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24 Cards in this Set
- Front
- Back
What are the six components of soil?
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1. sand and gravel
2. silts and clays 3. dead organic material 4. living organisms (soil flora and fauna) 5. water 6. air pockets |
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List the six soil horizons in order from top to bottom.
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O,A,E,B,C,D
(mnemonic: Orange Apes Eat Boston Creme Donuts. Yeah, I came up with that all by myself.) |
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Where is the O horizon and what does it contain?
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Top level of soil.
Contains surface leaf litter and decomposing organic material. |
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Where is the A horizon and what does it contain?
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2nd level of soil (counting top to bottom).
Also known as topsoil or humus. Rich in organic matter and contains lots of organisms. |
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Where is the E horizon and what happens there?
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3rd level of soil (counting top to bottom).
Zone of leaching: dissolved or suspended materials move downward. |
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Where is the B horizon and what does it contain?
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4th level of soil (counting top to bottom).
Also known as subsoil. Zone of accumulation: holds materials that have leached down from A and E horizons. Contains less organic material and more regolith. |
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What is regolith?
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The layer of loose, heterogeneous material covering solid bedrock.
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Where is the C horizon and what does it contain?
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5th level of soil (counting from top to bottom).
Contains broken-up rock with little organic material. Partially broken-down inorganic materials. |
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Where is the D horizon and what does it contain?
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Bottom level of soil.
Contains bedrock or parent rock. |
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List the six properties used to characterize types of soil.
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Color, texture, structure, consistency, porosity, moisture.
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What do different soil colors indicate about the composition of soil?
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Red or yellow soil: high iron content.
Black or brown soil: high organic content. |
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What is soil texture?
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The size and organization of particles.
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What is soil structure?
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The arrangement of particles in soil.
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What are some different types of soil consistency?
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wet, sticky, or dry
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What is soil porosity?
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The amount of space between grains.
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What is soil moisture?
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The presence of water in soil.
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What does a ternary diagram show?
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Soil texture and composition.
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What is soil taxonomy?
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There are 12 orders of soil taxonomy defined by the USDA. Each soil type has a different combination of features and is found in a particular climatic region.
examples: gelisols - cold climate tundra soils. andisols - formed from volcanic soils. (we don't have to know all the individual types of soils, just the general concept of the taxonomy) |
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What are some causes of environmental degradation of soil?
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1. water erosion (e.g. in Ethopia
2. wind erosion, e.g. in Somalia 3. toxic chemicals, e.g. in Uzbekistan 4. contamination from nuclear reaction explosion in Chernobyl (Sweden, Finland) |
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What effect does agriculture have on soil?
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Agriculture accelerates erosion. On the map of worldwide soil degradation, there is a high correlation between soil degradation and high agricultural activity.
Poor agricultural practices in particular can accelerate erosion, such as plowing down a slope rather than across it (contour plowing). |
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What is sheet erosion?
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Water flowing across a gently sloping, bare field removing a thin, uniform layer of soil.
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What is rill erosion?
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Little rivulets of running water gather together and cut small channels in the soil.
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What is gully erosion?
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Rills enlarge to form bigger channels or ravines that are too large to be removed by normal tillage operations.
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What is desertification?
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The conversion of productive land to desert by removal of vegetation and soil.
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