Des Moines, Iowa
January 23, 2008
Consider field selection,
compaction, residue management and soil fertility
Many growers still may be deciding whether to plant corn after
corn, soybeans or other crops following corn. Agronomy experts
with Pioneer Hi-Bred, a
DuPont business, say the most critical decisions begin with
analyzing highly productive fields, managing residue and
compaction in those fields, and maintaining soil fertility.
The trend toward corn after corn has been underway since grain
prices moved higher in late 2006. Last year, U.S. growers
planted a record 93.6 million corn acres, an increase from 78.3
million acres the previous year. Though the industry is
predicting a decrease in corn acres for 2008, corn acreage is
expected to remain at relatively high levels.
Choosing the Right Crops for the Right Fields
"For growers contemplating their crop rotation options, those
choosing corn after corn should start by selecting fields that
historically have higher corn yields, good drainage and
medium-textured soils with ample water-holding ability," says
Paul Gaspar, Pioneer agronomy research scientist in Mankato,
Minn. "Seedbeds need to be in top shape to handle the growing
season challenges, no matter which rotation plan is in place.
"At planting time, however, corn-after-corn fields present a
more adverse environment for the corn seed and seedling. It's
difficult to wait, not knowing what the weather forecast holds,"
says Gaspar, "But don't plant corn-after-corn fields too early -
keep the planters in check if soils are below 50 degrees and
warmer weather is not in the forecast."
Wet fields also can cause problems. Surface compaction, sidewall
compaction and/or deep compaction can restrict root growth and
limit water uptake and yield, particularly if followed by
drought conditions.
"Managing residue from the previous crop is also a key factor
for a good start in 2008," says Gaspar. "Corn produces more than
twice the amount of residue as soybeans. Excessive corn residue
can result in much cooler soil temperatures and higher soil
moisture at planting and can be a concern no matter which crop
is going into the ground this spring. The goal is to clear
residue from the row area - potentially with row cleaners,
coulters or other residue management attachments on the planter.
These can help with more rapid germination and emergence,
particularly if there were challenges in distributing residue
evenly during harvest."
In looking at crop rotation choices, soil fertility should be
based on thorough soil testing and local Extension
recommendations. Soil tests are needed to determine soil pH and
existing levels of phosphorous and potassium. Soil pH should be
at or above 6.2 for growing corn. If planter attachments are
available for applying starter fertilizer, growers should
consider applying appropriate rates of nitrogen, phosphorus and
potassium at planting time. This will improve the uniformity and
speed of emergence of corn in cooler soils.
Corn residue ties up more nitrogen than soybean residue as it
decomposes, therefore growers should plan to apply about 50
pounds of additional nitrogen to corn-after-corn versus
corn-after-soybean fields.
"In high residue fields, consider using 50 pounds of starter
nitrogen to give plants a faster start," says Gaspar. "In all
fields, consider splitting nitrogen applications, if possible.
This can reduce nitrogen losses and help ensure corn plants have
adequate nitrogen throughout the season."
"Traditionally, growers have rotated fields in a combination of
corn and soybeans or other crops. That trend continued until
recent years, with the most significant production change
occurring in 2007," says Dr. Emerson Nafziger, crop science and
weed management specialist, University of Illinois-Urbana. "In
the past, there was some concern of negatively impacting yield
if rotation was not made each year, or in some cases, at least
every few years. However, the latest hybrids are holding their
own in agronomic terms through a combination of genetic
improvement and crop management practices. Today's hybrids have
better disease resistance, root systems and seed treatments,
particularly compared with hybrids from just a few years ago.
"Though corn-soybean rotations remain a stable production
practice, there is no strong indication that it will continue to
be the standard of stability," says Nafziger. "In fact, 2007
brought very positive signs for corn-after-corn production.
Yield tells the story and results were favorable this year for
many growers."
Larger farming equipment also has contributed to increasing
corn-after-corn rotations, adds Nafziger. The time once required
for corn planting has been reduced with the ever-increasing size
of equipment.
Reviewing Harvest Data
"Harvest data from the 'year of the corn' in 2007, will be of
particular interest to growers," says Murt McLeod, Pioneer
agronomy research scientist at Windfall, Ind. "With increased
corn-after-corn acreage, last year was an optimum time to
analyze efficacy data for hybrid performance and insect control.
For unknown 2008 growing conditions, selecting hybrids that have
a broad spectrum of insect control and strong root systems is
key."
Post-harvest research summaries in 2007 from multiple Midwestern
locations confirmed that Pioneer® brand hybrids with Herculex®
XTRA were consistently superior to other corn rootworm
management options, including other transgenic and soil
insecticides. In seven university and 11 Pioneer agronomy
science trials, Pioneer hybrids with the Herculex traits were
more effective against root damage, compared to hybrids with the
YieldGard® traits developed by Monsanto. For more information,
go to
www.pioneer.com/web/site/portal/menuitem.6f0ef67dddf0dcf1675d8df0d10093a0/.
Hybrids with Herculex XTRA insect protection contain both
Herculex® I and Herculex® RW to guard against a broader range of
above- and below-ground insects in corn than any other in-seed
product on the market. While offering good control of western
bean cutworms, research also showed that Herculex XTRA provided
the highest protection against black cutworms, excellent control
of European corn borer and southwestern corn borer, and good
protection against fall armyworms.
"Corn rootworm (CRW) larvae are one of the most destructive
insects of corn in North America," says McLeod. "Feeding on the
root system, damage from corn rootworms can affect standability
and limit water and nutrient uptake in the plant, impacting
overall plant health and grain development. The end result can
be yield loss of 10 percent to more than 30 percent which is
common with moderate to high corn rootworm populations in
untreated fields.
"Though corn rootworm pressure was less this past growing season
in several areas of the Corn Belt than the previous two years,
research trials were good indicators of yield performance during
lower pressure situations," McLeod said. "Higher yielding corn
is still the overall goal for growers, and hybrids need to
perform in all levels of insect pressure."
For further information on crop rotation and seedbed
preparation, contact your local Pioneer sales professional. In
addition to your local sales professional, Pioneer offers a
national network of agronomists to provide assistance.
Pioneer Hi-Bred, a DuPont business, is the world's leading
source of customized solutions for farmers, livestock producers
and grain and oilseed processors. With headquarters in Des
Moines, Iowa, Pioneer provides access to advanced plant genetics
in nearly 70 countries.
DuPont is a science-based products and services company.
Founded in 1802, DuPont puts science to work by creating
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DuPont offers a wide range of innovative products and services
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® Registered trademark of Pioneer Hi-Bred.
Herculex® insect protection technology by Dow AgroSciences and
Pioneer Hi-Bred. ®Herculex is a registered trademark of Dow
AgroSciences LLC.
® YieldGard is a registered trademark used under license from
Monsanto Company.
For additional information about our company or our products,
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