1. A lesson on the formation and composition of natural soil
By: Mrs. Poole

2. Table of Contents What is soil? How is soil formed?
What’s soil made of? (1)
What’s soil made of? (2)
Bar Graph
Table (Soil Composition)
Weathered rocks
Organic matter
Soil profile
4 layers of soil (O)
4 layers of soil (A)
4 layers of soil (B)
4 layers of soil (C)
Types of soil
Did you know… (1)
Did you know… (2)
Soil Movie

3. What is soil?
Soil is the product formed when rocks break down and mix with water, air, and rotting organic matter.
Soil holds plant roots.

4. How is soil formed? Soil is formed 3 different ways:
Rocks break down or weather
Earth carries materials by water, wind, and ice and drops materials in places where they settle and mix with other materials
Living and once-living things turn sand, silt, and rock pieces into a mixture that is food for more life to live and grow.
The plants attract animals, and when the animals die, their bodies decay.
Decaying matter makes the soil thick and rich. (YUM!)

5. What’s soil made of? 5 main ingredients of soil:
Minerals – weathered rock such as sand, silt, clay, pebbles
Air
Water
Organic matter (old leaves, dead plants and animals)
Living Organisms (tiny living things)

6. What’s soil made of? Water Minerals Air Organic Matter
Living Organisms

7. Bar Graph

8. Soil Composition Ingredient of Soil Picture Mineral Air Water
Organic Matter
Living Organisms

9. Weathered rocks
The weathering of rocks makes soil.

10. Organic matter decomposes and provides food for living organisms who eat and turn the food into soil.

11. Soil profile Soil changes as you dig deeper and deeper in the ground.
You can see changes in colors and textures.
Most soil has 4 layers:
Organic layer
Upper soil layer
Middle soil layer
Lowest layer

12. 4 layers of soil: O = Organic Layer 0-2 inches deep
Takes years to form
Living things live here
Millions of dead plant and animal organisms are decomposing here
Organic

13. 4 layers of soil: A = Upper Soil Layer 2-10 inches deep
Many plant roots found here
Dark soil because many chemical reactions as plants & animals grow and die
Lots of bacteria which helps chemical reactions.
Upper Soil Layer

14. 4 layers of soil: B = Middle Soil Layer 11-30 inches deep
Less living things, less air, less darker topsoil
Plants don’t grow well here
Can find human artifacts like arrowheads or pottery here
Middle Soil Layer

15. 4 layers of soil: C = Lowest Layer 31-48 inches deep
Soil color is orangish/yellowish
More sandy or more gray clay
Many pebbles and rocks
Least amount of living/dead things
Could still have lot of water
Lowest Layer

16. Clay Sand Silt Found near coastal regions and deserts.
Organization chart
Sand
Silt
Clay
Found near coastal regions and deserts.
Course or gritty feeling.
Found where water interacts with soil.
Smooth or slippery feeling.
Found all over the world.
Sticky and rich in clay.

17. Did you know… Soil makes up the outermost layer of out planet.
There are over 70,000 kinds of soil.
The color of soil depends on how much chemical reactions are taking place in the soil.
What kind of soil do we have in Cobb County?

18. Click on black rectangle
Did you know…
5 tons of topsoil
spread over 1 acre
would only be as thin as a dime!
1 Asian elephant = 5 tons
Click on black rectangle

19. Click on the picture to watch a movie
Soil Movie
Click on the picture to watch a movie
Note: You must login Video streaming when you click on the above picture.