The document discusses soil erosion, including its definition, causes, effects, and methods to control it. Soil erosion is the loss of topsoil from land by water or wind. It is caused by both natural processes like water flowing downhill and human activities such as overgrazing, deforestation, and overcropping. This accelerated erosion degrades soil quality and reduces crop yields. Control methods center around maintaining ground cover through practices like mulching, cover crops, and crop rotation, as well as using barriers like terraces and contour ploughing to prevent topsoil loss from water runoff. Overall, controlling erosion sustains agricultural productivity and environmental quality.

1. PRESENTED BY:
BIGYAN THAPA
STUDENT OF BPH @ (VCTS)
SITAPAILA, KTM
13/12/201501 Introducing
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Soil Erosion

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3. Contents
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1. Introduction/Definition
2. Types
3. Causes
4. Control measure /Preventive measures
5. References

4. Soil: some definitions
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 Soil can be defined as the organic and inorganic
materials on the surface of the Earth that provides the
medium for plant growth. Soil develops slowly over time
and is composed of many different materials. Inorganic
materials, or those materials that are not living, include
weathered rocks and minerals. Weathering is the
mechanical or chemical process by which rocks are
broken down into smaller pieces. As rocks are broken
down, they mix with organic materials, which are those
materials that originate from living organisms. For
example, plants and animals die and decompose,
releasing nutrients back into the soil.
 http://study.com
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5. Introduction
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 Soil Erosion
Erosion is the loss of soil from land. Wind and water are
constantly eroding soil.
Erosion occurs when soil is transported from one location by
wind and water and moved to a new location, such as lakes and
rivers.
Soil erosion is a natural process that usually occurs slowly
enough that new soil can be made to replace it. Accelerated
erosion is caused by human impact on land use such as over
grazing and poor farming practices. Erosion decreases soil
fertility and this causes a decrease in crop production.
If the soil has eroded, the crops will not grow very well.

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8. Soil Erosion is caused by:
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Natural Process Human Activities
Water flowing downhill Overgrazing
Wind Construction activities
Deforestation
Over cropping

9. Overgrazing
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Overgrazing when large number of animals are
grazed in small area the vegetation is removed faster
than it can re-grow leaving the top soil exposed to
the elements .

10. Over Cropping
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When land is continuously farmed, the nutrients are
drained from the soil which destroys soil structure and
makes it less fertile.

11. Deforestation
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Large areas of forest are cut down leaving bare
landscape. Tree and plant roots prevent soil erosion.
When they are removed the soil dries out due to
constant exposure to the sun and is easily blown or
washed away.

12. Problem caused by soil erosion
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Loss of valuable topsoil
Burying valuable topsoil
Damage of fields
Plant productivity decline
Desertification

13. Control of soil erosion
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 While protecting and improving land investment,
controlling soil erosion will:
 • sustain or improve crop yields
 • reduce drainage costs
 • retain nutrients and chemicals where applied
 • reduce hazards when working on eroding soil, and
 • help improve water quality.

14. For effective erosion control
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• maintain good soil structure
• protect the soil surface by adequate crop and
residue cover, and
• use special structural erosion control practices
where necessary.

15. Method of control
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1. Cover Method
o Mulching
o Cover crops and green manures
o Green manures –also usually legumes
o Mixed cropping and inner cropping
o Early planting
o Crop residues
o Agroforestry

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 Mulching : is the covering of the soil with crop
residues such as straw, maize, stalks ,etc. These
covers protects the soil from the rain drop impact
and reduces the velocity and run off and wind . It is
also useful as an alternative to cover crops in dry
areas where a cover crop should complete for
moisture with the main crop.

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18. 2. Barrier Method
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o Man- made terraces
o Contour ploughing
o Contour barriers
o Natural terraces

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Thank You for your Active
Participants during my
presentation
13/12/2015Env. Health Presentation