Soil and Site
Evaluation
Getting the Dirt on Soils
By
Dr. David Lindbo, NCSU
Cooperate Extension
1
Acknowledgement
This work was supported [in part] by the National Decentralized
Water Resources Capacity Development Project with funding
provided by the U.S. Environmental Protection Agency through a
Cooperative Agreement (EPA No. CR827881-01-0) with
Washington University in St. Louis. The results have not been
reviewed by EPA or Washington University in St. Louis. The
views expressed in this presentation are solely those of NCSU, and
University of Arkansas and EPA and Washington University in St.
Louis do not endorse any products or commercial services
mentioned in the presentation.
2
What are 4 things
we cannot live
without?
3
AIR
4
SUNLIGHT
5
WATER
6
SOIL
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Does Soil
=
Dirt?
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
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NO
Dirt is the stuff under
your fingernails or what
you sweep off the floor
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
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Soil Facts
¾ Topsoil
is the most productive layer
¾ Five
tons of topsoil spread over an acre is
only as thick as a dime
¾ Soil
supplies water and nutrients for plants
¾ Most
of our food comes from soil
¾ It
can take more than 500 years to form one
inch of topsoil
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
10
Soil Facts
¾ An
acre of corn gives off 4000 gallons of
water a day in evaporation
¾ Soil
Scientist have identified over 70,000
different soils in the U. S.
¾ Erosion
¾ Soil
of soil clogs rivers and lakes
influences the life spans of roads
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
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Soil Facts
¾ Soil
¾1
is alive….
gram of soil contains up to a billion bacteria
¾ There
many thousands of types of bacteria
in soil
¾ 15
tons of soil per acre pass through
earthworms each year
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
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Soil Facts
¾ Soil
is the largest single wastewater
treatment unit in North Carolina
¾ 3.5
million North Carolinians rely on soil to
treat and disperse wastewater
¾ Soil
is extremely effective at wastewater
treatment
¾ Best
of all…
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
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Soil makes
great mud pies
…and is just
plain fun!
14
What is a soil?
And why do we care?
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
15
A soil is a porous
natural body of
mineral, air, water
and organic matter
that changes, or has
changed, in
response to climate,
topography, time,
and organisms.
This is the text book definition. Basically, it says that soils are dynamic and
reflect the conditions that they formed under. Because they do reflect the
environment in which they formed we can use their morphology to
understand more about the environment. Thus soils can be like a very smart
canary in the coal mine – if we know how to interpret their song.
16
Soil Science Society of America
soil: (i) the unconsolidated mineral or
organic material on the immediate surface
of the earth that serves as a natural
medium for the growth of land plants.
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Rule .1935 (41) Soil
“Soil” means the naturally occurring body of
porous mineral and organic materials on the
land surface. Soil is composed of sand-, siltand clay-sized particles that are mixed with
varying amounts of larger fragments and some
organic material. Soil contains less than 50%
of its volume as rock, saprolite, or coarse-earth
fraction (mineral particle greater than 2 mm).
The upper limit of the soil is the land surface,
and its lower limit is “rock”, saprolite, or other
parent materials.
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Soil Definition
“Soil” means the naturally occurring body
of porous mineral and organic
materials on the land surface.
The upper limit of the soil is the land
surface, and its lower limit is “rock”.
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What is a soil?
And why do we care?
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
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Importance of Soil to
On-site Wastewater
¾ Biological
treatment
¾ Chemical treatment
¾ Physical treatment
¾ Dispersal
Just as in a wastewater treatment plant soils treat the wastewater I much the
same way.
21
How does soil treat wastewater?
Well
Aerobic soil
Groundwater
Aerobic soil is needed to treat – remove
pathogens – and disperse the treated
wastewater back into the environment
22
What is a soil?
And why do we care?
What is a soil? What does it mean to you? Does it have and special
meaning to you? Before answering these questions consider what you see
in the soil.
23
What is soil made
of?
Soil is composed of
minerals,
organic matter,
air,
water
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Soil is made of:
¾ Solid
z
z
z
Minerals
Dead organic material
Living organic material
¾ Pore
z
z
material
space
Air
Water
Soil has two major components that can be subdivide into 5 five components
overall. Their relative amounts will alter the properties of the soil but no one
is more important than another.
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What does the site
evaluator need to
know?
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Next lectures
¾ Parent
Material
¾ Topography
¾ Soil Texture
¾ Soil Structure
¾ Soil
Consistence
¾ Soil
Color
¾ Profile
Description
¾ Site Evaluation
¾ Determination of
LTAR
¾ Soil Survey
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Summary
¾
Soils are the living skin of the earth
Soils treat wastewater
Soils are complex
¾
SOILS SUSTAIN LIFE
¾
¾
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