Spring will arrive before we know it. There will be new growth emerging from
seedlings and plants that have been dormant through the winter. With sufficient
moisture, life will spring forth across the range, thus beginning a new growing
season. However, last year was dry and many native grass pastures have been
heavily used this winter in many cases leaving little residual forage.
Now is the perfect time to begin planning how to manage native grass pastures
for this season.
Much of the planning depends on the goals for the pasture and exactly what
there is to work with. If you have significant stands of the preferred tallgrasses,
such as Big bluestem, Little bluestem, Indiangrass, Switchgrass and perhaps
Eastern gamagrass, you are probably at an advantage over those who do not. But
even if you have a presence of these grasses, it will benefit you to plan to
manage grazing around these key species. The easiest means to discuss this without
writing a dissertation is to give an example.
Eastern gamagrass at Coffey Ranch |
The Noble Foundation Ag Division operates several properties in southern Oklahoma.
At the Coffey Ranch, on a 20-acre pasture (one of the least productive), a mixture
of desirable native grasses including Eastern gamagrass was broadcast and then
trampled into the soil with cattle. Several springs later, the resident manager
of the Coffey Ranch, Kent Shankles, noticed what appeared to be seedlings of
the more desirable tall grasses. He conferred with several Ag Division forage
specialists, and we decided to change the grazing management of the pasture
for the season. Previously, the pasture was dominated with mid-seral grasses,
predominantly broomsedge bluestem, and had been grazed intensely and often (rotationally)
during the early growing season, leaving a 2- to 3-inch residual plant height
and returning for another grazing event in about 25 to 30 days. The objective
of this type of grazing was to use a less-desirable forage as much as possible,
delaying the onset of growth of reproductive structures. The new grazing strategy
was to graze the pasture only long enough to maintain a minimum of a 6-inch
residual on the desirable grasses, which turned out to be mostly Eastern gamagrass
with some Switchgrass, and extend the recovery period to 45 to 60 days during
the early growing season and even longer later in the season when moisture conditions
were poor. We guessed we would be sacrificing some grazeable production in the
short-term for long-term benefit of the stand.
The results were surprising. At the end of the growing season when managing
the grazing for the Eastern gamagrass plants, the grazed production from the
pasture had actually increased over previous years totals, from about
30 AUDs (animal unit days AUD = 26 lbs. DM per acre) to 58 AUDs. The
following years showed an increase in AUDs upwards of 90 AUDs when the same
grazing management was practiced. After each growing season, plant residuals
exceeded 10 inches going into the winter, and, furthermore, this occurred during
the late 1990s, which were not known as abundant rainfall years.
All that said, the only reason why this was observed and documented was because
Kent was looking at his pastures in the spring prior to turning in the cattle.
The question then became, "How many tallgrass plants does it take to impact
the grazed production?" Upon establishing ten random transects, the basal
intercept (ground level) of plants along these transects averaged just over
5 percent the third and fourth years post emergence. Granted, not all tallgrasses
have the same growth structure as Eastern gamagrass, but the take-home message
is it does not take very many tallgrass plants to significantly impact production.
If you have tallgrasses present in native grass pastures, address grazing management
to improve or sustain range condition. That does not mean everyone should rotationally
graze cattle through pastures as indicated in this example, but recovery periods
and residual plant heights need to be a significant part of the management scheme.
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