Soil formation, soil horizons, and soil composition basics from an intro Earth science course.
30 cards · basic cards · AI-written, checked twice. Edit anything.
- What are the four main components of soil?
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Rock and mineral particles, organic matter, water, and air- What is the O horizon?
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Layer of decomposing leaves, twigs, and organic matter at the soil surface- What is the A horizon?
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Topsoil rich in organic matter and humus, usually dark colored- What is the B horizon?
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Subsoil where minerals leached from above accumulate, usually lighter colored- What is the C horizon?
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Layer of partially weathered parent material and rock fragments- What is the R horizon?
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Bedrock layer of unweathered parent rock- Define weathering in soil formation
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Physical and chemical breakdown of rock into smaller particles- What is mechanical weathering?
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Physical breaking of rock by frost action, water, wind, or root pressure- What is chemical weathering?
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Breakdown of rock minerals through oxidation, hydrolysis, or acid reactions- What is soil texture?
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The relative proportions of sand, silt, and clay particles in soil- What is soil structure?
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The way soil particles are arranged and bonded into aggregates- What is humus?
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Dark, stable organic matter from decomposition of plants and animals- Name three soil organisms involved in soil formation
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Bacteria, fungi, earthworms, arthropods, and plant roots- What is infiltration?
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The downward movement of water from the soil surface into the soil layers- What is percolation?
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The continued downward movement of water through soil horizons
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