Soils Flashcards
Soil is produced by ________.
weathering
3 types of weathering:
- Mechanical weathering (i.e., freeze-thaw);
- Chemical weathering (i.e., chemical reaction with water - oxidation, hydrolysis and carbonation.); and
- Biological weathering (e.g., tree roots splitting rock apart - C. Shield).
Silicates formed in higher temperatures are more or less brittle than those formed in lower temps?
more
What are the best conditions for weathering?
warm and wet
Soil horizons:
O - organic matter
A - organic matter mixed with rock and mineral fragments
E - zone of leaching
B - zone of accumulation
C - weathered parent material partially broken down
Bedrock
Leaching
When water dissolves soluble materials and carries it away (leachate).
What are the 3 components of soil?
- Sand
- Silt
- Clay
Loam is a balance of what 3 components of soil?
All of them! Sand, silt, and clay.
What is lithification?
The process in which sediments compact under pressure, expelling connate fluids, and eventually becoming solid rock.
In other words, lithification is a process of porosity destruction through compaction and cementation (e.g., shale is lithified clay)
Pedalfer soils vs. pedocal soils
Pedalfer soils - characteristic of more humid regions
Pedocal soils - characteristic of more dry regions
How many orders does the most popular, simplistic soil classification have?
Twelve Soil Orders
Describe the properties of lateritic soils. Where are they causing problems?
Laterite is derived from the word ‘brick’ - when vegetation cover is taken away, lateritic soils bake in the sun and become hard and unproductive.
Lateritic soils are a problem in many LDCs where rain forests are cleared for farmland. Soils quickly become leached; the biomass in a rainforest is the reservoir for soil nutrients, not the soil.
Erosion
The breakdown and removal of material from one location to another.
Is soil considered a renewable or non-renewable resource?
Non-renewable (relative to the human timescale).
What has been the saving grace for Dust Bowl prone regions?
Irrigation has mitigated the risk of another dust bowl disaster, however, these same regions are running into water shortages from the depletion of aquifers.
