ARUN SIR PRESENTATION AT ANIMATION CENTRE

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S.ARUN KUMAR
(ASISTANT DIRECTOR)

SOIL
 The top layer of earth’s surface that is capable of
sustaining life.
 Is a three dimensional natural body occurring on the
surface of earth that is the medium for plant growth
and whose characteristics have resulted from the
forces of climate and living organisms acting upon
parent material as modified by relief over a period of
time.

It is the deterioration of soil by the
physical movement of soil particles
away from the original site. Water,
wind, moving ice, sea waves and the
use of implements by human beings
etc, are the agents of erosion.(Biotic
& abiotic causes)
SOIL EROSION

INDECATORS
• Mounds of relic soils around plants and
under pebbles.

 IT RESULT IN THE LOSS OF FERTILE TOP SOIL THAT IS
SUPPORTING CULTIVATION
 LOSS OF PLANT NUTRIENTS
 MAKING LAND UNSUITABLE FOR CULTIVATION BY THE
FORMATION OF RAVINES AND GULLIES
 SOIL ENTERING THE WATER COURSE REDUCES WATER
QUALITY,REDUCES THE EFFICIENCY OF DRAINAGE SYSTEMS
AND STORAGE CAPACITY OF LAKES AND RESERVOIRS.
 SOIL IN WATER IS A POLLUTANT AND IN THAT WAY INHIBIT
FISH SPAWNING AND ENTRY OF LIGHT INTO WATER THAT IS
NECESSARY TO SUSTAIN LIFE IN WATER
 THE FERTILIZERS/CHEMICALS IN SOIL MAY AFFECT QUALITY
OF WATER FOR DRINKING.
 CAUSE DAMAGES TO ROADS,RAILS AND WATER TRANSPORT
LOSSES DUE TO EROSION

Others
2.71 m ha
Degraded forests
24.90 m ha
Water logged
3.20 m ha
Salt affected
6.32 m ha
Ravines
2.68 m ha
Wind erosion
10.46 m ha
Water erosion
57.16 m ha
Status of land degradation in India (Total Area: 329 m ha)
Source: MOA, 1994

Rain drops falling on earth surface from a height
dislodge the fine soil particles from the soil mass. This
detached soil particles are carried away in suspension
along with overland flow. The flowing water over the
land surface also can dislodge large number of soil
particles of varying size and ultimately get transported
to streams.

Movement of particles
by various agents
(TRANSPORTATION)
PROCESS OF SOIL EROSION
Loosening & dislodging
of Particles
DETACHMENT
/EROSION
Deposition of the
transported particles
(SEDEMENTATION)

INDESRIMINATE CUTTING DOWN OF TREES
OVER GRAZING OF VEGETATIVE COVER
FOREST FIRES
REMOVAL OF PLANT NUTRIENTS AND ORGANIC
MATTER BY INJUDICIOUS CROPPING PATTERN
CULTIVATION ALONG SLOPES
FAULTY METHODS OF IRRIGATION
GROWING CROPS THAT ACCELERATE EROSION
CAUSES OF SOIL EROSION

TYPES OF EROSION
NATURAL/GEOLOGIC ACCELERATED
 Erosion of soil in its natural
state
 Rate of erosion is low and
generally invisible.
 Soil forming process.
 There is equilibrium between
soil formation and soil loss.
 It happens under biotic and
abiotic pressure.
 Rate of erosion is high and is
visible
 Soil degrading process
 The equilibrium between soil
formation and soil loss is
broken and loss is higher
than formation

DIFFERENT FORMS OF WATER EROSION
Loss of soil due to water movement is called water
erosion. Excess rainfall generating run off causes water
erosion and is increased by the sloping lands.
Rain drop erosion/Splash erosion
Sheet erosion
Rill erosion
Gully erosion
Stream bank erosion
Sea coast/shore erosion
Land slide/land slip
Ravine formation

Rain drop
erosion/Splash
erosion
• It is the first step in the water erosion
process. Splashing/detachment of
soil particles occurring by the impact
of falling raindrops is called splash
erosion. Soil granules are loosened
and beaten into pieces. The falling
drops at a speed of 9 m/sec can
create force of 14 times its weight.
By this action the soil becomes a
flowing mud. It can splash soil
particles to about 60 cm ht and 150
cm away.
• Except in slopping lands it cannot
make impact because soil particles
only to very small distances.

SHEET EROSION • The removal of a more
or less uniform thin
layer or sheet of soil by
running water from
sloping land is called
sheet erosion. The
splashed soil seal the
soil pores and prevent
infiltration and also
cause sheet erosion

RILL EROSION
• It is an advanced form of sheet
erosion which occurs due to
concentration of flowing water. As a
result of water washing down the
slope small finger like rills begin to
develop on land surface. If not
cultivated these rills may increase in
number size and shape.

RAVINE FORMATION
• Ravine is a parallel set of deep and narrow
gullies with abrupt sides. They are formed
from un attended rills. It is usually
associated with river systems.

Causes of ravine formation
• Abrupt changes in elevation between river
bed and adjoining land
• Deep and porous soil strata with high
erodibility
• Poor vegetative cover
• Backflow of water during recession period

STREAM BANK EROSION
• Scouring of soil material from stream
bed and cutting of stream bank by the
force of flowing water. Stream erosion
happens at lower end of water
channels where as gully erosion is
towards upper portion of channels.

SEA COAST/SHORE EROSION
• Tidal waves of the sea and
rough and roaring waves
dash on the coast every time
swallowing bits of land. High
velocity winds may intensify
the hazards of this erosion

LAND SLIDE /LAND SLIP
• It is the downward and outward movement
of soil forming material composed of
natural rocks, artificial fills or combination
of these materials.
• Land slip-Smaller mass moving all on a
sudden.
• Land slide-bigger mass moving slowly
moving through initiating as slips

Causes
• GEOLOGIC-weak geology, lack of
vegetative cover
• HYDROLOGIC-Water seeping and over
saturation
• SEISMIC-Earth quakes

Topography
 Length of slope
 Degree of slope
Slope = Vertical /Horizontal
= tan x

Degree & length of slope
• Steep slope-Velocity increase, depression
storage
• Slope increase four times velocity doubles
and erosive power increase four times
• Quantity 32 times size -64 times
• Length of slope increase also soil erosion
increase

Relative proportion of sand silt and
clay(particle size distribution)-texture
• Clay - < 0.002 mm dia
• Silt - 0.002 - 0.05 mm dia
• Sand - 0.05 - 2 mm dia
• >2 mm- gravel

Effect of texture on erosion
Coarse texture
• More sand
• Light soil
• Less erosion
• Easily detachable but
difficult to transport
Fine texture
• More clay and silt
• Heavy soil
• More erosion
• Silt is easily detachable and
transportable
• Clay not easily dispersed
but low infiltration and
hence more run off and
erosion

Soil structure
• Arrangement/grouping of soil particles
• Granular-more infiltration and less runoff.
• Compact soil-less infiltration and more
runoff

SOIL ORGANIC MATTER
• Plant and animal residues in various stages
of decomposition
• Provide ground cover, sponge,less
evaporation
• Increase permeability & water holding
capacity and reduce erosion
• Life of soil, Improve structure
• Sandy soil-2%
• Clay and silt-3%

SOIL PERMEABILITY
• Ability of soil to allow air and water to
move through soil.
• High permeable-less erosion and less run
off

Agronomic Vs Mechanical
• Slow establishment
• Long life
• Low cost
• Protective
• Remunerative
• Productive
• Self multiplicating
• Soil forming
• Less skills
• Conserve bio diversity
• Eco friendly
• Fast result
• Less life
• High cost

Biologic and agronomic
• Crops or Vegetation
• Agronomic practice
• Required even in areas where mechanical
measures are adopted for uniform infiltration
and moisture distribution

TIMELY SOWING/CANOPY
MANIPULATION
• Maximum erosion when the soil is bare
without any crop cover.
• Establish the crop as early as possible.
Closer spacings.
Maize June 25 July 1 July 7
Canopy(july
30)
48% 20% 15%
Splash
produced
14.5 g 18.4g 20.5g
yield Max Min

CONTOUR FARMING
• Ploughing,seeding,planting,interculture in
contours
• Easy effective and low cost
• Forms ridge and furrows
• Most effective in slopes upto 2- 6% slope
• Consrve moisture,reduce erosion increase
production

Inter Cropping
• Growing two or more crops simultaneously in
the same field following specific row or lne
arrangement.
• Effective land use,resource use.

Inter Cropping
system Yield(q/ha) Inter crop yield
Maize 28.6
Maize+pigeonpea 28.2 6.2
Sorghum 34.4
Sorghum+pegion
pea
33.5 5.5
Sorghum 33.5
Sorghum+greengram 30.8 7.3

Strip cropping
• Alternate rows of erosion permitting and
resisting crop.
• Planted on contour for water erosion control.
• Against prevailing wind direction for wind
erosion control.
• Usually a strip of cereal with pulse is
alternated.

MIXED CROPPING
• Small holding does not permit strip crop
• One main crop and one subsidiary crop
• Provide good land cover
• Different root zones
• Ensure at least one crop in adverse climatic
conditions.

Conservation tillage
• Tillage is the mechanical manipulation of the
soil to create necessary soil conditions
congenial for plant growth.
• Conservation tillage –minimum disturbance to
top soil.
• Zero tillage, minimum tillage, mulch tillage
• 30% of crop residue cover is maintained.

• Conservation tillage is any system that reduces
the number of tillage operations maintains
residue cover on the soil surface, and reduces the
losses of soil and water relative to conventional
tillage. It is a set of innovation technologies
including no-till and various reduced or minimum
tillage systems such as mulch tillage, strip tillage,
and ridge tillage. Reduced or minimum tillage
includes any system in which a soil is disturbed
less than in conventional tillage but more than in
no-till.

No-till and reduced-tillage farming leaves old crop
residue on the ground instead of plowing it into soil.
This covers the soil, keeping it in place.
Here, corn grows up out of a “cover crop.”
Figure 8.16f

Reduces erosion
Saves fuel
Cuts costs
Holds more soil
water
Reduces soil
compaction
Allows several crops
per season
Does not reduce
crop yields
Reduces CO2
release from soil
Can increase
herbicide use for
some crops
Leaves stalks that
can harbor crop
pests and fungal
diseases and
increase pesticide
use
Requires
investment
in expensive
equipment
DisadvantagesAdvantages
Trade-Offs
Conservation Tillage

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Mulching
• Plant residues or other materials over soil
surface.
»ADVANTAGES

Properties of plants to be selected as
barriers
• Erect,stiff uniform,dense permanent hedge
• Perennial
• Not to Spread as weed
• Repel rodents
• Deep penetrating roots
• Sprout new tillers
• Not compete with crop
• Farmer friendly
• Bio mass to be economic value

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MECHANICAL/Enginee
ring measures

Concept
Intercept long slope into shorter ones.
Does not allow to reach critical velocity.
Reduce/alter degree of slope.
Increase the time of
concentration/opportunity time.

LAND LEVELLING/GRADING
• Reshaping the land to a planned grade.
• Uneven- No uniformity in irrigation
waterappliction,fertilizer distribution etc.
• It enhances irrigation water use efficiency
• Low r.f areas reduce run off & max infiltration

LAND LEVELLING/GRADING
• Criteria for land levellig
– Soil (depth,texture,infiltration)
– Topography (slope)
– Cropping pattern(kind of crop,irrigation,returns)
– Rainfall
– Desire of farmers.

Bunding
• It is an embankment of suitable cross section
constructed across the slope to break the
slope length. These are the best for ground
water recharge.
– Contour bunding.
– Graded bunding.

Contour bunding
• Along the approximate contour
• Suitable from 2-6% slope,< 800 mm r.f,and
relatively permeable soils.
• Is adopted where leveling is impossible for
cost

STONE PITCHED CONTOUR BUND
(PUERTORICCAN TYPE CONTOUR
TERRACE WALL)
 Top width including
pitching: 45 to 50 cm
 Thickness of pitching:
15 to 22 cm
 Side slope
 Uphill side of earth
fully: 1.5:1
 Downhill side: 1:5 to
1:3
 Foundation: 15 to 20
cm

Graded bunding
 6-10 % slope
 Or Clay soil
 Or rainfall more than 800mm
 Safely dispose run off
 Drainage channel
Merits & Demerits Page 16 ofyr text

Bench terracing
 Step like fields by half cutting and half filling
 6-33%slope. Or up to 50%
 In lower slopes for uniform water impounding

Suitability
Type Slope Soil type Rain fall,mm
Level 8-50 % Medium to
deep
<2500-3000
Inward sloping 8-50 % Medium to
deep
<2500-3000
Outward
sloping
8-50 % Shallow <1200
Puertorican
type
8-50 % Shallow to
deep
<1500

Puertorican Type Terrace/California type
• Soil is not disturbed for making a terrace in a single
stroke or time
• A hedge of suitable grass is planted in a single or
double row on contour at pre-determined spacing.
• The interspace between the two hedge lines of grass
planted is cultivated and tilled to take crops.
• The tilled soil slowly moves towards the vegetative
hedge and gets deposited against this barrier.
• The process continues for 3 to 4 years till it becomes
level .
• Guatemala (Tripsacum laxum) and Hybrid Napier have
been found effective for this purpose in the Nilgiris.
• This is much cheaper and does not disturb the top soil.

Strip terraces
• With lesser terrace width of 1-1.5 m
• Design
– Maximum depth of cut (D)
– Maximum admissible cut for given slope
– Width of terrace.
1.Terrace spacing
2.Terrace gradient
3.Terrace cross section

NON ARABLE LAND CONSERVATION
MEASURES

Contour trenching
– Break slope length
– Reduce erosive velocity
– Reduce run off
– Retention of water

Check dams
 Functions of check dam
 Reduce the channel gradient
 Reduce velocity of flow and silt carrying capacity
 Percolation & ground water recharge
 Promote vegetation growth in channels.

Components of check dam
Spill way to carry the flow
Anchoring to side and bottom
Apron that absorb impact of falling water

Check dams
 Temporary
 Semi permanent
 Permanent

XS-b-W-IÄ (sN¡v Umw) BRUSH WOOD

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Permanent structures
• Where other inadequate or impractical
• Volume of peak run off is very high
• Sites where frequent maintenance not
possible
• High degree of risk for life/property

Permanent structures, only if
• Help in stabilizing gully and store water
• Adequate to handle Qp
• To be constructed with permanent
material

Wind erosion, also known as
eolian erosion, is a dynamic
process by which soil particles
are detached and displaced by
the erosive forces of the wind.
Wind erosion occurs when
the force of wind exceeds the
threshold level of soil’s resistance
to erosion.

Causes of wind erosion
• crushed or broken soil surface crusts during windy
periods;
• a reduction in the plant cover, biological crusts,
and litter, resulting in bare soil;
• a decrease in the amount of organic matter in
the soil, causing decreased aggregate stability;
• long, unsheltered, smooth soil surfaces
DRY soil conditions-Arids & semi arids

EFFECTS OF WIND EROSION
• REMOVAL OF TOP SOIL
• SCALDING ON SOIL SURFACE
• ROOT EXPOSURE
• SOIL TEXTURAL CHANGES ATTRITION AND
WINNOWING
• EXTENSION OF DESERTS
• HIGH DUST CONCENTRATION IN ATMOSPHERE
CAUSING HEALTH HAZARDS
• DAMAGE TO ROAD, RAIL, BUILDING
• SAND DEPOSITS

Wind erosion control
Shelter belt

149
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1 In.{Kmw IS-emkv nÀ½n-¡m³ þ 900enäÀ
1 In.{Kmw kn´-änIv ss^_À þ 2000 enäÀ
1 In.{Kmw Mutton nÀ½n-¡m³ þ 70000enäÀ
1 I¼q-«À nÀ½n-¡m³ þ 30000 enäÀ
1 S¬ sÃv nÀ½n-¡m³ þ 4000 enäÀ
1 enäÀ Milk nÀ½n-¡m³ þ 900 enäÀ

• The water storage capacity of a particular
region remains the same
• The consumption increases
with increase in population
corresponding to changes in life style

RAIN WATER HARVESTING
• Kerala state is receiving 80-90 % of rain fall in
a period of 5-6 months and for the rest 6-7
months it is under water insecurity. The fun
about Kerala is, 8500 million cubic metre
water is excess in monsoon and 7200 million
cubic metre deficit in summer. This demands
a very meticulous planning for rain water
harvesting in the state

 The land of 44 rivers is only a fallacy as
the total amount of water that all the
rivers contain together is less than
2/3rd of Godavari.
We have no major rivers and only 4
medium and 40 minor rivers. The
largest river is Periyar with a length of
240 km.
Kerala is having only < 2 % area under
irrigation.

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Physiographically it is demarcated as 48%
high land, 42 % mid land and 12% low land.
Due to these features of topography the
water gets very little time to infiltrate into
the soil and the entire rain fall takes very
short time to reach the sea. Due to this
reason only 6-12% rain is recharged in to
the ground in Kerala. With this, the state
has to support a population density of
819/km2.

Rainfall availability
• Reeipt-400 million hectare meter
–69 million surface water
–45 million ground water
–This 114 million is 29%
–The rest 71% goes to the
sea or get evaporated

C´y þ {]XnioÀj Pee`yX
• Stress 1700 m3
• Water scarce 1000 m3
1955 5300 M3
1990 2200 M3
2005 2000 M3
2025 1465
2050 1235

Sl No. District /Assessment Unit
Categorisation for future ground
water development (Safe/ Semi-
Critical/Critical/Over-exploited)
1 Kollengode Critical
2 Nenmara Safe
3 Thrittala Critical
4 Ottapalam Safe
5 Alathur Safe
6 Pattambi Safe
7 Palakkad Critical
8 Attappadi Semi-critical
9 Kuzhalmannam Safe
10 Mannarkkad Safe
11 Chittur Over exploited
12 Sreekrishnapuram Semi-critical

Water harvesting
• Is the collection, storage and conservation of
rainfall for its productive use in irrigation,
domestic and industrial uses.
• Is the technique of collection and storage of
rain water that runs off a natural or manmade
catchment such as watersheds rooftops,
compounds, rocky surfaces or hill slopes

Water harvesting techniques
• 1.In situ - where rain fall is received
• 2.Surface water harvesting
• 3. Roof top

2.Surface water harvesting
Dug outs
Flt areas
Embankment type
Hilly areas

RWHS
• Catchment
• Gutter
• Drain pipes
• First flush
• Filter unit
• Storage tank
• Collection sump and
pump unit

Underground cistern
Just like an underground tank but with more storage
Arid regions for reducing evaporation loss.

Artificial Recharge
Artificial Recharge :
Augmentation of Ground
water reservoir at a rate
exceeding that under natural
condition

ARTIFICIAL RECHARGE BY
SUBSURFACE METHODS
Pond/ tank with shaft
Recharge pit
Recharge trench
Recharge well
Injection well
Sub surface dams

Dug well recharge
 Dried up dug wells/ wells in
which water levels have declined
can be recharged
 Source of recharge can be rain
water from storm/tank/canal/
Roof top
 Recharge water should be passed
through desilting chamber, after
desilting the recharge water is
taken to bottom of well/ below
the water level.
 Periodic chlorination.

Recharge shaft/ Injectionwells
 Efficient and cost
effective structures
 Back filled with
inverted filter
 Suited for deep water
levels (upto 15m)
 Silt water can be used

HOW much water do I use ???
Use Litres/person
Drinking 3
Cooking 4
Bathing 20
Flushing 40
Washing-clothes 25
Washing Utensils 20
Gardening 23
Total 135
Consumption range 50 Ltrs/300 ltrs per person per day

A dripping tap could waste as much as 90 litres a week.
Brushing your teeth with the tap running wastes almost 9 litres a minute.
Rinse out from a tumbler instead.
Cool water kept in the fridge means you won't have to run the tap for ages to
get a cold drink.
Don't use your washing machine until you've got a full load. The average
wash needs about 95 liters. A full load uses less water than 2 half loads.
Every time you boil an egg save the cooled water for your houseplants.
They'll benefit from the nutrients released from the shell.
Fit a water saving device in your cistern and save up to three litres a flush.
Grow your grass a little longer. It will stay greener than a close mown lawn
and need less watering

And human dwelling conditions could not get worse

ARUN SIR PRESENTATION AT ANIMATION CENTRE

ARUN SIR PRESENTATION AT ANIMATION CENTRE

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ARUN SIR PRESENTATION AT ANIMATION CENTRE