Soil Flashcards
(17 cards)
Define soil
a natural layer of material on Earth’s surface made up of minerals, organic matter, water and air.
How does soil form?
Over long period by breakdown of rocks, decay of plants and animals. Forms through natural processes that change and move materials in soil layers/horizons.
What does pH of soil indicate?
Alkalinity or acidity
Another word for soil layer?
Horizon
What is eluviation?
Removal/washing out of minerals or organic matter from upper layers by water soaking into the ground. Minerals move downwards through soil.
How does eluviation affect upper layers?
Lighter coloured, nutrient-poor upper layers
Illuviation?
Accumulation in lower soil layers, where washed out materials settle.
How does illuviation affect lower layers?
Forms darker, denser subsoils
What is humification
Formation of humus (dark organic material) from decayed animals and plants
What element/nutrient is humus rich in?
Nitrogen
Is humus good or bad for soil fertility
good
What is leaching
Dissolving/removal of nutrients from soil
How does soil interact with atmosphere?
- Provides oxygen, CO2 with organisms, plant roots
- Rain and temps affect weathering
How does hydrosphere affect soil?
- Water> eluviation, plant growth, moisture
How does lithosphere interact with soil?
Bedrock provides mineral content of soil.
How does rock type influence the soil
Influences texture, pH, drainage
How does biosphere influence soil
- Plants, animals add organic materials like humus
- Microorganisms help decompose material, recycling nutrients
