Lesson 2 Flashcards
What is the size range of soil particles?
Boulders in diameter meters to clay partials less then .002 in diameter.
What is the size range of Sand
.2mm to .05mm
What is the size range of Silt?
.05mm to .002mm
What is the size range of Clay?
Less then .002mm
What are fine earth particle fraction size
Less then 2mm in size
What are 4 f characteristics of Fine Earth Fractions
- They are less then 2mm in size
- They are sand, silt, and clay
- They have the greatest surface area
- They are the most chemically and biologically active
What is the size range of Colloidal particles?
Less then .005 in diameter
What are Colloidal Particals
small solid particles that are suspended in a fluid phase
What are the effects of Colloidal particles
They are physically and chemically reactive
What is an example of Colloidal Particles
Clay
How soil texture described
- Size of particle
- Proportion of Sand, Silt, Clay
- USDA Soil Texture Triangle
How is soil Particle size measured
- Feel Method
- Ribbon Test
- Soil buoyancy test
What is used for a soil buoyancy test
Hydrometer
What is another name for aggregate
Peds
What are aggregates
Soil particles held together by stabilizing agents
How are aggregates described
By there shape size and stability
When does soil have structure
When soil particles are aggregated
How is soil structure characterized
By each horizons aggregated particles and the effort to be broken apart when handled.
What are 5 aggregate shapes
- Granular
- Blocky
- Prismatic
- Columnar
- Platy
Describe Granular Structure shape and where they can be found.
Horizon A, they are Spherical shaped
Describe Blocky Structure and where its found
Horizon B, Cube shaped
What is sub-angular blocky
Rounded corners
What is angular blocky
Not rounded corners
Describe Prismatic Structure and where it can be found
B horizon, longer then wide, angular edges and tops
Describe Columnar Structure and where it can be found
B horizon, In columns, tops and sides are rounded
Describe Platy Structure and where it can be found
Horizon E, thin and flat
What are the 2 types of Structure-less Soil
- Massive
- Single Grain
What is Massive structure
All particles are stuck together, no individual aggregates
What is single Grain Structure
Each particle acts individually
What are 7 causes for aggregate stay together in a structure
The pushing together and pulling apart due to;
1. Water
2. Shrinking
3. Swelling
4. Freezing
5.Thawing
6. Roots
7. Animals
What is weak aggregate structure
Aggregate braces apart with little handling
What is moderate aggregate structure
Soil can be removed from horizon in an aggregate structure
What is strong aggregate structure
Aggregates no not readily fall apart when handled
When is structure strength used
When describing each structure
When is a structure a structure
Once particles are stuck together
How is aggregate stability characterized
- It is the resistance of destruction by water
- Stabilizing agents
What are 3 ways minerals influence soil
- The rate of soil formation
- The amounts and types of soil nutrients available to plants
- The bonding ability and cation exchange capacity
That is definition of Cations
An Ion that is positively charged
What is an ion
A charged atom or molecule
What is organic matter and what 5 elements does it contain
- Any carbon based compound
- Contains hydrogen, oxygen, phosphorus nitrogen and sulfur
What are 4 characteristics of Humus
- Highly decomposed organic matter
- Organic glue
- Highly charged
- Has large surface area per unit mass
What is consistence
- The measurement of soils cohesion and adhesion
- The measured resistance to deformation and rupture
Name 3 types of consistence
- Dry
Sandy loam: individual grains do not stick together - Moist
Loose or extremely firm depending on soil - Wet
Sticky
Why does Clay influence the three consistence measurements of wet moist dry
- Increases the hardness of dry soil
- Increases firmness of moist soil
- Increases stickiness and plasticity of wet soil
Describe Pores in soil
- Air and water flow within
- Comes in all sizes and shapes
What is the difference between Intra and Inter aggregate pores
- Intra- larger pores around aggregate, carry more water
- Inter- pores inside of aggregate
What is Vesicular when associated with pores
Do not transmit water or air
What are macropores
Large pores that drain quicker
What are Micropores
Smaller pores
