Biosphere- Soils Flashcards
Soil is a dynamic three phase system: solid, liquid and gas. What percentage of the soils do each of these make up
25% air
25% water
45% mineral
5% organic matter
Soil functions -3 examples
Support plant life
Habitat
Storage
filtration
How much more carbon do soils store than the atmosphere and vegetation respectively
Twice more than the atmosphere
3X more than vegetation
What is pedogenesis
Soil formation
Is soil renewable
No, it takes thousands of years so can be seen as non renewable
What is soil leaching
The movement of water down the soil profile to the lower soil horizons
What are the O,A,B and C soil horizons
O= organic A= subsurface B= subsoil C= parent material
What do soils form on
Rock surfaces and unconsolidated materials
Parent material controls:
Weathering rates Soil chemistry (inc pH)
How does climate affect soils
Affects rate of weathering and decomposition
Rainfall redistributes materials
Affects vegetation and organic matter inputs
How does landscape position and hydrology affect soils
Landscape position alters soil hydrology with implications for soil processes
Water logging alters the chemistry of soil minerals and affects decomposition
What is soil fertility
The soils ability to support the desired crop
Soil must provide adequate amounts of…
Water
Air (porosity and humidity)
Nutrients (cation exchange capacity and nutrient availability)
Factors that affect soil fertility
Soil texture
Soil fertility
Porosity
Density =
Mass divided by volume
