Transcript SOIL … It`s more than just dirt!

SOIL …
It’s more than just dirt!
Learn all that you ever wanted to know
about the stuff beneath your feet.
What is soil?
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Soil is formed as a result of weathering.
It is made from particles of rocks, minerals,
dead plants and animals, living organisms,
gasses and water.
The particles of rocks and minerals have
broken away from larger ones through
weathering.
Most of these pieces are very small.
What’s an organism, and what is it doing in my soil?
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Organisms are living plant or animal life.
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They are very important to soil.
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Some of them are decomposers.
Decomposers
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These are tiny organisms that break down dead
animals and plants into NUTRIENTS!
NUTRIENTS are substances needed by living
things.
The decomposers take dead organisms and
turn them into nutrients that plants and animals
can use for food.
Without decomposers, plants can not grow.
Soils have layers
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If we dig a hole in the ground, we can see that
the soil has layers.
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We can look at these layers in a cross section.
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These cross sections are called Soil Profiles.
Soil Profile
They show us the different layers of soil.
Topsoil
Subsoil
Bedrock
Bedrock
Let’s start from the bottom.
Bedrock is the solid rock that
lies underneath the soil. It can
be within inches of the surface,
or many feet below. Because it
has no nutrients, and it is
tightly packed, there is no
organic mater here. (organic
mater is things that are or were
alive.)
Bedrock
Subsoil
The stuff in the middle.
Subsoil is just below the
topsoil. It is made up of tiny
particles of rocks and minerals
mixed with larger ones.
Subsoil
It has very few organisms in it
because it is tightly packed, and
has few nutrients.It is hard for
plants to grow there.
Topsoil
This is the good stuff!
Topsoil
Topsoil is finer than subsoil,
and is usually darker in
color. That is because it is
loaded with nutrients and
organic matter. It has an
abundance ( a lot) of
organisms.
Why is topsoil cool?
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Without topsoil, plants have a very hard time
growing. They just can’t get what they need
from subsoil.
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Topsoil forms over a long period of time. In
Utah, it takes about 1,000 years to create 1
inch of topsoil.
What is topsoil made of?
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45% : Minerals (clay, silt, sand, gravel, rock)
25% : Water (Sometimes a little more or less)
25% : Air (organisms need this)
5% : Organic Matter (Both living and dead
organisms)
We Must Save The Topsoil!
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If topsoil is cleared of plants to hold it down, it
can be swept away by erosion.
When this happens, it is very hard to grow
plants there again.
We must protect topsoil from erosion by
making sure that the plants holding it down are
healthy.
That’s the end. Now, go dig a hole.