Weathering and Erosion

Weathering

Weathering is the breaking down of rocks, soils and minerals as well as artificial materials through contact

with the Earth's atmosphere, biota and waters.

Weathering by frost wedging

Mechanical weathering

mechanical weathering is a physical process.

Water weathered tree

How is a plant or animal an agent of mechanical weathering?

Plants and animals are agents of mechanical weathering. The seed of a tree may sprout in soil that has collected in a cracked rock. As the roots grow, they widen the cracks, eventually breaking the rock into pieces. Over time, trees can break apart even large rocks. Even small

plants, such as mosses, can enlarge tiny cracks as they grow.

Animals that tunnel underground, such as moles and prairie dogs, also work to break apart rock and soil. Other animals dig and trample rock aboveground, causing rock to slowly

crumble.

Biological weathering

Roots growing

into rock

Animals burrow

Badger

Erosion

Erosion is the process by which soil and rock are removed from the Earth's surface

by natural processes such as wind or water flow

Erosionby wind

Erosion by water

Leaching

Leaching is the process of extracting minerals from a solid by dissolving

them in a liquid

Rain water is slightly acidic

Rain water is slightly acidic because Carbon dioxide forms carbonic acid

when mixed with water

Major factors involved in how fast weathering occurs

Climate, mineral composition, amount of water

Soil Horizons

The layers in a soil profile are called horizons

Soil horizons

soil and climate related

Warmer temperatures and high rainfall increase rate of soil formation. Cooler

temperatures and less rain slow it down.

Conserve soil

Some ways to conserve soil are Contour farming/shelter belts, cover

crops, and strip crops.

Shelter belt

Contour farming

Cover crops

Strip crops

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