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Technical report on the characterization of the
agro-ecological context in which Farm Animal
Genetic Resources (FAnGR) are found:
Sri Lanka
A report submitted to the FAnGR Asia Project - June 2004
B.V.R. Punyawardena
Ph.D, M.Phil, B.Sc(Agric.) Hons.
TABLE OF CONTENTS
Table of contents
i
List of tables
iii
List of maps
iv
List of figures
v
Executive summary
vi
Introduction
1
Location
1
Geology
1
Climate
2
Major soil types of Sri Lanka
4
Flora and Fauna
8
Forest resources
8
Present situation
8
Current trends in the forestry sector
11
Water resources
15
Surface water
16
Ground water
21
Pastoral resources
22
Land use and land degradation
25
Socio-economic conditions
29
Livestock industry in Sri Lanka
32
Agro-ecology
39
Livestock production systems and AERs
42
Ruminant production systems (Siriwardena, 1999)
43
i
Mid & Up country intensive system
43
Wet & Intermediate zone semi intensive system
44
Dry & Intermediate zone extensive system
44
Dry zone intensive system
45
Non-ruminant production systems
45
Poultry
45
Pigs
46
Bio-physical and agro-ecological characteristics of target sites
46
Hambantota and Lunugamwehera target sites.
48
Potential and limitations Reddish Brown Earths (Rhodustalf)
54
Potential and limitations Low Humic Gley soils (Tropaqualf)
55
Siyambalanduwa target site
55
Panama and Pottuvil target sites.
59
Potential and limitations of Regosols and Alluvial soils
66
Thirappane and Galenbindunuwewa target sites.
66
References
74
ii
LIST OF TABLES
Table 1
Important great soil groups of Sri Lanka with equivalent great soil groups
of Soil Taxonomy (USDA, 1975)
7
Table 2
Taxic diversity of plants in Sri Lanka
10
Table 3
Forest extent by type
10
Table 4
Natural forest area by districts (ha) – 1994
14
Table 5
Designated forest areas in Sri Lanka (as at 1999)
15
Table 6
Surface water resources of Sri Lanka
19
Table 7
Present status of small tanks in the drier region of Sri Lanka
20
Table 8
Extent of land under pasture and estimated yield of pasture
24
Table 9
Land use in Sri Lanka (as shown in the land use map of 1988)
27
Table 10
Arable land, their uses and other land use types in Sri Lanka
28
Table 11
Selected target sites and their respective administrative units & AERs
46
Table 12
Average climatic conditions of the DL5 agro-ecological region of
Sri Lanka
51
Table 13
Hydrological characteristics of major rivers in target sites
53
Table 14
Tanks found in the Hambantota DS division
53
Table 15
Tanks found in the Lunugamwehera DS division
54
Table 16
Average climatic conditions of the DL1b agro-ecological region of
Sri Lanka – Angunakolapellessa
Table 17
58
Average climatic conditions of the DL2 agro-ecological region of
Sri Lanka
62
Table 18
Tanks found in the Pottuvil DS division
65
Table 19
Average climatic conditions of the DL1b agro-ecological region of
Sri Lanka - Maha-Illuppallama
70
Table 20
Tanks found in the Thirappane DS division
72
Table 21
Tanks found in the Galenbindunuwewa DS division
73
iii
LIST OF MAPS
Map 1
Climatic zones of Sri Lanka
3
Map 2
Agro-climatic zones of Sri Lanka
5
Map 3
Generalized soil map of Sri Lanka
6
Map 4
Protected areas under the Department of Wildlife Conservation and Forest
Department
12
Map 5
River basin map of Sri Lanka
17
Map 6
Surface water potential of Sri Lanka
18
Map 7
Generalized landuse map of Sri Lanka
26
Map 8
Land degradation map of Sri Lanka
30
Map 9
Vulnerability to food insecurity in Sri Lanka
33
Map 10
Spatial distribution of cattle in Sri Lanka (as on 2001)
34
Map 11
Spatial distribution of Buffaloes Sri Lanka (as on 2001)
35
Map 12
Spatial distribution of Goat in Sri Lanka (as on 2001)
36
Map 13
Spatial distribution of Pigs in Sri Lanka (as on 2001)
37
Map 14
Spatial distribution of Poultry in Sri Lanka (as on 2001)
38
Map 15
Agro-Ecological Regions of Sri Lanka
40
Map 16
Target sites of the FAnGR Project in Sri Lanka
47
iv
LIST OF FIGURES
Figure 1
Average monthly rainfall at Hambantota (1921 - 1990)
49
Figure 2
Average monthly rainfall at Lunugamwehera (1983 - 1999)
50
Figure 3
Average monthly rainfall at Siyambalanduwa (1943 - 1980)
57
Figure 4
Average monthly rainfall at Panama (1950 - 1988)
60
Figure 5
Average monthly rainfall at Pottuvil (1983 - 2003)
61
Figure 6
Average monthly rainfall at Maradankadawala (1970 - 1999)*
68
Figure 7
Average monthly rainfall at Kahatagasdigiliya (1941 - 1963)*
69
v
Executive Summary
A variety of animals are raised in Sri Lanka including neat cattle, buffaloes, pigs, poultry,
sheep and goats under different environments and management systems. Meanwhile, it has
been evident that the population of the indigenous livestock of Sri Lanka is gradually
decreasing while some breeds/species have already been lost or are near at extinction.
Hence, it is important to conserve and utilize this broad genetic base to enhance the
productivity of livestock of the country in a sustainable manner. Spatial distribution of
livestock species, in particular their wild relatives, has a direct relationship with the
environment, in other word the agro-ecology of the island. Therefore, this report has
attempted to describe the main agro-ecological characteristics of the island in terms of biophysical and socio economic environment.
Sri Lanka has been delineated in to 46 Agro-Ecological Regions (AER) that spread across
three major climatic zones, namely Wet, Intermediate and Dry zones of the country. These
AERs represent an uniform climate, soils and terrain conditions and as such each AER
exhibits more or less similar characteristics in terms of natural vegetation while land use and
farming systems find their best expression within a zone.
Despite being a relatively small island, Sri Lanka's forests are strikingly diverse due to
spatial variation of rainfall, altitude and soil. These forests posses a very high bio-diversity
along with endemic fauna and flora. At the beginning of the last century, Sri Lanka had
about 70% of land area under natural forests. However, it has now been dwindled to around
20 per cent of the total land area due to various socio-economic reasons. Out of total land
area of the country, nearly 80% comes under the some form of state control of which about a
third is under the forest cover and another third is under agriculture.
Human settlements,
home gardens, urban and industrial areas, transportation and a variety of other uses including
undeveloped land account for the balance.
With increasing population, the land/man ratio of the island has declined from 2.7 ha/head to
0.36 ha/head within last 100 years. This decreasing trend will be continued even in the future
as population continues to increase. Meanwhile, the problem of scarcity of land for human
vi
use will be further aggravated due to land degradation. Even though soil erosion is the most
important manifestation of land degradation in Sri Lanka, loss of land productivity through
salinization/alkalization, desertification, eutrifiation and indiscriminate waste disposal can
not be neglected.
It is clear that most of the natural resources related to livestock production are currently
under some form of "stress "due to various physical and socio-economic reasons. This has
led to exposure of animals in to harsh environmental conditions and subsequently the
reduction of productivity them.
Therefore, the need of conserving FAnGR to enhance the
livestock production of the country is perceived than ever before. In the light of possible
financial assistance through FAnGR Asia Project, seven target sites covering four
administrative districts of Sri Lanka were selected to execute a full project on FAnGR. In the
process of selection of target sites, parameters such as abundance of indigenous livestock
species, agro-ecological diversity and poverty level of the people living in the area were
considered.
This report contains comprehensive details on bio-physical and agro-ecological
characteristics of target sites, namely, Hambantota, Lunugamwehera, Siyambalanduwa,
Pottuvil, Panama, Thirappane, and Galenbindunuwewa.
vii
Technical report on the characterization of the agro-ecological context in
which FAnGR (Farm Animal Genetic Resources) are found: Sri Lanka
Introduction
Location
Sri Lanka is located in the Indian Ocean between the latitudes of 50 55' N and 90 51' N and the
longitudes of 790 41' E and 810 53' E covering an area of 65,610 km2 . It is an elongated pearshaped tropical island with a maximum length of 434 km from Dondra Head on the south to
Point Pedro on the north, and a maximum width of 227 km from Colombo on the west to
Kalmunai on the east. There are also a few small islands scattered along its coast.
Sri Lanka lies in close proximity to the southeastern coast of India with which it shares a
continental shelf. A narrow strip of water (Palk Strait) has, however, separated two countries
since the Miocene epoch causing disruption of faunal migratory routes. This, along with the
subsequent brief land linkages with the sub-continent due to oscillation in sea level, has had
a significant bearing on the flora and fauna of Sri Lanka.
Geology
The geology of the island, which has many features in common with that of the Indian subcontinent, has endowed Sri Lanka with considerable mineral resources. About 90 per cent of
the land are consists of Precambrian crystalline rocks.
On the basis of lithology, structure
and age, the Precambrian rocks have been sub-divided into 3 major groups (Cooray, 1984),
namely, Highland Series, Southwestern Group and Vijayan Complex. The Highland Series is
composed of metasediments and closely associated with charnokite gneisses. It occupies a
broad belt running across the center of the island from southwest to northeast, and it thus
includes the whole of the central hill country and part of the northern plain. The
southwestern group occupies the southwestern sector of the island. The Vijayan Complex
occupies the lowlands to the northwest and southeast of the Highland Series.
viii
Other rock types found in Sri Lanka are of more limited distribution and consists of Miocene
limestone sedimentary deposits which extend northward from Puttlam and cover the Jaffna
peninsula and as a small outcrop at Minihagalkanda in the southeast. Two small occurrences
of Gondwana sediments (Jurassic deposits) are found in Tabbowa and Andigama within a
distance of 35 km in the northwestern province. Quaternary or recent deposits that are found
in the coastal areas consisting of sands, sand stones, clays, gravels and coral reefs. The gem
bearing gravels, also of quaternary origin are restricted spatially and found mainly in the
Sabaragamuwa province.
Climate
The dynamics of the atmosphere are extremely variable over Sri Lanka due to its location
near the equator and influence of the monsoonal circulation over south Asia. Subsequently,
climate of Sri Lanka, particularly rainfall, varies strikingly both over different space and time
scales. Moreover, presence of a central mountainous region with a peak elevation of 2,524
m has a major effect on the climate of various regions and produces much sharper climatic
contrast between southwestern quadrant and the rest of the island.
Rainfall distribution in Sri Lanka has traditionally been generalized in to three climatic zones
(Map 1) in terms of “Wet Zone” in the southwestern region including central hill country,
and
“Dry Zone” covering predominantly, northern and eastern part of the country, being
separated by an “Intermediate zone,” skirting the central hills except in the south and the
west.
In differentiating aforesaid three climatic zones, land use, forestry, rainfall and soils
have been widely used.
The Wet zone receives relatively high mean annual rainfall over
2,500 mm without pronounced dry periods. The Dry zone receives a mean annual rainfall of
less than 1,750 mm with a distinct dry season from May to September. The Intermediate
zone receives a mean annual rainfall between 1,750 to 2,500 mm with a short and less
prominent dry season.
Being located in the low latitudes and surrounded by the Indian Ocean, Sri Lanka shows very
typical maritime-tropical temperature conditions.
These conditions are characterized by
greater daily than annual temperature ranges and moderate average
2
3
temperatures in comparison with the more continental tropics. Temperature conditions in Sri
Lanka are also characterized by a significant temperature decrease in the central highlands
according to the vertical lapse rate of temperature, approximately around 5-6°C for every
1,000 m rise in elevation. However, descending southwest monsoon winds over the central
hills towards lee side get warmer adiabatically causing ambient temperature be increased
along with decreased humidity. Hence, in this region, fall of temperature with rising altitude
is not very distinct compared to the same elevations of the other side of the central hills, Wet
zone.
As low temperature is an important climatic factor affecting plant growth in the Wet and
Intermediate zones of Sri Lanka, a sub-division based on the altitude takes into account the
temperature limitations in these two climatic regions. In this delineation, the Low- country is
demarcated as the land below 300 m in elevation and the Mid-country with elevation
between 300 - 900 m while the Up-country is the land above 900 m elevation. Both Wet and
Intermediate zones spread across all three categories of elevation while the Dry zone is
confined to the Low-country resulting seven agro-climatic zones covering the entire island
(Map 2). There is a considerable variation of temperature across these agro-climatic zones.
For example, average temperature in the coastal Wet zone is 27 0 C and it decreases to about
20 0C in the Mid country and further dropping to 13 - 16 0 C in the montane areas of the Up
country. The entire Dry zone which consists of lowland plains, except for a few isolated
hills, has a mean annual temperature of 30 0 C, although maximum temperature may even
exceed 37 0 C occasionally. In general, the seasonal variation of temperature throughout the
island is minor, but there is a general tendency for higher temperatures during the period of
Match to October while December and January are cooler when temperatures at high
altitudes may even drop to around zero at night
Major soil types of Sri Lanka
The soils of Sri Lanka have been classified at great group level for the whole country (Map
3) and series level information are available for some parts of the country. Moorman and
Panabokke (1961) identified 14 great soil groups in the country. These 14 great soil groups
fall under nine soil orders out of 10 soil orders of the USDA soil taxonomy of 1975 (Table
1).
4
5
6
Agriculturally, important and widely spread soil orders are Alfisol, Ultisol and Oxisol.
Further, the soil orders Entisol, Inceptisol, Vertisol and Histosol also have been used for
agriculture under suitable hydrological conditions as determined by rainfall, irrigation and
flooding.
Table 1 Important great soil groups of Sri Lanka with equivalent great soil groups
of Soil Taxonomy (USDA, 1975)
Soil order
Sub-order
Great Soil Group
Great Soil Groups in Sri Lanka
Alfisol
Ustalfs
Rhodustalfs
Reddish Brown Earths
Haplustalfs
Non-Calcic Brown soils
Tropoaqualfs
Low-Humic Gley soils with low BS
Natraqulfs
Solodized Solonetz
Rhodudults
Reddish Brown Latasolic soils
Aqualfs
Ultisol
Udults
Plinthudults
Tropudults
Oxisol
Ustults
Tropustults
Humults
Tropohumults
Aquults
Tropaquults
Ustox
Eutrustox
Red Yellow Podsolic soils
Low-Humic Gley soils with high BS
Haplustox
Red Yellow Latosols
Vertisol
Usterts
Pellusterts
Grumusol
Aridisol
Orthids
Salorthrids
Solonchaks
Entisol
Aquents
Tropaquents
Fluents
Tropofluents
Ustents
Tropustents
Psamments
Quartzipsamments
Auepts
Tropaquepts
Half Bog soils
Tropepts
Ustropepts
Immature Brown Loam soils
Fibrists
Tropofibrists
Hemsists
Tropohemsists
Saprists
Troposaprists
Inceptisol
Histosol
Alluvial soils of variable texture & drainage
Bog soils
7
While chemical and physical properties of these soils have been discussed by Alwis and
Panabokke (1972) a detailed account on potential and constraints of these soils for
agriculture and other land uses can be found in Somasiri (1982).
Flora and Fauna
The rich and diverse flora of Sri Lanka consists of an estimated total of nearly 4,000 species
and varieties of flowering plants, classified into 200 families and 1,350 genera. In addition,
about 1,100 species of lower plants (liverworts, mosses, ferns and fern allies) in about 250
genera are on record (National Atlas, 1988). Grasses, legumes, orchids and sedges are the
largest Sri Lankan families. Apart from species diversity, Sri Lanka is blessed with very high
taxic diversity (Table 2). Taxic diversity (Taxonomic diversity) is the diversity above species
level. Species that are very different from each other contribute more to overall diversity
than closely related species (Wijesundara, 2004). Meanwhile, about 25% of the flowering
plants of Sri Lanka are endemic. A variety of factors such as climate, geology and altitude
determine the species composition in a given area and thus the vegetation types and their
zones.
Despite its small size, the island is home to 625 species of terrestrial vertebrates, a thousand
varieties of fishes in its inland and territorial waters.
Among vertebrates, there 84
mammalian species, 12% of which are considered to be endemic (National Atlas, 1988).
Moreover, there are wild species of buffalo, cattle, fish and fowl but with the notable
exception of marine fisheries (NARESA, 1991).
Forest resources
Present situation
Climate, the main determinant of forest distribution, does not preclude the presence of forest
in any part of Sri Lanka except in a few locations. Despite being a relatively small island, Sri
Lanka's forests are strikingly diverse due to spatial variation of rainfall, altitude and soil.
The Wet zone contains lowland rain forests, characterized by a high density of tall trees with
straight, columnar boles reaching heights of 30 - 40 m in the canopy. These forests believed
to be the richest in the country in terms of species diversity and endemic fauna and flora, and
found in the southwestern quarter of the island ranging from sea level to an altitude of 1,000
8
m where they give way to sub-montane forests. The latter grade in to montane forests that
occur at altitudes between 1,500 - 2,500 m with a lower canopy and denser under growth.
Their stems are often covered with lichens, bryophytes and other epiphytic plants. Wet zone
forests show a progressive decline in canopy height and culminate in the unique "Pigmy
forests" that occur at elevation above 2,000 m.
The forests in the Dry zone comprise mainly dry monsoon forests with a relatively open
canopy of trees less than 20 m in height and thorny scrub forests that occur in the semi-arid
areas covering the northwestern and southeastern regions of the island. The lowland
Intermediate zone located between Dry and Wet zones, contains moist monsoon forests.
Other distinct forest types in the island are fragmented mangrove vegetation and riverine
forests that occur along the banks of rivers flowing through the Dry zone (MOFE, 2000).
Sri Lanka has a natural forest cover of around 2,046,599 ha (Table 3). Of this, 463,842 ha
contain open canopy sparse forests while the balance comprises closed canopy forests. All
categories of closed canopy natural forests are not equally abundant. The dry monsoon
forests located mainly in the northern and eastern regions (Table 3) are the most widespread
and cover an area of about 1,094,287 ha (Table 3). The next in extent is the moist monsoon
forests of the Intermediate zone.
In contrast, valuable lowland rain forests cover only
141,549 ha while sub-montane and montane forests are even scarce. Mangrove swamps in
Sri Lanka are also not extensive as they are fragmented and occur in a narrow tidal belt
extending less than 1 km landward from the mean low water tidal level. It covers an extent
of 8,687 ha (Table 3).
Plantation forests in Sri Lanka consist mostly of even-aged monocultures of Teak,
Eucalyptus or Pine. A few mixed plantations of broad-leaved tree species such as Jak, and
Mahogany have also been established (NARESA, 1991)
9
Table 2 Taxic diversity of plants in Sri Lanka
Sub-class
No. of
No. of Orders
Orders in
in Sri Lanka
%
the world
No. of
No. of
families in
families in
the world
Sri Lanka
%
Magnolidae
8
8
100
38
18
47.4
Hamamelidae
11
2
18.2
24
4
16.7
Caryophyllidae
3
3
100
14
12
85.7
Dilleniidae
13
10
76.9
78
34
43.6
Rosidae
18
17
94.4
112
57
50.9
Asteridae
11
10
90.9
47
30
63.8
Alismatidae
4
4
100
16
7
43.8
Arecidae
4
3
75
5
4
80
Commelinidae
7
6
85.7
16
8
50
Zingiberidae
2
2
100
8
5
62.5
Lilidae
2
2
100
19
10
52.6
83
67
80.7
377
189
50.1
Total
Source: Wijesundara, 2004
Table 3 Forest extent by type
Type
Area (ha)
Lowland rain
141,549
Moist monsoon
243,877
Dry monsoon
1,094,287
Sub montane
68,838
Montane
3,108
Mangrove
8,687
Riverine dry
22,411
Sparse open
463,842
Total natural forest
2,046,599
Source: Forestry sector master plan, 1995
10
Current trends in the forestry sector
At the beginning of the last century, Sri Lanka had about 70% of land area under natural
forests (Wijesinghe et al, 1993). By 1992, however, the amount of closed canopy natural
forest had dwindled to around 23.8 per cent of the land area (MOFE, 2000). Table 4 shows
the distribution of different forest types in different administrative districts as at 1994 and
reveals that 31 per cent of the land area of the island is covered by natural forest of which 7
per cent consists of sparse forests. The present extent of natural forests in the country, and
the abundance of the different forest types are not due to natural forces alone, but have been
greatly influenced by human actions.
In general, the main reasons for the rapid loss of forest cover in the island during fast few
decades are clearing for irrigation, agriculture, human settlement, hydro-power generation,
timber extraction and forest encroachment by local people (MOFE, 2000). As the population
continued to increase, there was a pressure for land to meet the demand from above sectors
of the economy which resulted deforestation rate of over 40,000 ha per year between 1956
and 1983 and had accelerated to an annual rate of 54,000 ha between 1983 and 1992
(Wijesinghe et al, 1993). Recognizing the urgent need for conservation of Sri Lanka's natural
forests, considerable efforts have been taken to address the issue. Currently about 55% of
the total area under natural forest is reserved and administered by either the forest
department or the department of wild life conservation.
The designated areas under these
two departments constitute 17% and 13% of the total land area, respectively (Map 4). The
designated areas under the forest department in 1995 comprised Forest Reserves, Proposed
Forest Reserves and National Heritage and Wilderness Areas (MALF, 1995).
Protected
areas under the department of wild life and conservation are consisting of Strict Natural
Reserves, National Parks, Nature Reserves, Jungle Corridors and Sanctuaries (Table 5). In
total, Sri Lanka's Protected area network covers an impressive 14% of the total land area
(MOFE, 1999). Even though, it is a very favorable situation compared to other countries of
South Asia, it is still considered inadequate to conserve country's rich bio-diversity and
critical hydrological features due to poor representation of Wet zone forests in it.
For
example, the forest department trough its National Conservation Review study has found that
20 to 50% of species in selected plant and animal groups occur in the forests of just four
districts of the Wet zone.
11
12
Many of these species are rare and limited in distribution and a total of 119 woody plant
species are restricted to single forests, while 41% of these rare species are endemic (MALF,
1995). This issue has now been partly addressed by the inclusion of Wet zone's conservation
forests that are species rich and contain many of the endemic species and important
watershed areas, within the Protected Area network (MOFE, 2000).
Since 1970 the forest department has established 40 biosphere reserves within its Reserve
forests or Proposed reserve forests. They vary from 10 to 55,000 ha and total of 120,000 ha.
This program began as an activity of IUCN's International Biological Programme and later
continued under the UNESCO's Man and Biosphere Programme (NARESA, 1991). In the
natural forests of the Dry zone, under the Forestry Master Plan, deforestation and
exploitation for timber supply will continue everywhere except in the "Protected areas"
under the department of wild life conservation and the biosphere reserves under the forest
department.
There are around 600,000 ha in these reserves. However, even within these
areas encroachment and illicit felling continue. In the Wet zone region (Low country, Mid
country and montane region) the forest is estimated as 278,000 ha.
In the Low and Mid
country and in the Mahaweli catchment, the area of forest has been depleted to about 8% of
the land area resulting unfavorable forest/land ratio. Hence, according to the Forestry Master
Plan, no forest alienation would be permitted in the Wet zone (NARESA, 1991).
Deforestation being the major and most important environmental problem in Sri Lanka, in
recent years there has been a positive change in forest policy conferring a greater role on the
forest department for forest conservation as opposed to its prime objective of managing
forests production the past. The forest policy 1995 and Forestry Sector Master Plan 1995
and several management plans developed by the department clearly reflect this mandate.
Despite these initiatives, forest offences continue to report in courts and other judicial
institutes.
Meanwhile, the forest department and the department of wild life conservation
have now acknowledged that remedying this problem needs greater participation of local
people in forest and wildlife management and conservation (MOFE, 2000).
13
Table 4 Natural forest area by districts (ha) - 1994
District
Ampara
Anuradhapura
Badulla
Batticaloa
Colombo
Galle
Gampaha
Hambantota
Jaffna
Kalutara
Kandy
Kegalle
Kilinochchi
Kurunegala
Mannar
Matale
Matara
Monaragala
Mulaitivu
Nuwara Eliya
Polonnaruwa
Puttalam
Ratnapura
Trincomalee
Vaunia
Total
% of total
land area
Montane
93
Sub-
Lowland
Moist
Dry
Riverine
montane
rain
monsoon
monsoon
dry
45190
69265
180083
3353
21770
3888
1577
1832
18903
273
220
935
8504
3655
20240
14258
11791
17517
13302
14
739
1943
48
3108
0.05
5314
519
65
12831
16686
768
41337
2174
63558
31078
3977
2649
47266
15816
68839
1.04
38194
141549
2.14
292
1421
3710
187
122
539
260
70
3545
1827
89
19169
822
10160
Mangrove
4755
4
243877
3.68
32374
8153
111389
15237
516
113627
153769
68093
79452
3545
110491
103182
1094287
16.54
312
795
1261
6
4544
463
523
814
2264
1826
1491
22411
0.34
8687
0.13
Sparse
41760
116693
27843
16325
36
1699
20
55077
298
1266
5980
492
6042
14766
11762
9207
2076
52569
17987
3273
22949
17104
4491
17629
16503
463842
7.01
Grand total
166667
296776
54271
52818
1868
20789
429
79454
1380
21576
33222
15938
38728
24746
25207
84015
21977
235171
172219
42920
138831
99634
66849
131441
119685
2046599
30.93
Lowland rain forest - > 2,500 mm rainfall, < 1,000 m elevationMoist monsoon forest - 1,800 - 2,500 mm rainfall, < 1,000 m elevation
Dry monsoon forest - < 1,800 mm rainfall Sub-montane forest - > 1,800 mm rainfall, > 1,000 m Elevation,
Source: Administration report - Department of forest conservation
14
Table 5 Designated forest areas in Sri Lanka (as at 1999)
Category
Number
Area (ha)
Percentage
Forest department
Forest Reserves
177
518,199
7.8
Proposed Forest Reserves
217
621,147
9.4
1
11,187
0.2
395
1,150,533
17.4
Strict Natural Reserves
3
31,573
0.5
National Parks
13
524,660
10.0
Sanctuaries
52
256,902
3.8
Nature Reserves
3
38,720
0.6
Jungle Corridors
1
10,364
0.2
72
862,219
13.0
National Heritage
Sub-total
Wild life conservation department
Sub-total
Source: Forest and Wild life departments
Water resources
Water resources of a country can be divided in to two categories, namely, surface water
and ground water. Surface water occurs in rivers, streams, lakes, marshes, reservoirs and
ponds. Rainfall is the main source of water for both surface and ground water in Sri
Lanka supplemented by mist, fog and dew in certain montane areas. The principal
geographical determinant of water resources of the island is the highland massif in the
south-central region located across the passage of two opposing monsoonal winds. The
moisture laden monsoonal winds are intercepted by the hills in the central region leading
to unique rainfall pattern.
The mean annual rainfall of Sri Lanka is around 2,000 mm
which distributed over the surface area of 65,619 km2 gives an average volume of
131,230 million m3 of fresh water annually (Arulananthan, 1985). This volume of water
supports the vegetation of the country, recharges the ground water, fills the storage of
15
various reservoirs and lakes and supplies the daily needs human and livestock.
What
does not use run offs the surface or percolates in to the soil to reach the sea as river flow.
Average annual river flow is 31% of the rainfall and equals 40,680 million m3 (Bocks,
1959) while the balance, 90,550 million m3 is used for above purposes and evaporation in
to the atmosphere.
The radial drainage pattern that carries surface water down from the high watersheds
includes 103 distinct natural river basins that cover 90% of the island (Map 5).
The
remaining 94 small coastal basins contribute little to water resources of the country
(Arumugam, 1969). River basins originating from the wetter parts of the up country are
perennial while many of those in the Dry zone are only seasonal.
Surface water
Water that remains from rainfall after evapotranspiration and infiltration losses may
generally be considered as available surface water. Amounts are measured in terms of
water discharged by the rivers (m3 /year) or as units of water depth distributed over the
land surface as hectare-meters (HM). Annual surface run-off of Sri Lanka is estimated as
5 HM (Table 6). Much of this water now serves the irrigation and hydro-power projects
and only less than 3.3 HM escapes to the sea. About 79% of the run-off water from the
Wet zone is escaped to the sea while corresponding value from the Dry zone remain
around 50% (Table 6). Despite its favored location in the humid tropics and lying on the
path of two opposing monsoons, the distribution rainfall of Sri Lanka over the year and
over the country is not very much conducive in every aspects of the economy. The
greater part of the island especially the Dry zone and Intermediate zone is liable to dry
spells lasting several months. Areas of water surplus, however, are not uncommon along
the coastal belt of flood plain, villus and mangrove swamps. NARESA (1991) has shown
the surface water potential of the different districts of the country (Map 6). It reveals that
about 75% of the country has potential of less than 1 m of surface water per annum. It
also shows that about 50% of the area of country has surface water potential of less than
0.5 m per annum.
This is well below the evapotranspiration requirement of the
vegetation of the area.
16
17
18
Elements of Sri Lanka's surface water balance are subject to substantial annual variability
due to dynamic nature of rainfall governing mechanisms of Sri Lanka so that
consideration of averages can be misleading.
Variations are about 10% annually in the
Wet zone, 15% in the Dry zone and up to 20% on the east coast (NARESA, 1991).
Hence, attempts have been made to store the surface run-off for various uses since
ancient times. Therefore, Sri Lanka has unique distinction in the history of mankind of
having developed "Hydraulic civilization" even before the Christian era.
The hydraulic
structures that have survived to this day, such as long canals with imperceptible gradients,
Bisokotuwas, Ralapanawas, and cascades of village tank systems, bear an ample
testimony to the high achievements in surface water management and technology
(Madduma Bandara, 1998).
It is evident that in the Dry zone mainly the attempts had
been to store run-off water for use during dry periods.
In the Wet zone, diversion
structures have been built across perennial rivers and stream flow to provide the water to
places where it is not sufficient or available.
There are over 15,000 small reservoirs
known as "small tanks" found in Sri Lanka. Table 7 shows present statues of the small
tanks in the drier region of the island. It can be seen that the highest number as well as
highest density of small tanks are in the North Western province (NWP) and North
Central province (NCP). Meanwhile, the highest proportion of abandoned tanks is in the
Southern province (SP), Lower Uva, Eastern province (EP) followed by the Northern
province (NP) and the NCP. In general, the average tank density is one tank per 2.6 km2 f
or NP, NCP and SP. For the NWP the density is around one tank per 1.2 km2 . This
conforms to both the nature of the overall rainfall regime as well the nature of
geomorphology of the region.
Table 6 Surface water resources of Sri Lanka
Wet zone
Dry zone
Island total
Mean annual rainfall (mm)
2,424
1,450
1,937
Mean annual run-off (HM)
2.58×106
2.55×106
5.13×106
Run-off/Rainfall ratio (%)
65.1
35.8
40.5
Escape to the sea (HM)
2.04×106
1.3×106
3.33×106
75.83
51.11
64.91
Escape as a % of total run-off
Source: Ranatunga, 1985
19
Table 7 Present status of small tanks in the drier region of Sri Lanka
Province and area (km2
Number of small tanks
Operating
Northern 3,709
Total
Abandoned
608
816
1,424
North Central 10,365
2,095
1,922
4,017
North Western 7,760
4,200
2,273
6,473
653
757
1,410
Lower Uva 2,901*
16
543
553
Eastern (south of
-
1,017
1,017
48
425
473
7,620
7,753
15,373
Southern 2,849
Mahaweli) 3,885*
Eastern (north of
Mahaweli)*
Total
*Includes only the Dry zone part of the province
Source: Panbokke et al, 2002
Apart from these small tanks, Sri Lanka has relatively large number of major reservoirs.
Irrigation department (1965) has published the register of the irrigation projects in Sri
Lanka. This document has listed 64 major irrigation projects, 162 medium scale projects,
3,279 minor projects, 1,763 anicut projects, 46 flood protection, drainage and salt water
exclusion projects and 25 lift irrigation projects. This register has not been updated since
1975 even though some major irrigation and hydropower projects such as Mahaweli,
Samanala Wewa, Kirindi Oya and Kukule Ganga etc. have been commissioned
thereafter.
In Sri Lanka role of wetlands in maintaining the surface water balance can not be under
estimated. Wetlands comprising of swamps, marshes, fens and bogs are natural waterstorage features on the landscape. Wetlands play a crucial role in preventing flooding at
the other end of rivers while providing the habitat for variety of flora and fauna, some of
which are endemic to Sri Lanka.
In the headwaters and watershed, they store water
during heavy rains, slowing runoff into streams and reducing flood peaks. Some of the
20
trapped water returns directly to the atmosphere through evaporation or plant
transpiration, and while a few wetlands recharge groundwater, they slowly release the
water they hold to their outlet stream. In general, wetlands typically have a large inlet and
a small outlet. There are 41 wetland sites in Sri Lanka. (Scott, 1989). However, the
importance of wetland ecosystems was not understood during the post-colonial era of the
country.
In Colombo and its suburbs, a considerable area of natural wetlands has been
lost to construction of infrastructure, thus creating several environmental problems,
which include flooding and poor drainage.
However, the value of wetlands and flood
plains have received increasing attention and Sri Lanka is now a party to the international
treaty and convention on the protection of wetlands of international importance. Several
proposals have been considered to mitigate some of the hazards associated with the
destruction of natural wetlands.
A growing body of national laws and institutions and
scientific management information is being successfully attempted for the sustainable
development of wetlands in the country.
Ground water
From ancient times, ground water extracted trough dug wells has been the main source of
naturally clean, potable water supply that served domestic purposes and still remains the
principal source of domestic water supply in the rural sector. In Sri Lanka, rainfall is the
only source of supply of fresh water that seeps through the surface for circulation and
storage as ground water. As nearly 90% of the total land area of the island is occupied by
metamorphic crystalline rocks, called "hard rocks" of which both pore space and
permeability is relatively low, ground water is not present equally everywhere in the
country. In the Dry zone where ground water is most valuable for irrigation as well as
domestic use, several distinct categories of ground water sources have been identified.
They are: shallow Krastic aquifers (Miocene limestone) in Jaffna peninsula, shallow
unconfined aquifers on the sandy Regosol formation around the coast of mainland and
islands
such
as
Kalpitiya,
deep
confined
sedimentary
limestone
formations
of
Vanathavillu and Mulankavil and ground water occurring in the weathered and fractured
zones of the hard metamorphic rock complex, alluvial plains of major rivers/drainage
systems and major irrigation areas of the Dry zone. Use of ground water for farming in
Sri Lanka has been confined traditionally to the northern and eastern provinces, which are
21
deprived of perennial water resources. Systematic exploitation of shallow and deep
aquifers of the north started in early 1960s.
Since 1970s, farmers in the North-central
province also have started to use ground water of the hard rock aquifers for cultivation
through shallow, large diameter dug-wells, popularly known as the agro-wells. Although,
ground water is an excellent source of water, its availability, extractability, rate of
depletion and quality etc. depend on a number factors.
These factors depend on the
characteristics of the water bearing substrata (the geological formation that hold water
under ground) and external factors such as recharging area, general hydrology, rainfall,
infiltration, run-off, soil storage and evapotranspiration of the recharging area. However,
being environmentally very sensitive source of water, indiscriminate extraction of ground
water may lead to catastrophic consequences and therefore, regionally based extraction
guidelines for safe limits and well-density should be worked out.
Pastoral resources
As in many countries in the region, in Sri Lanka the cheapest source of animal feed are
pasture and fodder out of which pasture constitutes the major source of nutrients of
animals grazing on natural pastures. In Sri Lanka, with a total land area of 6.56 million
ha, the open natural grasslands in different climatic zones make up an extent of about 0.4
million hectares (Sivalingam, 1977). There are about 20,000 ha grasslands, mainly in the
government farm, under improved grasses with at least double the fodder yield of
indigenous grasses (NARESA, 1991). The important species of grass and fodder that
support the livestock industry in Sri Lanka are, Guinea grass in the Mid country, Dry
zone and parts of the Intermediate zone; Bracharia spp. and natural pasture varieties in
the coconut triangle and parts of the Dry zone; and a combination of Guinea grass and
large number natural pasture species in the rest of the island (Siriwardena, 1999). The
natural grasslands consist of four main types, namely, Damana, Villu, Dry & Wet
Patanas.
Damana type natural grasslands are Savannah type vegetation found in the lowland Dry
zone especially in its eastern region. However, it is different from the typical Savannah
forest on the eastern slopes of the central highland between 300 to 900 m altitudes in
terms of composition of the tree species. Savannah forest in the eastern slopes is an open
22
plant community of scattered trees amidst a sea of grass where main trees are occupied
with Terminalia chebula (Aralu), T. belerica (Bulu), Emblica officinalis (Nelli), Careva
arborea (Kahata), Diospyros melanoxylon (Kadumberiya) with two main species of
grasses,
Imperata
cylindrica
(Iluk)
and
Cymbopogon
confortiflorous
(Mana).
Nevertheless, the principal tree species in the Damana grasslands or Savannah forest in
the lowland Dry zone of the eastern region constitutes Limonia acidissima (Divul),
Manikara hexandra (Palu) Acacia leucophloea (Keeriya) amidst Imperata and other
grasses (National Atlas, 1988). There are over 80,000 has of Damana grasslands in the
Dry zone (Sivalingam, 1977).
Villu is natural grassland associated with moist conditions in the Dry zone around
abandoned irrigation tanks, backswamps of major rivers and streams, and waterholes.
Both Villu and Damana provide a home for the wild animals and also permit the domestic
ungulates to fend within their means. During greater part of the Major rainy season
(October to February), Maha season, about 25,000 ha of Villu grassland remain inundated
with Mahaweli waters (Sivalingam, 1977). Dry Patana grasslands occur mainly in the Up
country Intermediate zone, especially in the Uva basin and western slopes of the
Knuckles range.
Principal grasses are Cymbopogon confortiflorous (Mana) and
Themeda tremula.
Occasional trees Carea arborea (Kahata) are present. Wet Patana
grasslands occurs in the Up country Wet zone at elevation above 1,400 m where there is
no moisture deficit periods.
It is characterized by Chrysopogon - Pollinia - Arundinella
grasses with Rhododendron (Maha ratmal) trees. The largest expanse of this grassland is
Horton Plains. They are also found in Moon Plains, Sita Eliya, Elk Plains, Ambewela,
Pattipola, and Kandapola areas (National Atlas, 1988). Both these Dry and Wet Patanas
in the Montane region extent over an area of about 65,000 ha (Sivalingam, 1977). Even
though, these land only marginally suitable for arable farming, they are ecologically
important in controlling soil erosion and for the sustenance of wildlife. In addition to
these large-scale natural grasslands, animals are being fed with pastures available under
some other form of land uses.
Piyasinghe (1984) categorized 10 major forms of lands
with pasture along with their respective annual dry matter production (Table 8).
23
Table 8 Extent of land under pasture and estimated yield of pasture
Extent (ha)
Total Dry Matter
production
(MT/year)
Un-irrigated highlands in the Dry zone
325,000
325,000
50,000
200,000
30% of the land area under coconut
140,000
560,000
5% of the hill country tea estate land
4,500
31,500
55,000
55,000
120,000
120,000
5,000
10,000
20,000
40,000
150,000
300,000
13,000
130,000
882,500
1,771,500
Villus in the Dry zone
Patana lands in Montane regions
Herbage from paddy lands ) 2 months of
grazing between seasons)
Road sides etc.
Grazing land in the Wet zone
Fallow paddy land
Improved pasture in farms
Total
The Table 8 reveals that pasture production potential of un-irrigated highlands in the Dry
zone is 1 MT/year while grasses in land under coconut produces 4 MT per year. In
contrast, improved pastures in large-scale farms have the potential of yielding 10 Mt per
annum.
Hence, at present it is estimated that with 882,500 ha of pasturelands in the
country produce 1,771,500 MT total DM of grass and fodder in a year. However, this
resource base can not support the feed requirement of the livestock of the country. The
deficit of fodder requirement in relation to fodder production has been estimated to be 2.8
million MT (Siriwardena, 1999). Hence, it is clear that some other means of feed supply
should be worked out in order to bridge the deficit. In the light of no extra lands to bring
under pasture, utilization of crop residues, agro-industrial by-products and other nonconventional feed resources would be an appropriate strategy to overcome the continuing
problem of livestock feed scarcity in the island. Such strategies would be of particular
importance for the areas having distinct dry season between two rainy seasons. In these
24
regions, the pasture production during the dry period is well below the pasture
requirement.
Therefore, areas such as Intermediate and Dry zones where the annual
rainfall rhythm depicts a distinct bi-modal pattern demand either pasture conservation
during wet period or use of alternative feed resources during the dry period or both. Apart
from the quantity of pasture, the quality of available pasture during dry periods decline
rapidly as pasture and fodder mature rapidly during dry spells. Apart from the Dry and
Intermediate zones, this is a common problem in the areas of Mid and Up country during
Mid January to Mid March where long dry spells are frequent resulting both quality and
quantity of forage resources to decline sharply.
Land use and land degradation
Sri Lanka has a total land area of 6.56 m.ha out of which nearly 80% comes under some
form of state control. In general, nearly one-third of the total land area is under forest
cover and another one-third is under agriculture. Human settlements, home gardens,
urban and industrial areas, transportation and a variety of other uses including
undeveloped land account for the balance.
Although the total extent of the land set apart
for forestry and wild life exceeds the total area of agricultural lands, much of the former
are in ecologically marginal dry areas such as Yala and Wilpattu National Parks (National
Atlas, 1988).
The most recent scientific land use mapping exercise was undertaken by the Survey
Department of Sri Lanka during 1983-1988 period and identified 7 major categories of
land use such as Arable lands, Built up and residential lands, Forests, Range lands,
Wetlands, Barren lands and Water bodies (Table 9 & Map 7). The arable lands include
croplands (all cultivated) and sparsely used lands. The croplands are the lands cultivated
continuously.
These lands include tea, rubber, coconut, rice, vegetable, export-
agricultural crops and non-traditional plantation crops such as sugar cane and cashew etc.
The sparsely used croplands include "Chena" lands (slash & burn agriculture) and
abandoned plantations, which are cultivated now and then.
The category of urban and
residential lands includes built up lands, associate non agricultural lands (archeological
reservations) and homesteads.
25
26
The forestlands includes natural forest and forest plantations. The rangeland consist of
scrub lands and grasslands. Grasslands comprise of both natural (Patana & Villus) and
cultivated grasslands. The marshy lands and mangroves are grouped as wetlands. Rocky
lands and erosional remnants are grouped as are grouped as barren lands.
All natural
water bodies and reservoirs in the inland are included in the category of water bodies.
Table 9 Land use in Sri Lanka (as shown in the land use map of 1988)
Type
Extent (ha)
%
Arable land
Cultivated
1,641,100
Sparsely used
1,288,500
Total
2,929,600
44.92
Built up and Residential
Built up & associated nonagricultural lands
Homestead
Total
29,200
781,300
810,500
12.42
1,759,800
26.98
593,500
9.09
Wetlands
61,800
0.95
Barren lands
77,500
1.18
Water bodies
290,500
4.45
Forest lands
Natural & plantations
Range lands
A recent study on land use types in Sri Lanka shows that rice, the staple food of the island
occupies in about 41.8 % of the total arable land while tea, rubber, and coconut occupy in
11.0, 9.2 and 25.2 per cent from the arable land, respectively (Table 10). Eight per cent of
the arable land is occupied with subsidiary crops along with another 3.8% under the other
export crops.
27
Table 10 Arable land, their uses and other land use types in Sri Lanka
Agricultural land
Proportion %
Area (ha)
25.0
1,640,250
Paddy
41.8
685,625
8.0
131,220
Coconut
25.2
413,343
Rubber
9.2
150,903
11.0
180,428
Other export crops
3.8
62,330
Sugar
0.6
9,842
Tobacco
0.4
6,561
Subsidiary crops
Tea
Forest & woodlands
27.1
1,778,031
Homesteads
11.9
780,759
7.7
505,197
19.6
1,285,956
8.7
570,807
100.0
6,561,000
Scrubland
Sparsely used croplands
Others (including inland water)
Total Land area
Source: National Environmental Action Plan (1988 - 2001), Ministry of Forestry & Environment
It has also been estimated that nearly 80% of land holdings are less than 1.2 ha and over
40% of them are less than 0.4 ha of the total land area. With increasing population, the
land/man ratio of the island has declined from 2.7 ha/head to 0.36 ha/head within last 100
years (Gamage, 1997). This decreasing trend will be continued even in the future as
population continues to increase. Meanwhile, the problem of scarcity of land for human
use will be further aggravated due to land degradation, a process that diminish or impair
land productivity. According to the FAO estimates of 1989, the total extent of degraded
land due to soil erosion in Sri Lanka is about 700,000 which is about 10% of the total
arable lands of the country. Deforestation has been the major cause of land
degradation/soil erosion in Sri Lanka. Sri Lanka had a forest cover of nearly 80% in
1880. Significant land degradation began during the past 150 years, particularly after the
advent of commercial plantation agriculture during colonial period.
In 1900, with a
28
population of only 3.5 million, Sri Lanka had approximate forest cover of 70 per cent.
By 1953, when population reached 8.1 million, natural forest cover had diminished to
approximately 44% and when population doubled by the mid 1980s, the forest was cut by
nearly half, to less than 25 per cent (NARESA, 1991).
The high degree of soil erosion reduces the long-term productivity of the land since the
fertile top-soil is eroded. Some studies have shown that crop yields have declined 3 to
7.5% after 1 mm of soil loss due to natural erosion and 10 to 25% loss after 8 mm of soil
is eroded (Marsh, 1971). Land degradation due to soil erosion could occur in all agroecological regions of the island, although its intensity could vary according to the rainfall
regime/intensity, soil type, slope, ground cover and management practices.
The worst
affected area is the Mid country where intensity of rainfall is high, slopes are moderate to
high and erodibility of soils is also relatively high. At higher elevation, although slopes
are steep, rainfall intensities are relatively lower.
In the Low country, where rainfall
intensities could be high, slopes are less steep and soil possesses a considerable resistance
to the erosion.
Even though soil erosion is the most important manifestation of land degradation in Sri
Lanka, loss of land productivity through salinization/alkalization, dystrification (lowering
of soil acidity), eutrifiation (increase of certain nutrients impairing the plant growth) and
indiscriminate waste disposal can not be neglected (Map 8).
Socio-economic conditions
Sri Lanka has a population over 19 millions as at 2002 with a range of 1.3-1.5 per cent
annual population growth. Population is projected to reach 22.3 million by 2021 and to
stabilize at about 25 million by 2046. Sri Lanka is one of the world’s most densely
populated countries.
Population density was estimated as 287 persons per square
kilometer in 1994 and has increased to 295 persons in 2000. The estimated mid year
population density in year 2003 was 307 per square kilometer. Population in Sri Lanka is
unevenly distributed across the country and is concentrated mainly in the Wet zone,
which include both maritime provinces with higher level of development and hill country
districts having large scale plantations.
29
30
In the nineteen-fifties and sixties, the Sri Lanka economy depended primarily on export
oriented
commercial
plantations
of
manufacturing existed prior to 1950.
plantation-based economy.
tea,
rubber
and
coconut.
No
significant
By 1973, Sri Lanka was still essentially a
Over a third of the food requirements were imported.
Cultivation of paddy and other food crops is very vulnerable to the vagaries of the
weather, as modern methods of irrigation and water control has not yet been widely
adopted.
The modern industrial sector, established mainly towards the end of the
nineteen-sixties was heavily dependent on imports and still producing well below the full
capacity.
Until the mid-seventies, the government controlled most economic activities
and most industries were government operated monopolies. In 1977, with the adoption of
open economic policies and industrialization led to a growth in the economy.
An
economic liberalization programme started in 1989 increased the market orientation of
the economy, emphasizing export led growth and development of the private sector.
Despite severe civil strife, these economic reforms resulted in relatively high growth rates
of 5.6 percent on annual average during 1990-94. In year 2003, Sri Lanka recorded a
broad based 5.9% real economic growth (Central Bank, 2003), a continuing recovering
after her economic set-back in year 2001. Sectoral composition of GDP in 2003 show
that service sector comprises 55% of the GDP while industry and agriculture account for
26 and 19 per cent, respectively. The per capita GDP of Sri Lanka at market prices is 947
US $ (Central Bank, 2003)
Despite all these, poverty has persisted in Sri Lanka over the decades except with a slight
drop in 1970s. The rural and estate sectors have high levels of poverty compared to the
urban sector. As a result of withdrawal of several subsidy schemes during recent past and
increasing inflation rate, the poverty has become an integral aspect of the society and the
economy of Sri Lanka. Apart from other consequences, the poverty will deprive people,
at all times, have physical and economic access to sufficient, safe and nutrious food to
meet their dietary needs and food preferences for active and healthy life, in other words
they are vulnerable to food insecurity.
A recent study conducted by the World Food
Programme of the UN has categorized country's 323 DS divisions in to 3 groups in terms
of the food security, namely, Most vulnerable, Less vulnerable and Least/not vulnerable
(Map 9). This map is a composite product of 22 biophysical and socio-economic
31
parameters developed in a GIS environment. A detailed description on parameters and
methodology can be found in Satharasinghe (2003). This study shows that out 323 DS
divisions, 148 are either "Least vulnerable" or "Not vulnerable" to food insecurity. Most
of them are located in the Wet zone or adjoining Intermediate zone. There are 82 DS
divisions, which are "Less vulnerable" to food insecurity, located mostly in the
Intermediate zone, and adjoining Wet and Intermediate zones. There are 93 DS divisions
in the country that are "Most vulnerable" to food insecurity of which majority found in
the Dry zone of Sri Lanka, particularly in the North-east province.
Livestock industry in Sri Lanka
The current population estimates indicate that there are around 1.51 million cattle, 0.64
million buffaloes, 0.45 million goats, 0.07 million pigs and 10.6 million poultry (Dept. of
Census & Statistics, 2002). Livestock are spread throughout all regions of the country
with concentration of certain farming systems in particular areas because of agroclimatic, market and cultural reasons (Map 10 - 14).
A variety of animals are raised in the country including neat cattle, buffaloes, pigs,
poultry, sheep and goats.
Cattle and buffaloes are raised for dairy, draught and for
slaughter. Pigs and sheep are raised exclusively for slaughter while goats are raised both
for slaughter and supply of milk.
The dairy and poultry industries of the country
represent more prominent and organized sectors of the country's livestock industry.
Cattle and buffalo keeping is generally distributed throughout all regions of the country.
In the up and mid-country, cattle keeping is primarily for milk. In the low country wet
zone and in the coconut growing area buffalo form an integral part of agriculture
providing draft power, weed control and manure as well as being used for milk
production. In the dry zone these species are regarded as a source of insurance by the
small-holders as they provide a store of wealth and access to cash by means of animal
sales, and milk. In irrigated areas of Mahaweli settlement scheme in Dry Zone, cattle and
buffalo are kept mainly to produce milk and draft power. In total nearly half of the cattle
in the country are found in the dry zone (Map 10).
32
Map 9 : Vulnerability to food insecurity of Sri Lanka
33
34
35
36
37
38
Goats are largely found in the Dry zone (Map 12).
The total number of animals
slaughtered at registered abattoirs is around 97,000 animals with an extraction rate of
18.8% 1300 MT of mutton are produced. More recently the rearing of goats for milk
purpose is becoming popular in the urban areas of the country.
Pig farming is concentrated in the Western coastal “pig belt” (Map 13) are undertaken as
intensive systems (10-15 fatterners) and extensive systems (1 to 2 pigs kept by small
farmers in a predominantly subsistence system).
Approximately 26,300 pigs are
slaughtered every year producing 5,500MT of pork.
Swill and rice bran are the most
common feeds used for pigs.
Poultry production is concentrated in Western and northwestern part of the country as a
commercial venture (Map 14). Most of the operations found in these areas are medium –
large scale having 1,000 – 10,000 birds. Annual poultry meat and egg production in the
country stands at 88 million kg and 954 million, respectively.
Agro-ecology
An
agro-ecological
region
represents
a
particular
combination
of
the
natural
characteristics of climate, soil and relief (Panabokke, 1996). When an agro-climatic map,
which can be considered as areas where the integrated effect of climate is uniform
throughout the area for crop production, is superimposed on soil and terrain the resulting
map identifies agro-ecological regions.
Thus, each agro-ecological region represents an
uniform agro-climate, soils and terrain conditions and as such would support a particular
farming system where certain range of crops and farming practices find their best
expression.
The demarcation of the island into 46 agro-ecological sub-regions is shown in the Map 15
(Punyawardena et al, 2003). The main distinguishing characteristics of each agroecological region is denoted by a 4-character code consisting of letters and a number.
Three major climatic zones are indicated by the first upper case letter of the code (W, I
and D). The second upper case letter of the code (L, M and U) denotes three categories of
elevation. The numerical character in the third place of the code represents a more
39
40
detailed moisture regime (rainfall and evaporation combined) with a degree of wetness on
the scale of 1 to 5 where 1 being the most favorable. The lower case letter in the fourth
place indicates a sub-region as determined by rainfall distribution and other physical
environmental factors where degree of wetness decreases a → f.
In the Wet zone, there are 15 agro-ecological sub-regions. Four sub-regions found in the
Up-country wet zone show a distinct variation in the distribution of the South West
Monsoon (SWM) rains. Being in the most effective area of the SWM rains, WM1a,
WL1a and WU1a sub-regions receive the highest amount of rainfall in the country. Apart
from the amount and distribution of SWM rains, relative effectiveness of North East
Monsoon (NEM) rains has also played a vital role in distinguishing 6 sub-regions in the
mid- country wet zone.
The four months period from December to March is relatively
"dry" in WM3a agro-ecological sub-region while there are two distinct dry periods in the
WM3b due to reduced effectiveness of SWM rains over this sub-region.
In the Low-
country Wet zone, amount and distribution of SWM as well as First Inter Monsoon (FIM)
rains were important in identifying the 5 agro-ecological sub-regions. Meanwhile, the
months July, August and December in WL3 agro-ecological region does not receive
adequate amount of rainfall and hence cannot be considered as wet months. As such, 4
months period extending from December to March is relatively "dry" in this region.
The Intermediate zone consists of 20 agro-ecological sub-regions out of which 15 subregions are in the central hills.
Varying degree of effectiveness of different rainfall
governing mechanisms across the central hills has caused variety of growing
environments in this region.
There are 7 agro-ecological sub-regions in the Up country
Intermediate zone out of which IU1 is reported to receive the highest annual rainfall
among all sub-regions of the entire Intermediate zone. Being in the Knuckles range, this
region receives ample amount of rains from NEM while the contribution from SWM
rains is also substantial. Complex geographical settings of the IU3 agro-ecological region
which encompasses almost whole of the so-called "Uva basin" have resulted 5 agroecological sub-regions due to high spatial variability of intermonsoonal and NEM rains in
this region. Meanwhile, being located in the rain shadow area of the SWM, this region
41
does not receive adequate rains during June to September resulting in dry and windy
environment. The Mid country Intermediate zone has 7 agro-ecological sub-regions.
Most of these sub-regions also do not receive adequate rains from SWM and, hence, 4
months period from June to September is relatively dry. Low country Intermediate zone
consists of 5 agro-ecological sub-regions. Other than IL2, all other agro-ecological subregions in the Low country Intermediate zone resemble a bi-modal rainfall distribution.
Since Second Inter Monsoon (SIM) and NEM rains are the only effective rainy seasons in
the region, the IL2 agro-ecological region exhibits a distinctly uni-modal rainfall
distribution along with a long and pronounced dry period from April to September.
In the Dry zone, there are 11 agro-ecological sub-regions with different rainfall
distribution and edaphic features. The DL3, DL4 and DL5 agro-ecological regions of the
Dry zone receive the lowest annual rainfall of the country in combination with some soil
limitations that are found in these regions. Out of 11 agro-ecological sub-regions, only
DL1a and DL1b are characterized by two discernible peaks in the rainfall distribution and
thus, support crops in both Maha and Yala growing seasons. Those agro-ecological subregions found in the eastern sector of the Dry zone, i.e., DL1c, DL1d, DL1e and DL2a
and DL2b, exhibit a distinct uni-modal rainfall pattern, and support only the crops in
Maha season. The rest of the agro-ecological sub-regions of the Dry zone also support
only the Maha crop since Yala rains in those sub-regions are not adequate to meet the
evapotranspiration requirements.
Livestock production systems and AERs
Compared to many countries in the region, Sri Lanka has no exception that major sources
of feeds for ruminants are pasture and fodder, which includes tree fodder. Therefore,
spatial population distribution of ruminants in Sri Lanka has a direct relationship with the
environment, in other word the agro-ecology of the island. However, spatial distribution
of poultry and Pigs which do not depend directly on pasture are less related to the agroecology while some other factors such as socio-economic and religious aspects may play
a major role in deciding the spatial distribution of these two animals.
42
Based on the feeding practices of major livestock, the ruminant production systems are
consisting of 5 major groups (Siriwardena, 1999) while non-ruminants having 2 major
production systems.
Ruminant production systems (Siriwardena, 1999)
UP country
Mid country
Wet & intermediate
Intermediate
Dry zone
Intensive
intensive
zone
& dry zone
intensive
System
system
semi-intensive
extensive
system
System
system
Zero grazing
Zero grazing
Combination of
free grazing
Zero grazing
With high
with moderate
tethered and/or
in crop/stock
Levels of
levels of
free grazing
integrated
Concentrate
concentrate
with limited
system
Feeding
feeding
feeding of
concentrates
Mid & Up country intensive system
The main crop grown here is tea.
Rainfall is fairly well distributed throughout the year
while the temperature is conducive for temperate breeds of livestock. The estate workers
keep dairy cattle mainly of improved European breeds under stall-fed condition.
have no own lands.
They
For forage requirement, they have to depend on natural grasses
grown in the canal bunds, waste and uncultivated lands are cut and fed to the cattle
together with concentrate feeds.
In the village-based system, farmer owns a piece of land and their farming is mainly
crop-livestock integration.
They are engaged in commercial oriented intensive vegetable
cultivation. Dairy cattle are kept mainly to get manure and the milk is often a secondary
43
income.
The main grasses found here are Panicum maximum (wild type) and Panicum
repense.
Wet & Intermediate zone semi intensive system
This system exists mainly in the coconut growing area of the low-country. Cross breeds
of Jersey, AMZ Sahiwal are popular animals in this system.
They have medium
production potentials of about 4-5 liters of milk/day. In normal practice animals are tied
to the coconut palms and rotate the location during the daytime or let loose in large
plantations or in fallow paddy lands.
Live fences erected with Glyricidia type trees
provide additional source of feeds to the animals.
In some instances, leguminous cover
crops like Pueraria and Centrosema are grown under the coconut plantations. They also
serve as a source of animal feed. It is found that considerable proportion of coconut lands
is inter-cropped with Banana, Pineapple, Coffee and Pepper like crops to increase the
land use efficiency.
In pepper inter cultivation, usually Glyricidia sticks are used to
support the pepper vines. The excessive growth of Glyricidia is lopped and such would
also provide a fair amount of biomass for livestock production.
Coconut meal, the by
product of coconut oil extraction process with rice bran forms the most popular
combination of concentrate feed supplement in this system. At present, inter-cropping of
improved grasses under coconut plantations is also catching up gradually.
Dry & Intermediate zone extensive system
This zone is typified by use of indigenous breeds. They graze for most of the year on
bunds, tank beds, villus and scrub jungle.
During good cropping seasons, the animals
may be moved some distance to scrub jungle. There is almost no use of concentrates and
little use of crop residues although buffaloes are fed rice straw.
The herd size is
comparatively large and varied from 30 to 200 heads of cattle mainly of indigenous and
some Indian crosses.
Use of natural tree fodder such as Accacia leucophloea
(Katuandara). Azadirachta indica (Kohomba), Drypetes sepiaria (Weera), Grewia
microcos (Keliya, Kohukirilla), Grewia polygama (Boru damaniya) Grewia tiliaefolia
(Damaniya, damina) is common in these areas.
These herds utilize feed resource of
wildlife.
44
In this system, animals are kept as a live saving and they are sold at any moment when
there is a need of money. Slaughter of cattle for home consumption is rarely practiced.
However, milk is sold mainly to the local market.
The buffaloes are used for draught
purposes in the northern dry zone while dairy buffaloes are common in the southern dry
zone and part of the north-central province for curd production.
Dry zone intensive system
The dry zone intensive system operates in Mahaweli settlement area under irrigation
facilities.
Since the major crop grown in this region is paddy, a substantial amount of
paddy straw and rice bran is available for livestock feeding. In addition, the crop residues
of maize and legumes are also available during the harvesting period of respective crops.
Some of the sugar cane factories and their contract grower systems are also located in this
production.
Thus, molasses feeding along with roughages as a multi nutrient block has
become a popular feeding practice in this area. But, farmers do very limited feeding of
sugar cane tops and bagasses to their animals.
Tree fodder and improved forages
growing in open areas, and bunds are also becoming popular.
The herd size in this
system is fairly small and the keeping buffaloes are less common. Local×Zebu crosses
are used for land preparation purposes. The lands in this area are fully occupied in most
of the time of the year.
Non-ruminant production systems
Poultry
The poultry industry is consist of multitude of small producers and a few large producers.
The intensive poultry production systems are concentrated in Western and North Western
part of the country as a commercial venture where easy access to market facilities and
input are available with improved infrastructure facilities. Most of the operations found in
these regions are medium to large scale having 1,000 – 10,000 birds. The extensive
production systems are scattered throughout the island as a backyard system.
45
Pigs
Pig farming is concentrated in the Western coastal “pig belt” as intensive systems (10-15
fatterners) and extensive systems. Under the extensive pig farming, small farmers keep 1
to 2 pigs as a scavenging system. It is understood that localization of the pig industry in
Sri Lanka is mainly due to the cultural and social reasons than that of its environmental
adaptability.
Bio-physical and agro-ecological characteristics of target sites
It has been evident that the population of the indigenous livestock is gradually decreasing
while some breeds/species have already been lost or are near at extinction. Hence, it is
important to conserve and utilize this broad genetic base to enhance the productivity of
livestock of the country in a sustainable manner.
Therefore, in the light of possible
financial assistance through FAnGR Asia Project, seven target sites covering four
administrative districts of Sri Lanka were selected to execute a full project on FAnGR
(Table 11 and Map 16). In the process of selection of target sites, parameters such as
abundance of indigenous livestock species (Map 10 - 14), agro-ecological diversity (Map
15) and poverty level of the people living in the area (Map 9) were considered.
Table 11 Selected target sites and their respective administrative units & AERs
AgroTarget site/DS division
Administrative
Province
District
ecological
region
Hambantota
DL5
Lunugamwehera
Hambantota
Southern
DL5
Siyambalanduwa
Monaragala
Uva
DL1b
Pottuvil
Panama
DL2a
Ampara
North-eastern
Thirappane
Galenbindunuwewa
DL1b
DL1b
Anuradhapura
North-central
DL1b
46
47
Hambantota and Lunugamwehera target sites.
These two DS divisions are located in the Hambantota administrative district of the
Southern province of Sri Lanka.
According to the agro-ecological map of Sri Lanka
(2003), these two sites fall under the DL5 Agro-Ecological Region (AER). The DL5 AER
of Southern Dry zone is considered as the driest part of Sri Lanka with an annual average
rainfall of 900 mm and annual dependable rainfall of greater than or equal to 650 mm.
The distribution of rainfall is not conducive any form of crop growth having a longer
growth cycle.
Considerable amount of rainfall, nearly 70% of the annual total receives
only during mid-October to mid-January, the Maha season (Map 15, Figure 1 & 2). The
Yala rains of about 300 mm between mid March to mid May are not adequate to raise a
crop. The period between mid May to September is dry and windy with very high
temperatures and evaporation rates. The daytime maximum temperature in this region
could vary from 30 to 35 degrees of Centigrade depending on the time of the year. The
highest temperatures are being recorded during May to September, the dry period of the
year (Table 12).
Natural vegetation of both DS divisions is predominately scrubland with thorny type
species with isolated trees and patches of trees.
Meanwhile, tank beds of abandoned
small tanks found in these two target sites could be converted to grazing lands with
improved varieties. Moreover, there is a considerable extent of land that is salt affected,
especially in the lowest position of the catenary sequence in Lunugamwehera target site.
For some part of these salt affected lands, irrigation water is also available. In some
cases, drainage water coming from the upper catenary positions could also be used.
Hence, establishment salt tolerant pasture species could be one of the best form of land
use for such lands, making the way for animal husbandry with appropriate breeds that are
adaptable to high temperature conditions prevailing in the area.
48
Figure 1 Average monthly rainfall at Hambantota (1921 - 1990)
200
180
160
Rainfall mm
140
120
100
80
60
40
20
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
49
Figure 2 Average monthly rainfall at Lunugamwehera (1983 - 1999)
250
Rainfall mm
200
150
100
50
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
50
Table 12 Average climatic conditions of the DL5 agro-ecological region of Sri Lanka (Location: Weerawila/1990-1996)
Jan
0
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Max temp. ( C)
31
32
33.4
34.1
33
34.4
33.6
34
32.8
32.6
31.8
29
Min temp. (0 C)
21.3
21.6
21.7
22.5
22.5
22.8
21.7
21
20.6
20.8
20.3
19.2
Rainfall (mm)
77.3
49.8
32.8
92.6
72.2
24.6
28.5
39.3
68.4
117.1
274.9
158.5
Evaporation (mm/day)
4.4
4.9
5.9
4.6
5.2
6.2
6.8
7.6
7.1
5.3
4.0
4.0
Wind velocity (kmph)
7.7
7.4
6.2
4.8
9.8
12.1
12.6
13.2
10.5
8.2
5.0
6.6
Bright sunshine Hours
7.1
7.7
8.2
6.7
7.6
5.7
6.2
7.6
7.7
5.4
5.8
5.7
RH (%) - morning
79
77
73
75
75
72
76
79
79
61
80
81
RH (%) - evening
71
68
68
72
67
66
68
79
71
73
74
78
51
Malala Oya and Karagan Oya are the major streams that flow through the Hambantota
DS division while Kirindi Oya is the only stream that flows through Lunugamwehera DS
division (Table 13 & Map 5).
Catchments of these three streams, which are relatively
small, are mainly concentrated in the Dry zone and posses intermittent flows. However, a
part of the catchment of the Kirindi Oya lies in the Intermediate zone. There is large
number of tanks in the Hambantota DS division (Table 14) out of which Bandagiriya tank
is the prominent one and others mostly belongs to the category of small tanks.
Bandagiriya tank is fed by both Malala Oya and diverted water of Lunugamwehera
reservoir. However, most of the small tanks found in the area are either abandoned or
heavily silted.
There are 14 tanks in the Lunugamwehera DS division (Table 15)
including the Lunugamwehera major reservoir, built in 1980s and Weerawila Wewa and
Pannegamuwa Wewa. Even though Lunugamwehera reservoir is one of the few recently
built major irrigation schemes of Sri Lanka with an irrigable area of 13,000 ha, on
average it does not receive the estimated design discharge in 3 out of 4 years. This is
mainly due to over estimation by about 20% of basin water availability during the
planning phase (IIMI, 1990). Therefore, crop failures have become frequent problem in
this irrigation scheme with a serious issue of poverty and malnutrition of settlers and their
dependents. A study conducted by the world food programme in 2003 has flagged
Lunugamwehera DS division as an area of "Most vulnerable" to food insecurity while
Hambantota DS division falling under the category of "Less vulnerable" (Map 9).
It is unlikely that more investment will be made available to rescue this ill-fated irrigation
project in the near future. Hence, there is a greater potential for livestock farming in this
region. However, care must be given to choose suitable livestock species for the region
as high temperature regime may hinder the potential performance of animals.
52
Table 13 Hydrological characteristics of major rivers in target sites
Basin
Name of
Catchment
Precipitation
Discharge
%
No.
basin
area (km2 )
volume (Million
volume (Million
Discharge
m3 )
m3 )
19
Karagan Oya
58
67
15
22
20
Malala Oya
399
434
74
17
22
Kirindi Oya
1165
1606
476
22
34
Helawa Ara
51
82
28
34.5
35
Wila Oya
484
653
215
33
36
Heda Oya
604
967
394
41
37
Karanda Oya
422
676
196
29
38
Semane Ara
51
82
25
31
67
Yan Oya
1520
2269
300
19
90
Aruvi Aru
3246
4592
568
12
Source: National Atlas, 1988
Table 14 Tanks found in the Hambantota DS division
Name
Name
1
Bandagiriya Wewa
12
Weligatta Wewa
2
Kelliywalana Wewa
13
Anokkan Wewa
3
Weheragoda Wewa
14
Nabada Wewa
4
Palessa Wewa
15
Kuda Wewa
5
Andara Wewa
16
Metigatta Wewa
6
Kapuwatta Wewa
17
Koholangoda Wewa
7
Keligama Wewa
18
Hangaranga Wewa
8
Juligama Wewa
19
Divul Wewa
9
Kalupalla Wewa
20
Kattana Wewa
10
Rambuk Wewa
21
Beligas Wewa
11
Gat Wewa
53
Table 15 Tanks found in the Lunugamwehera DS division
Name
Name
1
Sinikku Wewa
7
Ijukpelessa Wewa
2
Kadawara Wewa
8
Degaldehera Wewa
3
Kukulkatuwa Wewa
9
Kotakumbuka Wewa
4
Lutana Wewa
10
Pannagamuwa Wewa
5
Punchi Appu Jandura Wewa
11
Weerawila Wewa
6
Unctu Wewa
12
Lunugamwehera Reservoir
13
Kikiliwidda Wewa
Being a semi-arid region, the crop or pasture production in these two sites is largely
determined by climatic and edaphic features. Reddish Brown Earth (RBE) with high
amount of gravel is the predominant soil type of this region that can be found on crest,
upper and mid slopes of gently undulating to undulating highlands.
Low Humic Gley
(LHG) soil is the most commonly found soil type in valley bottoms with inclusion of
pockets of Solodized Solonetz where soil drainage is very poor. Potential and limitations
of these two predominant soil types are given below.
Potential and limitations Reddish Brown Earths (Rhodustalf)
This is the most widespread soil type in the Dry zone including two target sites under
review. It occupies in crest and well-drained mid and upper slopes of the catenary
sequence. The structure is weak to moderate sub-angular blocky.
The soil moisture
relationship is characterized by low water holding capacity with a rapid release of soil
moisture at tension lower than one atmosphere. The soil is extremely hard when dry,
friable to firm when moist and sticky when wet. A good account of physical properties of
RBE can be found in Joshua (1988). This soil type possesses good chemical
characteristics compared to other soil types of the country. The soil reaction is slightly
acidic to neutral with 60 to 80% base saturation.
54
RBE is characterized by having a gravel layer in the sub-soil and therefore root growth is
restricted due to shallow depth. It becomes easily slake under heavy rainfall and make
tillage operations are difficult, thus, can operate only under limited moisture range. As
soil moisture is lost at low tensions, soil moisture stress is very common even in short dry
spells. As the structure is weak, it is highly vulnerable to soil erosion and requires
adoption of soil moisture conservation measures. The presence of characteristics gravel
layer in the sub-soil hinders the downward movement of water and hence, an
improvement to drainage during rainy seasons is essential.
Potential and limitations Low Humic Gley soils (Tropaqualf)
Next to the RBE, Low Humic Gley soils (LHG) are the most extensive great soil group in
Sri Lanka with no exception in these two target sites.
This soil group is essentially a
hydromorphic soil located in the footslopes of undulating landscape of the Dry zone.
However, due to low rainfall and highly saline ground water in Hambantota and
Lunugamwehera DS divisions, a greater proportion of the LHG in these two DS divisions
are salt affected. The base saturation is in the range of 90 to 100% and free carbonates
are present at varying depth of the sub-soil and thus, soil reaction is moderately alkaline.
The water holding capacity of the soil is fairly good because of the presence of high
amount of clay with smectite. The most suitable land use for this soil group is paddy and
when the soil bears high salt contents, the salt tolerant grasses are the most appropriate
land use. Cultivation of upland crops or non-water loving plants is a difficult task in this
soil due to poor drainage condition.
In some places, drainage improvement has to be
done before the establishment of any crop or grass to facilitate flushing out of salts and
excess water coming from the higher positions of the catena.
Siyambalanduwa target site
The Siymbalanduwa DS division is located in the Monaragala administrative district of
the Uva province of Sri Lanka and belongs to the Wellassa region of the ancient
kingdom. According to the agro-ecological region map of Sri Lanka (2003), this DS
division
comes
under
the
DL1b
Agro-Ecological Region (AER). An important
characteristics of the DL1b AER is the presence of well defined two rainy seasons,
55
namely, Yala and Maha with annual average rainfall of 1,600 mm and annual dependable
rainfall of greater than or equal to 900 mm. The Maha or major rainy season is from
October to late January and the Yala, minor rainy season is from late March to mid May.
Hence, monthly rainfall records depict a bi-modal rainfall pattern with two marked dry
seasons, one during February to mid March, which is short and moderate, and the other
during mid May to September which is long and protracted (Map 15). Nearly 70% of the
annual total rainfall occurs during the Maha season while the balance occurs during the
Yala season. Months from June to September are generally rainless. Even if it rains, it
will be far below the evapotranspiration requirement due to prevailing high temperature
and winds (Table 16). However, in contrary to other parts of the DL1b AER, this area
receives considerable amount of rains during January and February through northeast
monsoon rains (Figure 3). This is mainly attributed to its proximity to the eastern coast
where northeast monsoonal winds begins to shed its moisture. Therefore, dryness during
February to mid March may not be so severe as compared to other typical DL1b regions
of the Dry zone.
Natural vegetation of Siyambalanduwa DS division is "moist deciduous forest".
However, due to clearing of forest for shifting or "Chena" cultivation, what is left of the
forest vegetation is quite small and predominant type existing vegetation is secondary
vegetation of scrub jungles.
Heda Oya is the only major stream that flows through the Siyambalanduwa DS division
(Map 5).
Unlike the other target sites in the Hambantota district, the Siyambalnduwa DS
division is not blessed with large number of tanks having only Heda Oya reservoir, Una
Ela reservoir and Polgahagama Wewa in operation.
The world food programme study
(2003) has categorized the Siyambalanduwa DS division as an area of "Most vulnerable"
to food insecurity (Map 9) and it could be attributed to lack of large number of surface
water reservoirs in the area.
56
Figure 3 Average monthly rainfall at Siyambalnduwa (1943 - 1980)
350
300
Rainfall mm
250
200
150
100
50
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
57
Table 16 Average climatic conditions of the DL1b agro-ecological region of Sri Lanka (Location: Angunakolapelessa/1992 -2001)
Jan
Max temp. (0 C)
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
30.9
31.6
32.8
32.7
32.6
32.3
32.3
32.5
32.1
31.6
30.8
30.6
Min temp. ( C)
22.0
22.2
22.6
24.3
25.1
24.6
24.7
24.4
24
23.5
23
22.5
Rainfall (mm)
63.9
67.0
55.4
100.4
95.2
64.4
42.0
41.3
112.8
167.3
235.0
111.4
Evaporation (mm/day)
4.1
4.6
5.3
4.5
4.5
4.6
5.0
5.1
4.7
4.0
3.4
3.6
Wind velocity (kmph)
6.2
5.5
4.8
4.8
6.9
7.9
8.5
8.6
7.4
5.7
4.3
5.3
Bright sunshine Hours
7.1
8.3
8.9
8
7.5
7.2
7.4
8.1
7.1
6.5
6
6.1
RH (%) - morning
84
84
81
82
81
81
79
78
79
82
85
85
RH (%) - evening
70
71
69
75
73
72
70
67
69
75
78
68
0
58
Being in the Dry zone, predominant soil type of the Siyambalanduwa DS division is well
and imperfectly drained Reddish Brown Earth (RBE) on the convex uplands and lower
mid slopes of gently to undulating landscape.
Low Humic Gley (LHG) soil, the poorly
drained member of the catenary sequence is the most commonly found soil type in the
concave valleys and bottomlands. Potential and limitations of these two predominant soil
types of the target area have already been discussed in a preceding section.
Panama and Pottuvil target sites.
Both these target sites are located in the Pottuvil DS division of the Ampara
administrative district of the northeastern province of Sri Lanka. According to the agroecological region map of Sri Lanka (2003), Panama falls under the DL1b AER while
Pottuvil is coming under the DL2a AER. Even though, Siymbalanduwa target site, which
was discussed in the preceding section and Panama site, are located in the same AER, the
DL1b, rainfall distribution of Panama is quite different from the typical rainfall
distribution of DL1b.
Generally, Panama resembles a uni-modal rainfall distribution
(Figure 4) where as bi-modal pattern is the characteristics rainfall distribution of DL1b
(Figure 3). Under such situation Panama should have been categorized under DL2 AER
where the characteristics rainfall distribution is uni-modal. However, delineation of DL2
was primarily based on the presence of Non Calcic Brown (NCB) Soils as the
predominant soil type. Since Panama is characterized by having RBE soils with no NCB
soils or its associations, it has been compelled to categorized Panama under the DL1b
AER.
Panama area receives about 1,500 mm annual rainfall with 1,150 mm of annual
dependable rainfall.
Nearly 80% of the annual rainfall is received during the Maha
season. None of the months in the Yala season receive rainfall in excess of
evapotranspiration and hence, a Yala season is not discernible in the region (Figure 4).
Pottuvil target site is located in the DL2a AER where predominant soil type is NCB and
monthly rainfall distribution is uni-modal (Figure 5). Hence, it does not permit year
around cultivation unless irrigation water is provided. The annual dependable rainfall of
this region equals or exceeds 1,300 mm. The Maha season at both target sites is relatively
longer compared to other parts of the Dry zone, starting from October to February
receiving nearly 80% of the annual rainfall (Figure 4 & Figure 5).
59
Figure 4 Average monthly rainfall at Panama (1950 - 1988)
350
300
Rainfall mm
250
200
150
100
50
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
60
Figure 5 Average monthly rainfall at Pottuvil (1983 - 2003)
350
300
Rainfall mm
250
200
150
100
50
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
61
Table 17 Average climatic conditions of the DL2 agro-ecological region of Sri Lanka (Location: Aralaganwila/1992 -2001)
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
0
29.7
31.5
34.1
31.8
35.6
34.5
34.5
35
35.3
33.5
31.2
29.6
0
Min temp. ( C)
21.2
20.7
21.2
23.3
23.9
24.1
24.2
23.5
22.9
22.8
22.7
22
Rainfall (mm)
245.4
141.2
14.5
111.4
64.9
19.8
35.0
31.8
88.7
184.6
387.9
358.0
Evaporation (mm/day)
3.3
4.0
5.1
4.9
5.6
6.7
7.0
7.0
6.2
4.8
3.5
3.0
Wind velocity (kmph)
3.2
3
3
3
3.7
6.3
6.9
5.9
4.7
3.8
2.7
3
Bright sunshine Hours
6.2
7.5
9
8
8.6
7.2
7.6
8.4
7.6
6.5
5.5
5.1
RH (%) - morning
92
91
86
82
77
69
68
70
70
80
89
92
RH (%) - evening
77
70
58
65
60
56
54
54
55
66
77
80
Max temp. ( C)
62
At both Panama and Pottuvil, the period between mid May to September is dry and
windy with very high temperatures and evaporation rates. The daytime maximum
temperature in this region could vary from 30 to 37 degrees of Centigrade depending on
the time of the year. The highest temperatures are being recorded during May to
September, the dry period of the year (Table 17).
Natural vegetation of both these target sites is predominately "Dry evergreen forests".
Helawa Ara and Wila Oya are the major streams that flow through Panama area while
Heda Oya, Karanda Oya and Semane Ara find their way to the eastern coast through
Pottuvil area (Map 5). Catchments of these three streams, which are relatively small, are
mainly concentrated in the Dry zone and posses intermittent flows.
There is a large
number of small tanks in the Pottuvil DS division with some lagoons (Table 18). The
world food programme study of 2003 has flagged Pottuvil DS division as an area of
"Less vulnerable" to food insecurity and is among 4 of such DS divisions in the Ampara
district out of total of 19 DS divisions (Map 9).
Being in the DL1b AER, the predominant soil types in the Panama area are well and
imperfectly drained Reddish Brown Earth (RBE) on the convex uplands and lower mid
slopes of gently to undulating landscape of inland. Low Humic Gley (LHG) soil, the
poorly drained member of the catenary sequence is the most commonly found soil type in
the concave valleys and bottomlands. Potential and limitations of these two predominant
soil types of the target area have already been discussed in a preceding section. In
addition, sandy Regosols are found along or near to the coastline usually as elongated
strips. Generally, Regosols show no structural development and both surface and subsurface soils are single grain. Soil reaction is neutral with a base saturation of 75 to 90%.
64
Table 18 Tanks found in the Pottuvil DS division
Name
Pottuvil area
Name
Panama area
1
Kirikovi Kulam
1
Helawa Kalpuwa
2
Serolai Kulam
2
Kunikala Kalpuwa
3
Tamara Kulam
3
Solambe Kalpuwa
4
Pallanchi Wettiya Kulam
4
Weddana Kalpuwa
5
Manthodai Kulam
5
Pannakala Wewa
6
Siriyawa Kulam
6
Helawa Wewa
7
Rota Kulam
7
Panama Wewa
8
Semani Kulam
8
Viagalla Wewa
9
Arugam Kalapu
9
Wedagama Wewa
10
Paladi Kalapu
10
Miyangoda Wewa
11
Nalitta Wewa
12
Watawana Wewa
13
Naulla Wewa
14
Uipassa Wewa
15
Ullawera Villu
16
Eratil Tank
17
Rugam Well Kulam
Although, the sandy Regosols have a rapid infiltration, the infiltrated water is stored in
the under lying static Gyben-Herzberg lens of fresh water, which permits stable human
settlement and agricultural production on this landscape even in the very dry environment
(Panabokke, 1996). Apart from these soils, Alluvial soils could be found in either side of
banks of river and streams with a variable texture and drainage. Soil reaction of the
Alluvial soils of the Dry zone is slightly acid to slightly alkaline with a base saturation of
60 to 90%. As reported by Alwis and Eriyagama (1969), "the best Dry zone vegetation
occur on these soils. Paradoxically, some of the worst vegetation also exists on Alluvial
65
soils where a high water table or very clayey texture impedes aeration.
In general, tall
trees with other mesophytic species of the Dry zone are found on these soils".
Potential and limitations of Regosols and Alluvial soils
The most significant feature of Regosol is the occurrence of Gyben-Herzberg lens of
fresh water for cultivation. However, over exploitation of lens of fresh water could lead
to contamination of ground water by brackish water from the sea. Tillage operations in
these soils are very easy.
As the soil is highly permeable, micro irrigation is the most
suitable type of irrigation for these soils. It also helps to reduce the accumulation of
added nutrients in the ground water.
Alluvial soils posses good physical characters and
highly productive. As these soil occur near to rivers and streams, surface and ground
water availability is relatively higher compared to other soils of the area. Depending on
the location, flooding and poor drainage may become a problem in Alluvial soils.
Thirappane and Galenbindunuwewa target sites.
These two DS divisions are located in the Anuradhapura administrative district of the
North-central province of Sri Lanka. According to the agro-ecological map of Sri Lanka
(2003), these two target sites fall under the DL1b Agro-Ecological Region (AER). The
main features of the DL1b AER have been adequately described in a preceding section,
therefore
needs
no
further
elaboration.
However,
it
must
be
noted
that
Galenbindunuwewa being closer to the DL1 e may experience uni-modal rainfall pattern
with an extended Maha season and poor Yala rains (Figure 7). For the special need of this
report, however, the general climatic condition of the DL1b AER of North-central
province has shown in the Table 19. As there was no rain measuring stations from
respective target sites, rainfall climatology of the two sites has shown using data from
nearby stations (Figure 6 & 7).
Natural vegetation of both DS divisions is "moist deciduous forest". However, due to
clearing of forest for shifting or "Chena" cultivation, what is left of the forest vegetation
is quite small and predominant type existing vegetation is secondary vegetation of scrub
66
jungles. Meanwhile, tanks beds of abandoned small tanks found in these two target sites
could be converted to grazing lands with improved varieties.
Aruvi Aru is the major stream that flows through the Thirappane DS division, which has
fairly large catchment across the Dry zone (Map 5). There are a large number of small
tanks in the Thirappane DS division along with some big tanks such as Nachchaduwa
Wewa in a cascade system (Table 19). However, most of the small tanks found in the
area are either abandoned or heavily silted. A study conducted by the world food
programme in 2003 has flagged Thirappane DS division as an area of "Most vulnerable"
to food insecurity amidst large number small tanks available in the area. It suggests that
even though the number is higher, these tanks operate well below their capacity due to
siltation and disturbance in the respective minor catchment of the cascadei .
Yan Oya is the major stream that flows through the Galenbindunuwewa DS division,
which has a relatively small catchment compared to Aruvi Aru ( Table 13 & Map 5). As
in the case of Thirappane DS division, Galenbindunuwewa DS division has also been
blessed with large number of small tanks along with Hurulu Wewa in a cascade system
(Table 21). However, most of the small tanks found in the area are either abandoned or
heavily silted. The world food programme study in 2003 has identified the Thirappane
DS division as an area of "Most vulnerable" to food insecurity amidst large number small
tanks found in the area. Short-sighted efforts to develop each tank in isolation has made
tremendous damage to these tanks cascades resulting reduced inflow conditions along
with increased siltation.
i
Cascade or chain of tanks is series of small reservoirs that are constructed at successive locations down
one single common water course.
67
Figure 6 Average monthly rainfall at Maradankadawala (1970 - 1999)
*
250
Rainfall mm
200
150
100
50
0
Jan
Feb
*Nearest raingauge station to Thirappane
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
68
Figure 7 Average monthly rainfall at Kahatagasdigiliya (1941 - 1963)
350
300
Rainfall mm
250
200
150
100
50
0
Jan
Feb
Mar
Apr
Nearest rain gauge station to Galenbindunuwewa
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
69
Table 19 Average climatic conditions of the DL1b agro-ecological region of Sri Lanka (Location: Maha-Illuppalama/1992 -2001)
Jan
Max temp. (0 C)
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
29.4
32
33.8
33.9
33.1
32.1
32.4
32.7
33.1
31.5
30.2
29.2
Min temp. ( C)
20.9
20.8
21.7
23.7
25
24.8
24.6
24.4
23.8
23.2
22.6
21.7
Rainfall (mm)
101.6
129.6
29.9
175.5
77.8
26.2
21.0
38.6
82.2
248.0
304.8
185.5
Evaporation (mm/day)
2.9
3.8
4.8
4.6
4.7
4.8
5.3
5.5
5.0
3.6
2.6
2.5
Wind velocity (kmph)
4.0
4.2
4.4
4.9
9.6
12.4
12.4
12.1
10.4
6.5
3.5
3.6
Bright sunshine Hours
6.9
8.6
9.5
8.6
8.9
7.9
7.6
8.2
8.1
6.7
5.6
5.6
RH (%) - morning
97
86
82
82
80
80
79
78
78
83
87
89
RH (%) - evening
71
61
51
65
67
66
62
61
64
74
79
70
0
70
Being in the Dry zone, the crop or pasture production in these two sites is largely
determined by climatic and edaphic features. Reddish Brown Earth (RBE) with high
amount of gravel is the predominant soil type of this region that can be found on crest,
upper and mid slopes of gently undulating to undulating highlands.
Low Humic Gley
(LHG) soil is the most commonly found soil type in valley bottoms.
Potential and
limitations of these two predominant soil types have already been discussed in a
preceding section and therefore, will not elaborate here.
Table 20 Tanks found in the Thirappane DS division
Name
Name
1
Nachchaduwa Wewa
17
Meegassegama Wewa
2
Thirappane Wewa
18
Kon Wewa
3
Sembukulama Wewa
19
Alistana Wewa
4
Wellamudawa Wewa
20
Kudagama Wewa
5
Hammilla Kulama Wewa
21
Wagaya Kulama Wewa
6
Hinnawatta Wewa
22
Bulankulama Wewa
7
Pahala Mawata Wewa
23
Vendarankulama Wewa
8
Wettan Kulama Wewa
24
Ittikattiya Wewa
9
Selesti Maduwa Wewa
25
Periya Kulama Wewa
10
Tammennagala Wewa
26
Puduk Kulama Wewa
11
Ulan Kulama Wewa
27
Uttimaduwa Wewa
12
Aiyatiyagama Wewa
28
Muriyakadawala Wewa
13
Amanakattuwa Wewa
29
Karuwalagas Wewa
14
Siwalagala Wewa
30
Galkulama Wewa
15
Torapitiya Wewa
31
Eru Wewa
16
Mahakanumulla Wewa
32
Periya Maduwa Wewa
72
Table 21 Tanks found in the Galenbindunuwewa DS division
Name
Name
1
Hurulu Wewa
17
Aswayabendi Wewa
2
Ichchan Kulama Wewa
18
Pahala Kantegama Wewa
3
Kele Kumbuk Wewa
19
Taranagollewa Wewa
4
Kanni Maduwa Wewa
20
Maha Keligama Wewa
5
Gatalawa Wewa
21
Kuda Himbutugollewa Wewa
6
Divul Wewa
22
Maha Himbutugollewa Wewa
7
Pahala Nittawa Wewa
23
Bora Wewa
8
Palugalla Wewa
24
Siyambala Wewa
9
Jayanthi Wewa
25
Rotagollagama Wewa
10
Rambewa Wewa
26
Kolongas Wewa
11
Karawalagas Wewa
27
Muwapitiya Wewa
12
Ulpotagama Wewa
28
Uddiyan Kulama Wewa
13
Elapatgama Wewa
29
Tammenawa Wewa
14
Thimbirigas Wewa
30
Manakkettiya Wewa
15
Ranorawa Wewa
31
Galwetiya Wewa
16
Upuldeniya Wewa
32
Yakalla Wewa
73
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