Soil Flashcards
The collection of natural bodies on the earth’s surface supporting or capable of supporting plants
Soil
What is soil?
The collection of natural bodies on the earth’s surface supporting or capable of supporting plants
The collection of natural bodies earth’s surface…
…supporting or capable of supporting plants
What percentage of an ideal ag soil does organic matter make up?
5%
What percentage of an ideal ag soil do minerals make up?
45%
What percentage of an ideal ag soil does water make up?
25%
What percentage of an ideal ag soil does air make up?
25%
Solid matter making up a soil
Parent material
What is parent material?
Solid matter making up a soil
What are the two types of soils?
Residual soils and Transported soils
What are residual soils?
Soils that remain at the site of formation
What are transported soils?
Soils that are transported from the site of its parent material(s)
What are the four factors that contribute to soil formation that were discussed in class?
Climate, Time, Biota, Topography
What two features of climate have a strong impact on soil formation
Temperature and preceipitation
In what kind of climate would there be a thick layer of chemically weathered soil?
A hot and wet climate
In what kind of climate would there be a thin mantle of mechanically weathered soil?
A cold and dry climate
What climate feature specifically influences soil fertility?
Precipitation
True or False: Precipitation impacts biota
True
How is time a factor in soil formation?
Weathering influences parent material(s)
What is biota?
Plants and animals living in the soil
Plants and animals living in soil are called…
Biota
Micro-organisms play an active role in…
…the decay of plant and animal remains
What important process do biota contribute to regarding soil formation?
Nitrogen fixation
What is nitrogen fixation?
Certain bacteria can take nitrogen from the atmosphere and “fix” it, or turn it into a form that plants can use
Name the two soil conservation concerns discussed in class
Urbanization and Pollution
Why is soil important regarding climate change?
Soil holds CO2 instead of it going into the atmosphere
Slopes affect the amount of soil erosion and…
…water content of soil
Waterlogged soils in poorly drained bottomlands have copious amounts of…
organic matter
Do saturated soil conditions speed up or slow down decay?
It slows down decay
Vertical section through all soil horizons
Soil profile
What is a soil profile?
A vertical section through all soil horizons
What are soil horizons?
Horizontal differences in the soil that divide it into layers
Horizons that compose topsoil
O and A horizons
Horizontal differences in soil divide it into layers
Soil horizons
Soil horizons in descending order:
O horizon; A horizon; E horizon; B horizon; C horizon
Which soil horizon is considered subsoil?
B horizon
Which soil horizon has highest biodiversity?
O horizon
Which layer of O horizon has recognizable plant litter?
Upper layer
Which layer of O horizon has humus?
Lower layer
What is humus?
Partly decomposed organic matter
True or False: A horizon has high biodiversity
True
What type of matter mostly comprises A horizon?
Mineral matter
True or False: A horizon has more humus than O horizon
False
Which soil horizon is lightest in colour?
E horizon
What 2 process are caused by water percolating in the E horizon?
Eluviation and Leaching
What is eluviation?
The washing out of fine soil components
What is the washing out of fine soil components called?
Eluviation
What is the process of water carrying soluble materials to depth called?
Leaching
What is leaching?
When water carries soluble minerals to depth
At which horizon does eluviation deposit material?
B horizon
What is B horizon also known as?
Zone of accumulation
What accumulates in the B horizon?
Fine clay particles
Which horizon is partly altered parent material?
C horizon
Which horizon is not considered true soil?
C horizon
What are the 3 types of soil erosion?
Sheet, Rill, and Gully erosion
Which is larger: Rills or Gullies
Gullies
Water flowing over surfaces and carrying dislodged soil particles is what type of erosion?
Sheet erosion
