plants have even emerged.
Peter
Thomison, OSU Extension Corn Specialist,
gives the following proven practices that will help get a corn crop off
to a
good start.
Perform
Tillage Operations Only When Necessary
and Under the Proper Soil Conditions.
Avoid
working wet soil and reduce secondary
tillage passes. Perform secondary tillage operations only when
necessary to
prepare an adequate seedbed. Shallow compaction created by excessive
secondary
tillage can reduce crop yields. Deep tillage should only be used when a
compacted zone has been identified and soil is relatively dry. Late
summer and
fall are the best times of year for deep tillage.
Complete
Planting by Early May
The
recommended time for planting corn in
northern Ohio is April 15 to May 10 and in southern Ohio, April 10 to
May 10.
However if soil conditions are dry and soil temperatures are rising
fast (and
the 5 to 7 day forecast calls for favorable conditions), start planting
before
the optimum date. During the two to three weeks of optimal corn
planting time,
there is, on average, only one out of three days when field work can
occur.
Avoid early planting on poorly drained soils or those prone to ponding.
Yield
reductions resulting from "mudding the seed in" are often much
greater than those resulting from a slight planting delay. In
2011 and
2012, many Ohio growers observed that their later planted corn yielded
better than
early corn due to unusually favorable rainfall and temperature
conditions in
late July and August.
Adjust
Seeding Depth According to Soil
Conditions
Plant
between 1-1/2 to 2 inches deep to provide
for frost protection and adequate root development. Seeding depth
should be
monitored regularly during the planting operation and adjusted for
varying
weather and soil conditions. Irregular, especially shallow planting
depths
contribute to uneven plant emergence, which can reduce yields.
Adjust
Seeding Rates on a Field-by-Field
Basis
Adjust
planting rates by using the yield
potential of a site as a major criterion for determining the
appropriate plant
population. Higher seeding rates are recommended for sites with
high-yield
potential with high soil-fertility levels and water-holding capacity.
OSU plant
population studies conducted from 2006 to the present suggest that on
highly
productive soils, with long term average yields of 190 bu/acre or more,
final
stands of 33,000 plants/acre or more may be required to maximize
yields. Lower
seeding rates are usually preferable when droughty soils or late
planting
(after June 1) limit yield potential. On soils that average 120 bu/acre
or
less, final stands of 20,000 to 22,000 plants/acre are adequate for
optimal yields.
On soils that average about 150 bu/acre, a final stand of 30,000 plants
per
acre may be needed to optimize yields. Seeding rate can be cut to lower
seed
costs but this approach typically costs more than it saves. Most
research
suggests that planting a hybrid at suboptimal seeding rates is more
likely to
cause yield loss than planting above recommended rates (unless lodging
becomes
more severe at higher population levels) and harvest delays occur. When
early
planting is likely to create stressful conditions for corn during
emergence,
e.g. no-till in corn residues in early to mid April, consider seeding
rates 10
to15% higher than the desired harvest population. Follow seed company
recommendations to adjust plant population for specific hybrids.
Plant
a Mix of Hybrid Maturities
Planting
a mix of hybrids with different
maturities reduces damage from diseases and environmental stress at
different
growth stages (improving the odds of successful pollination) and
spreads out
harvest time and workload. Consider spreading hybrid maturity
selections
between early‑, mid‑, and full‑season hybrids‑for example, a 25‑50‑25
maturity
planting, with 25 percent in early‑ to mid‑season, 50 percent in mid‑
to full‑season,
and 25 percent in full‑season. Planting a range of hybrid maturities is
probably the simplest and most effective way to diversify and broaden
hybrid
genetic backgrounds.
Plant
full‑season hybrids first
Planting
a full‑season hybrid first, then
alternately planting early‑season and mid‑season hybrids, allows the
grower to
take full advantage of maturity ranges and gives the late‑season
hybrids the
benefit of maximum heat unit accumulation. Full‑season hybrids
generally show
greater yield reduction when planting is delayed compared with short
‑to mid‑season
hybrids.
For
more information, visit the Darke County OSU
Extension web site at www.darke.osu.edu,
the OSU Extension Darke County Facebook page or contact Sam
Custer, at 937.548.5215.
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