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Erosion
is the abrasion, corrosion and
wearing off of layer of soil and
rocks of the Earth’s crust due
to continuous natural physical
and chemical processes. This can
be due to combinations of
external factors like heat,
cold, gases, water, wind,
gravity and plant life. Erosions
generally can be divided into
geological erosion, affecting
rocks and soil and soil erosion.
Soil
Erosion
Naturally,
dissipated and loss of soil will
be balance by formation of new
soil. Places of lush vegetation,
occurrence of rainfall would be
absorbed by the efficient root
systems of these plants or
evaporated by the grass and
leaves, which also acts as
windbreaker, before it can reach
the ground. Besides that, the
roots acts as grip for intact
and strong foundation of the
soil in holding the soil in
place against the action of both
rain and wind.
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Unfortunately,
due to overwhelming development
in logging, agriculture and
mining, contributory factors to
pollution, lush vegetations of
forest are destroyed, thus
speeding the erosion of certain
types of soil. In the mean time,
over population of domesticated
animals like cattles leads to
overgrazing leads to transition
from grassland to desert, couple
with the mismanagement of
cultivation on soil speeding to
infertility of soil.
Geological
Erosion
In
this erosion, weathering, rain,
cold and water acts as the
corrosion agent. Weathering
sparks the start of corrosion of
rock, causing changes to the
surface layers. In dry climates
like savannah and desert,
expansion of the top layer of
rock due to heat of the sun and
cracks from the lower layer will
break at different rates as it
consists of different minerals.
The remaining smaller fragments
will be carried by wind and
piled up as sand dunes at
deserts or washed away by sudden
rainstorm.
Meanwhile
at damp climates, it comes with
the combination of chemical and
mechanical activities. Water
droplets in the atmosphere
reacts with carbon dioxide to
form carbonic acid, ingredient
of acid rain. During rainfall on
earth, acid rain will dissolves
onto the minerals or decompose
it. This nature of erosion is
intensified by high
temperatures.
In
cold climates, frost physically
break up the rock as rainwater
seeps into the cracks and pores
of the rocks combine with sudden
expansion when freezes.
As
it is the same with landslide,
running water provides the
powerful agent of erosion. Upon
draining the topsoil containing
nutrient contents which provides
fertility, stones caried along
will also corrode banks and bed.
Besides that, frozen rivers play
a part in the erosion of valley
by the glacier movements in
removal of the loose material
which it travels over the
surface, leaving the barren rock
surface. Glaciers tend to
actively corrode the solid rock,
which cause severe abrasion,
grinding and scouring the
bedrock which forms the walls
and floors of the mountain
valleys.
Coastal
erosion is due to the action of
waves, storms, tsunamis and
ocean currents. This is
especially severe in cutting
flat platforms of lands, where
corrosion of rocky cliffs can
spark the onset of massive
landslide, leading to loss of a
portion of land.
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