That stuff you
walk on, . . .
dig in, . . .
That stuff you build your house on, . . .
bury your garbage in, . . .
sweep off your driveway.
That stuff you grow your food in.
How good is it?
How good do you want it to be....
when it's growing
What is soil?
Soil is minerals (from ground up, weathered rocks) and
organic matter (from decayed plants and animals and insects)
and space (which is filled with water or air or sometimes
Soil is sand and silt and clay, usually found in various
combinations. The particular combination determines your
soil type. Silty clay loam, sandy clay, silt loam are all
soil types. Your soil type determines how you farm.
Sand is made of large particles which can be
easily seen. Sandy soil drains quickly, losing nutrients
Silt contains relatively fine particles that feel
smooth and floury.
Clay contains the finest soil particles. They can
be seen only with the aid of an electron microscope and
becomes slick and sticky when wet. Clay soils drain slowly,
causing stagnation and run off.
You can do a test of your soil type at home.
- Take about a cup of soil.
- Put it in a quart-sized jar.
- Fill the jar with water and cap it tightly.
- Shake well to moisten all soil particles.
- Then, set it aside for a day or two where it won't be
disturbed. When you check it, the
soil particles will have settled out in layers; sand on
the bottom, then silt, then clay, then the organic matter
The top layer, the decomposed
organic material, determines the nutritional quality of your
soil. It also helps develop the air-water relationship of
your soil. A sandy soil is helped by the water-holding
qualities of organic matter. A clay soil is helped by the
clumping qualities of organic matter, separating the small
clay particles into larger clumps, leaving spaces for
Nutrient and pH tests
To test your soil for nutrient
levels and pH, you will need a soil test. This can be done
at home with a kit. Check your local farm store or
garden/nursery store. Or, for more complete results, send a
soil sample to a lab. Some universities do soil testing
through their extension service; if not, soil samples can be
mailed to a lab. Check with your local Extension Service or
look in the Yellow Pages under Soil Labs.
Improving Your Soil
Improving your soil does not mean fertilizing.
Fertilizer is for the plants.
It does mean improved drainage, added depth, and
The best way to do that is by adding organic matter.
Adding decomposed organic matter (compost), spreading
manure, and turning under green cover crops are all
effective methods of increasing the organic matter content
of your soil.
Sufficient organic matter in the soil allows for both
better drainage and better water-retention. Clay soils drain
better with a higher organic matter content. And other
soils, when rich in organic matter, absorb more rain water
before eroding and retain that water for a longer time.
Regular additions of organic matter will also deepen the
layer of topsoil. That's where most of a plant's roots are.
Organic matter provides food for the soil's microbrial life
who then provide nearly all of the nutrients plants require
for proper growth.
Soil improvement also involves tillage. The method of
tillage used affects the soil structure and how well what
organic matter is there is utilized.
Traditional plowing is no longer considered the correct
method of working in organic matter. If a green manure crop
is plowed in, the organic material is loosened, turned over,
and buried under the soil that was below it. Deprived of
oxygen by this layer of soil, the organic material cannot
decompose and therefore gives no benefit to the soil.
Traditional plowing also creates hardpan, a pervasive soil
problem that blocks root growth, blocks drainage, and blocks
capillary action of sub-surface water. The tradition method
of disking a field until the soil is finely pulverized can
also be detrimental. Soil structure is compromised, and the
small, finely pulverized particles of clay and silt are be
easily blown or washed away.
New (?) methods of disking in crops are becoming more
frequently used. Planting into the previous crops is also
becoming more frequent.
Some photographs courtesy of
Oregon Dept of Agriculture.
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