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17 Cards in this Set
- Front
- Back
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Soil |
the loose, weathered material on the Earth's surface in which plants can grow |
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Bedrock |
the solid layer of rock beneath the soil |
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Soil is composed of |
a mixture of rock particles, minerals, decayed organic material, water, and air |
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Humus |
is a dark-colored substance that forms as plant and animals decay |
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fertility of soil |
is a measure of how well the soil supports plant growth |
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loam |
soil that is made up of equal parts of clay, sand and silt |
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soil horizon |
is a layer of soil that differs in color and texture from the layers above or below it |
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topsoil (often called A Horizon) |
a crumbly dark brown soil that is a mixture of humus, clay and other materials |
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subsoil (often called B Horizon) |
consists of clay and other particles washed down from the A horizon |
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C Horizon |
Contains only partly weather rock |
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Scientists classify soil into major types based on: |
climate, plants, soil composition, and whether it is acidic or basic |
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Acidic |
means it reacts strongly with some metals and changes blue litmus to red |
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Basic |
means it feels slippery and changes red litmus paper blue |
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Litter |
means when plants shed leaves they form a loose layer |
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Decomposers |
are organisms that break the remains of dead organisms into smaller pieces and digest them with chemicals |
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What five materials make up soil? |
rock particles, minerals, decayed organic material, water and air |
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How do soil horizons form? |
gradually over time soil forms in layers that differ in color and texture |
