Soil erosion in India by Chris Dunstan Soil erosion in India by Chris Dunstan Cynffig Comprehensive SchoolCynffig Comprehensive School

Key idea on WJEC Key idea on WJEC specificationspecification

1.6 Key question : What are the 1.6 Key question : What are the environmental challenges and solutions environmental challenges and solutions facing India?facing India?

The causes and consequences of soil The causes and consequences of soil erosionerosion

What are we learningWhat are we learning?? What are the causes of soil erosion?What are the causes of soil erosion?

Himalaya case study, Terai NepalHimalaya case study, Terai Nepal

What are the effects of soil erosion?What are the effects of soil erosion?

What ways can you manage soil erosion?What ways can you manage soil erosion?

Case study :Management of soil erosion in the Case study :Management of soil erosion in the Rajasthan DesertRajasthan Desert

Soil not oilSoil not oil

What are the Causes of soil erosionWhat are the Causes of soil erosion ? ?

In the forests of Assam and Madhya Pradesh, In the forests of Assam and Madhya Pradesh, shifting cultivationshifting cultivation, is , is

practised by the tribal people in these areas, is a major cause of practised by the tribal people in these areas, is a major cause of

destruction of forests.destruction of forests.

Unregulated grazingUnregulated grazing In the north-western Himalayas, grazing by cattle, In the north-western Himalayas, grazing by cattle, sheep and goats is the most important cause of depletion of the vegetation sheep and goats is the most important cause of depletion of the vegetation cover and soil erosion.cover and soil erosion.

Intensive felling to obtain supplies of fuel or timberIntensive felling to obtain supplies of fuel or timber, and clearance , and clearance

of forests of forests for extension of cultivationfor extension of cultivation under the pressure of demand for under the pressure of demand for

agricultural land from the increasing population.agricultural land from the increasing population.

4. Considerable erosion results from 4. Considerable erosion results from faulty land use faulty land use practices on farmlandspractices on farmlands themselves. Failure to practise themselves. Failure to practise such measures as ploughing along the contours on sloping such measures as ploughing along the contours on sloping lands, proper crop rotations and in particular growing of lands, proper crop rotations and in particular growing of cover crops are causes of erosion.cover crops are causes of erosion.

5 . Deforestation 5 . Deforestation Vegetation acts as a protective cover against the forces Vegetation acts as a protective cover against the forces of wind and water and protecting the soil from being of wind and water and protecting the soil from being washed or blown away.washed or blown away.Forests, provide the most effective protection against Forests, provide the most effective protection against erosion on hill slopes. They break the force of run-off by erosion on hill slopes. They break the force of run-off by impeding the flow of rainwater down the slopes and by impeding the flow of rainwater down the slopes and by absorbing large quantities of it in their dense mat of absorbing large quantities of it in their dense mat of undergrowth.undergrowth.

This absorbed water flows away slowly over a period of time In this way, the hill This absorbed water flows away slowly over a period of time In this way, the hill

slopes are protected from erosion, the flow of streams is regulated, the danger of slopes are protected from erosion, the flow of streams is regulated, the danger of

floods is reduced and sufficient quantities of water are available in dry periods.floods is reduced and sufficient quantities of water are available in dry periods.

When the protective cover of forests is destroyed rainwater flows down the When the protective cover of forests is destroyed rainwater flows down the slopes unimpeded at great speed and carries with it large quantities of soil slopes unimpeded at great speed and carries with it large quantities of soil and other loose material. The hill-slopes are denuded of valuable soil and in and other loose material. The hill-slopes are denuded of valuable soil and in the foot-hill zone where this mass of sands and gravels is deposited are the foot-hill zone where this mass of sands and gravels is deposited are rendered unproductive.rendered unproductive.

Most of the water flows away during the rainy periods with the result that on the Most of the water flows away during the rainy periods with the result that on the

one hand floods are more frequent and more severe and, on the other, little water one hand floods are more frequent and more severe and, on the other, little water

is available during the dry periods. Ground-water, supplies are also reduced as is available during the dry periods. Ground-water, supplies are also reduced as

much less water is absorbed in the soil than before. much less water is absorbed in the soil than before.

Deforested & eroded HillslopesDeforested & eroded Hillslopes

Pupil task: flowchart designPupil task: flowchart design

Produce a flowchart to show the causes of soil Produce a flowchart to show the causes of soil erosion that are associated with DEFORESTATION.erosion that are associated with DEFORESTATION.

You could use some of these key words:You could use some of these key words: FloodsFloods RunoffRunoff Underground vegetation matUnderground vegetation mat Protective coverProtective cover Foot hillFoot hill Ground Water suppliesGround Water supplies

HIMALAYAN Terai, Nepal Soil erosion case studyHIMALAYAN Terai, Nepal Soil erosion case study

90% of the population are rural subsistence farmers. 90% of the population are rural subsistence farmers.

Increases in fuel wood demand, fodder tree cutting and Increases in fuel wood demand, fodder tree cutting and

construction means that Deforestation rates have increased construction means that Deforestation rates have increased

Terrace construction for agriculture on steep marginal land Terrace construction for agriculture on steep marginal land

has led to increases in soil erosion.has led to increases in soil erosion.

Reductions of fuel wood supply lead to increased use Reductions of fuel wood supply lead to increased use

of dung for fuel reducing nutrient status of hill slope of dung for fuel reducing nutrient status of hill slope

soils.soils.

Terrace soils degrade - giving higher erosion ratesTerrace soils degrade - giving higher erosion rates

Changes in river flow regime and high sediment yields Changes in river flow regime and high sediment yields

lead to river bed deposition and increased siltation of lead to river bed deposition and increased siltation of

reservoirs and increased flood stages on the Gangetic reservoirs and increased flood stages on the Gangetic

plain.plain.

What are the Effects of soil erosionWhat are the Effects of soil erosion ? ?

Physical damagePhysical damage is the most visible is the most visible

form of soil loss. Gravity pulls form of soil loss. Gravity pulls

constantly at soil, moving it down hill, constantly at soil, moving it down hill,

causing soil slips, earth clips, cracks, causing soil slips, earth clips, cracks,

creep and slumps.creep and slumps.

Monsoon rainfallMonsoon rainfall is a major source of is a major source of

soil erosion. The results from this soil erosion. The results from this

study estimate current soil erosion study estimate current soil erosion

rates for Kerala to be in the order of rates for Kerala to be in the order of

19-150 tonne/ha/yr which are higher 19-150 tonne/ha/yr which are higher

as compared to non-monsoon rainfall as compared to non-monsoon rainfall

erosion of the UK of 0.23-1.5 tonne/ha erosion of the UK of 0.23-1.5 tonne/ha

from a typical site.from a typical site.

What ways can you manage soil erosionWhat ways can you manage soil erosion ? ?

1.1. Regulation of land useRegulation of land use.—Retiring cultivated lands in highly erodable areas .—Retiring cultivated lands in highly erodable areas

from cultivation and bringing them under forests or grazing ; restrictions from cultivation and bringing them under forests or grazing ; restrictions

on or closure of grazing in badly eroded areas, and settlement of shifting on or closure of grazing in badly eroded areas, and settlement of shifting

cultivators to permanent cultivation.cultivators to permanent cultivation.

2.Afforestation and preservation of forests2.Afforestation and preservation of forests by scientific forest by scientific forest management.management.

3. Improvement of land use practices on farm lands3. Improvement of land use practices on farm lands. This includes . This includes

such measures as ploughing along the contours and strip-cropping such measures as ploughing along the contours and strip-cropping

on sloping lands; proper crop rotations ; application of adequate on sloping lands; proper crop rotations ; application of adequate

manures and fertilizers manures and fertilizers

4. Engineering measures4. Engineering measures.—Under this are included construction of bunds .—Under this are included construction of bunds and terraces, check dams and channels for drainage of surplus water.and terraces, check dams and channels for drainage of surplus water.

Why is it soil conservation important for Why is it soil conservation important for IndiaIndia ? ?

Soil conservation if of Soil conservation if of utmost importance for a utmost importance for a country like country like IndiaIndia which is which is mainly has an mainly has an agricultural agricultural economy. economy.

A large part of India’s A large part of India’s population depends on the population depends on the soil for their livelihood and soil for their livelihood and hence soil erosion and the hence soil erosion and the measures of soil measures of soil conservation taken up to conservation taken up to prevent soil erosion are of prevent soil erosion are of key concern for the Indian key concern for the Indian government. government.

Case study :Management of soil erosion in the Case study :Management of soil erosion in the Rajasthan DesertRajasthan Desert

What is the Issue?= Desert and semi-desert conditions occur in Rajasthan What is the Issue?= Desert and semi-desert conditions occur in Rajasthan

and there has been advance of the desert and encroachment of sand on fertile and there has been advance of the desert and encroachment of sand on fertile

lands due to desertification and soil erosion. lands due to desertification and soil erosion.

There has been a programme of action which includes:There has been a programme of action which includes:

1.Creation of a vegetation belt—five miles wide—1.Creation of a vegetation belt—five miles wide—along the western border of along the western border of

Rajasthan.Rajasthan.

2. Improvement of land-use practices2. Improvement of land-use practices, especially the creation of shelter belts of , especially the creation of shelter belts of

trees by cultivatorstrees by cultivators

3. A Desert Research Station3. A Desert Research Station is being set up at Jodhpur to investigate the is being set up at Jodhpur to investigate the

problems of desertification. Research on soils, land-use and afforestation problems of desertification. Research on soils, land-use and afforestation

practices would be undertaken at this station. practices would be undertaken at this station.

Soil not oilSoil not oil Condemning industrial agriculture and industrial bio fuels as recipes for Condemning industrial agriculture and industrial bio fuels as recipes for

ecological and economic disaster, Shiva’s champion is the small, ecological and economic disaster, Shiva’s champion is the small,

independent farm. independent farm.

What we need most in a time of changing climates and millions hungry, she What we need most in a time of changing climates and millions hungry, she

argues, are sustainable, biologically diverse farms that are more resistant to argues, are sustainable, biologically diverse farms that are more resistant to

disease, drought, and flood. Calling for a return to local economies and disease, drought, and flood. Calling for a return to local economies and

small-scale food production.small-scale food production.

In In Soil Not OilSoil Not Oil, Indian scientist and agricultural activist , Dr Vandana Shiva, connects , Indian scientist and agricultural activist , Dr Vandana Shiva, connects

the food crisis, peak oil prices and climate change to show that a world beyond a the food crisis, peak oil prices and climate change to show that a world beyond a

dependence on fossil fuel and globalization is both possible and necessary.dependence on fossil fuel and globalization is both possible and necessary.

Terai, Nepal: Khet TerracesTerai, Nepal: Khet Terraces

Thank you to the following for allowing use of Thank you to the following for allowing use of the images:the images:

www.grida.no/general/2832.aspxwww.grida.no/general/2832.aspx www.theglaciertrust.typepad.comwww.theglaciertrust.typepad.com www.unu.edu/mountains2002/photoexhibwww.unu.edu/mountains2002/photoexhib

it/descriptions.htmit/descriptions.htm