Unit 2: Soil Vocabulary

Soil

provides nutrients for plants: made of

rock, humus, clay, silt, and sand

Weathering

break down of rocks: creates soil

Topsoil

upper soil- natural product of subsoil and

bedrock and it is the best for plants

Subsoil

made up mostly of clay and under the

topsoil

Bedrock

The bottom layer of soil and the worst for plants to

grow

Humus

decayed matter found in top soil and does

not hold water well

Sand

Grains of worn down rock, larger than silt-

has few nutrients and does not hold water

well

Silt

Very small broken pieces of rock, smaller

than sand and larger than clay

Clay

Contains nutrients and holds water well-

can be red or yellow, smallest grain size

Conserve

To save

Erosion

Processes by which rock, sand, and soil are broken down and carried away (i.e. weathering, glaciation)

Creep

Type of Wind Erosion, Small soil particles roll or slide while maintaining contact with the ground.

Saltation

Type of Wind Erosion, Grains of soil bounce across the ground.

Suspension

Type of Wind Erosion, Soil moves through the air like in a dust storm

Sheet

Type of water erosion, loss of thin uniform layers of soil over a full field

Rill

Type of water erosion, channels or rills forming runoff, randomly located

Ephemeral

Type of water erosion, channels / depressions that form in the same place each year

Gully

Type of water erosion, large channels not able to be repaired by tilling of fields

Streambank

Type of water erosion, erosion of the sides of a stream over time

Identify the layers of soil

Porosity

Percentage of open spaces between grains in a rock. Ability to hold water

Permeability

Ability of rock or soil to allow water to flow through it. Sand has highest permeability.

Loam

A mixture of gravel, sand, silt, clay, and organic matter