S O I L E R O S I O N

SOIL EROSION

By: Cathlin Aseron, Rachelle Azcarraga and Pauline Tomelden

What is Erosion?

– is a gravity driven process that moves solids

(sediment, soil, rock and other particles) in the

natural environment or their source and deposits

them elsewhere.

Causes of Soil Erosion WIND (Wind Erosion)

- Erosion caused by the winds of high velocity that more

likely occur in dry areas where soil is loose and

unprotected by vegetation. Because of this high velocity of

the wind, wind abrasion occurs. This is seen in ventifacts,

or rock fragments that have been cut and polished by the

sandblasting action of windblown sediments. Loose rock

particles that are blown away by the wind can cause

deflation. Example of this is the desert pavement.

Causes of Soil Erosion WAVES

- Erosion produced by the waves and currents in the ocean.

Large waves pound the shore with tremendous force,

producing a hydraulic-lifting action that dislodges large

masses of coastal rocks. The blocks fall to the ocean

bottom, where they undergo more erosion along with other

wave-battered rock debris that has accumulated there. The

sand and rock fragments grind each other and scour the

shore.

Causes of Soil Erosion WATER

- Steeper slope causes water to flow faster. When water flows

rapidly, more soil are carried away.

- Slow moving water carries fine particles. Fast moving water

carries stones, and even big rocks. As water flows, big rocks strike

other particles. The particles break into smaller pieces and are

carried away by water. Water eventually slows down and large

particles settle followed by sand. Fine particles are deposited along

the way. This is the way by which floods cause erosion.

Causes of Soil Erosion GRAVITY

- When the rock is loosened by weathering it is

subject to erosion by gravity. Such erosion may

occur slowly and imperceptibly, as soil creeps

downhill over a period of years; or it may occur

suddenly, as in a dangerous landslide. Down slope

movements of rock and soil caused by gravity are

knows as “mass wasting”.

Causes of Soil Erosion

- As it moves material from higher elevations to lower elevations

where other eroding agents such as streams and glaciers can then

pick up the material and move it to even lower elevations.

- Mass-movement processes are always occurring continuously on

all slopes; some mass-movement processes act very slowly;

others occur very suddenly, often

with disastrous results such as

landslides.

What can we do to prevent this?

Reforestation

– is the planting of trees to replace those that were burnt or cut.

– trees reduce the amount of flowing water. Roots of trees

absorb water and hold the soil together. Leaves that fall on the

ground holds the soil.

Growing grass/ Planting Vegetables

– grass and vegetables help prevent soil erosion.

Grass: it has thick roots that holds the particles of the soil. If

there is no grass, wind will carry the topsoil away.

What can we do to prevent this?

Contour Plowing and Terracing

Contour Plowing is cultivating along curve lines that go around the hill

at a fixed level. Contour Plowing slows down the runoff of soil water

from the land.

Terraces keep water from the hillside. The water is absorbed and does

not follow directly down hill. It also prevent soil from moving down hill.

Planting trees around farmlands

– farmers plant rows of trees(wind breakers) to surround big

areas of farmland. These trees protect the farm from the

wind that causes soil erosion.

What can we do to prevent this?

Strip Cropping

– is the alternate planting of grasses and crops. It prevents

the top soil from being blown away by the wind or washed

away by rain. Grasses that remain after the crops are

harvested hold the soil together.

QUESTIONS!

NUMBER 1Enumerate 3 causes of Soil Erosion and 4

ways that we can prevent Soil Erosion. (It should come from the ones that we discussed)

– Gravity, Water, Waves, Wind

– Reforestation, Planting vegetables/growing grass, Contour Plowing and Terracing, Planting trees around farmlands, Strip Cropping

NUMBER 2What is Strip Cropping?

– It is the alternate planting of grasses and crops.

NUMBAR 3 Why can Contour Plowing help prevent Soil

Erosion?

– It absorbs water, and it prevents the water from going down hill.

NUMBER 4Define Erosion in your own words.

– It is when the solid particles such as sediments, rocks and other particles in the natural environment are deposited elsewhere.

NUMBER 5 Enumerate 2 causes of Soil Erosion, and

explain why it is a cause. – Wind: It occurs in dry places where soil is

loose and unprotected by vegetation. – Water: Fast moving water can carry small

particles and even rocks, that can strike other particles too.

– Waves: Large waves can pound the shore making it to break more particles.

– Gravity: Mass-wasting – Down slope movements of rock and soil caused by gravity.

NUMBER 6Enumerate 3 ways to prevent Soil Erosion

and explain why it is a way to prevent it.– Reforestation, Contour Plowing,

Terracing, Strip Cropping, Planting vegetables/Growing grass, Planting trees around farmlands.

NUMBER 7 Why is it necessary to plant trees around

one’s farmland? – It protects the farm from the wind that

causes soil erosion.

NUMBER 8 What is the difference between the two

causes of Soil Erosion? Waves and Water. – Waves pound shores with tremendous

force directly while, fast moving water carry big rocks that strike other particles that break down to smaller particles.

NUMBER 9 Why is Gravity a cause of Soil Erosion? – Due to the heaviness of the soil, it can

easily be pulled down by gravity. – Change of climate

NUMBER 10Give 3 ways that a student can do to

prevent Soil Erosion.– Not picking flowers or plants, plant plants

in your garden, promote the importance of preventing soil erosion