EAE 09 Soils Flashcards
What part of the soil is the A horizon?
Topsoil
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What part of the soil is the B horizon?
Subsoil
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What part of the soil is the R horizon?
Weathered or decomposed
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What part of the soil is the O horizon?
Organic materials
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What is the definition of soil?
The uppermost part of earth’s surface, that forms a natural median for growth of land based vegetation.
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What is Loam textured soil?
4 points.
Soil that is ideal for plant growth and is:
- 25% Air
- 25% Water
- Biomass/O.M. 5%
- 455 minerals.
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How much of vegetated land is considered degraded?
17% or 1 in 6 hectares.
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What is Humus?
Dark organic matter whose original components can no longer be recognized.
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What is the relationship between air and what in soil?
Water and air take up the same amounts of space in soil and are therefore higher proportions of one mean lower proportion of the other.
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Is all water in soil available to plant why or why not?
No as some water is held in micropores unavailable to plants.
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What are the main factors which influence weathering and erosion?
4 points.
- Rock type
- Topography
- Rainfall
- Wind exposure
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How is surface area affected by the breakdown of a rock?
The more broken down it is the higher the surface area
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What is the primary factor in determining soil formation?
Parent material.
Soil forms much slower from bedrock then it does from alluvium.
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What are the characteristics of alluvial deposits?
2 points.
- Soils follow pattern of sediments.
- Finer soils form further away.
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Why are soils from igneous rocks fertile?
They form a clay rich soil.
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What does temperature affect in soils?
3 points.
- Water balance in the soil.
- Rate of chemical reactions.
- The soil biota present.
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