Land degradation, causes, conservation

1. Environmental Studies
&
Disaster Management
Somanath Sarvade
Assistant Professor (Agroforestry)
College of Agriculture Balaghat
E-mail: somanath553@jnkvv.org
Jawaharlal Nehru Krishi Vishva Vidyalaya,
Jabalpur

2. LAND RESOURCES
‘A nation that destroys its soils destroys itself’- Franklin D. Roosevelt
Land as a Resource
• Land area constitutes about 1/5 of the earth surface.
• To meet out the challenging demand of food, fibre and fuel for
human population, fodder for animals and industrial raw material
for agro based industries, efficient management of land resources
will play critical role.
• Soil, water, vegetation and climate are basic natural resources for
agricultural growth and development.

3. Land degradation
It can be defined as any change in the land that reduces its condition or
quality and hence its productivity or productive potential. It occurs whenever
the natural balances in the landscape are changed by human activity, through
misuse or overuse. The major land degradation problems are:
• Wind erosion
• Water erosion including mass movement of hill slopes
• Dry land salinity
• Irrigation-induced salinity
• Soil surface scalding
• Water logging
• Soil acidity
• Soil structure decline
• Soil fertility decline or nutrient loss
• Vegetation decline and degradation, such as weed infestation and
lack of it
• Tree regeneration
• Loss of flora and fauna and hence of biodiversity

4. Type Ministry of agriculture
and co-operation
Sehgal and Abrol NBSS&LUP
1980 1985 1994 1997 2005
Soil
erosion
150.0 141.2 162.4 167.0 119.19
Saline
and
alkaline
soil
8.0 9.4 10.1 11.0 5.95
Water
logging
6.0 8.5 11.6 13.0 14.3
Shifting
cultivatio
n
4.4 4.9 9.0 7.38
Total
degradati
on
168.4 175.1 175.0 187.8 146.82
Trend in land degradation in India (area in million
hectares)

5. Causes for land degradation
Causes for land degradation
Deforestation: Forest soils contain much organic matter. When a forest is
cleared, the trees are burnt, which leads to an immediate loss in organic matter.
Cutting forest for fuel wood is another form of deforestation.
Over grazing: When insufficient amounts of grass litter are left for the soil, the
soil organisms die and the soil loses fertility.
Agriculture: Over irrigating farmland leads to salinization, as the evaporation of
water brings the salts to the surface of the soil on which crops cannot grow.
Over irrigation also creates water logging of the top soil, so that crop roots are
affected and the crop deteriorates. The use of more and more chemical
fertilizers poisons the soil and eventually the land becomes unproductive.
Industrialization: Industries and mining operations can pollute soils.

6. Salinization
It refers to accumulation of soluble salts in
the soil. Concentration of soluble salts
increases due to poor drainage facilities. In
dry land areas, salt concentration
increases where poor drainage is
accompanied by high temperature. High
concentration of salts affects the process
of water absorption hence affects the
productivity.

7. Soil erosion
• Soils support variety of crops.
• Misuse of an ecosystem leads to the loss of valuable
soil through erosion by water/rainfall and wind.
• Soil erosion means soil is washed away into
streams, transported into rivers and finally lost to the
sea.
• It is more severe in hill slopes as in Himalayas and
western ghats called as Ecologically Sensitive Areas
(ESAs).
• Destruction of natural vegetation cover by over
felling and overgrazing is the genesis of soil erosion.
• Water and wind are the principal causes for the
removal of soil from one place to another.

8. Severity of
erosion
Annual soil
loss range
(ton/ha)
The share of
the total
affected
area (%)
Annual loss
of soil
(million tons)
Slight ≤5 24 401
Moderate 5–10 43 1406
High 10–20 24 1610
Very high 20–40 5 640
Severe 40–80 3 666
Very severe ≥80 1 255
Total 4978
Levels of soil erosion of varying severity for India
Source Singh et al. (1990)

9. Causes for soil erosion
• When trees are cut or the soil ploughed,
as the plant roots bind the soil, their
destruction allows the soil to be readily
moved by wind or flowing water.
• Disturbance of the cycles involving
humans and nitrogen. Dependency on
fertilizers rich in nitrogen increases the
nitrogen content of soil and adjacent
water ways. If fertilizers are not used,
soil fertility continues to decline.

10. Factors affecting erosion
There are mainly three factors that will be affecting erosion
Natural factors:
• Heavy rains on weak soil: Rain drops loosen soil particles and
water transports them down hill.
• Vegetation depleted by drought: Rain drops are free to hit the soil,
causing erosion during rainfall. Winds blow away the fine particles
during droughts.
• Steep slopes: Gravity pulls harder: water flows faster, soil creeps,
slips or slumps downhill.
Sudden climate change:
• Rain fall: Erosion increases unexpectedly rapidly as rainstorms
become more severe.
• Drought: Water dries up and the soil becomes a play ball of winds.
A sudden rain causes enormous damage.
• Changing winds: Areas previously sheltered, become exposed.

11. Human-induced factors:
• Change of land: The land loses its cover, then its soil biota, porosity
and moisture.
• Intensive farming: The plough, excessive fertilizer and irrigation
damage the land, often permanently.
• Housing development: Soil is barred; massive earthworks to
landscape the subdivision; soil is on the loose.
• Road construction: Roads are cut; massive earth works, leaving
scars behind. Not enough attention is paid to rainwater flow and
maintenance of road sides.

12. Landslide
• A landslide (or landslip) is
a geological phenomenon
which includes a wide
range of ground
movement, such as rock
falls, deep failure of slopes
and shallow debris flows,
which can occur in
offshore, coastal and
onshore environments.

13. • Although the action of gravity is the primary driving force for a
landslide to occur, there are other contributing factors affecting the
original slope stability.
• Typically, pre-conditional factors build up specific sub-surface
conditions that make the area/slope prone to failure, whereas the
actual landslide often requires a trigger before being released.

14. Causes of landslides
Landslides are caused when the stability of a slope changes from a stable to
an unstable condition. A change in the stability of a slope can be caused by
a number of factors, acting together or alone.
Natural causes of landslides include:
• Groundwater (pore water) pressure acting to de-stabilize the slope
• Loss or absence of vertical vegetative structure, soil nutrients, and
soil structure (e.g. after a wildfire)
• Erosion of the toe of a slope by rivers or ocean waves
• Weakening of a slope through saturation by snowmelt, glaciers
melting, or heavy rains
• Earthquakes adding loads to barely-stable slopes
• Earthquake-caused liquefaction de-stabilizing slopes (see Hope
Slide)
• Volcanic eruptions

15. Man Induced Landslides
• Human race has exploited land
resources for his own comfort by
constructing roads, railway tracks, canals
for irrigation, hydroelectric projects, large
dams and reservoirs and mining in hilly
areas.
• Moreover productive lands under crop
production are decreasing because of
development activities.
• These factors are affecting the stability of
hill slopes and damage the protective
vegetation cover.
• These activities are also responsible to
upset the balance of nature and making
such areas prone to landslides.

16. Human causes include:
• Vibrations from machinery or traffic
• Blasting
• Earthwork which alters the shape of a slope, or which imposes
new loads on an existing slope
• In shallow soils, the removal of deep-rooted vegetation that
binds colluvium to bedrock.
• Construction, agricultural or forestry activities (logging) which
change the amount of water which infiltrates the soil.

17. Water Logging
• Excessive utilization of irrigation may
disturb the water balance which can lead to
water logging due to rise of water table.
• Anaerobic condition due to poor availability
of oxygen in water logged soils may affect
respiration process in plants which will
ultimately affect the productivity of water
logged soil.

18. Desertification
Desertification is a process whereby the
productive potential of arid or semiarid
lands falls by ten percent or more.
Desertification is characterized by de-
vegetation and depletion of groundwater,
salinization and severe soil erosion.
Causes of desertification
• Deforestation
• Overgrazing
• Mining and quarrying

19. Shifting Cultivation
• Shifting cultivation is a practice of
slash and burn agriculture adopted
by tribal communities and is a main
cause for soil degradation
particularly tropical and sub tropical
regions.
• Shifting cultivation which is also
popularly known as ‘Jhum
Cultivation’ has lead to destruction
of forest in hilly areas.
• It is responsible for soil erosion and
other problems related to land
degradation in mountainous areas.

20. CONSERVATION AND EQUITABLE USE OF NATURAL
RESOURCES
Role of an Individual
• Natural resources like forests, water, soil, food, minerals and energy
resources play an important role in the economy and development of a
nation.
• Humans can play important role in conservation of natural resources.
• A little effort by individuals can help to conserve these resources which
are a gift of nature to the mankind.

21. Roles to conserve water
• To minimize the evaporation losses irrigate the crops, the plants and
the lawns in the evening, because water application during day time
will lead to more loss of water due to higher rate of evapo-
transpiration.
• Improve water efficiency by using optimum amount of water in
washing machine, dishwashers and other domestic appliances, etc.
• Install water saving toilets which use less water per flush.
• Check for water leaks in pipes and toilets and repair them promptly.
• Don’t keep water taps running while they are not in use.
• Recycle water of washing of cloths for gardening.
• Installing rainwater harvesting structure to conserve water for future
use.
• Brief description of role of individual to conserve different types of natural
resources is given below:

22. Energy conservation for future use
• Turn off all electric appliances such as lights, fans, televisions,
computers, etc when not in use.
• Clean all the lighting sources regularly because dust on lighting
sources decreases lighting levels up to 20-30%
• Try to harvest energy from natural resources to obtain heat for
example drying the cloths in sun and avoid drying in washing
machine.
• Save liquid petroleum gas (LPG) by using solar cookers for cooking.
• Design the house with provision for sunspace to keep the house
warm and to provide more light.
• Avoid misuse of vehicles for transportation and if possible share car
journey to minimize use of petrol/diesel. For small distances walk
down or just use bicycles.
• Minimize the use air conditioner to save energy

23. Protect soil health
• Use organic manure/compost to maintain soil fertility
• To avoid soil erosion does not irrigate the plants by using
fast flow of water.
• Use drip and sprinkler irrigation to conserve the soil.
• Design landscape of lawn in large area which will help to
bind soil to avoid erosion.
• Provide vegetation cover by growing of ornamental plant,
herbs and trees in your garden.
• Use vegetable waste to prepare compost to use in
kitchen gardening.

24. Promote sustainable agriculture
• Diversify the existing cropping pattern for sustainability of agriculture
• Cultivate need based crop
• Maintain soil fertility
• Make optimum use of fertilizers, pesticides and other chemicals for
production and processing of agriculture products
• Save grains in storage to minimize the losses
• Improve indigenous breeds of milch animals for sustainable dairy
production systems.
• Adopt post harvest technologies for value addition

25. Equitable Use of Resources for Sustainable Life Style
• In last 50 years, the consumption of resource in the society has increased
many folds.
• There is a big gap in the consumers lifestyle between developed and
developing countries.
• Urbanization has changed the life style of middle class population in
developing countries creating more stress on the use of natural resources.
• It has been estimated that More Developed Countries (MDC) of the world
constitute only 22% of world’s population but they use 88% of natural
resources.
• These countries use 73% of energy resources and command 85% of income
and in turn they contribute very big proportion of pollution.
• On the other hand less developed countries (LDCs) have moderate industrial
growth and constitute 78% of world’s population and use only 12% of natural
resources, 27% of energy and have only 15% of global income.

26. • There is a huge gap between rich and poor. In this age of
development the rich have gone richer and the poor is becoming more
poorer.. This has lead to unsustainable growth.
• There is an increasing global concern about the management of
natural resources.
• The solution to this problem is to have more equitable distribution of
resources and income.
• Two major causes of unsustainability are over population in poor
countries and over consumption of resources by rich countries.
• A global consensus has to be reached for balanced distribution of
natural resources.

27. • For equitable use of natural resources more developed
countries/rich people have to lower down their level of
consumption to bare minimum so that these resources can
be shared by poor people to satisfy their needs.
• Time has come to think that it is need of the hour that rich
and poor should make equitable use of resources for
sustainable development of mankind.

28. Thank You