"Tired" Pastures
By Wayne Burleson
As we study how well our intensive pasture management programs are going, I'm concerned about observing something I call,
"Tired" Pastures. These are grasslands that show signs of low vigor, unhealthy plants and the invasion of unwanted weedy
species. This is where the art and science of Range Management come together, that is having good observation skills to make
comparisons of side-by-side similar looking pastures and begin to pick up the differences.
Interestingly, when I mentioned my concerns about a certain paddock on a Wyoming
ranch, they said, we did not have our animals in that particular paddock. Oh! Oh! I was
scratching my head. Later that evening, when I was watching a video of their calving, guess which paddock they were
in -- The same one that I had the concerns about. See,
conducting a pasture walk can reveal valuable information. The simple pasture walk method (done in 15 minutes) does work.
This "Tired" Pastures syndrome is showing up on several grazing cells.
On one longtime intensely managed Wyoming ranch, I found certain paddocks without
litter, the soils were low in organic matter and a general downward trend in total
production. This syndrome "tired" look doesn't show up right a way, but it's a gradual year after year slow progress lowering the health and condition of the grassland.
These grazing cells were not overgrazed because of the fast rotation - sometimes only five
days per paddock. Instead, I believe these ranchers have become very efficient at
harvesting too much grass off their ranches. I believe that these "tired" pastures are
caused because very little litter is cycling back into the soils.
What do you look for in "tired" pastures? Good indicators are: narrow leaves, thin stems,
short length of seed head, shallow roots, short weak root system, low lateral leaf growth, low quantity of forage, short plant appearance, soils low in organic
matter, poor mineral cycle, soils with lots of bare ground, no standing litter, low plant density and diversity,
compacted soils, low water permeability, dying plants and low total production.
You can determine if you have "tired" pastures relatively fast by conducting a Pasture
Walk on several pastures comparing them to each other. Often the neighbor's pasture with a different management scheme will help you to judge what's going on.
One simple place to look when determining the health of grassland is to study what is
going on between the plants. Finding high amounts of bare soils are good indicators of "tired" pastures. To help prove this point, I use a soil thermometer. Stick the
thermometer probe into the bare soils and take a reading, then stick it into covered soil. On a warm
sunny day you will discover very hot soils reaching 130 degrees Fahrenheit and on adjacent shaded soils only 80 degrees.
You can imagine what happens when
raindrops hit these hot soils. Evaporation is high, causing the loss of
valuable water for your plants. Even more important is the effect of
very hot soils on certain microorganisms.
When you allow your soils to become
bare, on a very hot day, you will cook some of these organisms that are
extremely important to healthy soils.
I also mentioned the words "tired" pasture to a grazing expert
and friend of mine, Burt Smith, from Hawaii. Here is his response.
"Your concern about "tired" paddocks is fully justified.
Our 1995 trip through North America was taken to find out if there was
any commonality to problems that experienced intensive grazers were
facing; there are.
“Tired” paddocks were one of
those things that my wife and I repeatedly witnessed, regardless of
where we were. In the east it is less obvious than in drier regions, but
still noticeable. Another observation we made was that the roadsides
(county, state, and federal roads, not just interstates) are looking a
whole lot better than the pastures that border them. My more recent
trips to the mainland, while not near as intensive as in '95, reaffirm
these observations.
"It has been fairly well documented that the Corn Belt is losing
some 7.5 tons of soils per acre. Using this value and taking a high
average corn yield of 200 bushels per acre it is costing around 1.5
pounds of soil for every pound of corn harvested in the U.S. Corn Belt.
Other farmlands have similar losses and also, the removal of nutrients
from our farms and ranches to urban centers.
A
simple back of the envelope calculation using just the nutrients
contained in sheep and cattle that have been slaughtered in U.S. urban
plants for the last 90 years, indicates an amount of mineral, that if
spread evenly across every acre in the continental U.S., is equivalent
to a loss 130 pounds of minerals per acre. This is more noticeable on
range lands than in wetter climes."
Another observation Burt made was the distance from the root/shoot
interface in perennial bunch grass and the soil surface between the
bunches. "When most grasses started growth, it is at the soil
surface or more likely in a slight depression. I know of no bunch grass
tillers that lives longer than 30 years, most live between five to 10.
If the height between the root/stem junction and the soil surface
between plants is divided by the age of the clump, five to 30 years
(depending upon your optimism), the result is how much soil, in inches,
has been lost per year.
"The first time I tried this was on some 'good' rangeland (BLM
definition not mine) outside of Elko Nev., it came out about a tenth of
an inch a year. Since then, I have cut through a lot of bunch grass and
made similar measurements with similar results. So what happens to the
soil between plants?"
Burt went on to say, "The key is in understanding systems and
dynamic systems in particular. In General Systems Theory (which is the
study of entire systems) there is a theorem, rule, or whatever one
wishes to call it, that essentially states that in dynamical (living)
systems, every part of that system is there for the benefit of other
parts; and that these parts, acting collectively, begets a whole, which
has traits that are larger, and often unexpected, than just a
consideration of the various parts would suggest. (The whole is larger
than the sum of its parts thing.)
"Other major tenets are; the relationship among parts is a greater
factor than the parts themselves. Each component of a living system
optimizes its production to conform for the needs of other parts and
hence the entire organism. The key word here is optimize. Parts of a
healthy system optimize, only cancers maximize."
If you find some of these concerns on your own lands, what can you do
about it? Well, if you are tired, you need rest. Rest is a tool that
producers often overlook. In reality, if the cycling of organic matter
is low, speed up your rotation and leave more standing forage and litter
covering the ground. Don't take it all! Monitoring these factors is
critical. Simply stated, if you are not monitoring, you are not
managing.
(Wayne Burleson is a well-known land management consultant working out
of Absarokee, Mont. You can visit with Wayne at (406) 328-6808 or E-mail
him at rutbuster@montana.net )
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