SOILS OF
SRI
LANKA
ALLUVIAL SOIL
Major characteristics of Alluvial Soils
are:1)These are of Transported origin.
2)Alluvial soil as a whole is very fertile.
3)According to their age, these soils have been classified
into 2 types:~Old Alluvium or Bhangar Soil
~New Alluvium or Khaddar Soil
4)These soils contain adequate proportion of Potash, Lime
and Phosphoric acid.
5) Silk, clay, gravel and sand the main constituents of
alluvial soil.
6)They are ideal for the growth of crops like sugarcane,
pawatta,corn,rice,etc
7)It is commonly found in riverbed and flood plains.
By-Ananya Smirti
REDDISH BROWN LATOSOL
SOIL
Reddish brown latosol soils are the next
prominent soil group found in the wet zone of
Sri Lanka. Most of these soils occur on terrains
that have been incised by ecological erosion.
These soils are relatively young. The texture is
mostly sandy clay loam and the structure is
strong crumb to granular under natural
vegetation. These soils are normally deep, soil
reaction is slightly acidic and the cation
exchange capacity may vary from 4-15 c mol kg1 in surface soils.
Characteristics:
1 .)
2 .)
3 .)
4 .)
5 .)
6 .)
7 .)
8 .)
9 .)
Organic matter content is low
Narrow coastal regions of Sri Lanka & in slopes of
mountains
Cation exchange capacity is high
Nitrogen & phosphoros content is low and so
fertilizers are to be given many times in small
quantities.
Calcium & magnesium are present in good
quantities.
It is neutral in nature.
It has underground water layer capacity
Because of rich water drainage capacity
,irrigation is a problem.
Coconut & cashew are mainly grown.
The yellow color in the map shows regosol soil
By Krittika , Ankita, Antara , Mohona & Dolly
1. Physical Characteristics of Red-Yellow Podzolic
soils:
The physical properties of Red Yellow Podzolic are
favourable for wide-ranging agricultural purposes.
The fertility of wet zone soils is poor because
these soils have been extensively leached due to
high rainfall. The CEC values of most of the soils
are low. Therefore, special fertilizer management
practices on these soils are required. The base
saturation of the dry zone soils remains at a
higher range.
2. Area of Red-Yellow Podzolic soils in
Srilanka
1525906 hactors.
3. Crops Grown:
Rice.
PPT BY: TRIPARNA, EKTA, DEBARATI
LATOSOL SOIL
Latosol is a name given
to soils found under
tropical rainforest s
with a relatively high
content of iron and
aluminium oxides.
Crops grown:Potato, onion, tobacco
GRUMOSOL SOIL
Characteristics:-
 Horizon A of grumusol soil is black in colour
 Contains enough amount ofCalcium and
Magnesium
 Cation exchange is about 65-90
 Water drainage is ill due to high clay content
 It is very difficult to use for cultivations because
soil stick in wet condition and hardens under dry
condition
 Too hard to machinaries
Distribution Seen in :•
•
•
•
Southern parts of Jaffna district
Thunukaya area
Murukan area
Mannar district
Cultivating crops:Suitable for paddy cultivation
Vegetables and cereals can be cultivated by
means of irrgation.
BOG AND HALF BOG SOILS
THE COLOUR OF THESE SOILS RANGE FROM ASH BROWN TO
BLACK. BOG
AND HALF BOG SOIL HAVE A VERY HIGH CATION EXCHANGE
CAPACITY THAT IS 100-200 .IT CONTAINS HIGHEST AMOUNT OF
ORGANIC MATERIALS DRAINAGE IS POOR. SOIL IS BEINGCOVERED
BY WATER. ACIDITY IS HIGH ,ie: PH VALUE IS BETWEEN 4.0-5.0.
H2S(HYDROGEN SULPHIDE) CAN BE POISONOUS AS SOIL IS BEING
UNDER FLOOD. IT IS FOUND IN THE VALLEYS OF WET ZONE,NEAR
RIVER BASINS AND COLOMBO,KALUTHARA,GALLE AND MATHARA
.GREENS CAN BE CULTIVATED ON A RAISED BEDS IN BOG AND
HALF BOG SOIL.CULTIVATION OF VEGETABLES ALSO CAN BE
FORMED IF DRAINAGE IS POSSIBLE. UNDER FLOOD CULTIVATION
SEDGES CAN BE CULTIVATED.
IMMATURE BROWN LAOMY
SOIL
Characteristics:Immature brown loamy soil is a juvenile soil; in
the soil profile thickness of the first horizon is about
15cm -25cm colour is varied from dark brown to dark
ash brown special feature of the soil is that flake
graphite has spread out all over the soil profile. The
thickness of second horizon is about 60cm. Third
horizon contain flake graphite. This soil contain low
amount of organic material and nitrogen. It is slightly
acidic soil. Cation exchange capacity is 10 to 20 and
base saturation is in between 50 to 70. Immature
brown loamy soil is found in districts of wet zone
such as Kegalle,Kandy,Kurungala and on the slope of
hills in the dry zone. Immature brown loamy soil is
found in districts of wet zone such as
Kegalle,Kandy,Kurungala and on the slope of hills in
the dry zone. Plants with short root system such as
grass, vegetables and yam can be cultivated because
depth of soils is less. Tea, Rubber, Coconut, Pepper
and areca nut are suitable if soil is deep.
LATOSOLIC SOIL OF SRILANKA
Characteristics- The colour of its subsoil is red
or yellow brown.It contains less amount of organic
materials,nitrogen,phosphorous,pottasium &
magnesium.it is slightly acidic.It is highly erosive
in nature &retension of moisture is low.
Area- It stretches from north to Puttalain
through Mannai by one side and again from
middle of north to Mullative by other side.
Crops grown-Plants like
chilly,onion,peanut,tobacco cashew,orange can
be cultivated here.
Reddish Brown Earth
Soil
CROPS GROWN
Crops such as paddy, maize, green gram,
cowpea, chilli, vegetables, onions, tea, rubber
and coconut can be cultivated on reddish brown
earth soil.
CHARACTERISTICS
These soils are reddish to reddish brown in
colour and found in the upper and mid slopes of
the landscape in the dry zone. The normal depth
is about 1.0-1.2 m. and the water holding
capacity ranges from 100-140 mm/meter depth
of soil. The steady infiltration rate ranges from
1-5 cm/hr. The percolation rates of the wet
puddled soils for the first time exceeds 100
mm/d and remains at a higher value of 10-20
mm/d even after 6 years of continuous
puddling.
AREA
Area of reddish brown soil in Sri Lanka are –
vanuiya,
trincomalee,
anuradhapuraya,
polonnaruwa,
ampara,
monaragala,
hambantota.
REDDISH BROWN LATOSOLIC SOIL
• Thickness of the horizon A of Reddish brown latooolic soil is about 30
meters. It is very thin in cultivated fields.
• This soil has moderate fine texture. Organic materials and nitrogen are
little bit of low.
• It contains potassium, calcium and magnesium moderately. Phosphorus
content is less.
• Better cation exchange capacity. It is 12-20.
• Depth, texture and water drainage maintain is at a better level.
• Base saturation is 20-30.
• Soil is slightly acidic.
• The soil has distributed in districts such as Kandy, Mathale,
Kurunagala, Nuwara-Eliya and Kegalle.
• Tea, rubber, cocoa, pepper, coffee, clove, cardamom, fruits and
vegetables can be cultivated successfully in the reddish brown latosolic
soil.
CALCAREOUS SEDIMENTS OF SRILANKA
Calcareous mine
The term calcareous can be applied to a sediment,
sedimentary rock, or soil type which is formed from, or
contains a high proportion of, calcium carbonate in the form
of calcite or aragonite.
Marine sediments
Calcareous sediments are usually depositedshallow water
near land, since the carbonate is precipitated by marine
organisms that need land-derived nutrients. Genera
lly speaking, the farther from land sediments fall, the less
calcareous they are. Some areas can have interbedded
calcareous sediments due to storms, or changes in ocean
currents.
Calcareous ooze is a form of calcium carbonate derived from
planktonic organisms that accumulates on the sea floor. This
can only occur if the ocean is shallower than the carbonate
compensation depth (CCD). Below this depth, calcium
carbonate begins to dissolve in the ocean, and only noncalcareous sediments are stable, such as siliceous ooze or red
clay.
Calcareous soils
Calcareous soils are relatively alkaline, in other words they
have a high pH. This is because of the very weak acidity of
carbonic acid. Note that this is not the only reason for a high
soil pH. They are characterized by the presence of calcium
carbonate in the parent material and may have a Calcic
horizon, a layer of secondary accumulation of carbonates
(usually Ca or Mg) in excess of 15% calcium carbonate
equivalent and at least 5% more carbonate than an underlying
layer.[2]
DESERT SOIL
Characteristics
Contains soluble salts.
90% sand & 5% clay.
Rich in Nitrates & Phosphates.
Friable, sandy & low moist content.
Areas
Arid & semi arid regoins of
Rajasthan, Haryana, Punjab &
Gujarat.
Crops grown
Barley
Millet
NON-CALCIC BROWN SOIL IN SRI LANKA
Characteristics:
Color range from dark brown to ash brown.
Mostly Non-calcic brown soil contains sand.
Horizon B has more than 40% of base
saturation and a high amount of clay than
horizon A. This soil can be found in dry zone.
Nitrogen in the top layer of this soil is
decomposed. This is a slightly acidic soil and
has much of Calcium and Magnesium. Cation
exchange capacity is 5-11. Structure is
breakable.
Distribution:
Non-calcic brown soil is distributed in
Ampara, Baticalloa, some areas of Galoya
Valley and area in around Mahawa in Sri Lanka.
Cultivating crops:
Crops like Cereals, green gram, Cowpea,
Peanut, Sugar canes, Chilli, vegetables and
onions can be cultivated in non-calcic brown
soil by applying correct conservation
techniques and better irrigation.
Solodized Solonetz soil
Median values of pH, conductivity, organic and
inorganic carbon, and mechanical analyses are
reported for nine solodized solonetz soils and
eight solonetz-like soils. A regional Dark Brown
prismatic profile is included for comparison.
These data show that for solodized solonetz soils
the A horizons are moderately acid, with the
A2 and A3horizons showing the greatest acidity.
The B1 is neutral, and the lower B and C
horizons are alkaline in reaction. The solonetzlike profiles show a similar trend, but pH values
are higher in the A horizons. Conductivity rises
progressively from the A1 horizon downward in
the solodized solonetz group, whereas in the
solonetz-like group the conductivity remains
very low throughout.