GEOG 1F91 Lecture Notes - Soil Texture, Permanent Wilting Point, Eluvium
21 Apr 2014
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Document Summary
Soil organic matter: humus, colloids, compost, acts as a glue to hold soil together, binds with clay to form clay-humus complex . Soil characteristics: colour, several diagnostic characteristics that give indications of what the soil is like. A reflection of chemical and biological processes operating in the soil. Certain diagnostic colours: red: oxidized iron (well-drained, yellow: hydrated iron (poorly drained, black: highly organic (usually wet, white: salty (usually dry, soil texture. Refers to the proportion of sand, silt, and clay present. Texture controls number & size of pores. Controls moisture characteristics (e. g. pore pressure, eluviation/illuviation, water holding capacity) fig. Soil doesn"t always operate as a series of individual particles. Held together by the clay content & organic matter. Single grain, blocky, platy, granular, prismatic, massive: water holding capacity. Storage capacity: held against gravity by capillary tension. Both wilting point and storage capacity are determined by soil texture.
