Corn Following Corn: Strike 2?
This article was originally published on September 23, 2011 and expired on October 23, 2011. It is provided here for archival purposes and may contain dated information.
Corn following corn may be
getting its second strike this season, said University of Illinois Extension
agronomist Emerson Nafziger.
"Despite different planting
season and crop conditions in 2011 than in 2010, we are again hearing that corn
following corn is producing lower yields than corn following soybean in many
areas," Nafziger said. "In
some cases, I've heard reports of corn following soybean yielding in the range
of 230 bushels per acre, while corn following corn in the same area planted
with similar practices is yielding in the 160 to 170 range. We don't expect
corn following corn to average 60 or 70 bushels less than corn following
soybean over whole areas, but this does illustrate what will again be a significant
issue in some fields this year."
Nafziger said it was easy to
attribute last year's decreased yields in corn following corn to weather. In
2011, he doesn't have as clear a picture about why growers are seeing this
What happened this year to
result in a second year of substantial yield loss in corn following corn?
Nafziger offers the following:
1. The spring of
2011 started out well, with some corn planted in early April. Almost all of
this was corn following soybean, given that such fields tend to dry out faster
and need less work in the spring. It turned wet and cool after that, and
planting stalled at about 10 percent complete through the rest of April. So
planting was, on average, late in 2011.
2. Once the
calendar turned to May and it dried up enough for field work, planting got
underway in a big rush with about 60 percent of the crop planted over the first
two weeks of May. Many fields planted during this period were wetter than
ideal. And because fields that were in corn the year before almost always dry
out more slowly than those that were in soybean, those who started planting
corn following corn in early May planted into even wetter and cooler soils than
those planting after soybean. This not only caused more compaction, "undoing"
much of the benefit of tillage last fall, but it also brought issues of residue
interference, seed placement, and effects of heavy equipment in many
3. As a result of
the above, many reported that corn following corn looked bad from the start,
with uneven stands, poor color, and other problems associated with planting
into such cool, wet conditions. Some who attempted to apply extra nitrogen,
foliar nitrogen, micronutrients, or other things to try to "bring the crop
around" generally found that these didn't do a lot of good. Starter
fertilizer helped some to make stands look more uniform, but did not completely
solve the problem.
4. The heavy
rainfall in May and June in some areas was a repeat of what we saw in 2010. But
with the crop not nearly as far along in 2011 and with June temperatures not as
high as in 2010, immediate effects of this heavy rain on the corn crop were not
as severe in 2011 as in 2010. This did delay the return of the crop to normal
color and growth in corn following corn.
5. When the rains
stopped in many areas in late June, and soils dried in July and August, the
effects were much more severe in most corn-on-corn fields than in fields where
corn followed soybean. Due to drier
soils, root systems generally developed better and remained healthier in 2011
than in 2010. But with compaction, slower growth due to less (and a less green)
canopy, residue, possible tillage effects, and other factors at work in corn
following corn, it seems that the ability of the roots to extract water
compromised in corn following corn compared to corn following soybean. Both
crops seemed to pollinate okay, but corn following corn showed more leaf stress
in July and August, and reduced light interception was evident in many fields
where corn followed corn. This increased kernel abortion and decreased the
ability of the crop to fill the kernels it had.
6. In the driest
areas, corn following corn lost canopy color and died prematurely, often before
corn following soybean. This stopped the filling of kernels, and in many cases,
led to more stalk quality problems.
After corn-on-corn has done so well in recent years, many
growers are discouraged to have a second year of lower yields in many
corn-on-corn fields. Many will find that their profitability will be higher
with corn following soybean than corn following corn this year, even accounting
for what have often been lower returns from soybeans than from corn in recent
years, Nafziger said.
"We can't simply decide to
plant more corn acres following soybean in 2012 than we did in 2011; we planted
only about 9 million acres of soybeans in Illinois both years, and acres of
corn following soybean the next year can't exceed that number," he said.
"So as long as corn acreage stays near the 12 million acres of recent
years, some 20 to 25 percent of Illinois corn will have to be corn following
Given the severity of this
problem and the fact that it has now happened a second year, Nafziger requests
that anyone experiencing this problem send him an e-mail at firstname.lastname@example.org describing a) a brief description of the yield
differences; b) where the problem is occurring the worst; and c) if there are
any corn-on-corn fields that seem to have escaped this problem to yield nearly
as well as corn following soybean and possible explanations for the differences.
For more information, read The
Bulletin online at bulletin.ipm.illinois.edu/.
Source: Emerson Nafziger, Extension Specialist, Crop Production, email@example.com
Pull date: October 23, 2011