Transcript Soil PowerPoint from Jason M BIG

I am beneath your feet and under your nails; I am the
history of the land as it lives and dies, builds and erodes
away. I shatter rock, sustain forests and control the
climate. I am a living membrane that draws essential
minerals and nutrients from the earth, and to which all
terrestrial life eventually returns.
Who am I?
SOIL
The Dirt on Dirt
Soil Development and keys to using
the right soil for the right thing.
Soil is an often
overlooked and under
appreciated resource,
often abused and
surprisingly
endangered.
Farmers constantly battle erosion to keep
topsoil on their fields.
Even without erosion, fields exposed by
poor farming practices can loose 3 ft. of
topsoil a year due to decomposition
alone.
Not to be taken for granted- Let’s
look at what we use this valuable
resource for….
Agriculture
Ecology and Habitat…
Building On….
Building With….
Kaolinite
Burning…for fuel…
Controlling Climate…..
Soil both stores
and releases
Carbon Dioxide.
There is twice as
much carbon
stored in soil that
in the atmosphere!
Art and Inspiration…
Gauguin’s paintings of Tahiti
Recognize this
movie?
The deep red soils of Ray Charles’ southern home were
used to set the scene in the movie RAY.
What is it that makes Soil in the
first place?
•
•
•
•
•
Parent Material
Organisms
Climate
Relief
Interacting over TIME
Parent Material
Exposed rocks or minerals from which soil forms.
This could be from a retreating glacier, volcano or
landslide.
Parent Material can affect soil
fertility
Serpentine
Organisms
• Help weather (break down) rocks
• Create and mix in soil organic matter
(decaying plants and animals…..)
Climate- Temperature and
Rainfall
• Controls rates of chemical weathering
• Controls accumulation of Organic Matter
Desert
Low Rain:
low weathering
High Temperature:
low organic matter
Tropical
High Rain:
High weathering
High Temperature:
low organic matter
Temperate
Medium Rain:
Medium
weathering
Low Temperature:
High organic
matter
Relief - lay of the land
All of these factors interact over
time to form the SOIL PROFILE
Soil Profile - Horizons
• O Horizon- decomposing organic matter
(plants and animals)
•A Horizon- topsoil = organic matter and
weathered rocks and
minerals (parent material)
•B Horizon- weathered rocks and minerals
•C Horizon- slightly weathered parent
material
Color is often used to define the
different horizons.
• O Horizon- dark brown or black
in color
•A Horizon- lighter browns but still
dark in color
•B Horizon- strong red or yellow in
highly weathered
soils, otherwise light
gray
•C Horizon- color unimportantusually solid or
filled with large
rocks.
Different Soil Profiles give clues
as to the age, climate, pH, water
movement and fertility of a soil.
What horizons do you see?
• O – dark color lots of nutrients from
decaying plants
• A
• B- no red or yellow means med to low
rainfall or very little iron
• C
What horizons do you see?
•O – medium color some nutrients from
decaying plants
•A
•B- Strong red- highly weathered,
oxidized iron in soil
•C
Forest Soil with High pH
•O – lots of partially decayed organic
matter
•A- washed clean (silica) from heavy
weathering. (also called E layer)
•B- some weathering, yellows but no
bright color
What horizons do you see?
• No real horizon
development
• Too young
• Not enough rainfall
Standing Water affects the soil!
Tollund Man- 2000 yrs old
Blue/Gray ‘GLEYING’
Summary
• Soil is an often overlooked but valuable resource
• It is constantly changing and developing, forming
a Soil Profile
• Factors of soil formation:
• Parent Material
• Climate
• Organisms
• Relief
What can we tell from a Soil
Profile?
• Climate
• High Rainfall = highly weathered, reds and yellows
• Low Temperatures = lots of organic matter
• Fertility
• Associated with organic matter
• pH
• Look for heavy leaching of colors from A horizon
• Water movement
• Look for GLEYING or mottling in the soil
Tune in Tomorrow, and
make land use decisions for….
The Medeiros Dirt Ranch!