GEOG 1220 Lecture Notes - Lecture 42: Parent Material, Water Cycle, Soil Horizon
16 May 2016
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Document Summary
-ecological functions: moisture sink and pathway for hydrological cycle. 38% of freshwater is in the soil, gives properties of infiltration re-radiation of energy via colour (albedo)- dark reflects heat, light reflects habitat (especially insects) evaporation (via temperature) underlying processes: Depends on management extreme erosion desertification (becomes desert) Soil: a complex plant-supporting system that consists of disintegrated rocks, organic matter, water, gases, utrients and microorganisms. Solum (life supporting soil) + subsoil (inorganic portion resting on bedrock) O horizon (organic rich upper layer)- 3-5 percent, decaying organix matter (detritus) determines fertility. Zone of eluviation (downward movement of dissolved material) infiltration capacity minerals dissolve. Roots suck up nutrients from here, bring back to surface- nutrient cycle. Most soil contains 3-5% organicmatter within 10-40 cm of surgace. Organic energy system (soil provides and retains nutrients/chemicals, absorbs moisture) Particles classified by average diameter (sand, silt, clay) Sand more air between- rate of water penetration is rapid.
