Soil

1. THE SOIL PROFILETHE SOIL PROFILE

2. The 6 Soil RolesThe 6 Soil Roles
Soil’s role includes:
erving as a foundation
mitting and absorbing gases
roviding habitat
nteracting with water

3. The 5 Factors of FormationThe 5 Factors of Formation
oil is formed by…
arent Material: the original “Mom & Pop” soil transported from
elsewhere, usually by wind or water, at different speeds
limate: the amount, intensity, timing, and kind of precipitation that
breaks down parts of ecosystem (i.e. rocks, trees) into soil
opography: Slope and Aspect affect the angle of the land and
position toward/away from the sun that soil will be exposed to
iological: Plants, animals, microscopic organisms, and humans
interact with soil in different ways

4. What is a Soil Profile?What is a Soil Profile?
Soil Profile is a vertical cross-section of layers of soil found in a
given area. Below are two examples of soil profiles.

5. What is a Soil Horizon?What is a Soil Horizon?
oil horizons are the layers in a soil profile used to classify soil
types.
orizons based on color, texture, roots, structure, rock
fragments, and any unique characteristic worth noting.
aster Soil Horizons are depicted by a capital letter in the order
(from top down): O, A, E, B, C, and R

6. O-HorizonO-Horizon
he “Organic Matter” Horizon
urface-layer, at depths of 0-2 feet
ark in color, soft in texture
umus - rich organic material of plant
and animal origin in a stage of
decomposition
eaf litter – leaves, needles, twigs,
moss, lichens that are not
decomposing
everal O-layers can occur in some

7. A-HorizonA-Horizon
Topsoil” or “Biomantle” Horizon
opmost layer of mineral soil, at depths
of 2-10 feet
ome humus present, darker in color
than layers below
iomantle - most biological productive
layer; earthworms, fungi, and bacteria
live this layer
mallest and finest soil particles

8. E-HorizonE-Horizon
he “Leaching Layer” Horizon
mall layer between A & B horizons
t depths of 10-15 feet
ight in color, mainly sand & silt
oor mineral and clay content due to
leaching – the loss of water-retaining
plant nutrients to the water table
oil particles larger than in A horizon but
smaller than in B horizon

9. B-HorizonB-Horizon
he “Subsoil” Horizon
t depths of 10-30 feet
ich in clay and minerals like Fe & Al
ome organic material may reach
here through leaching
lant roots can extend into this layer
ed/brown in color due to oxides of
Fe & clay

10. C-HorizonC-Horizon
he “Regolith” Horizon
t depths of 30-48 feet
ade up of large rocks or lumps of
partially broken bedrock
east affected by weathering and
have changed the least since their
origin
evoid of organic matter due to it
being so far down in the soil profile

11. R-HorizonR-Horizon
he “Bedrock” Horizon
t depths of 48+ feet
eepest soil horizon in the soil profile
o rocks or boulders, only a
continuous mass of bedrock
olors are those of the original rock
of the area

12. How to Make a Soil ProfileHow to Make a Soil Profile
-4 copies of Master Soil Horizons Worksheet
0 sticky notes per group (7 per person)
-4 pairs of gloves
large glass bowl
one-cup measuring cup
whisk
spatula
.5 cups skim milk
packages vanilla Instant Jell-o pudding mix
tiny Ziploc bag Coconut w/green food coloring + raisins
small Ziploc bag crushed chocolate graham crackers &
frosting
n large glass bowl, whisk 3.5 cups milk with 2
pkgs. vanilla Instant Jell-o pudding mix until
smooth. Let stand 5 minutes.
hile waiting, refer to your version of “The Soil
Profile” powerpoint to review order that
horizons should be. You have A, E, B, R, O, C, and
vegetation as horizons. It’s up to you to order it!
fter 5 minutes, use spatula to scoop pudding in
middle of bowl, allowing for the “dry
ingredients” (the bags of various crushed up
cookies) to encircle the pudding along the sides
of the glass bowl. This creates a vertical cross-
section of soil layers visible to you.
se sticky notes to label each horizon on outside of
bowl.
ill out Master Soil Horizons Worksheet using
observations of Soil Profile Dessert.
Ingredients ListIngredients List DirectionsDirections