Biosphere Flashcards
What is Soil?
Soil is made of rock, dead plants, air, animals and water. As you dig into soil, you’ll see that it’s made of different layers or Horizons.
What are the different types of weathering?
Physical weathering, Biological weathering and Chemical weathering.
What is Physical weathering?
A break down of rocks by changes in temp, freeze thaw weathering or the effect of wind, rain and waves. More common in cold climates.
What is Biological weathering?
A break down of rocks by people, plants, animals, fungi and microorganisms.
What is Chemical weathering?
When rocks are chemically altered by slightly acidic rainwater reacting with minerals in the rock to form new minerals. More common in warmer climates.
Mull Humus
Warmer climates with increased rate of decomposition forms thick carbon-rich organic soil layer full of nutrients and well mixed by soil biota. Found in deciduous woodlands.
Mor Humus
Colder climates with slower rate of decomposition forms a thin humus layer. It is easy to separate the litter, decomposition and humus horizons.
What is Translocation?
The downward movement of water or materials in the soil.
As water travels through the soil it dissolves minerals (solution) and carries material (suspension) through the soil profile.
This results in some horizons being depleted and others enriched.
What is Eluviation?
A horizon that has been depleted and lost material is called the eluvial horizon (E horizon) and the zone of leaching.
Found towards the top of the soil profile where iron and clay are dissolved by water as it infiltrates through the soil.
Light in colour as they lack organic material and minerals.
Require high precipitation.
What is Illuviation?
A horizon that has gained material is called the illuvial horizon (I horizon).
Found below the eluvial horizon, where minerals accumulate.
Dark in colour and dense.
Require high precipitation.
What is Waterlogging?
Waterlogged soil doesn’t have any air in the pore spaces so anaerobic conditions are present.
Cannot support soil biota.
Causes blue/grey colour in a process called gleying.
Characteristics of Brown Earth
- Abundant soil Biota
- Long tree roots
- Found in Deciduous woodland
- Dark brown A horizon
- Light brown B horizon
Characteristics of Podzol
- Short roots
- Coniferous Woodland
- Lighter A horizon
- Reddish brown B horizon
Characteristics of Gley
- Very little soil biota
- Dark brown/Grey A horizon
- Waterlogged Blueish grey B horizon
- Red/Orange Mottling in horizon B produced by iron compounds
