Geography Chapter 12

Geography Chapter 12 - Chapter 12 Notes Soils Soil and...

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Chapter 12 Notes: Soils Soil and Regolith: - Thin layer on top of Earth’s crust o About 15 cm deep (worldwide average) - Regolith: inorganic material that results from rock weathering o Top layer of regolith is different in amount of biochemical weathering - Soil: complex combination of minerals, decaying organic matter, living organisms, gases, and liquid solutions o Generally occupied by plant roots o Nurtures life o Fundamental interface between the four spheres o Surface of lithosphere almost always represented by soil o Soil often recognized by color o Depth is also important, but is only obvious when exposed through excavation Soil-Forming Factors: - Geologic Factor: o Parent material: source of rock fragments in soil o Nature of parent material influences soil characteristics o Young soils very reflective of the rocks or sediments from which they resulted - Climatic Factor: o Temperature and moisture significant to soil formation o Chemical and biological processes accelerated by high temperatures and moisture - Topographic Factor: o Slope and drainage are significant o Lowering of top and bottom of soil - Biological Factor: o All soils contain some quantity of living organisms o Plant and animal contributions to soil development o Pedoturbation o Earthworms most important: Innumerable tunnels, mixed by water Crumbly surface Digestive actions increase porosity and resist raindrops, lessening erosion Casts excreted by earthworms Rearrange material in the soil Nitrification promoted o Microorganisms enhance biological decay - Time Factor: o Soil processes very slowly o Length of time needed depends on parent material and environmental conditions
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This note was uploaded on 11/23/2011 for the course GEOG 1114 taught by Professor ? during the Fall '08 term at Oklahoma State.

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Geography Chapter 12 - Chapter 12 Notes Soils Soil and...

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