1. How can we define soil with what we know?
How Soil Forms
How can we define soil with what we know?

2. What is Soil? Loose weathered material Found on the Earth’s surface
Plants use to grow

3. What is Bedrock? Solid layer of rock Usually beneath soil
When weathered becomes soil

4. What makes up soil? Rock particles from weathered bedrock Minerals
Water
Air
Decayed organic material

5. What makes soil good for growing plants?
The Humus: dark in color
Creates space for Air and Water
Contains nutrients
Phosphorus,
Nitrogen
Sulfur
Potassium
Fertile soil is high in humus

6. What makes soil good for growing plants?
The Texture: size of soil particles
Clay is smooth and silky
Heavy
High water content
Sandy is coarse and grainy
Light
Low water content
Fertile soil has equal mixtures of particles: Loam

7. Why? How does soil form? From weathering and mixing
Layers called horizons
Soil is made up of 4 horizons
Warm, rainy climate develop soil faster than cold, dry climates
Why?

9. Does everyone have the same soil?
NO…..Why?
There are different types of soil depending on ….
Climate
Plants
Soil composition

10. How does climate affect soil?
Cold climates
Slow soil formation
Thin topsoil
Hot climates
Fast soil formation
Rainfall and wind erode soil away
Moderate climates
Thickest fertile soil

11. How do plants affect soil?
Plants can grow and die creating humus
High vegetation that is NOT removed is high in fertility

12. How does composition affect soil?
Particle size determines
Vegetation
Water content

13. How do living organisms affect soil?
Some organisms mix the soil
Some organisms aerate the soil
Make space for air
Decomposers make humus

14. Decomposers Chemically breakdown dead organic material
Fungi, worms, bacteria….
Create the humus

15. Burrowing animals Aerate Make space for water Mix soil
Provide nutrients through waste