The Geography of Soils – Flashcards
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What is a ped?
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A ped is an individual unit of soil particles.
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What is a pedon?
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A pedon is the basic sampling unit used in soil surveys. It is a hexagonal column from 1 to 10m2 in surface area.
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What is a polypedon?
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A polypedon is the soil unit used in preparing soil maps, a soil individual constituting an identifiable series of soil in an area.
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What is the organic zone horizon of soil?
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The organic zone is derived by plant and animal litter that was deposited on the surface of the soil. Over time, this may mix into the soil.
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What is the zone of accumulation?
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The zone of accumulation, usually underneath the organic zone, is made up of a dark, rich organic layer containing humus and clay particles. It provides important nutrients for plants.
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What is the zone of eluviation?
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The zone of eluviation, underneath the accumulation zone, is affected by the process of water rinsing the upper horizons and removing fine particles and minerals.
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What is the zone of illuviation?
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Characterized by the letter B, this zone contains the deposition of materials (clays, aluminum, and iron) leached from the upper horizons.
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What is the zone beneath the zone of illuviation?
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The zone beneath the zone of illuviation is characterized by the letter C, and is mainly comprised of weathered parent material for the soil.
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What is the zone beneath zone C?
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Zone R is beneath zone C. Zone R contains the bedrock, or parent material of the soil.
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What is the solum?
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The solum comprises horizonz A, E, and B, and is referred to as the truly definable soil, or pedon. Horizons A, E, and B are the accumulation, eluviation, and illuviation zones.
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What three factors are involved in the formation of soils?
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The three factors involved in the formation of soils are dynamic (climate and organisms), passive (relief, parent material, time), and human intervention.
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What is relief?
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Relief is the slope and orientation of the soil.
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Describe oxisols.
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Oxisols are extremely leached and iron rich due to the persistent amounts of moisture. This soil is found predominantly in tropical areas.
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Describe aridisols.
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Aridisols are pale soils with marked periods of soil moisture deficit and generally inadequate soil moisture.
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Describe mollisols.
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Mollisols are soils that are noticeably dark with high amounts of organic material, humus rich, and are well structured.
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Describe alfisols.
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Alfisols are moderately weathered soils beneath humid temperate forests and are comprised of a moderate organic layer and high amounts of clays in the B horizon.
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Describe ultisols.
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Ultisols are highly weathered soils similar to alfisols with a redder color; found in subtropical regions.
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Describe spodosols.
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Spodosols are highly leached and strongly acidic soils without structure and are found under cool humid forests. Illuviation of oxides and clays in the B horizon form the Spodic horizon.
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Describe entisols.
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Entisols are recent or undeveloped soils containing a lack of vertical horizons. They are true soils which have not had sufficient time to develop horizons.
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Describe incepitsols.
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Inceptisols are weakly developed soils only slightly more developed than entisols. They are typically infertile.
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Describe vertisols.
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Vertisols are heavy clay soils that contain more than 30% swelling clays which swell significantly when saturated and shrink significantly when dried.
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Describe histosols.
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Histosols are formed from the accumulation of thick organic matter (i.e. peat bogs, swamps) in extremely moist areas.
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Describe andisols.
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Andisols are composed of volcanic ejecta and weathered volcanic materials.
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Describe gelisols.
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Gelisols are cold and frozen soils of high latitutdes and high elevations. They are slowly developing soils with possible areas of permafrost.
