Soil

Broken rocks, minerals, living organisms and decaying organic matter

Decaying organic matter

Brown earth, podzol and gley

Horizon’s (O,A,B,C)

Breaks apart parent rock to form regolith, clay particles join together

Organisms eg algae/ lichens colonise which add organic matter when they die (Humus)

Movement in any form in any direction, has greatest effect with very high/ low rainfall

Washing down of soluble minerals

Washing down of small suspended insoluble minerals to lower horizons

Where minerals are moved to horizon C

Brown earth Podzol Gley

Aeration Temperature Texture/ structure Water availability pH

Surface litter, partly decomposed organic matter

Topsoil with humus, living organisms and inorganic minerals

Subsoil with clay, iron, aluminium compounds accumulated from leaching

Weathered parent material and partially broken down inorganic mineralz

Parent material - the crust limestone bedrock, alkaline/ neutral granite bedrock: acidic

Time Human activity Vegetation/ animals

Soils natural equilibrium

Erosion (e.g wind and water) Degradation (e.g leaching and pollution)

Water and wind erosion, Chemical and physical degradation

Overgrazing Deforestation Agricultural activity Overuse of vegetation Industrial activity

Overgrazing Over cropping Deforestation Urbanisation Unsustainable agriculture inc. cultivation methods

Leaves deflect heavy rain, roots hold soil together and humus absorbs large quantities of water BUT unprotected surface soil washed away during heavy rain (sheet wash) or channels develop on hillside (gullying)