Understanding Soil Formation

Parent Materials

•Classified by the way they were moved and scattered.

Parent Materials•Moved by glaciers•Loess - occurred from blowing of soil after

glaciers melted and dried•Most Desirable

•Outwash - occurs during melting; larger items deposited first, smaller items deposited last

•Glacial Till - No layers•Can contain pebbles to boulders

Parent Materials

•Deposited by flooding streams and rivers•Alluvium -

Bottomlands and flood planes

Parent Materials•Bedrock - Shale,

Sandstone, or Limestone •Organic Matter - Usually

swamp vegetation that has accumulated•Known as Peat and

Muck (muck is more decomposed than peat)

Topography•Steepness(degree),

length, shape, direction•Nearly level soils are

generally poorly drained

•Moderate to steep slopes are generally well drained

Time / Weathering•Physical Weathering•Temperature, Water, Wind, •Freeze/Thaw

•Chemical Weathering•Rainwater is mildly acidic•Oxidation

Climate•Rainfall - slowly by surely erodes•Wind wears away at rock•Hot Summer/cold Winter -

Freeze/Thaw•Humid area - more leaching than

dry areas

Organisms•Plants, Insects, Organisms

•Greatest affect on soil formation is the plants that once grew in it•Native Vegetation

•Example: common native vegetation in the Midwest.•Tall Prairie Grass•Prairie Soils

•Deciduous-hardwood forests•Timber Forests

•How is the Midwest different from Northern Utah?

Organisms