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Freeze Injury on Forages is Variable Across the
State – Mark Sulc, OSU Extension
Forage Specialist
In just the past few days
I’ve had the opportunity to observe alfalfa in west central and
northeast Ohio,
and have been amazed at the variation in freeze injury by location. Near Springfield, our alfalfa plots were
severely frosted back, and on Friday there was very little green growth
visible. Nearly all the top growth
has been killed back to the crown and the plants have to initiate new buds
and start completely over. Given
that level of injury, I expect the first harvest will be delayed by two
weeks at minimum.
The picture at Wooster today was very different. The alfalfa looked much better at Wooster, and is
recovering very nicely. First
harvest has probably been delayed by a week or less. The alfalfa growth at Wooster had many green shoots that were
growing nicely, with just the tips frost injured. A week from now I suspect no lasting
effects of the frost will even be visible there.
The contrast between those two
locations was quite remarkable. I
suspect the delayed breaking of dormancy in northeast Ohio
resulted in much less freeze injury to the alfalfa compared with
further south near Springfield. I will be peeking
a close eye on the alfalfa near Springfield
and providing reports in the coming weeks.
Meanwhile, do keep a close eye on the alfalfa, especially regarding
weevil feeding.
It was also quite interesting to
see the difference between species in freeze injury. At Springfield,
where the alfalfa was severely injured, our red clover trial was not and
looked just fine. The red clover
must have broken dormancy later, and was less susceptible when the cold
weather hit. Several perennial
ryegrass varieties were severely winter injured in our trial at Springfield. We will report those varietal
differences in our annual forage performance trials report in the fall.
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Adjusting Corn Management
Practices for a Late Start
As prospects for a timely start
to spring planting diminish, growers need to re-assess their planting
strategies and consider adjustments. Since delayed planting reduces the
yield potential of corn, the foremost attention should be given to management
practices that will expedite crop establishment. The following are some
suggestions and guidelines to consider in dealing with a late planting
season.
Although the penalty for late planting is important, care should be taken
to avoid tillage and planting operations when soil is wet. Yields may be
reduced somewhat this year due to delayed planting, but effects of soil
compaction can reduce yield for several years to come.
If you originally planned to apply nitrogen and herbicides pre-plant, consider
alternatives so that planting is not further delayed when favorable
planting conditions occur. Although application of anhydrous N is usually
recommended prior to April 15 in order to minimize potential injury to
emerging corn, anhydrous N may be applied as close as a week before
planting (unless hot, dry weather is predicted). In late planting seasons
associated with wet cool soil conditions, growers should consider
side-dressing anhydrous N (or UAN liquid solutions) and applying a minimum
of 30 lb/N broadcast or banded to stimulate early seedling growth. This
latter approach will allow greater time for planting. Similarly, crop
requirements for P and K can often be met with starter applications placed
in bands two inches to the side and two inches below the seed. Application
of P and K is only necessary with the starter if they are deficient in the
soil, and the greatest probability of yield response from P and K starter
is in a no-till
situation.
Keep time expended on tillage passes and other preparatory operations to a
minimum. The above work will provide minimal benefits if it results in
further planting delays. No-till offers the best option for planting on
time this year. Field seedbed preparation should be limited to leveling
ruts left by last year's wet, problem harvest - disk or field cultivate
very lightly to level. Most newer planters provide
relatively good seed placement in "trashy" or crusted seedbeds.
Final tillage passes just before planting can be beneficial in suppressing
weeds, but may not be practical this year. In many cases, it will be more
profitable to complete planting first and control weeds with post planting
applied herbicides. Planting into seed-beds which contain emerged weeds
will make post planting weed control critical. Herbicide resistant corn
including Roundup Ready and Liberty
Link hybrids may offer definite advantages in these situations. Effective
burn-down applications will help minimize the potential for major weed
problems developing later in the season.
Don't worry about switching hybrid maturities unless planting is delayed to
late May. If planting is possible before May 20, plant full season hybrids
first to allow them to exploit the growing season more fully. Research in Ohio and other Corn Belt
states generally indicates that earlier maturity hybrids lose less yield
potential with late plantings than the later maturing, full season hybrids.
With no-tillage or reduced tillage, increase seeding rates 10% over those
used with conventional tillage. Consult seed company recommendations for
specific hybrid planting rates under reduced tillage. Lower yields in
no-till can sometimes be related to sub-optimal
plant populations at harvest.
Source: C.O.R.N Newsletter 2007-10
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Air Temperature and Corn
Emergence
According to the USDA-NASS http://www.nass.usda.gov/ as of Sunday, April 29, corn planted in Ohio was at 19 percent,
4 days behind last year and 6 days behind the five-year average. Cooler and
wetter than normal weather has slowed corn planting down considerable
compared to recent years. What impact will these conditions have on corn
that has already been planted?
In past years, we have observed that early planted corn that was in the
process of germinating or as far along as the V1 stage (one leaf collar
visible) survived freezing temperatures in late April with little impact on
crop performance or plant stand. Agronomists generally downplay the impact
of low temperature injury in corn because the growing point is at or below
the soil surface until V6 (six leaf collars visible), and thereby
relatively safe from freezing air temperatures. However when dry corn seed
absorbs cold water as a result of a cold rain or melting snow, “imbibitional chilling injury” may result. Cold
water can cause similar injury to seedling structures as they emerge during
germination. Such physiological injury was widely observed in 2005 when
early planted corn in various stages of germination and emergence was
subjected to a period freezing rain and snow followed by temperatures at or
below 50 degree F for about 10 days. What we’ve experienced thus far
in 2007 is mild in comparison to 2005.
To assess the impact of these freezing temperatures on emerged corn, check
plants about 5 days after the freezing injury occurred (and preferably when
growing conditions conducive for regrowth have
occurred). New leaf tissue should be emerging from the whorl. You can also
observe the condition of the growing point (usually located ½ in to 3/4 in
below the soil surface) by splitting seedlings lengthwise. If the growing
point appears white to light yellow and firm several days after the frost,
prognosis for recovery is good.
Of greater concern with regard to the viability of germinating and emerging
corn is how long soils will remain saturated. Cool temperatures and wet
weather provide the right conditions for the development of seedling blight
diseases. Cold temperature injury can play a significant role in
predisposing plants to root infection and blight. Under normal conditions
plants can continue to grow and produce new roots, but when other injuries
occur, new roots cannot develop rapidly and Pythium
and other soil fungi can kill stressed plants. Seed treatment fungicides
generally remain effective from 10 to 14 days but under saturated
conditions the duration of protection may be shorter.
For more detailed information on corn germination and emergence, I’d
encourage you to check out a series of excellent articles (noted below)
which Dr. Bob Nielsen, my counterpart at Purdue University
has recently written. These articles include great photos that will assist
your understanding of these growth and development processes.
Nielsen, RL (Bob). 2007. Germination Events in Corn. Corny News Network, Purdue Univ. [On-Line]. Available at: http://www.kingcorn.org/news/timeless/GerminationEvents.html .
Nielsen, RL (Bob). 2007. The Emergence Process in Corn. Corny News Network,
Purdue Univ. [On-Line]. Available at http://www.kingcorn.org/news/timeless/Emergence.html .
Nielsen, RL (Bob). 2007. Requirements for Uniform Germination and Emergence
of Corn. Corny News Network, Purdue
Univ. [On-Line].
Available at http://www.kingcorn.org/news/timeless/GermEmergReq.html . (URL verified 4/23/07).
Nielsen, RL (Bob). 2004. Corkscrewed Corn Seedlings. Corny News Network, Purdue Univ. [On-Line]. Available at http://www.kingcorn.org/news/articles.04/Corkscrew-0501.html
. (URL verified 4/23/07).
Source: C.O.R.N. Newsletter – 2007-11
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Reporting Likely Damage from the
April Freeze to Tree and Small Fruit Crops –
Dr. Diane Miller, OSU Extension Fruit Specialist
Congressman Zack Space,
Ohio’s 18th Congressional District and member of House
Agriculture Committee, conducted a phone conference call Friday, April 20,
2007 to learn about the impact of spring freezes on fruit and vegetable
farmers in his district and other areas of the state.
A critical message from the meeting
is that every fruit (tree, small or grape) and vegetable farmer who believes
the freeze caused economic damage to his/her business should immediately
contact his/her local Farm Service Agency (FSA) office to report
damage. This has to be done within
15 days of when you suspect that you have damage. This should be done whether or not you
have FSA crop coverage (different forms for with and without coverage).
The local FSA office will then
report to USDA and this is the line of action for any disaster
declaration. As of April 20, only
14 Ohio
counties had reported likely damage.
If you have not reported your likely damage to your local FSA office
yet, please do it immediately.
Congressman Space also strongly suggested contacting your
Congressional District representative and/or Senators and make the aware of
your particular situation. Issues
worthy of discussion include your immediate needs, and also improvement of
perennial crop insurance programs and disaster assistance programs. Again it is very important that fruit and
vegetable growers effected by this, some are
saying 1 in 50 year freeze event, let your voice be heard. This may open up some help and assistance
for growers who will have reduced crop income this season.
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May
– June, 2007