This document summarizes best practices for high-yield corn production based on national corn yield contest winners. Key practices include selecting hybrids with top yield potential, applying nitrogen fertilizer at key growth stages, planting early at optimal populations in 30-inch rows, and using foliar fungicides which increased yields 80% of the time. Contest winners also employed crop rotations, starter fertilizers, and weed control programs utilizing multiple herbicides to manage resistance. Adopting several of these proven practices can help growers accelerate corn yield gains.

1. High-Yield Corn Production
This presentation summarizes management practices
used by NCGA national contest winners, many of
which can be applied to all corn production fields.

2. Corn Yield Trends
US yields are increasing by
over 2 bu/acre/year due to
genetic and agronomic
improvements.
• Hybrid Yield Potential
• Transgenic insect resistance
• Drought tolerance
• High plant density tolerance
• Early season stress tolerance
Average corn grain yield in the US
• Insecticide seed treatments compared to average of winners (1st, 2nd
and 3rd place) of the NCGA national corn
• Herbicides that improve weed yield contest in 2002 to 2011*.
control
* Yields have increased by over six
• Higher plant populations bu/acre per year for irrigated classes and
• Foliar fungicides by almost 3.5 bu/acre per year for non-
irrigated classes.

3. Hybrid Selection
To achieve highest possible
yields, growers should select a
hybrid with:
• Top-end yield potential
• Full maturity for the field
• Good emergence under
stress
• Drought tolerance
• Disease resistance Seed brand planted by NCGA national corn yield
contest winners with yields over 300 bu/acre and 350
• Insect resistance bu/acre in 2007 to 2011.
• Good standability
Your DuPont Pioneer sales pro-
46 contest winners in the last fessional can help you select top
5 years have had yields over hybrids for your area with specific
300 bu/acre, with a majority insect-resistant traits and other
using Pioneer® brand hybrids. traits best suited for each field.

4. Crop Rotation & Soil Fertility
Most contest winners
planted a crop other than
corn the year previous to
the contest (see graph).
Add at least the level of
P and K that will be
removed by the crop.
• A 250 bu/acre corn crop
removes about 108 lbs
of P2O5 and 68 lbs of
K20 per acre.
Soil pH should be at 6.2 Crop rotation used by winners of the NCGA
or above for growing national corn yield contest in 2007 to 2011.
corn.

5. Nitrogen (N) Rates & Application Timing
Corn grain removes approximately
one pound of N per bu harvested,
and stover production requires a
half-pound for each bu of grain
produced.
• Fertilizer does not need to be the only
source of N, take credit for previous
legume crop, manure, soil organic
matter, and N in irrigation water.
Be sure that N is not limiting at key Timing of nitrogen application by
corn development stages. winners of the NCGA national corn
• N uptake by the corn plant peaks yield contest in 2007-2011.
between V12 and VT (tasseling).
• N requirement is high beginning at V6 and extending through the early dent
stage.
• Contest winners largely avoided fall N and applied pre-plant or at planting.
• Most contest winners also side-dressed N.

6. Starter, Micronutrients and Manure
Starter fertilizer was applied
by over half of contest
winners to ensure that
seedling plants had
sufficient soil nutrients in the
root zone for optimum early
growth and development.
Nearly half of contest
winners applied
micronutrients – primarily
zinc, boron and sulfur.
About one-third of contest
Use of starter, micronutrients and
winners applied manure to
manure by NCGA national corn yield
their fields, which supplies contest winners in 2007 to 2011.
N, P and K to the crop in a
steady form.

7. Planting Date
Winning contest plots are usually
planted as early as practical
for their geography.
• Lengthens the growing season.
• Moves pollination and initial ear-fill
earlier. When pollination is
completed in June or early July,
heat and moisture stress effects
may be reduced.
When planting early, stand Good stand establishment is a a
establishment is a primary primary concern when planting early.
concern.
• Seedling diseases have increased in recent years due to earlier
planting and higher levels of corn residue left on the soil surface.
o DuPont Pioneer provides a stress emergence score as well as a premium
seed treatment on all Pioneer® brand hybrids.

8. Planting Rate & Row Width
Genetic improvement of corn hybrids
for superior stress tolerance has
contributed to increased yields.
Higher population has increased
yield per unit area by optimizing yield
components: ears per acre, kernels
per ear and weight per kernel.
Contest winners overwhelmingly
chose 30-inch rows for their contest
plots, with a small number using 20-
Corn research plot in 30-inch rows.
inch rows and some using twin rows
on 30-inch centers.
• Research results on narrow and twin rows have shown advantages
averaging 1-2% in the central Corn Belt and about 4% in Minnesota and
the Dakotas.

9. Foliar Fungicide Use
A 2012 DuPont Pioneer
summary showed that in
475 DuPont Pioneer on-
farm and university studies
conducted from 2007 to
2011 a positive yield
response to fungicide
application occurred 80%
of the time, with an average
yield response of 7.0
bu/acre.
• More growers are
Foliar fungicide application by NCGA national
treating their corn
corn yield contest winners in 2007 to 2011.
acres with a foliar
fungicide.

10. Weed Control
In 2011, all winners used hybrids with
the Roundup Ready® Corn 2 gene in
their contest plots.
• Glyphosate was not typically the only
herbicide used.
• 75% of winners used 3 or more active
ingredients in their herbicide program.
This allowed growers to:
o Control weeds early
o Widen the window of control
o Include multiple modes-of-action to
manage resistant weeds and/or
prevent resistance development.
A pre-emergence followed by post-
emergence herbicide program is likely to
be the most reliable and effective.

11. Other Practices and Conclusions
In the last 5 contest years, insecticide seed treatments were used
by the vast majority of contest winners.
• Some used other practices such as multiple deep tillage trips; planter
calibration; soil and plant-applied insecticides; and “non-traditional”
products such as root enhancers, growth regulators, and growth
promoters.
• It may be difficult to evaluate the effect of individual treatments when
several are applied to a single plot. This complicates identifying useful
products for the future, even if improved yields are obtained in the plot.
Hybrid selection, crop rotation, nitrogen fertility, plant population,
planting date and foliar fungicides are critical
factors in achieving highest corn yields.
• Growers using these practices are rapidly accelerating corn yields in
contest plots as well as on production acres.