1. Soil Formation
2.1.3 – Explain how natural actions such as weathering, erosion(wind, water and gravity) and soil formation affect Earth’s surface.

2. Concepts to know:
Soil – loose covering of broken rock particles and decaying organic matter.
top soil – the uppermost layer of soil.
Transported soil – soil that has been moved away from its parent bedrock.
Residual soil – soil located above its parent material

3. Concepts to Know Soil profile – a vertical sequence of soil layers.
Soil horizon – A distinct layer or zone within a soil profile.
Humus - The organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms

4. Concepts to Know
Bedrock – Unweathered, solid parent rock.

5. Soil formation starts with…
Weathering
Erosion
Deposition

6. Then you add in…
Some living organisms such as bacteria, fungi and insects.
They die, decay and add nutrients to the soil.

7. And then….. The texture improves as this continues.
The soil’s capacity to hold water increases.

8. Soil Profile
This is a vertical sequence of soil layers.

9. Soil layers A layer – rich in humus and minerals
B layer – medium size particles, drainage, poor in humus
C layer – large particles; little to no plant or animal life
Bedrock - solid

10. Factors that Affect Soil Formation
Weathering (mechanical/chemical)
Parent rock composition
Climate conditions
Topography –slopes, valleys, north/south of the equator

11. Soil Fertility Factors
Mineral and nutrients (humus) availability
The number of microorganisms – breathing, water filtration
Rain – amount of precipitation/year
Topography – elevation
Valley more fertile than slope- south more fertile than northern exposure (sun light/rays)
Soil acidity

12. Soil fertility
Soil fertility is the measure of how well a soil can support growth of plants.
Soil fertility depends on the amount of organic matter in it.
Having different sized particles is better for water filtration than uniform size.

13. Soil Texture
Clay – smallest
Silt – medium
Sand – largest

14. Can you dig it?!?!?