Pasture Management
August 22, 2005
Why pay attention to your soils? Long-term soil
health is directly related to how much money you can put into your
pockets. Soils and soil quality determine plant vigor. Soil organic
matter content is the key indicator of soil health.
Soil organic matter is important for maintaining soil structure. Soils
with good soil structure generally have lower erosion rates, higher
water infiltration rates and higher water-holding capacities and also
serve as an important nutrient reservoir.
Besides, I say, “If you can learn to feed the soils, the soils will feed
you.” Healthy soils equate to a healthy life. Healthy soils are alive
with all kinds of small critters living in them, eating away, making
carbon, the black color in soils, called carbon sequencing.
So it’s just logical, that if we can estimate and learn how to sustain
and even improve soil, you can then capture more ‘solar dollars’ (a free
source of energy). You won’t have to go to town and buy that same energy
with ‘paper dollars’.
A client of mine once asked me, “Wayne! What is the fastest way to grow
more soils?” I thought about that question and responded: Find a chunk
of long-term rested ground, like 10 year old CRP land—highly erode-able
land set aside for conservation and government payment.
Then graze and trample all that old dead non-cycling plant matter into
the ground. Do this during a dry, non-growing time. By doing this, you
have just speeded up a healthy soil making process by incorporating new
organic matter.
The biological principle here to remember is: Down yellow litter, feeds
small soil critters.
How to determine soil health:
I pull a plug of soil, 2” x 2” x 4” deep, that fits nicely into my hand.
I then photograph this plug for record keeping. I use a digital camera
and snap a picture holding the plug up in the air with the background
location of where I dug the plant. This gives me fast visual upper
surface soil profile record.
I use a small trowel, two inches wide and four inched long that has a
bent handle which allows me to tap it into hard ground with a small
hammer. This saves me from packing a heavy shovel around in remote
pasture locations.
I can see and feel certain soil health indicators in this plug (see
photo). There are 3 key soil health indicators that I look for using
this method: Soil type, soil organic matter content, and soil
compaction.
I first look for soil compaction, because that is the one healthy
indicator that we have some control over. Compaction problems visually
show up below the surface organic matter as shiny smooth layers of soil,
all pushed together.
Monitoring this way I once found heavily compacted soils, where the
roots would only grow in the cracks of the clay soil, which was
responsible for greatly lowering the forage production.
I next look for organic matter content. Organic matter is the vast array
of carbon compounds in various stages of decomposition. Visible organic
matter shows up as thatch (dead and decaying plant parts in the very top
layer), roots, and occasional underground bugs and worms. Another item
to look for is the very small black particles that give soils that great
earthy smell. These are the results of organic mater decomposition.
I also determine the type of soils I sample. Take a small portion the
soil from the plug in your fingers, wet it and rub it between your
fingers.
If the polishes make a shiny smooth sticky coating on your fingers and
is grayish brown, it’s probably clay,
If it feels very smooth and slippery, but not quite polished and is dark
tan, it’s probably silt.
If it feels gritty (small sand particles), and is light tan, it’s
probably sandy soils.
If it crumbles and is dark in color, not especially gritty, smooth and
shiny, you probably have a loamy soil.
In reality, there are all kinds of different soils. Usually in mixtures
of all these different elements, but you can come close to what the
major soil types are. Each soil type has their inherited limitations and
advantages.
What’s handy about this way of assessing soil health is that you can
quickly compare one area to others. For example, I thought I had found a
compaction problem in one pasture I was inspecting one day. So I dug a
soil plug, and found no compaction. This soil was full of small stones,
rocks and sand which does not compact. You need that sticky clay
particle to form a compaction layer.
Another example that surprised me was on inspecting a grazing cell
center where the water and fencing configuration is built like the
spokes of a wagon wheel. We found tall grass all around the cell center.
However, when I went to dig up some chucks of sod to observe the root
structures, I had to jump up and down on the shovel like a mad man. We
had nice tall healthy looking grass, but the heavy clay soil was very
compacted.
Just adjacent to this cell center was an area fenced off from livestock
grazing, that we called the “TEST REST AREA”. A long-term observation
area of what no grazing looks like. I went to jump onto the shovel in
this small fenced off area and about fell on my face. My shovel easily
fell into this soft fluffy soil.
What’s going on here?
Compaction on the outside was caused by livestock grazing and soft
fluffy soils appeared on the no-grazed area! This cell center was
constructed on heavy gumbo clay soils. Gumbo is on of a variety of
fine-grained soils that become waxy and very sticky mud when saturated
with water. When these soils are highly compacted and dry out, they
become very hard, and would make fine bricks.
However, comparatively speaking, the grass was much thinner and shorter
in the non-grazed area The owner of the non-grazed lands walked by this
exclosure and told me, “Long-term rested soils do not grow good cow
feed, and Wayne, it doesn’t even pay taxes”.
The lesson learned here: If you graze livestock at high stock densities,
be careful of compaction. Plan alternative areas and enough rest to
allow these compacted soils to fluff with spring and fall frost heaving
actions.
Bottom line, soil health is the key to growing strong abundant dense
vigorous forage for any livestock operation. Next time you walk your
pastures, dig some plugs and see what’s happening to the soils below the
surface. On top of your soils follow this one controlling rule: Keep the
soils covered! —Wayne Burleson
Wayne Burleson is a land management consultant working out of Absarokee,
Montana. You can visit with Wayne at (406) 328-6808 or E-mail him at
rutbuster@montana.net. Wayne also has an educational web site at
www.pasturemanagement.com.
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