OSU
Extension, Darke County...
Fall
Pasture Management
By Justin Petrosino, ANR Extension
Educator
October 12, 2011
As we transition into
fall and look ahead to winter most of us who are in agriculture are
concentrating on harvesting corn and beans and planting wheat. With
that flurry
of activity it is easy to forget about fall and winter management
concerns for
pastures.
During July and August many of us
were concerned about the severe lack of rainfall and coinciding lack of
forage
growth, especially with our cool season grasses. Those with extra
paddocks that
are dominated by a fescue species set aside the paddocks for winter
stockpiling. If you were lucky enough to have the extra grass now is a
great
time to take stock of your hay supply and make sure there is enough to
make it
through the winter. Also see if there are enough reserves to keep the
cattle
fed if we endure another wet spring. If you have not already, be sure
to sample
your hay for nutritive value. The long wet spring took a toll on hay
quality,
especially first cutting hay. It takes more low quality hay to sustain
an animal
than high quality hay, although they will eat high quality hay faster!
With fall comes the first frost of
the season. In a grazing situation frost brings with it two
considerations for
grazers. According to Rory Lewandowski, AgNR Educator, Athens County,
frost can
severely impact the safety of weeds and forages in the sorghum family.
Forages
like sudangrass and sorghum sudan mixes and weeds like johnsongrass and
shattercane can produce prussic acid after a frost. The compound
contains cyanide
and is very toxic to livestock. According to Rory animals should not
graze
sorghum plants “…on nights when frost is likely as high levels of
prussic acid
are produced within hours after a frost after a killing frost”. Rory
recommends
waiting 5 to 7 days after a frost event to graze areas. Also note that
if a new
frost occurs the cycle starts all over again.
Dr. Marc Sulc, OSU Extension Forage
Specialist, warns us that livestock should not graze a pure legume
stand after
a frost. After a frost pure legume stands have an increased risk to
cause
bloat. Dr. Sulc recommends waiting several days after the frost to let
damaged
plants dry and to include hay in the diet of animals eating pure legume
or high
legume stands.
Another fall management point for
pastures is to make sure pasture species have the fertility they need
to
continue healthy growth. Fall is an optimal time to soil sample
pastures to
determine their nutrient needs. Soil fertility is of the utmost
importance for
pastures. In a mixed grass and legume pasture a concentration of 35%
legumes
can provide the nitrogen needed for the mixture. However, these legumes
require
optimal conditions to produce the nitrogen including a soil pH range
between
6.5 and 6.8 and a good grazing management program. Recycling of
phosphorus and
potassium under a management intensive grazing system is typically 80%,
with
20% leaving the forms of meat and milk. If open grazing is utilized
manure will
be concentrated in loafing areas. This manure will either need to be
spread or
substituted with commercial fertilizer. The easiest way to manage
manure is to
manage the animals. A rotational grazing system will reduce the need to
spread
the manure mechanically.
Finally fall is an optimal time to
control perennial and biennial weeds. Thistles, dandelion, and locust
are
currently pumping carbohydrates from the leaves to the roots. Systemic
herbicides like glyphosate and 2,4-D will catch a ride with the sugars
and kill
the roots of the plants.
For more information on fall pasture
management there are many options.
The first is the BEEF Newsletter at http://beef.osu.edu. Three guides
available
at the Extension Office are the Ohio Agronomy Guide, The Weed Control
Guide,
and the Forage Field Guide. The best resource we have in Ohio is Bob
Hendershot. He will be at 4007 Route 66B in Houston, Ohio, on Thursday,
October
13, 2011, at 6:00 pm for the Shelby County Pasture Walk.
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