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