Soil Science #1

Parent Material

What Is Soil?

Soil: The unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants. (NRCS 2007)

Soil FormationParent Material: Material (unconsolidated) in which soils form

Climate: Temperature, rainfall, light, elevation

Plant and Animal Life: In and on soil

Relief: 3-D features (“lay of the land”)

Time: For soil forming processes to act on parent material

General Processes….Laurentide Glacier covered New England 80,000-12,000 years ago

Glaciers scrape land, pick up rocks, and shapes the land-Ice over 5000 feet high!!

As galciers melt/retreat parent material is redistributed

Cambrian

Ordovician

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Types of Parent Material

Parent Material Particle Size Process Features

Glacial Till Sand, Cobble, Gravel

Material “dropped” by glaciers

Jagged edges – not worn by flowing water – loamy/silty/sand – not stratified - TUNBRIDGE

Types of Parent Material

Parent Material Particle Size Process Features

Glacial outwash deposits

Gravel, sand Glacial meltwater (along rivers above floodplain)

Soils exist in layers (strata) of similar particle size- WINDSOR

Types of Parent MaterialParent Material Particle Size Process Features

Alluvial Deposits

Silty, Sandy, Loamy

Material carried by recent streams

In streams below floodplain – stratified - HADLEY

Types of Parent MaterialParent Material Particle Size Process Features

Lacustrine Silt, Clay Glacial lakes allowed small particles to settle

Little stratification - VERGENNES

Types of Parent MaterialParent Material Particle Size Process Features

Organic Deposits

Organic Decomposing plant material in depressions (ponds)

Can be up to 50” thick- CARSLILE