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Corn and Frost
5/18/2004
Ron F. Meyer
Area Extension Agent
(Agronomy)
Colorado State University Extension
Golden Plains
Area |
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When low temperatures occur in a region and the potential for
frost or freeze exists, there are several factors that dictate the extent and
severity of frost damage to the corn crop. One of the most important
factors is plant maturity. Young corn plants are less susceptible
to frost injury that leads to plant death since the growing point is below
ground and protected from freezing temperatures. More mature plants have
more exposed leaves and can have growing points above the soil surface
beginning at the six-leaf collar stage (about 12 inches tall). When the
large leaves of these corn plants are frozen, they can form a tightly twisted
whorl that is difficult for the emerging leaves to penetrate.
Another
factor that determines post-frost plant recovery potential is plant health just
prior to frost. If plants have been under stress due to cold
temperatures, herbicide injury, excessive moisture or disease they are less
able to recover from even minor frost damage. Likewise, when growing
conditions following a frost event are not ideal, corn plants may be slow to
recover and more susceptible to death.
Practices that inhibit soil
radiation can increase the probability of frost damage:
Tillage
systems that leave heavy previous crop residue coverage in a field tend to
intercept radiant heat from the soil. This prevents the moderation of
nighttime temperatures that often occurs near the soil surface in fields with
little or no residue. Without soil heat radiating upward at night, young
corn leaves are more susceptible to frost damage.
Soil moisture
can also influence soil radiation potential, with increased heat capacity in
wet compared to dry soil. This explains the decreased corn frost injury
in fields or portions of fields recently irrigated compared to those that were
not irrigated before a frost (Elmore and Doupnik, 1995).
A reliable way
to determine frost impact is to wait until after three to five days with daily
high temperatures above 70°F and check for evidence of new growth.
Remove dead whorls and look for erect, lime green leaf growth inside the corn
plant. Another sign of active growth is a “rippled” leaf effect
within the whorl when the plant is cut lengthwise. The
“rippled” leaves indicate new growth occurring since the frost and
leaves are backing up behind the damaged, knotted whorl.
When growers
experience frost damage in a corn field they are faced with several management
options. They may choose to do nothing, leaving the field as it is
and allowing plants to recover on their own. Another option is for
growers to replant their corn field to another crop. A final
management choice is to clip corn plants after frost to remove the dead
and decaying tissue found above the growing point.
Clipping frozen corn
plants to remove dead tissue has been studied by several researchers.
While results are somewhat variable, the general conclusion is that clipping
does not enhance yield in most situations, and often further reduces yield as
compared to not clipping damaged plants.
A Wisconsin study (Carter,
1995) showed that post-frost clipping reduced grain yield by 15 to 34% at three
sites and increased yield by 10% at one site. At two additional sites,
clipping had no effect, positive or negative, compared to doing
nothing.
Similar results in Nebraska suggest that post-frost clipping is
an unreliable method of promoting recovery from early season frost (Elmore and
Doupnik, 1995).
Source: Pioneer Crop Insights |
Page Created and Maintained by: Perry D. Brewer, Area
Extension Agent (Technology Education/Youth)
5/24/2004 |
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