CAUSES AND CONSEQUENCES OF SOIL DEGRADATION

2. INTRODUCTION :
Past and present human intervention in the utilization and manipulation of
environmental resources are having unexpected consequences such as soil
degradation.
Soil degradation is the decline in soil quality caused by its improper use usually
for agricultural postural, industrial, or urban purposes.
UNITED NATIONS ENVIRONMENTAL PROGRAMME,1993
defined it as a process that leads to decline in a fertility
or future productive capacity of soil as a result of human
activity.
HISTORICAL PROSPECTIVE:
Unep’s project GLASOD was implemented and
coordinated by ISRIC. Later world map of the status of
human induced soil degradation was published on 1990
oldeman. In 1992, world resource institute reported that
3 billion acres land world wide had been seriously degrade
since world war II.

3. SOIL DEGRADATION
NATURALHUMAN -INDUCED
URBAN LAND
• Pollution
• Compaction
• Erosion
INDUSTRIAL LAND
• Soil Compaction
• Soil Contamination
• Acid Rain
AGRICULTURAL
LAND
PHYSICAL
• Pan formation
• Hard-setting
CHEMICAL
• Leterization
• Calcification
• Leaching/
Illuviation
BIOLOGICAL
• Decline in
soil diversity
PHYSICAL
• Compaction
• Crusting
• Water imbalance
• Impeded erosion
• Runoff
CHEMICAL
• Acidification
• Nutrient depletion
• Leaching
• Nutrient imbalance
• Salanization/alkanization
BIOLOGICAL
• Decline in soil organic C
• Soil biodiversity reduced
• Decrease in biomass C
Principal Types Of Soil Degradation: (I) Natural (II)human-induced

4. Soil Degradation Is A Serious Global Problem And May Be Caused By Physical Chemical Biological Geological
Anthropogenic Causes.
1 . DEGRADATION BY WATER :
Soil degradation is caused by water erosion where water
particles are detached by the effect of running water. It includes –
A. Rill Erosion – This Occurs Where Water Runs In Very Small
Channels Over The Soil Surface.
B. Sheet Erosion – This Means When An Uniform Soil Is
Removed Over An Entire Surface Area. This Helps In Causing Soil
Degradation.
C . Gully Erosion – This occurs when rills flow together to make larger streams. they tend to
become deeper with successive flow of water and can become major obstacles to cultivation.

5. D. Bank Erosion- This is caused by water cutting into the banks of streams and
rivers. Example - Ajay river
2. SPLASH EROSION :
The soil erosional caused by
water droplets from precipitation -
is called splash erosion. This type of
erosion deteriorates the soil quality
and quantity and finally degrades the
soil.
It is a serious issue in
country like united kingdom where
44% of the arable land is at some
short of risk by rainfall. These are
of two types -
3. DEGRADATION BY WIND :
This leads to decrease fertility as the soil particles are get picked up in the
wind and taken away by the wind. It can have very serious impact on how the soil
can be utilised.
 Example - 1970s DUST BOWL crisis in central united states.

6. 4. SOIL EROSION :
Soil degradation is to some intend related with soil erosion. The
universal soil loss equation A = RKLSCP is an attempt to predict the amount of
erosion that will take place in an area on the basis of certain factors which increase
susceptibility to erosion –
• A = the predicted soil loss
• R = climatic erosivity /
rainfall erosivity index
• K = soil erodibility
5. WASTE LAND :
These are the lands which are economically unproductive ,ecologically
unsuitable and subject to soil degradation. Waste lands are of two types -
WASTE LAND
CULTURABLE
These include waterlogged land
marsh and saline land, mining and
industrial wasteland.
Example- Raniganj mine area.
UNCULTURABLE LAND
This includes barren rocky
areas , steep slope, snow
capped areas
• L = slope length
• S = slope gradient
• C = cover and management
• P = erosion control practice

7. 6. LAND SLIDE :
The sudden movement of the soil and the
weathered rock material down the slope due to the
gravity is called landslide. this is caused by deforestation
in hilly areas, excessive mining in hilly areas, etc.
7. CAPILLARY ACTION :
Salt from the lower layer move up by capillary action during summer
season and are deposited on the surface of the soil. Thus the quality of the soil
decreases and causing the degradation of the soil.
The other physical causes are deterioration of soil structure ,pan formation
,soil use, hard setting etc.

8. 1. CHEMICAL WEATHERING :
Chemical weathering may cause change in mineralogical properties of
soil like feric (Fe+++) convert into ferrous (Fe++) and manganic (Mn+++) convert
into manganous. The sudden change in the quality degrades the soil.
e.g. In lime stone region carbonation process degrades the soil.
2. SALINIZATION :
Salinization is the accumulations of salts on or near the earth
surface which results completely unproductive soils and ultimately caused
by irrigation method and evaporation of saline ground water etc. (European
commission ,2000).
e.g. In arid and semi arid region this is very common.
3. ACIDIFICATION :
This soils are form due to excessive leaching of cations with high rainfall, resulting in lowering of pH and loss of
soil fertility
e.g. - acid soil develops in humid and per humid areas like Assam, Bihar etc.

9. 1. DEFORESTATION :
Over cutting of vegetation may accelerate the soil erosion process,
especially during rainy season.
2. INDUSTRIALIZATION :
Development of the industries for the economic growth of the country lead
to excessive deforestation and utilization of such in soil as way that has lost its natural
up gradation quality.
4. URBANIZATION :
Urban growth, road construction are major causes in soil degradation. For this valuable
agricultural land is often lost .
3. IMPROPER CROP ROTATION :
Due to shortage of land, increase of population ,and economic pressure ,the
farmers have adopted intensive cropping pattern of commercial crops in place of more
balanced cereal-legume rotations. During last two decade the area under food crops
decreased and that under non food crops increased. Intensive cultivation leads to removal
of large quantities of nutrients from the soil which results to the soil infertility.

10. 5. OVER GRAZING :
In India pasture land is
decreasing day by day due to
expansion of agricultural land.
Recent satellite data show
that the area under pasture
land is severely degraded due
to excessive grazing.
The unchecked and
indiscriminate grazing on
forest land also leads to
degradation of forest soils.
Over grazing directly leads to
disappearance of vegetation
which is one of the important
causes of wind and water
erosion in dry lands.
6. MINING :
Mining disturbs the
physical, chemical and
biological features of the
soil, the impact of mining on
soil depends on the physical,
chemical properties of the
waste generated.
The soil profile is
changed, the top soil is
turned deep inside the
terms. The erodible material
is almost devoid of organic
matter and lacks in mineral
plant nutrient.
7. IMPROPER USE OF
FERTILIZER :
Soil fertility is reduced due
to prolonged intensive cultivation,
the farmers maintain
productivity of soil by applying
chemical fertilizer but make less
use of organic manures.
All though the yield can be
maintained by using fertilizers
that provide deficient minerals
yet there use often results in
deficiencies of other nutrients.

11. 8. OVER POPULATION :
Day by day the population density is increasing so the amount of man land
ratio is decreasing respectively and huge pressure create on land.
On the other hand due to huge demand of vegetables more agricultural
work is mandatory. these point also create pressure on land. as a result soil
degradation occurs.

12.  BIOLOGICAL CAUSES :
Biological as well as organic matter serve as a reservoir of chemical elements that are essential
for plant growth. Biological causes include floral faunal and microbial activities.
 Loss Of Soil Micro Organism - Soil organism is important factors of soil degradation. Difference
type of micro organism like bacteria , fungus , algae and protozoa etc. plays an important role in the physical
and chemical properties .As a result different changes come in soil properties. This type of changes can able
to degrade the soil in an area.
 Microbial Activities – Decomposition of organic matter produces carbonic acids(H2Co3),the
solvent action of carbonic acid on the mineral constituents of the soil is responsible for the removal of large
quantities of base forming cations (e.g. Ca++ and mg ++) by dissolution and leaching.

13. Soil degradation can be either a result of natural hazards or
due to unsuitable land use and inappropriate land management
practices. It can be categorised in two group -
CONSEQUENCES OF
SOIL DEGRADATION
Direct Indirect
• Soil Infertility
• Low Productivity
• Loss Of Arable
Land
• Natural Disaster
• Deterioration Of
Water Quality
• Impact On
Biodiversity
• Increased
Flooding
• Pollution And
Clogging Of
Waterways
• Drought &
Aridity
• Salinization
• Acidification

14. 1. LAND DEGRADATION :
Soil quality decline is one of the main causes of land degradation and it
considered to be responsible for 84% of the every diminishing acres (FAO, 2011).
70% of agricultural land suited for raising livestock or crops is already degraded in
Africa (FAO, 2011). About 40% of the world’s agricultural land is severely diminished
in quality because of erosion and the improper use of chemical fertilizers.
Soil degradation directly affects 1.5 billion people globally (Pugsley, 2013).
2. SOIL INFERTILITY :
Due to the continuous carry-out of the top soil, the amount of nutrient among it started to decline. It is observed
that the amount of loss of fertility through erosion is 20 times greater than the consumption of crops globally.
3. DEGRADATION OF WATER QUALITY :
The increase in the turbidity of water and the contribution of nitrogen and
of phosphorus can result in eutrophication which degraded the quality of water for
agricultural and livestock purpose .
4. IMPACT ON BIODIVERSITY :
Soil degradation may involve perturbation of microbial communities,
disappearance of the climax vegetation and decrease in animal habitat, thus
leading to a biodiversity loss and animal extinction. And it is estimated that
27,000 species lost each year due to land and soil degradation.

15. 5. NATURAL DISASTER :
Natural disasters such as mud flows, floods are responsible for the death of
many living beings each year.
6. DROUGHT AND ARIDITY :
Drought and aridity are results highly influenced and amplified by soil
degradation. It is concerned with natural environments in arid and semi-arid areas.
According to the UNO drought and aridity are - anthropogenic induced factors
especially as an outcome of soil degradation. It can be occurred by overgrazing, poor
tillage methods.
7. POLLUTION AND CLOGGING OF WATERWAYS :
Most of the soil eroded from the land together with the chemical
fertilizers and pesticides utilized in agricultural fields are discharged into
waterways and streams. With time, the sedimentation process can clog waterways
which ultimately create scarcity and damage marine and freshwater ecosystems.
8. DEFORESTATION :
According to the FAO,
deforestation occurred by the soil
degradation in 2014 of various countries
can be shown by the following diagram -

16. 9. SOIL ACIDIFICATION :
Lowering of the soil pH caused by the build up of H+ & Al3+ ions in the
soil and the leaching of base cations. i.e. Ca2+, Mg2+, K+, Na+ etc.. Top soil & sub
soil acidity (pH < 5.5) affect around 30 % & 75% respectively of the total ice free
land area of the world.
Top soil & sub soil acidity (pH < 5.5) affect around 30 % & 75% respectively
of the total ice free land area of the world
10. SOIL SALINIZATION :
Is defined as a change in the salinity status of the soil. It can
be caused by improper management of irrigation schemes , mainly in the
arid and semi arid regions covering small area. Finally salinization takes
place where human activities lead to an increased evapotranspiration in
soils on salt containing parent material or with saline ground waters.
11. INCREASING FLOOD :
The destruction of the forest in the river catchment is
caused of rapid erosion which lead to the amount of deposit of
mass debris on the river bed – which reduce the water holding
capacity of the stream and ultimately flood occurs.

17.  INDIRECT CONSEQUENCES
3. TRANSPORTATION :
Roads and railway lines are eroded by flood water that creating hindrance in
transportation.
2. THE RISK OF FAMINE :
Due to the infertility , soil erosion , shortage of land ,production of food continuously decline and
on the other hand the world population increase rapidly , which may create risk of famine
1. ECONOMIC LOSS :
The estimated costs for land degradation are US $40 billion per year (FAO, 2011). It occurred
due to the increased use of fertilizers, loss of biodiversity and loss of unique landscapes.

18.  Some of the used methods across the world, to conserve the soil & to take optimum benefits
1. Afforestation :
The planting of trees on a large scale – is known as afforestation. It reduce wind speed and free flow of
water to carry out the soil and reduce the soil degradation.
2. Mulching:
The bare ground between plants is covered with organic matter. I.E. Straw – which helps to retain the soil
moisture.
3.Contour Barriers :
Stones, grass, soil are used to build barriers along contours. The trenches are made in front of the barriers
to collect water.
4. Rock Dam :
Rocks are piled up to slowdown the flow of water. This prevents rills and gully development and further soil
erosion.
5. Terrace Farming :
This is a process in which hill slopes are used as cultivable land. The farmers cut terraces in slopes to create
flat areas for cultivation.
6. Crop Rotation :
This is a cropping practice in which different crops are grown in systematic succession. It helps to add
nutrient to the soil & reduce the pests.

19. 7. Contour Ploughs :
This is a cropping method in which the farmer ploughs the land along a slope rather than up & down the
slope which prevent the soil degradation.
8. Shelter Belts :
In the costal and dry regions, rows of trees are planted to check the wind movement to protect the soil
cover.
People can be a major asset in receiving a trend towards degradation. However, then it to be healthy, politically and
economically motivated to care for the land, as subsistence agriculture, poverty and illiteracy can lead important
causes of laws and policies aimed directly at preventing soil degradation.