The Lithosphere and Pedosphere Flashcards
Difference between weathering and erosion:
- Weathering is the mechanical and chemical breakdown of the material.
- Erosion is the movement of material by weather, wind and water etc.
The composition of teh crust:
83% of the crust mass is made up by
oxygen 47% Silicon 28% Aluminium 8 %
What are Silicates and Aluminosilicates
Minerals containing:
Silicates: Si, O
Aluminosilicates: Al, Si, O
Difference between minerals and rocks?
- Minerals have definite chemical composition and atomic structure.
- Rocks are composed of several minerals.
Three different major categories of rocks:
- Igneous: Formed by molten rock, granite
- Sedimentary: petrified, fossilized materials
- Metamorphic: Formed by chemical or physical alteration; temp, pressure
Why is weathering good?
- Release of chemical elements
- soil formation
- Nutrients
Wheathering is needed for good soil, what is needed for weathering?
- Climate (temp)
- Biotic (acids)
- Resistance (High resistance rock gives poor soil)
What are secondary minerals, soil colloids?
Whats forming clay
Very imortant in soil
How many percent of land is agricultural?
37%
Components of soil:
- Mineral material
- Organic matter (living and dead)
- Water
- Air
The soil “horizons”:
- A horizon: Top soil, agr soil
- B horizon: plough layer, subsoil
(A and B importand for water) - C horizon: The lower part that has not been altered by weathering and bio-activity.
- Bedrock
Why is clay important in soil?
Clay particles are small enough to hook up with nutrients. clay particles have a negative charge and atract positive nutrients.
A good soil contains a mixture of:
clay and stable soil organic matter
What is CEC?
Cation Exchange Capacity
- Thats the total amount of exchangeble cations that a soil can absorb.
- Large means: fertile and can buffer against acidity
- Depends on pH
What is SOM and what is it good for?
Soil Organic Matter (3-5%)
- Stores nutrients
- Creates stability of soil aggregates (fertility)
- Increase water holding capacity
