Download Soil Notes

Soil
Characteristics
• Regolith - The
layer of rock and
mineral fragments
that cover almost
all land as a result
of weathering.
• Soil is the part that
supports the
growth of plants.
Soil Composition
1.
2.
3.
4.
Mineral matter (broken-down rock)
Organic matter (humus)
Air
Water
Good soil = at least 50% mineral and
organic matter!
Texture
• Soil has different
particle sizes.
• Texture supports
ability for plant
life.
• Loam (in the
center) is best
because it holds
Make sure you know how to
water
read this soil chart!!
Soil Chart
What type of soil is made up of 20%
clay, 40% silt and 40% sand?
Medium Loam
What type of soil is made up of 40%
clay, 40% silt and 20% sand?
Clay
What type of soil is made up of 30%
clay, 10% silt and 60% sand?
Sandy Clay Loam
Soil Formation Factors
1. Parent material- the source of the mineral
matter.
2. Time- the longer it forms, the thicker it
gets.
3. *Climate*- has the greatest effect.
● Similar soils can be made in the same
climate, even if they have different
parent material!
Soil Formation Factors
4. Organisms- aid fertility
-plants- main source of
organic matter
-microorganismsdecomposition
-burrowing animalsmix things up!
Soil Formation Factors
5.
Slope - Steep or flat?
flat areas = little erosion & drainage
steep slopes = greater erosion
Soil Profiles
Soil Profiles- show the characteristics from
the surface down.
Soil Horizons- each individual zone
3 Main Horizons
• A Horizon – called topsoil
Consists mostly of organic
matter, lots of insects, fungi
and microorganisms – where
most decomposition takes place
• B Horizon – called subsoil
Consists of clay particles washed
out of A horizon
• C Horizon –
Consists of weathered parent
material (rock)
Soil Erosion
Water is a big factor…it causes the most soil erosion!
But so are WE…
Human activities remove the vegetation that covers soil!
Without cover, the soil is EASILY eroded!