Will Corn Following Corn Face Decreased Yield?
This article was originally published on March 25, 2011 and expired on April 25, 2011. It is provided here for archival purposes and may contain dated information.
The 2010 season was a
disappointing one for corn growers in many parts of Illinois, said University
of Illinois Extension agronomist Emerson Nafziger. With a statewide average
yield of only 157 bushels per acre, just 4.2 bushels higher than the U.S.
average, and the third-worst yield in the past decade, many Illinois producers
are hoping for a more bountiful 2011.
Over the past 10 years, the
Illinois corn yield has averaged 13.7 bushels per acre above the U.S. national
average, and has been below the national average only once (by 4.9 bushels in
2005) and above it by as much as 25.1 bushels (2008).
"The major problem in 2010
was heavy rainfall in June that resulted in standing water and saturated soils,
which in turn resulted in nitrogen loss and damage to root systems which could
not be repaired," Nafziger said. "As a result, affected fields and
parts of fields ended up with shortages of both nitrogen and water, problems
made worse by high temperatures and early maturity, and in some cases by dry
weather during the latter part of the grainfilling period."
Corn following corn was
particularly hard hit in 2010, and there were numerous reports of larger yield
penalties for corn following corn compared to corn following soybean than most
have seen for a number of years, he added.
In research trials conducted
since 2003, Nafziger saw similar results. He has been comparing continuous
corn, corn rotated with soybean, and corn following either corn or soybean in a
Nafziger said that the rule of
thumb for many years has been that corn following corn yields about 10 percent
less than corn following soybean. This difference has often been less than that
in some recent comparisons, but he said it varies depending on the year.
Across four northern Illinois
sites, the yield penalty for continuous corn was about 11 percent in 2008-09,
but 19 percent in 2010. Second-year corn in the corn-corn-soybean rotation
yielded only 5 percent less than corn following soybean in 2008-09, and 10
percent less in 2010, indicating that having soybeans even two years ago helps
lessen the yield penalty for corn following corn. At the two southern Illinois
locations, with considerably lower yields, the penalty for continuous compared
to rotated corn was substantially less, measured either as bushels or as a
percentage, he noted.
Despite the relatively poor
performance of corn following corn in 2010, Nafziger said most indications are
that this shouldn't be the expectation for 2011.
"Field and soil conditions
are much different than they were a year ago," he said. "None of the
factors of a year ago - late fall harvest, poor tillage conditions, lots of
fresh residue on the surface, and much nitrogen yet to apply - exist this
spring. We did a massive amount of tillage last fall, in some cases perhaps
more than was necessary."
One additional benefit for
producers is that it has not been wet for extended periods when soil
temperatures were warm since nitrogen was applied last fall. Most of the
nitrogen should still be present, with a good deal of it still in the ammonium
form and so not subject to loss.
"Though we can certainly
feel good about preparations we've been able to make for this spring, we know
from history that a good fall doesn't always mean a good crop the following
year," he cautioned. "Soils are starting to dry out nicely in some
areas, but we need to be careful not to
undo the compaction relief provided by last fall's tillage by driving on soils
before they're dry enough."
Waiting until soils are dry
enough at depth (not just over the surface) will help minimize compaction
effects, as will using controlled traffic, making fewer tillage passes, and
lowering tire pressure.
Nafziger encourages producers to
follow the same practices they have been using when planting corn following
corn this year.
"Our research shows that
both corn after corn and corn after soybean respond similarly to planting date
and to plant population, so those should change only as soil conditions and
productivity might indicate," he said. "We've never been able to
identify hybrids that do consistently better in corn following corn, though
corn following corn may tend to experience stress (primarily drought stress)
and foliar diseases more often, so that should be factored in. And corn
following corn typically needs a little more nitrogen — see the N
Rate Calculator for current numbers."
Remember the important things
this planting season, Nafziger said.
"Having good soil
conditions where the seed is placed and good rooting conditions beneath the
surface are critically important for corn no matter what the previous
crop," he said. "And the crop needs to be well provided with
nutrients and protected from pests. Once we cover these basics, the crop will
respond mostly to weather factors - water and temperature - that we don't
control. That has always been true, and will be true again in 2011."
Source: Emerson Nafziger, Extension Specialist, Crop Production, email@example.com
Pull date: April 25, 2011