Soil profile

Soil

1. THE SOIL PROFILETHE SOIL PROFILE

2. The 6 Soil RolesThe 6 Soil Roles
A
Soil’s role includes:
•S
erving as a foundation
•E
mitting and absorbing gases
•P
roviding habitat
•I
nteracting with water
•R
ecycling nutrients
•S
upporting human settlements

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

4. What is a Soil Profile?What is a Soil Profile?
•A
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?
•S
oil horizons are the layers in a soil profile used to classify soil
types.
•H
orizons based on color, texture, roots, structure, rock
fragments, and any unique characteristic worth noting.
•M
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
T
he “Organic Matter” Horizon
•S
urface-layer, at depths of 0-2 feet
•D
ark in color, soft in texture
•H
umus - rich organic material of plant
and animal origin in a stage of
decomposition
•L
eaf litter – leaves, needles, twigs,
moss, lichens that are not
decomposing
•S
everal O-layers can occur in some
soils, consisting only of O-horizons

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

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

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

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

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

12. How to Make a Soil ProfileHow to Make a Soil Profile
•3
-4 copies of Master Soil Horizons Worksheet
•3
0 sticky notes per group (7 per person)
•3
-4 pairs of gloves
•1
large glass bowl
•1
one-cup measuring cup
•1
whisk
•1
spatula
•3
.5 cups skim milk
•2
packages vanilla Instant Jell-o pudding mix
•1
tiny Ziploc bag Coconut w/green food coloring + raisins
•1
small Ziploc bag crushed chocolate graham crackers &
frosting
•1
medium Ziploc bag Chocolate chip & Vanilla wafers &
gummy worms
•1
small Ziploc bag crushed Vanilla wafers only
•1
medium Ziploc bag crushed graham crackers
•1
large Ziploc bag crushed Oreo cookies
•1
large Ziploc bag crushed chocolate chips
1.I
n large glass bowl, whisk 3.5 cups milk with 2
pkgs. vanilla Instant Jell-o pudding mix until
smooth. Let stand 5 minutes.
2.W
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!
3.A
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.
4.U
se sticky notes to label each horizon on outside of
bowl.
5.F
ill out Master Soil Horizons Worksheet using
observations of Soil Profile Dessert.
6.T
urn in worksheet to teacher. Only until you and
your team members turn in their worksheet can
you enjoy the delicious snack. You’re finished!
Ingredients ListIngredients List DirectionsDirections