Types of
soil erosion: Splash erosion,
Sheet erosion, Rill erosion, and Gully erosion
Splash erosion
Splash erosion is the first stage of the erosion process. It
occurs when raindrops hit bare soil.
The explosive impact breaks up soil aggregates so that individual
soil particles are ‘splashed’ onto the soil surface.
The splashed particles can rise as high 60cm above the ground and
move up to 1.5 metres from the point of impact
Sheet Erosion
Sheet erosion is the removal of soil in thin layers by raindrop
impact and shallow surface flow.
It occurs fairly evenly over an area.
It is so subtle
that it might not even be noticed until much of the valuable, nutrient-rich
topsoil has already been washed away.
If an accumulation
of soil and crop residue at one end of field it may be sheet erosion.
Soils most vulnerable to sheet erosion are overgrazed and cultivated
soils where there is little vegetation to protect and hold the soil.
Rill Erosion
Rill erosion is
erosion that results in small, short-lived and well-defined streams.
Rills are shallow drainage lines less than 30cm deep.
They develop when surface water concentrates in depressions or low
points through paddocks and erodes the soil
When rainfall does
not soak into the soil, it can gather on the surface and runs downhill, forming
small channels of water called rills.
Rill erosion is often described as the intermediate stage between
sheet erosion and gully erosion
The rills can usually be
removed with farm machinery.
Gully Erosion
Gully erosion can
be thought of as advanced rill erosion. In fact, if rills are not addressed,
they will grow into larger gullies.
Gullies are channels deeper than 30cm that cannot be removed by
normal cultivation.
Gully erosion over time actually lose less soil than sheet and
rill erosion
Gully erosion can spell big problems for
farmers because the affected land is not able to be used for growing crops, and
the big ditches create a hazard for the farmer driving his farm machinery over
the fields.
FACTS AND DEFINITIONS
The word erosion is derived from the Latin rodere meaning
to ‘gnaw’
Erosion is a natural process but is
often intensified by human land use practices.
Soil erosion is defined
as the wearing away of topsoil. Topsoil is the top layer of soil and is the
most fertile because it contains the most organic, nutrient-rich materials.
The impact of the raindrops loosens the material bonding it
together, allowing small fragments to detach. If the rainfall continues, water
gathers on the ground, causing water flow on the land surface, known as surface water runoff
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