Top Banner
What is Erosion? • The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".
31

What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Dec 23, 2015

Download

Documents

Mary Griffin
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

What is Erosion?

• The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Page 2: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

1890

                                                                      

ErosionThe first five pictures of this presentation are of the same rock, just in different time periods. Pay attention to the dates on the side of the

pictures and see what the water did to this rock.

Page 3: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

ErosionStill the same rock.

1910

                                                                    

   

Page 4: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

ErosionStill the same rock.

1920

                                                              

Page 5: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

What is Soil Erosion?

• In general terms soil erosion implies the physical removal of topsoil by various agents, including rain, water flowing over and through the soil profile, wind, ice or gravitational pull.

Page 6: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Types of Soil ErosionWind erosion: the removal soil particles by the force and

kinetic energy of the wind. These soil particles are transported and deposited when the wind energy drops.

Water erosion: caused by the kinetic energy of rain falling on the soil surface and by the mechanical force of runoff.

Gravity erosion: Mass movement of soil occurs on steep slopes under the influence of gravity. The process involves the transfer of slope-forming materials from higher to lower grounds due to self weight.

Page 8: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Climatic Factors

• The two most important climatic factors having a direct effect on erosion are precipitation and wind velocity. Other climatic factors have an indirect effect on soil erosion, such as water balance, temperature and relative humidity.

Page 10: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Soil Itself

• The susceptibility of a soil to erosion is influenced by its physical, hydrological, chemical and mineralogical properties as well as its soil profile characteristics. Important soil physical and hydrological properties that affect the resistance of a soil to erosion include texture, structure, water retention and transmission properties.

• AKA some soil can erode quicker than other soils (think clay verses sand)

Page 11: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Topography

• Slope gradient, slope length and shape of slope are the important variables of landform that affect erosion processes for all types of soil erosion, e.g., splash, sheet, rill, and gully erosion.

Page 12: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

FORESTRY PRACTICES

• Forests are logged by two different methods:• CLEAR CUTTING – every tree is cut down

whether it has value or not and the unnecessary trees are left

• SELECTIVE CUTTING – only certain trees are cut down depending on what they are needed for ( firewood, paper, furniture or lumber)

Page 13: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Clearstream

(a) Selective cutting

Fig. 9-6, p. 182

Major tree harvesting methods. If you were cutting trees in a forest you ownedwhich method would you choose and why?

Page 14: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Muddystream

(b) Clear-cutting

Fig. 9-6, p. 182

Page 15: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Cut 1year ago

(c) Strip cuttingUncut

Clearstream

Uncut

Cut 3–10years ago

Dirt road

Fig. 9-6, p. 182

Page 16: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

EVALUATING A CLEAR-CUT

• Company’s point of View• 1. Less expensive – provide timber or pulp at a

more competitive price• 2. safer for workers• 3. Company can choose which trees to plant –

get better price for when the area is logged again in the future.

Page 17: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

EVALUATING A CLEAR-CUT

• Ecological Point of View• 1. Soil erosion and runoff into local streams increases

– increasing growth of algae• 2. Eroded soil forms sediment in streams, affecting

spawning areas of fish.• 3.Removal of vegetation on the ground exposes the

soil, increasing the warming of the area in summer and cooling in winter

• Exposure also increases water loss from the soil.

Page 18: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

EVALUATING A CLEAR-CUT

• Clear-cut creates completely different abiotic and biotic conditions in the area.

• Ecosystem must change – therefore the community must change.

• Loss in forest plants – loss of forest animals• Ecotones are also created between the

remaining forest and the newly cut area.

Page 19: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

DEFORESTATION

• Is any removal of trees from the area of land.• Deforestation affects the environment in many

ways:• 1. Erosion – tree roots hold soil in place during

heavy rains• 2. Nutrient Loss – nutrients are washed away

with the rain instead of being absorbed by the trees

• Cont…

Page 20: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

DEFORESTATION

• 3. Temperature Change – the ground will absorb more energy (albedo effect?) and affect organism functions

• 4. Carbon Cycle Change - no trees to take in CO2 and to make O2

• 5. Food Web Changes – less producers at the beginning of food chains

• 6. Habitat loss – nesting areas and ground cover disappears

Page 21: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

What can help prevent erosion?

Page 22: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Techniques

• Modern techniques include- contour plowing- terracing- crop rotation- shelter belt

Page 23: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Ways of Preventing Erosion

• Prevent soil erosion by planting vegetation, trees, ground cover, shrubs and any other plants. The roots from these plants will help hold the soil in place. Soil will not be easily blown away by wind or washed away by the rain.

• Create windbreaks, which are Hedges or fences of trees designed to reduce erosion, especially wind erosion. Plant them on different plots of lands.

Page 24: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Ways of Preventing Erosion Part 2

• Grow crops on farm lands. When land is not being used, use cover crops because they help prevent soil erosion by wind or rain. Beans are often used as cover crops.

• Apply mulch, which is; a protective covering of rotting vegetable matter spread to prevent soil erosion. The topsoil is will not be likely washed or blown away, when it’s covered by mulch.

Page 25: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Plants can help prevent erosion! Look at the roots on these grasses.

Roots help hold the soil in place so that it doesn’t wash away.

Plant roots

Page 26: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Engineering Project

You always dreamed of being a farmer, so you left the city and bought an old farm in Kentucky. However, the more you learn about farming, the more you regret purchasing this farm. It has laid barren for 5 years and the top soil is beginning to erode away. If you want to save your investment, you must act quickly. The bank has agreed to increase your loan, but every penny you spend, you must pay back with interest.

Page 27: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

The picture below is your main field.

Page 28: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Design Criteria/ Constraint MatrixDesigns Criteria and Constraints (Rate 0-3) Totals

Last on Steep Land

Protect Against Water

Erosion

Readily Available

Cost Efficient

AEx: Mulch

1 2 3 3 9

B

C

D

Page 29: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Engineering project

1. What is your question/ problem?2. What were some soil conservation methods

you learned about today? (research)3. Which idea fits the constraints of your field

the best?4. Write the steps you would have to take in

order to save your field. Sketch your final design.

Page 30: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Evaluate

Switch design plans with your table partner and evaluate their plan.

List AT LEAST one thing they did well on.List AT LEAST one thing they could improve

upon. (Focus on the design, procedure steps, and

sketch.)

Page 31: What is Erosion? The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away".

Refine

Working with a group, refine your designs. You may combine them or choose one that you like best.

You will now create a mini-poster with your design. Include a decision matrix, sketch, and reasoning. Imagine you have to present this to a stranger who knows nothing about soil erosion. Make sure your poster explains using text and graphics.