Exam 1 Flashcards
Definition of soil
Is a dynamic natural body composed of Air, Water, Organic Matter, Minerals
Compositions of a normal soil
25% water
25% Air
5% Organic Materials
45% Minerals
5 factors of soil formation
Climate Parent material Time Topography Biota
Primary succession
Lichens appear with mosses, break down rocks, small grasses start to appear, more organic material and larger root system grasses appear with shrubs and trees and forests appear
4 ways soils can be moved
Ice
Gravity
Water
Wind
Ice
Terminal Moraine
Water
Alluvium
Marine
Gravity
Colluvium
Bedrock
Residual
Wind
Eolian
Loess
4 soil forming processes
Additions: Organic material build up (forests)
Losses: Loss of soil (erosion)
Translocation: Soil shifting/moving(weathering)
Transformation: Soil changes based on parent material (water evaporation)
Know your horizons in order
O A E B C R
O characteristics
Which is a humus or organic layer
A characteristics
- Which is considered to be the mineral organic layer.
* Which horizon is considered to be top soil.
E characteristics
Which horizon is not always present and is made up of components and not susceptible to leaching
B characteristics
- Which horizon is associated with an increase of clay content
- Which horizon (besides O and E) may not be present in an entisol
C characteristics
Which is an I consolidated parent material
R characteristics
Bedrock
3 physical properties
Color
Texture
Structure
Soil separates
Clay- Smooth
Silt- Fine
Sand- Gritty
Clay characteristics
- High water holding capacity
- Good for building lagoons, ponds landfills
- Best for most septic systems
Sand characteristics
- Low water holding capacity
* Good aeration
Silt characteristics
- High susceptibility to wind erosion
* Low strength
Soil filth qualities that affect it
Good water capacity
Good nutrient capacity
Good drainage
Review conservation tillage terms
Fallow is letting soil go without tillage, preparing for crop growth for 1 seasons it is used to put nutrients back into the ground
Macro-pores
Larger than .08mm
Micropores
Smaller than .08 mm
6 levels of soil taxonomic system
Order Suborder Group Great group Family Series
Entisols
Little if any profile development, very young
Inceptisols
Young profile development (B horizon) has began
Mollisols
Dark prairie soils, high fertility
Alfisols
High base, shallow soils, Mediterranean climates
Ultisols
Forested, subtropical soils
Vertisols
Dark swelling clay
Aridisols
Dry soils, semi-arid climates
Spodosols
Wet, acidic soil E horizon
Histosols
Organic soils
Andisols
Volcanic soils
Oxisols
Highly weathered, oxidized soils, tropical rain forests
Gelisols
Young soil characterized by a permafrost layer
What is the maximum amount of sand a silt loam can have?
49%
Which is the most important factor in soil formation
Climate
Name 1 macro-fauna and 1 micro fauna important to soil development
Macro fauna- worms
Micro fauna- bacteria
Give at least 3 characteristics of the previous soil series. Which soil order does it belong to? (Mollisols)
Great for agriculture
More of a silt mixture loam
Moderate pH level
Give at least 3 characteristics of the previous soil series. Which soil order does it belong to? (Ultisols)
Low pH
Holds heat
More silt
Which soil order is responsible for the productive wheat crop on the pacific NW
Andisols
Which soil order is prone to CaCO3 and sodium accumulation due to excessive evaporation and dominates the SW portion of the US?
Aridisols
Which soil order has bedrock closest to the surface, the majority of these are found in the Rocky Mountains
Entisols
Which soil order is characterized by its bright red color
Oxisols
Which soil order can be problematic for engineers because of its high shrink swell possibility
Vertisols
Which soil order is considered to be the most productive and dominates the Great Plains area
Mollisols
Which soil order develops under coniferous pine of central east Canada as well as northern Michigan and Wisconsin. It’s is characterized by a zone of eluviation
Andisols
Which soil order is characterized by cryoturbation
Gelisols
Why might profile development be delayed in Gelisols or Aridisols
The permanent layer of the low moisture content can hinder growth and development
Why is soil important? Why is it important to understand soil characteristics?
Soil gave life to everything. We need to understand soil so we can grow crops in the right soil or build houses that will not be destroyed by swelling of soil
The three major factors that have the greatest influence on the color of a soil are texture organic matter and water content
False
We use the munsell soil book to help us determine textures
False
Redoximorohic features are those associated with periods of flooding drainage
True
Mottling is considered to be a redoximorophic feature
True
A red soil means that it has clay texture
False
A red soil means that the Fe has been reduced
False
