Weathering and Erosion

Soil

Target #10- I can define the term “soil”

• One result of weathering is the formation of soil–Soil: a loose mixture of rock fragments and organic material•Characteristics determined by the parent rock–Includes composition, color, texture, and moisture level

Target # 11- I can describe a soil profile

Target #12- I can label the parts of a soil profile on a diagram

• Generally, soils will develop distinct layers over time–Soil profile: a vertical section of soil that shows the layers of horizons•Horizon: a horizontal layer of soil

• Draw the diagram on the board

• Horizon C–Bedrock: the solid, unweathered rock found beneath all the other layers–Regolith: the layer of weathered rock fragments just above the bedrock

Target #13- I can define all the parts of a general soil profile

Target #13 cont.

• Horizon B–Subsoil: contains clay, mineral deposits, and organic matter–Zone of Leaching: layer made of sand and silt, lost most of its minerals due to movement of water through the layer

Target #13 cont.

• Horizon A–Topsoil: a dark colored layer made of organic material, living organisms, and rock particles–Humus: the top, organic layer of soil made mostly of leaf litter and organic matter

Target #14- I can summarize why soil is important for environmental and societal function

• Soil provides for many important environmental and societal functions–Provides ecosystem

services critical for life• Acts as a water filter • A medium for growing• provides habitat for

billions of organisms,• contributes to

biodiversity

–Supplies most of the antibiotics used to fight diseases. –Humans use soil as:• a holding facility for solid waste• filter for wastewater• foundation for our cities and towns.

–Finally, soil is the basis of our nation’s agro-ecosystems• provide us with feed, fiber, food and

fuel.

Target #15- I can state How Nature and Humans Have Affected the Earth’s Soil

• Losing Dirt to Natural Disasters– Too much rainfall can lead

to mudslides or landslides– The stripping away of the

topsoil prevents plants from growing right away

• Losing Dirt to Man-made Disasters– Pollute it by dumping

chemicals and other wastes.

– Deplete it of nutrients by over farming

– allow livestock to over graze it

• Desertification– If too many animals are allowed to graze

for too long, the grass can be stripped away and the soil will lose its anchoring roots. The area can become a desert

• Soiled Soil– If soil is polluted due to events like

waste dumping, the soil becomes toxic and is potentially harmful to communities