soil & erosion chapter 14.3 & 14.4. what is soil? a loose mixture of rock pieces and organic...

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Soil & Erosion Soil & Erosion Chapter 14.3 & 14.4 Chapter 14.3 & 14.4

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Page 1: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

Soil & ErosionSoil & Erosion

Chapter 14.3 & 14.4Chapter 14.3 & 14.4

Page 2: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

What is soil?What is soil?

A loose mixture of rock pieces and organic A loose mixture of rock pieces and organic material that can support the growth of material that can support the growth of vegetation.vegetation.

Soil results from weathering.Soil results from weathering.

Page 3: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

Soil Profile & HorizonsSoil Profile & Horizons

Page 4: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

What’s Erosion?What’s Erosion?

EROSION- The breakup and EROSION- The breakup and removalremoval of of rock by moving natural agents (rivers, rock by moving natural agents (rivers, glaciers, wind, water) glaciers, wind, water)

Page 5: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

Types of ErosionTypes of Erosion

Soil erosion = as rock weathers it eventually Soil erosion = as rock weathers it eventually becomes very fine particles that mix with water, becomes very fine particles that mix with water, air, and humus to form soil.air, and humus to form soil.

Gullying = Plowing of furrows, or long, narrow Gullying = Plowing of furrows, or long, narrow rows. These furrows allow water to run swiftly rows. These furrows allow water to run swiftly over soil. As soil is washed away with each over soil. As soil is washed away with each rainfall, a furrow becomes larger & forms a small rainfall, a furrow becomes larger & forms a small gully. gully.

Sheet erosion = process by which water flows Sheet erosion = process by which water flows over a layer of soil & removes the topsoil.over a layer of soil & removes the topsoil.

Page 6: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

Soil ConservationSoil Conservation

Erosion rates are affected not only by natural factors but also by human activities. Certain farming & grazing techniques can also increase the rate of erosion.Land clearing removes protective ground covering plants & accelerates topsoil erosion.Soil conservation methods can help to prevent rapid & destructive soil erosion

Page 7: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

Soil Conservation MethodsSoil Conservation MethodsContour plowing: soil is plowed in curved bands that follow the contour, or shape, of the land.

Strip cropping: Crops are planted in alternating bands. Alternate between one band and a band that covers the surface of the land, known as a cover crop (Ex. corn & alfalfa). This cover crops help to protect the soil by slowing runoff.

Page 8: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

Terracing: Step-like ridges that follow the contours of a sloped field.

Crop rotation: farmers plant one type of crop one year and a different type of crop the next. Stops erosion in early stages.

Page 9: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

Gravity & ErosionGravity & ErosionMass movements – Movement of a large mass of sediment or a section of land down a slope caused by gravity.Types of fast mass movements:– Landslides - sudden movement of bedrock or

loose rocks down a cliff.– Slumps – Occurs along very steep slopes; large

block of soil and rock that becomes unstable and moves downhill.

– Mudflow - fast movement of a large amount of mud.

Page 10: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

← Slump

Mud flow

← Landslide

Page 11: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

SolifluctionSolifluction

Solifluction = slow, down slope flow of soil Solifluction = slow, down slope flow of soil saturated with water in areas surrounding saturated with water in areas surrounding glaciers at high elevations.glaciers at high elevations.

Creep = the slow downhill movement of Creep = the slow downhill movement of weathered rock material.weathered rock material.– Talus – piles rock fragments that accumulate Talus – piles rock fragments that accumulate

at the base of a slopeat the base of a slope

Page 12: Soil & Erosion Chapter 14.3 & 14.4. What is soil? A loose mixture of rock pieces and organic material that can support the growth of vegetation. Soil

LandformsLandforms

Three major landforms (physical features Three major landforms (physical features of Earth’s surface) that are shaped by of Earth’s surface) that are shaped by weathering and erosion:weathering and erosion:

1.1. MountainsMountains

2.2. PlainsPlains

3.3. PlateausPlateaus