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Soil Links

(Last Updated October 29, 2000)

Soil profile - a model of soil horizons. Below is from Elemental Geosystems

Horizons - continuum from organic to mineral content the deeper you go.
O - organic matter from plant and animal litter enters from above
A - organic matter mixed with humus, fertility retained by soil colloids
E - eluviation - leaching of clay, iron, aluminum; little organic matter
B - illuviation - accumulation of materials leached from above
C - weathered bedrock - mineral matter enters from below
R - parent material - bedrock or unconsolidated material

Example of a soil from a Tropical Rainforest (Af) climate
Oxisol - tropical rainforest soils - very fragile and infertile
tropical humid - intensly leached, practically no humus, low cation exchange capacity
laterization - enriched in iron and aluminum hydroxide (bauxite)

Example of a soil from a Desert/Dry (Bwh) climate
Aridosol - fertile soils of the Western US
desert, arid grass, brush
alkaline/basic soil - high cation exchange capacity - quite fertile, but fragile - little organic matter
calcification - caliche deposits in B and C horizons
salinization - precipitation of minerals to the top of the soil, basic soil

Elemental Geosystems Ch. 15 - Geography of Soil

Definition of Soil

World Soil Resources

Earthworms - the importance of in soil

Benefits of Soil Microbes

Microbial ecology

soil microbes

Geoindicators: Soil and sediment erosion , Soil quality

Soil profile

Soil profile images

Soil profile and horizons, soil processes - UWSP Geography 101

Sustainable Agriculture Educational Project - soil erosion

Alan's World