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Five Factors That Affect Soil Formation. Parent MaterialClimateLiving OrganismsTopographyTime or Weathering. Parent Material. Parent materials are formed by the disintegrations and decomposition of rockThey are classified according to the way they were moved and scattered. Parent Material. Many
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1. Understanding Soil Formation Prepared by
Eric Johannesen
Iowa-Grant High School
2. Five Factors That Affect Soil Formation Parent Material
Climate
Living Organisms
Topography
Time or Weathering
3. Parent Material Parent materials are formed by the disintegrations and decomposition of rock
They are classified according to the way they were moved and scattered
4. Parent Material Many soils have been formed from material originally moved by glaciers
Glacial origin soils are classified as…
Loess-Blowing soil after the glacier melted
Outwash-occurred when glaciers melted
Glacial Till-Was not moved by wind or water.
5. Parent Material Some soils are formed as a result of recent sediments deposited by streams as they flood.
This is called Alluvium
Alluvium is generally a water-borne material deposited on bottomlands.
6. Parent Material Bedrock
Shale
Sandstone
Limestone
Weathered bedrock can provide soil parent material
7. Organic Matter Occurs where formerly shallow ponds supported swamp vegetation.
The wet conditions slowed decay of the dead plants so the organic matter could accumulate
The two types of OM are…
Muck
Peat
8. Topography Refers to the slope characteristics of a soil
Degree of steepness
Length
Shape
Direction of slope
These factors influence the amount of rainwater runoff, or the amount that enters the soil, or collects in small depressions on the soil surface
Soils with steep slopes have a higher degree of runoff.
9. Living Organisms Organisms live in soil
Plant
Insects
Microbes
Organisms affect the soil formation
The greatest affect on the development of soil is from plants that once grew in it.
10. Living Organisms Prairie Soils
Have a dark and deep surface layer
Timber Soils
Tend to have a thin, moderately dark layer
Other living matter that influences the development
Earthworms
Animals
Burrowing animals
11. Weathering Two Types of Weathering
Physical Weathering
Affect of climatic factors such as
Temperature
Water
Wind
Chemical Weathering
Rainwater is mildly acidic and can slowly dissolve soil minerals
Oxygen will also react with the soil
12. Weathering Climate
Refers to rainfall, freezing, thawing, wind, and sunlight