Tuesday, September 12, 2006

Design and Development of a Low Cost Peiite Trailer for farm Transport

P L A G Alwis, L W S Pemasiri & N P G Pushpitha
Faculty of Agriculture, University of Ruhuna, Mapalana, Kaburupitiya, Sri Lanka

Transporting goods is a basic need for all farming operations. Transport facilities greatly influence the timing of fieldwork (seeding, fertilization) and determined the economic success of a farming enterprise by opening access to local markets. At present it can be estimated, about 20% of farm transport is done by mechanical trailer, 20% by traction animals and the remaining 60% by manual power. It is only available for few farmlands, which are close to good service roads. Lack of adequate transport causes late harvesting of crop is left in the fields because of lack of transports. It has been observed that poor transport is accountable for a total loss of about 25% of the harvests.

The objective of this study was to design and development of a low cost appropriate mounted type petite trailer for four-wheel tractor to solve the on-farm and farm–market transport problems.

The designed mounted type cart used for the experiments, consists of a wooden platform, a metal frame and tree point linkage for the attachment of the four-wheel tractor.

Fuel consumption (L/hr), traveling speed (km/hr), production cost per cubic meter space (Rs/m3), total weight (kg) and farmer opinion were considered as criteria for comparison of merits and demerits.

From the result, it was observed that the performance of developed trailer was significantly higher. The fuel consumption is twelve times lower and the total weight was ten times lower than the average conventional trailer. It was calculated that the traditional trailer is fifteen times can be recommended as better transporting equipment which is successfully used in on farm transport.


D M S H K Ranasinghe
Department of Forestry & Environmental Science, University of Sri Jayewardenepura

In order to meet the increasing demand of a growing population and increased aspirations, Sri Lanka has to increase and sustain production/procurement of essential items including food, energy, resources for shelter, apparels etc. Agroforestry which is a method of integration of trees and agricultural crops and/or animals can be considered an appropriate and useful method for achieving economic, environmental and social sustainability. There is an age-old agro forestry traditions in the country and numerous examples of its practices are to be found in all climatic zones. In addition to these, development of new management strategies using scientific and systematic management strategies for wider adoption have been a relatively recent approach.

This paper reviews the agroforestry interventions such as home gardens, farmers’ woodlots, use of agro forestry for management of watersheds, intercropping under coconut, energy plantations under coconut and alley cropping. Physical factors and government/ institutional variables are considered as external determinants while socio-economic factors of individual farm families contribute as inputs to the operation. Recommendations are also given to further develop their systems for sustainable development.


K W L K Weerasinghe1, K M Mohotti2, C N Herath2, A Samarajeewa3,
V Liyanagunawardena4 & H M G S B Hitinayake, 1
1 Faculty of Agriculture, University of Peradeniya, 2Tea Research Institute of Sri Lanka, 3Coconut Research Institute, Bandirippuwa Estate, 4Oxfam GB, No. 4, Kinross Avenue, Colombo 4

Earthworms have been well exploited in agriculture worldwide in maximizing crop production for many years. Amongst vermin-technology (Vermitech) practices, Vermiwash (Vw) has shown its field efficacy with many crops. Vw is the wash of earthworm’s celomic fluid and calcareous layer and the watery extract of the bedding materials, which is known to contain ample amounts of soluble macro and micronutrients, natural growth hormones, beneficial microbes, vitamins and amino acids etc. and nematicidal properties. However, the attributes to beneficial agronomic values of Vw have not yet been scientifically validated fully although this practice is extensively being expanded in India and Sri Lanka. Therefore, the present study investigated the biological and chemical properties of eleven sources of Vw resulted from different earthworm species and raw materials in different farms in Sri Lanka. Vw was tested as a source for hydroponics for lettuce in comparison with the Albert solution. The efficacy of regular foliar and soil applications of Vw on bush bean (Variety: Top crop), tomato (Variety: Thilina), nursery tea (cultivar: TRI 4071) and coconut (Variety: DxT) was also evaluated in comparison with vermicompost and conventional chemical inputs in a series of bioassays.

The results of analyses revealed varying levels of biological and chemical properties of the test samples but within the optimal range for plant growth. Vw exhibited significantly lower levels of N, P, K but was rich in Ca, Mg, Zn, Fe and Mn; pH and CEC were also in the required ranges. Vw significantly (p=0.05) influenced the soil microbial biomass although individual microorganisms were not identified; microbial biomass of Vw and control were estimated as 4.95 and 3.20 × 10-3 mg CO2/day/25g soil respectively. Vw proved as a better alternate source to Albert solution for lettuce growth under hydroponic culture. The root length, root and shoot biomass and total leaf area of bush bean were significantly (p=0.05) affected by Vw application compared to that of vermin-compost and synthetic fertilizer treatments. In nursery tea, Vw application lead to comparatively greater callusing of tea cuttings but the increase in root formation and shoot growth was not significant. Vw application boosted growth of coconut seedlings. However, no positive responses were seen with tomato.
The data suggested the potential exploitation of Vw in home gardening, indoor and container planting, biodynamic and organic farming etc. as a farmer friendly, culturally sensitive and economically viable natural product. Further work on attributes to plant growth such as determination of growth hormones, different doses and mass production of uniform quality Vw using different earthworm species and raw materials etc. would strengthen its sustainable use as an alternative growth supplement


D P Samaraweera & U K Jayasinghe-Mudalige
Department of Agribusines Management, Faculty of Agricultural and Plantation Management, Wayamba University of Sri Lanka, Makandura, Gonawila (NWP)

This study examines empirically the extent to which vegetable cultivating farmers in Sri Lanka are willing to adopt effective, economical and sustainable crop protection technologies such as Integrated Pest Management (IPM) instead of applying solely chemical pesticides to control pests. It uses primary data collected through a series of personnel interviews with a randomly selected sample of vegetable farmers (n = 100) that practice chemical control measures in the Kurunegala and Puttalam districts in the Wayamba Province from May to July in 2005.

The behavioural change in farmer attitudes and perceptions towards adoption of environmentally-friendly IPM techniques instead of applying chemicals on the vegetable cultivation on a regular basis were captured by means of two indexes – Additive Index (AI) and a Multiplicative Index (MI), which used the scores given by participants to the survey to a set of attitudinal statements (n = 17) explaining this behaviour on a Likert scale. The outcome of AI and MI were in turn modelled with the farmer’s socio economic characteristics, including the age, sex, level of education, income, managerial time, experience in farming, extent of land allocated for cultivation, crop type, availability of credit and extension facilities etc. to test significance of these factors on this behaviour. The results suggest that many of these have a significant impact on the farmer’s degree of responsiveness towards adoption of sustainable agricultural practices. The outcome of analysis highlights the need of provision of appropriate private and regulatory incentives for farmers to change their behaviour in this respect.

Key Words: Adoption, Attitude and Perceptions, behavioural Change, Integrated Pest, Management (IPM), Sustainable Agriculture


Mangala De Zoysa & M A P D P Wickramaratne
Department of Agricultural Economics, Faculty of Agriculture, University of Ruhuna

The agricultural and forest resources in Sri Lanka are diminishing while the population is still growing. Hence, designing of resource-efficient agro-forestry systems has considerable potential not only to improve forest and agricultural production but also to enhance and maintain overall productivity of sustainable small farm units. The different types of agro forestry systems in the country are highly diverse and complex in characters and functions. However, the productivity of agro-forestry system and the role in environmental conservation are lower than their potential due to lack of proper management practices. Green Productivity (GP) approach emphasizes the sustainable development of agro-forestry systems enhancing productivity and using resources efficiently while protecting the environment.

The paper attempts to discuss the concept, methodology, principle stage, implementation strategies and impact assessment of GP approach with the view of sustainable development of agro-forestry systems in Sri Lanka. The GP concept emphasizes environmentally sound technology transfer to keep agro forestry systems competitive; environmental regulations to extend farmers responsibility; and cleaner production enhancing productivity and environmental performance of the agro-forestry systems. The methodology of GP would consist of problem-solving steps, selecting tools, techniques and technologies useful for solving problems in agro forestry and application of socio-economic and environmental principles and values for agro-forestry improvements. The six principle stages of GP are described in terms of getting started to gain base-line information and identify problems in agro-forestry systems: generation and evaluation of GP options to meet the objectives and targets of the agro-forestry system: implementation of GP options involving performance and the targets being achieved: and sustaining GP through corrective options to achieve objectives and targets of the sustainable agro forestry systems.


D Senaratne, RT Serasinhe, K K Pathirana & N S B M Atapattu
Department of Animal Science, Faculty of Agriculture, University of Ruhuna

The effects of long and short-term buffalo grazing on plant species diversity under coconut were examined. 18 Murrah and Surthi pure and crossbred buffaloes were allowed to graze 3 hours a month for 6 months (short term grazing). Herbage from an adjoining coconut plantation was taken as the control. Quadrate sampling was adopted to analyze herbage up to species level and four random samples were taken at each event.

The Shannon diversity Index (H), species richness and evenness were calculated for each treatment.

Results showed that the diversity index and evenness in the undisturbed habitat (ungrazed coconut plantation) were 2.176 and 0.6679 respectively and were much higher than highly disturbed habitat (grazed plantation) where the same values were 0.4.747 and 0.2160. The short term grazing effect showed an intermediate results. In the ungrazed site there were greater number of plant species and more equitable the individuals in the community were distributed. Long term grazed coconut plantation had only 9 species and over 80% of the individuals belong to one species; Carpet grass (Axonopus affinis) the most common species in a grazing land. Grazing pressure was favorable to dominate prostate type plants. It was shown that grazing pressure whether short term or long term changed the abundance of plant species.

It is concluded that different levels of disturbance have different effects on plant species diversity.


D Senarathne, R T Serasinghe, K K Pathirana & N S B M Atapattu
Department of Animal Science, Faculty of Agriculture, University of Ruhuna

The objective of this study was to investigate the effect of grazing on some soil properties; bulk density (BD), true density, porosity, moisture content (MC) and pH. The effect of long term grazing (>20 yrs) was examined in a coconut - pasture - cattle integrated farming system in Kamburupitiya area. Short term grazing effect was compared with an adjoining coconut plantation permitting 18 buffaloes to graze for 6 months. Another adjoining ungrazed coconut farm soil was considered as control. Soil samples were taken from the topsoil using a core sampler (v = 98.21 cm2). Four replicate samples were taken three times with 30 days interval and analyzed in triplicates. Data were statistically analyzed using SAS.

Soils collected from the long term integrated farming site had a significantly higher (p < 0.05) average pH (5.58) than that of non-integrated sites (4.65). Reduction of acidity may be due to the improvement of soil nutrients via dung, urine and accumulation of litter. It was observed that the soil in integrated sites were comparatively dark in color. BD of integrated soil (1.15g/cm3) was significantly lower than that of non-integeated soil (21.26%) due to the better ground cover by dominant prostate type herbages compared to ungrazed soils where erect type herbages were prominent. Soil porosity also improved due to integration (47.76%) with that of non-integrated soil (43.76%). There was no significant difference observed under the effect of short term grazing. A considerable time period may be required to change to improved soil properties.

It is concluded that long term crop-livestock integration could improve the soil physiochemical properties.


P L A G Alwis
Faculty of Agriculture, University of Ruhuna, Mapalana, Kaburupitiya, Sri Lanka

Soil resistance to penetration or penetrability, which is measured by the penitrometer, has found numerous engineering and agronomic applications. The instrumentation and procedure are fairly simple and rapid, relatively non-destructive determinations are possible both in the field and the laboratory. The force or the work required to drive one of standard metal heads to a given depth has been found empirically to be correlated with soil depth, bulk density and moisture content. The information obtained is interpreted to make diagnoses or predictions regarding soil bearing strength and trafficability, degree of compaction, workability by agricultural implements and the consequences of tillage in terms of soil condition and crop yield.

Different types of penitrometers with spring loaded or proving0ring types are in common use. But these instruments are not suitable for local soil conditions due to inappropriate spring mechanism. It also requires high cost for calibration process.

A hammer type low cost appropriate mechanical ‘PLAG Upland penitrometer’ was designed and constructed. (Patent no: 13360). It consists of a carriage probe unit, one force applied unit and adjustable mainframe. It was used forr soil strength measurements of Red yellow Podzolic soil under forest cover in six different layers with ten replications.

The results show that the average soil strength values of the 2.5cm, 7.5 cm, 12.5cm, 17.5cm, 22.5cm and 27.5cm depth layers were 0.7M pa, 1.2M pa, 1.3M pa, 1.3M pa, 1.7 M pa and 1.6M pa respectively. The overall average soil strength of Red yellow Podzolic soil under forest cover was 1.3M pa and the cost of production of the design ‘PLAG Upland penitrometer’ was 10,000 rupees.


U K Jayasinghe-Mudalige1 & Alfons Weersink2
1Department of Agribusiness Management, Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, Gonawila (NWP)
2Department of Agricultural Economics and Business,
University of Guelph, Guelph, ON, Canada, NIG 2WI

This paper investigates the extent to which agri-environmental practices (AEPs) adopted by Canadian crop livestock farms were adjusted to the presence of urbanization. Seven AEPs: (1) water management; (2) wildlife conservation; (3) pesticide management; (4) fertilizer management; (5) manure management; (6) nutrient management; (7) grazing management, were considered.

It was hypothesized that farmers close to urbanized areas are more likely to adopt AEPs to minimize any conflict with their non-farm neighbors. The key explanatory variables included in the seven empirical models, which comprised of level of adoption of an AEP as the dependant variable, to explain the degree of urbanization were: (the distance (km) “as the crow flies” from the geographical centre of each Census Sub-Division to that of the nearest Census Metropolitan Area in Canada, and (2) population density (number of persons/km2) in the locale of each farming operation. In addition, a number of other standard control variables influencing the adoption of AEPs (e.g. type and size of farm, age of operator, ownership, income etc.) were also included.

The data from the Statistics in Canada collected through the “Farm Environmental Management Survey – 2001” (n=16053) were used. The results based on Logit Regression analysis imply that there are significant differences with respect to the adoption of AEPs in crop and livestock farms located in low versus high population density regions. The results imply in turn that farmers in urbanized areas face greater social and economic constraints, and thus likely higher costs, than their counterparts in more rural areas.


W M P S B Wahala1 Pien Huang2
1Department of Forestry & Environmental Science, University of Sri Jayewardenepura
2Harved Collage, USA

The foraging patterns of stingless bees are dependent on resource availability. Human alterations to natural areas will affect the condition of local habitats, and influence the bees’ foraging behavior. In this study, we assessed the familiarity of Trigona thoracica with two distinct habitats.This study investigates the familiarity of the stingless bee Trigona thoracica with two distinct habitats. It has the dual purpose of comparing foraging distance between the intact forest and disturbed environments, and of evaluating the idea that bees create memory patterns for navigational purposes en route to destinations. We hypothesized that bees forage more frequently in the natural environment than in the disturbed environment, and are therefore more familiar with forested terrain. We also suspect that bees are able to form a visual memory in transport, and that they will integrate cues they acquire in transition to guide themselves home from unfamiliar locations. We selected a (medium-sized) colony of Trigona thoracica at the base of a Ficus microcarpa tree near the entrance to the Khao Chong Peninsular Botanic Gardens. The nest was located in a relatively open area, adjacent to two distinct environments: a densely wooded forest to the east and an altered, semi-natural environment along a highway to the west. One transect line was placed in each of these two areas, and three release points along the transects were determined using GPS (East – Forest area: 350, 650, 1200m; West - Highway: 400, 800, 1200m).

Outgoing bees were collected in plastic bags and tagged with paint markers. Collections ranging in size from sixteen to seventy bees were then transported in an insect cage to designated release points either on foot or on motorbike. At each location, two samples (covered and uncovered) were released at staggered times. The two transects were completed over the course of three days, with a total of twelve releases. On each day we had similar sunny and dry weather conditions. On each day, the nest was observed from the first release to at least 1.25 hours after the last release; the activity of marked bees (entering or exiting the hive) was recorded, as well as the time of that activity. Percentage returns were calculated for each batch of marked bees released from each of the three releasing points on each transect, according to the recorded number of returns for each batch.

There was no significant difference between the number of covered and uncovered bees that returned. This leads us to believe that the bees do not form memory when they are artificially transported, which may be due to factors, which differ between artificial transport and normal flight behavior. Possible factors include the rate of movement, and the height of travel. Additionally, the mesh-and-plastic carrying cage may have skewed the bee’s exposure to sunlight and added an abnormal level of stress for the bee, altering the bee’s ability to assess the solar pattern. These factors would contribute to the bee’s incapacity to use egocentric methods for homeward navigation. We found that the bees are more familiar with the natural habitat than the disturbed habitat. The forage distance was determined to be 3.676 km in the forested area and 1.973 km along the highway.


S Hewage1 & Chen Po Hao2
1 University of Sri Jayewardenepura, Nugegoda, Sri Lanka, 2 Tunghai University, Taiwan

Antlions belong to the order Neroptera, class Insecta. They belong to the family Myrmeleontidae. The antlion name is applied to the larval stage of these insects. Adult insects of this family have four lace-like wings, similar to dragonflies. Pit building behavior is characteristic to the genus Myrmelon. There are different size antlions and they appear to consume different prey according to preliminary observations. Hence the hypothesis is to establish whether antlions have the ability to select their prey, and whether their level of hunger and their own body size affect prey selection.

Present study was conducted in Khao Chong Wildlife Extension and Conservation Center, Trang Province, Thailand.

In order to identify the predatory behavior of antlions, antlions were collected from the field and kept for about six hours for rest and recuperation, and allowed to make their pit. The experiment was conducted at room temperature. An ant was dropped in the center of the pit and resulting interactions were observed. Observation of the antlion was started as soon as the prey dropped in the center of the pit and ended with either the prey dead or escaped free from the pit.

In order to check whether antlions select their prey according to the prey size, starvation level and their own size, collected antlions were categorized into two groups according to body size (0.5-1.0 cm long and <1.0 cm long). Both size classes were sub-divided in to four groups of 15 individuals, and they were fed with ants. After feeding, each group was starved for a different length of time (0 hrs (level 0), 12 hrs (level 1), 24 hrs (level 2), and 36 hrs (level 3), prior to commencing the feeding experiment. Three types of prey were used for this experiment.

From the collected data predatory success for small and large antlions was calculated for each treatment. One sample T – tests were run in order to check whether there was a significant difference in predatory success between three types of prey at the same starvation level. In order to identify the relationship between predatory action and starving level for small antlions and large antlions a contingency analysis was conducted.
In order to identify the predatory action by prey type a second contingency analysis was carried out. Large antlions always attacked small prey and attacked large prey less frequently, but small antlions attack all prey with equal frequency.

According to results larger antlions attack more large prey as starvation level increased, but small antlions try to attack all prey without regard to size. However, predatory success was low for small antlions, when they attacked larger prey. Smaller antlions may be less experienced in assessing prey size or likelihood of success.

It was found that the selected time scale for the starvation levels was too long. Hence, it was difficult to compare the predatory success of different starvation levels.


K K I U Arunakumara1, U Wickramasinghe1, B C Walpola2 & S Subasinghe1
1Department of Crop Science, Faculty of Agriculture, University of Ruhuna, 2Department of Agricultural Chemistry, Faculty of Agriculture, University of Ruhuna

Gymnema sylvestre R.Br. belonging to family Asclepiadaceae, is naturally found in tropical forests of India and in some parts of Sri Lanka. This herb is best known for its ability to abolish the taste of sugar and has been used in the treatment of diabetes. A number of commercial herbal products are now available that contain varying amounts of gymnemic acids, the component responsible for the action against diabetes. Though the demand for the species is increasing rapidly, the commercial cultivation of the species is yet to be expanded. On the other hand it is felt that the natural regeneration of this important herb is poor and this study was carried out in Matara District of Southern Sri Lanka to assess the natural regeneration of the species.

An extensive survey was conducted in order to find the natural habitats and authenticity was confirmed for the mother plants found in the area. Flowering, fruiting and other important physiological phases of the plant were monitored and observations were made under natural conditions. Results revealed that Gymnema is propagated naturally by means of seed germination only. Flowering commences late in the year and mature pods release seeds from early February each year. The low moisture content of the seeds at the time of release together with dry environmental conditions result in very low germination and thus the natural regeneration of the species is poor though a single mother plant produces thousands of seeds at a season. Therefore, an alternative mode of multiplication should be made available in order to propagate and to conserve genetic stock of this useful plant.


C D Kaluthota, S N Gamage & U L S Kaluthota
Field Ornithology Group of Sri Lanka, Department of Zoology, University of Colombo

Painted stork is a Near Threatened species that uses wetlands as their feeding and breeding grounds. The breeding colony of painted storks at Kumana villu is one of the oldest known colonies in the island. Mangrove vegetation located in the middle of the villu provides ideal conditions for nesting not only for painted storks, but also for Black headed Ibises, Spoonbills, herons, egrets and even for the globally threatened Spot billed Pelicans.

A survey was done in the month of July to assess breeding status of the Pained Storks in this villu. The survey was land based where three mangrove vegetation patches (5000m2) were surveyed using a spotting scope (Nikon Fieldscope). First, all trees in each patches that contain painted stork nests were identified. Then number of nests on each tree, number of adults, hatchlings and fledglings on nests were recorded.

A total of 222 nests of painted storks were recorded. This comprised of 217 active nests of which 74 contained hatchlings while 133 nests contained fledglings. Average number of nests per tree was 3.13 while the number of nests per tree ranged from 1 to 10. Average hatchling size was 1.81 while average fledgling size was 1.78 where 61.35% nests contained 2 hatchlings or fledglings while 29.95% nests contained only one hatchling or fledgling. The nest height ranged from 1 to 10m with average nest height being 3.0m.

According to the available literature the breeding season of painted storks is from December to May. However, during this survey it was discovered that 98% of the nests were active as late as July indicating that there can be great deal of variation in the breeding strategies of painted storks. Furthermore, based on our studies we have estimated that there can be approximately thousand breeding pairs of painted storks in Kumana villu, making this one of the most important breeding sites for this species. Therefore this site should be continuously monitored in order to better understand the breeding behavior of painted storks.


W W R Wijesinghe1 & C M Maddumabandara2
1Ayurvedic Hospital, Anuradhapura, 2Department of Geography, University of Peradeniya

The Ritigala Strict Nature Reserve has an ideal setting for ethno botanic studies on account of its unique features. It is a living folder of information regarding bio diversity and is regarded as an ‘oasis of vegetation’. Therefore protection and conservation of its flora and fauna is of vital importance.

As this area extends over 1528 hectares, observation of encroachments is a difficult task. Forest clearance can be clearly observed by using aerial photographs of consecutive years. The aerial photographs may provide sufficient data to observe the land uses and vegetation types of the Strict Nature Reserve.

Aerial photographs of 1982 and 1992 were used as a tool to observe the usable pattern of the forest. The texture of the aerial photographs was studied and qualitatively it could be divided into three categories. Textural variations were significant. Restrictions of some textures could be observed to some specific areas, which can be explained as an effect of the Northeast monsoon rains.

The aerial photographs show improvement of the natural habitat of the forest area within a period of ten years from 1982 to 1992. No constructions were seen within the limits of the Strict Nature Reserve until 1992.

The study of aerial photographs indicated different patterns in the canopy cover. For instance, temporal changes observed in white canopies appeared significant. It is surmised that these white crowns are those of Mangifera zeylanica (Bl.) Hook.f (Etamba) in bloom.
Key words: Ritigala, Strict Natural Reserve, aerial photographs, temporal changes, Mangifera zeylanica (Bl.) Hook.f.


W W R Wijesinghe1 & C M Maddumabandara2
1Ayurvedic Hospital, Anuradhapura, 2Department of Geography, University of Peradeniya

The Ritigala Strict Nature Reserve has an ideal setting for ethno botanic studies on account of its unique features. It is a living folder of information regarding bio diversity and is regarded as an ‘oasis of vegetation’. Therefore protection and conservation of its flora and fauna is of vital importance.

As this area extends over 1528 hectares, observation of encroachments is a difficult task. Forest clearance can be clearly observed by using aerial photographs of consecutive years. The aerial photographs may provide sufficient data to observe the land uses and vegetation types of the Strict Nature Reserve.

Aerial photographs of 1982 and 1992 were used as a tool to observe the usable pattern of the forest. The texture of the aerial photographs was studied and qualitatively it could be divided into three categories. Textural variations were significant. Restrictions of some textures could be observed to some specific areas, which can be explained as an effect of the Northeast monsoon rains.

The aerial photographs show improvement of the natural habitat of the forest area within a period of ten years from 1982 to 1992. No constructions were seen within the limits of the Strict Nature Reserve until 1992.

The study of aerial photographs indicated different patterns in the canopy cover. For instance, temporal changes observed in white canopies appeared significant. It is surmised that these white crowns are those of Mangifera zeylanica (Bl.) Hook.f (Etamba) in bloom.
Key words: Ritigala, Strict Natural Reserve, aerial photographs, temporal changes, Mangifera zeylanica (Bl.) Hook.f.


P R Attygalle
River Basin Planning Division, Mahaweli Authority of Sri Lanka

Riparian or riverine zones consist of important vegetation that helps to stabilize the stream banks, trap silt and enhance the quality of stream water. However during the last century riverine vegetation has been heavily degraded due to human impact.

The study in the Kala Oya basin covered Kala Oya and fifteen of its tributaries. The NCR GRADSECT sampling methodology was adopted and 5m width 100m or more length 67 plots were randomly set out considering the length of the streams. All the trees, >10cm dbh, saplings >1m height and < 10cm dbh, seedlings, 1m height were recorded.

The results reveal 81 species of seedlings, 81 species of saplings and 61 species of trees in the study site. The recorded endemicity of seedling: sapling: tree is 4:2:2. Among the 1080 individuals recorded 532 were >20cm dbh, 539 were >10m in height and 431 had > 3m canopy cover. The most recorded tree species were Terminalia arjuna (270), Pongamia pinnata (161), and Ficus racemosa (91).

The stream wise species to individual ratio vary from 0.128 to 0.600. Five streams recorded over 20 species and they are Kala Oya (30), Siyabalanduwa Oya (27), Dambulu Oya (25), Welamitiyawa Oya (24) and Kalankuttiya Oya (23).

The most interesting finding is that there is natural regeneration within the zone and only basic silvisultural treatment is required to enhance the process. However in sites where heavy human impacts were observed planting of suitable species have been recommended.


N N Hettiarchchi1, I K Rajapakse2 & U K G KPadmalal2
1Forest Department, Sri Lanka
2Department Zoology, The Open University of Sri Lanka, Nawala, Sri Lanka

Handapanagala tank area is home for the largest Elephant aggregation (Elephas maximus maximus) in Wellawaya area during the dry season. Most of these Elephants come from different areas mainly from adjacent protected areas such as Yala, Udawalawe and Lunugamwehera National parks. The main traditional migratory route lies across the study area connecting Yala –through Demodara. The local migration is mainly due to lack of food and water within the protected areas.

The study attempted to find the food habits of elephants in Handapanagala area during dry season. This study was carried out for six months. The main objectives were to determine both food availability and feeding habits in relation to the habitats. Food availability and their Relative Importance Values (RIV) were estimated using line transect and direct observation method within study area. Relative importance values were comparatively high in species like Bauhinia racemosa (12.39 %), Fleuggea leucocarpa (17.32 %), Securinrega leucopyrus (14.3 %). Relative frequency value indicated that most common species distributed in the study area were Bauhinia racemosa, Dichrostachys cinera, Phyllanthus sp., Premna sp. The micro histological analysis was done to determine food habits of elephants. The major food plant parts in dung samples were analyzed to identify the categories of plants consumed by elephants. This study revealed that the major food items consumed by elephant during dry season were the monocotyledon leaves (65 %), Culm (12 %), Sheath (6 %) and Dicotylidens Bark (7 %) and, Woody fiber (2%). The predominant grasses identified in dung samples were Imperata cylindrica (Gini grass) and Panicum maximum (Illuk). The field observations revealed that the elephants were mainly consuming plants in families such as Leguminosae, Graminae, Euphorbiaceae and Verbenaceae. Majority of bark damages were seen in plants such as Bauhinia racemosa (RIV – 12.39), Treminalia arjuna (Kumbuk) and Phyllanthus spp. A total of 112 plant species were identified and 35 species (31% of the available plants) were consumed by elephants. The results indicate that the Elephants in the Handapanagala are grazers and mainly feed on tall grasses during the dry season. Results also indicated that there is an impact on forest tree species like Bauhinia racemosa, Fleuggea leucocarpa and Securinrega leucopyrus, which have high RIV. Since the present study was carried out during dry season, this should be continued during wet season to get a broad idea about the seasonal changes in food habits of Elephants.

Key words: Asian elephants, Food Availability, Food preferences, protected areas, micro histological analysis


D Jayantha1, P N Dayawansa1, U K G K Padmalal2, W D Ratnasooriya1 & J A Weerasinghe3
1Department of Zoology, University of Colombo, 2 Department of Zoology
The Open University of Sri Lanka, 3Department of the Wildlife Conservation

Guinea grass (Panicum maximum) dominated grasslands, a major habitat type in the Udawalawa National Park, is frequently occupied by wild elephants. Behaviour of juvenile elephants (4-6 years old) inhabiting the habitat was studied from April 2004 to March 2005. Focal animal sampling was employed to quantify behaviour and total time of observation was 3100 minutes.

The activity budget of the juveniles comprised of ten behaviour patterns; feeding (44%), resting (24%), locomotion (19%), play (5%), comfort (5%), drinking, social, exploratory, agonistic and anxious. Maximum feeding (55%) and minimum resting (13%) were recorded during late afternoons (1500-1800 hrs) whilst maximum resting (37%) and minimum feeding (29%) were recorded during late mornings (0900-1200 hrs). Locomotion and other behaviour patterns did not significantly vary with time. Time spent on feeding was higher in wet months (47%) than in dry months (39%). Resting was relatively higher in dry period (27%) than in wet (21%). P. maximum was the major food type consumed throughout the year while they fed on native grasses and herbs to a lesser extent (21-29%). Significant correlations between ambient temperature and time spent on feeding (r= -0.716) and resting (r = +0.751) were evident.
The Department of Wildlife Conservation and the Born Free Foundation, UK are acknowledged.


C D Kaluthota, D K Weerakoon & S W Kotagama
Field Ornithology Group of Sri Lanka, Department of Zoology, University of Colombo

Kumana villu is one of the oldest known breeding sites for many waterbird species that breeds colonially. The canopy of mangrove trees located inside the villu provides nesting facilities for the large water birds such as Painted storks, Spoonbills, Black headed Ibises, egrets, cormorants and globally threatened Spot billed Pelicans. A detailed study of this breeding colony was done in 1983 By Kotagama. After 22 years, the breeding bird survey was reinitiated in July 2005.

First, a roosting count was done to estimate the population size of breeding birds in the Kumana villu. The counts were conducted from 3 pre-identified locations between 1700 to 1900h in the 2nd week of July. Three mangrove vegetation patches of 5000m2 were chosen for a detailed nest count. In each patch, the number of trees used for nesting was recorded. Then for each tree, number of nests, the species to whom the nests belonged, the height of each nest and the current status of nesting were recorded.

Many species of birds use this villu for roosting while Painted Storks showed the highest population density (728). Among other water birds, spot billed pelicans (422), spoonbills (57), cormorants (187), egrets (184), Black headed Ibises (74) and darters (41) are the most common taxa. In 1983, 228 painted storks, 565 pelicans, 125 ibises and 609 egrets were recorded. Five flight paths of birds that come to roost were identified in 1983. However, only 3 flight paths were observed during this survey.

A total of 293 nests were recorded that belonged to five species namely purple herons, little cormorants, painted storks, spot billed pelicans and spoonbills. Most common nesting species in this period was painted stork and 97.6% of their nests were still active. In May 1983, total of 701 nests belonged to seven species were recorded and most nests were of painted storks (529). In 1983, nests of four additional species, grey herons, ibises, egrets and night herons were recorded while purple herons and cormorants were not recorded to be nesting.

The mangrove vegetation has changed from a diverse habitat to a single species (S. caseolaris) stand during last 22 years. Reduction of mangrove area was also observed. Further, invasion of the common weed species Typha angustifolia is another major change that has taken place during this period.

Isolated mangrove trees and trees that are located beyond the perimeter of the villu are not selected by birds for nesting. Low density of vegetation inside the villu is a limiting factor for breeding birds. Most remaining trees in the villu are not in good condition and therefore a replanting programme is recommended to ensure continuous breeding of this colony.


S Hewage & W T P S K Senarath
Department of Botany, Faculty of Applied Science, University of Sri Jayewardenepura

Anoectochilus setaceus, Zeuxine flava, and Zeuxine regia are three endangered medicinal plants belong to family Orchidaceae and sub family Neottioideae. They are widely used in traditional medicine. Due to its beautiful variegated leaves they are also used as ornamental plants and commonly known as Jewel Orchids.

The Methodology used to identify the natural distribution of these species was field observation in the sites. In order to identify the places where these species are growing knowledge of the traditional practitioners and village people were used. According to literature, these species are confined to tropical wet evergreen, sub montane and mid country wet ever green forests. In this study these three species were observed in particular locations in Kanneliya MAB reserve and Peak Wilderness sanctuary.

Anoectochilus setaceus is a rather common species found under the shade of trees among fallen leaves. It was found along the riverbanks in Kanneliya while in Peak Wilderness it was found in a valley close to a stream. They were confined to small patches with high humidity where it gets very low intensity of sunlight. Number of plants, which were observed in Peak Wilderness sanctuary, was high (150 plants/m2) while it was lesser (50 plants/m2) in Kanneliya. Distance between two forest patches where A. setaceus was found was about 50m in Peak Wilderness sanctuary while it was too far (>100m) in Kanneliya MAB reserve. Some patches had a distance of about 2km.

Zeuxine regia was found in disturbed sites in Kanneliya MAB along the trail closer to village, which situated at the boundary of the forest. In Peak Wilderness also this species was found closer to the main trail starts from Siripagama. These plants were found in places where there is no stream even within 500m. Z. regia was found among rocks where environmental conditions were very harsh but the soil was rather wet.

Zeuxine flava was observed along a trail situated within the village in Kanneliya far away from sites where other two species were distributed. Natural abundance is comparatively low for this species. In Peak Wilderness it was found along the same trail with Z. regia and A. setaceus but in different pockets. Environmental conditions of Z. flava are totally different when compared with the sites where other two species were found.

Anoectochilus setaceus was observed under same environmental conditions recorded by previous researchers, while other two species were found from entirely different environmental conditions from recorded data. Although literature reports that, Z. regia found together with A. setaceus under natural conditions, such combinations were not observed in both forests. They were found in entirely different locations.


C D Kaluthota & S W Kotagama

Field Ornithology Group of Sri Lanka, Department of Zoology, University of Colombo.

The IBA programme produces inventories of internationally recognized sites, which are vital for conservation of birds. These sites are identified using set of four standard global criteria. These criteria are designed to select representative areas of most important bird habitats, principally those that are under the most severe pressure. As birds are the best indicators for overall biological diversity, most IBAs will be significant for other animals and plants too. The reason for initiating a global IBA programme was obvious as throughout the world important sites for wildlife conservation are being destroyed, polluted or disturbed at an increasing pace. Habitat loss and modification is the single largest threat to biodiversity. Many threatened species are in fact threatened by the same factors at particular sites. Therefore, site-based conservation measures can conserve many species at the same time.

First task for the IBA programme was the identification of important birds for first three categories i.e. globally threatened species, restricted range species and biome restricted species. Ten species of globally threatened species are considered for the IBA programme since 14 of 24 globally threatened species recorded from Sri Lanka are vagrants. Twenty-four restricted range species including newly discovered Serendib scops owl are included in the second category. All nationally threatened species are also included in this category. Nineteen species are listed under biome-restricted species for this programme.

In Sri Lanka, 70 Important Bird Areas have been identified all over the island. From these IBAs, 47 supports globally threatened species while 56 sites facilitate restricted range species. 46 IBAs contained biome restricted species. For bird aggregations, 26 sites have been identified. Four IBAs namely Yala, Bundala, Gal Oya and Udawalawe are qualified under all four categories. 39 sites qualify for three of the four categories. According to the area of the IBAs, 25 sites are less than 1000ha in size while 27 IBAs are between 1000 and 5000ha. This shows the severity of fragmentation of the important areas. 71% of the IBAs are located in the South Western part of the island showing the importance of protecting wet zone forests, which are highly threatened by human disturbances.


S G S Vamathevan 1, N Bandara 1 & S Suthakar2
1Department of Forestry and Environmental Science, University of Sri Jayewardenepura
2Regional Agricultural Research and Development Centre, Northern Region, Vavuniya

One and only tank in the heart of the Vavuniya town is Vavuniya tank. The quality of water in the tank is degraded due to various anthropogenic activities. These activities include rapid urbanization and agricultural practices. The objectives of the study were to identify the sources of pollution to the tank and significance of the impacts from pollution and proposing measures to prevent further degradations of the tank.

Six sampling locations were selected. The samples were collected at a distance about 2-3 meters away from the edge of the water spread area of the tank and to a depth of 30-45cm for 3 days. Electric conductance (EC), pH and salinity were measured by portable meters and standard methods were used in the determination of Cl- (Chloride), NO3- (Nitrate), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Total Dissolved Solid (TDS) and Total Suspended Solid (TSS). The obtained values were compared with Sri Lankan Surface Water Tolerance Limits. Several pollution sources were also identified.

The results of the analysis elucidate that Cl- and pH were within the tolerance limit in all these locations but the TSS and NO3- were very high. Salinity and EC were very high at Waste Water Drainage site, College of Education site and close to the Rice Mill site. BOD and DO values were found to be high at the Waste Water Drainage site and close to the Rice mill site. Pollution sources identified during the study showed high number of Eichornia, Parthinium and Salvinia, improper solid wastes, oil, grease and wastewater. Other than these some encroachers are in the tank bed.


W L Sumathipala, K I A Kularathne & M M M Senevirathne
National Ozone Unit, Ministry of Environment and Natural Resources

With the development of halogenated hydrocarbons by E.I.Du Pont de Nemours & Co (USA) as refrigerants, there had been an increase in usage of these chloroflurocarbons (CFCs) in refrigeration applications worldwide since 1950, mainly because these substances have excellent thermodynamic and safety characteristics. In Sri Lanka the consumption of CFC was increased rapidly up to 1995 (Table 1). Scientists had discovered the effects of CFCs on the earth’s ozone layer in nineteen seventies and it was agreed by large number of countries to phase out the production and usage of CFCs by becoming party to the Montreal Protocol. The Montreal Protocol on Ozone Depleting Substances (ODS) was signed in 1987 to implement the phase out programme. Sri Lanka became a party to this Protocol in 1989 and is bound to implement phase out ODSs by dates specified by the Protocol. In order to reach that target, National Ozone Unit (NOU) was established in the Ministry of Environment and Natural Resources in 1994. NOU has implemented several projects in order to reduce consumption of CFC with the assistance of Multilateral Fund (MLF) of the Protocol.

Table 1 Use of CFC in Sri Lanka


Sri Lanka has introduced a licensing system in 1998 to control the imports of CFCs and so far achieved successful reduction of CFC consumption. The table 1 shows the downward trend of CFC consumption as a result of action taken by the NOU. As an Article 5 country under the Montreal Protocol Sri Lanka need to phase out CFC consumption by 2010. However, Sri Lanka has taken steps to phase out CFC by the end of 2007.

To achieve phase out as planned, three refrigerator manufacturers were funded to convert from CFC -11 to HCFC -141b and from CFC 12 to R 134a, converted an aerosol manufacturing plant from CFC 12 to Hydrocarbons and launched a scheme to pay incentives for converting CFC refrigeration plants to non-CFCs. In addition the NOU has taken steps in awareness creation, training of refrigeration technicians and recovery and recycling of CFC. As a result, consumption of CFC in the manufacturing sector has been phased out and remaining consumption in the servicing sector could be eliminated through projects already planned.

Apart from ozone layer depletion, CFCs are powerful greenhouse gases much stronger than CO2. Therefore it is important to reduce emission of CFC not only to save the ozone layer but also to prevent global warming and climate change.


N S Gamage1, K H Muthukuda Arachchi1 & T K Weerasinghe2
1Central Environmental Authority, 104, Denzil Kobbekaduwa Mawatha, Battaramulla,
2The Open University of Sir Lanka, Nawala, Nugegoda

The Kelani River could be ranked as the largest recipient of industrial effluents of the country. The pollution burden of this effluent is quite diverse ranging from food manufacturing industries to heavy industrial discharges from textile factories, tanneries, soap and cleaning preparations manufacturing plants and rubber factories. An attempt was made to estimate the liquid emission loads released annually into the Kelani River Basin by the above sectors.

Liquid emission loads were assessed in terms of Biological Oxygen Demand (BOD) and Total Suspended Solid (TSS) content. In certain cases special parameters such as Chemical Oxygen Demand (COD) and Chromium were also assessed because of chemical contamination and hazardous potential. In estimating emission loads Rapid Assessment Procedure and the Date Bade Urban Pollution Control Model were used as the guide.

The results of the study indicate that the Kelani River receives 766.73 tons of BOD and 462.04 tons of TSS annually from the above mentioned industrial sectors and 3.8 million cubic meters of annual industrial wastewater volume. In addition, the tanneries and leather finishing factories discharge untreated effluent, which is contaminated with chromium, a hazardous heavy metal having bioaccumulation potential, into the river basin. The amount of chromium released into the river is as high as 6.36 tons while the COD load from rubber manufacturing sector is 48.71 tons annually.

Keywords: Biological Oxygen Demand, Chromium Effluents, Liquid Emission Loads, Total Suspended Solids Content, Standard Industrial Classification (SIC), World Health Organization.


M A W Kumara & J M S J Bandara
Department of Civil Engineering, University of Moratuwa, Moratuwa

Transport infrastructure improvements in rural sector provide greater opportunity to access economic, social & education facilities. This issue is very crucial since it covers fundamental aspects of rural revitalization. The lack of acceptable transport infrastructure has led to the isolation of rural areas. Roads that do not belong to the National & Provincial road network are the secondary & tertiary road links that provide main access to most rural population in the country.

Situation in the local government setup is different from the national setup. Even though over 70,000 km of roads belong to local government authorities, budgetary allocation for road works is very minimal. Most of these unclassified roads are low volume earth or gravel roads and carry less than 150 vehicles per day out of which more than 85% are light vehicles such as bicycles, motor bicycles or three wheelers.

Local government authorities tend to allocate available funding to upgrade few gravel or earth roads to paved condition or to rehabilitate dilapidated paved roads arbitrary. As no funding mechanism for regular road maintenance is available these low volume roads get deteriorated not due to vehicle loading but due to environmental conditions. This arbitrary upgrading strategy used by local government authorities result in waste of resources with not much benefit to rural communities.

This paper attempts to identify sustainable & environment friendly strategies to upgrade and maintain low volume local roads at a satisfactory condition for a longer period. Use of appropriate geometric standards, selection of cost effective construction standards that satisfy the access & mobility needs of rural population is discussed. Use of locally available material, labour and equipment that provides environment friendly solution are compared & presented.


N S B M Atapattu
Dept. of Animal Science, Faculty of Agriculture, University of Ruhuna

Domestic ruminants contribute 16.5 % of the total methane emission to the environment and 3.5% of the global warming effect. Methane emission needs to be reduced by 10-20% to stabilize the methane concentration in the atmosphere. Emission of methane from ruminants can be reduced by two ways; reducing per animal emission by efficient fibre digestion and reducing the number of ruminants by efficient nutrient utilization. Feeding strategies based on fossil-fuel-demanding concentrate diets produce more Co2 and consume voluble natural resources while reducing methane. The most widely used second feeding strategy uses low quality forages and agro-industrial by products. Even though this practice reduces the problems associated with the first one, it emits more CH4 due to the deficiencies of many critical nutrients required for efficient microbial activity in the rumen. These critical nutrients are N, minerals such as P and S, readily available carbohydrates, true proteins and rumen undegradable proteins. Protozoal activity and low undegradable protein levels reduce both the quality and quantity of the amino acids and other nutrients absorbed in the small intestine. The composite result of the second feeding practice is increased total CH4 emission. Among the solutions discussed in this paper in addressing those problems, tree legumes could play a pivotal role. It is concluded that feeding strategies for ruminants should be based on materials such as forages and agro-industrial-by products that consumes less fossil fuels and natural resources. However, unless the problems associated with these resources are not properly corrected, this strategy would be countered productive.


R C Watawala1, J A Liyanage1, A P Mallawatantri1, & S S Liyanage2
1Department of Chemistry, University of Kelaniya,
2Department of Chemistry, University of Sri Jayewardenepura

Carbofuran (2,3 dihydro 2,2 dimethyl 7 benzofuranyl methyl carbamate) is the most popular pesticide used in Sri Lanka. The fate, degradation and dissipation, of carbofuran was determined in four soil groups in Sri Lanka in order to study the persistence of pesticide in soils after application.

Red yellow podzolic soils (Nuwara Eliya), Alluvials (Pugoda) and Regosols (Kalpitiya and Negombo) types were selected for the experiment.

For the degradation analysis, 10 g of each soil was incubated under 70% of maximum water holding capacity and 28 0 C of temperature at 13 hours light and 11 hours dark conditions. 0.05 Ci of 14C ring labelled carbofuran (98% of chemical purity) was added to each soil sample and incubated in the above conditions. Liberated CO2 collected to an alkaline solution was analyzed by using Liquid Scintillation Counter after 0, 1, 3, 5, 7, 14, 28, 56, 90 days.

For adsorption studies, 5 g of soil mixed with 1ppm pesticide solution was shaken for 16 hours in the room temperature. The supernant collected after centrifuging was analysed using High Performance Liquid Chromatograph having 18C Apollo column.

Carbofuran mineralization percentage was below 7.5% in all soils after 10 days but a significant different showed in Kalpitiya regosols, which had a rapid mineralization rate than other three soils. After 20 days mineralization in Kalpitiya was 12.5% and in Pugoda it was 7.5%. After 90 days Kalpitiya regosols showed over 60% of mineralization and in other three soils it was below 50%. During 90 days incubation period only 10% mineralization was showed in Nuwara Eliya red yellow podzolic soils.

In the adsorption study Kd value obtained were 1.64 for Nuwara Eliya, 0.63 for Kalpitiya, 0.2 for Pugoda and 0.11 for Negombo. Hence Nuwara Eliya has the highest adsorption rate and Negombo exhibited the lowest.

Nuwara Eliya has the highest organic matter among the selected soils and pesticide sorption can be expected to be the highest to Nuwara Eliya soils. The microbial degradation is expected to be high in soils having high organic matter but the degradation rate was highest in sandy soils in Kalpitiya. Hence it can be seen that chemical and other degradation is higher than microbial degradation of pesticides in soils in Sri Lankan conditions.


S S Paththinige, G A Chandana & R T Serasinhe
Faculty of Agriculture, University of Ruhuna

Broiler farming was popular among the rural farming community during last decade due to ever increasing consumer demand. Most of these farmers engage in broiler farming expect higher profits for their ventures but they do not consider about the hazards done to the surrounding environment. Therefore, the objective of this survey was to find out the causes, which negatively affect on the surrounding environment and advice farmers how to reduce the above impacts. A house survey was conducted in Kamburupitiya area by visiting the broiler farms to monitor the dust and ammonia levels in the cages, litter management, slaughtering process etc.

The results of this survey revealed that, all the farmers expect higher profits from their ventures while having little skill, knowledge and technology. 90% of the farmers have taken correct initial steps in the construction of cages considering north-south direction, selection of sloppy lands etc. However all the cages were located very close to the residential areas and public roads (less than 25m) due to security reasons. It was also found that the cages (100%) situated in sloppy lands were very close to the water bodies. Even if the north-south direction was correct 20% of the cages were situated under high shade condition preventing natural disinfection. 50% of the cages had metal roofing sheets, which lead to heat stress during daytime. It was also revealed that more than 50% cages had poor ventilation due to some barriers such as vegetation and closely constructed cages. 60% of the cages had very strong ammonia smell inside while 40% farms had strong ammonia smell due to poor litter management and ventilation. None of the farmers mixed the litter with lime and they did not turn and mix litter frequently or even not bothered to change the wet litter as well. Dust level was higher in 70% of the cages and medium in 30% of the cages leading the surrounding environmental problems. All the farmers processed chicken by them selves, but there were no problem of offal disposal. None of the farmers do record keeping, use of footbath and contact advisory services.
High concentration of ammonia and dust in the surrounding environment leads to cause respiratory problems in near by public and ammonia may leads to cause toxic effects also.

Most of these farms have over ten-year history but their knowledge about proper management practices has not updated. They just gather information from neighbour farmers and they have no theory knowledge about broiler management. If the farmers can be educated abut the proper management practices such as litter management, ventilation, proper housing and maintenance, proper waste disposal and disinfection of sheds etc. it is possible to maximize profit while minimizing the negative impacts on the environment.


G D G Chaturani, M P Jayatilleke & S Subasinghe
Department of Crop Science, Faculty of Agriculture, University of Ruhuna
Pterocarpus santalinus is a valuable medicinal plant, now included in red list of endangered plants under IUCN guidelines. Distribution of this plant in Sri Lanka is very limited and the local demand for ayurvedic purposes is still unreached. As conventional propagation techniques are not satisfactory, possibilities in in-vitro techniques seem to be promising, and callus culture is one aspect that has to be studied. Leaf parts, cotyledon parts, root segments, inter-nodal segments, and nodal segments from in-vitro seedlings were used as explants. 2,4-D and BAP were used separately in six different concentrations (1 mg/l - 6 mg/l) for callus initiation Full strength MS medium (Murashige and Skoog, 1962) was used with 30 g/l of sucrose and 8 g/l agar as the culture medium. Callus formation could be observed in every explant. However, large clumps of creamy white callus were obtained from nodal segments. Callus formation in root segments was very poor and showed brown color. In nodal segments, callus formation was started within two weeks and large clumps of callus were observed while slight swelling occurring on root segments, leaf parts and in cotyledon parts at the end of 4th week. Callus formation was best when the culture medium was supplemented with 3 mg/l of BAP. Though callus formation could be observed in 2,4-D, amount of callus formed was poor. Present studies revealed that MS medium supplemented with 3 mg/l BAP is ideal for callus induction in Pterocarpus santalinus and possibility of using nodal segments as initial explants.


M A N De Silva1, W T P S K. Senerath2 & K S S Sugathadasa1
¹Bandaranayake Memorial Ayurvedic Research Institute (BMARI), Navinna Maharagama
²Faculty of Science, Department of Botany, University of Sri Jayewardenepura

Pterocarpus santalinus L. is highly demanded rare medicinal plant, which is used in Ayurveda and not naturally occurred in Sri Lanka. It is used as home remedies since ancient times. There are records on few cultivated plants in dry areas especially in southern part of the country. Normally plants are propagated by fresh seeds, but it requires special treatment for seed germination. Not only that, the percentage germination is also very low. With the aim of developing a protocol for mass propagation through in vitro techniques, nodal cuttings, shoot tips and leaf discs from tender leaves at rejuvenation period were used as explants. Explants were cultured on basic Murashige & Skoog (MS) medium supplemented with Kinetin, NAA, BAP, IBA, & Calcium panthothenate at a range of concentrations and on B5 medium supplemented with BAP and Kinetin at different concentrations. While 3% (W/V) sucrose was added (pH = 5.7) to MS medium, 2% (W/V) sucrose was added to B5 medium (pH = 5.5). Agar at 0.8% was added to both media for solidification. Cultures were incubated at 25±1° C temperature and kept under different light intensities. Callus initiation was observed after 14-21 days of incubation in 16 hr light. Callus was initiated and continued growth only in 16hr light condition in MS medium. In B5 medium callus was initiated but not continued the growth any further. Best explant source for callus production was nodal cuttings. Embryogenic callus was obtained from leaf discs in MS medium, mainly from the cultures incubated in dark. Small amount of embryogenic callus was initiated under light conditions in the same medium. Embryogenic callus could be grown in cell cultures and thereby can produce large number of somatic embryos which may be lead to mass production of plants. The amount of callus production and the nature of callus depend on the explant type, growth regulators used and incubation conditions.Direct shoot elongation occurred at low percentage (10%) in MS medium supplemented with 0.2mg/L Kinetin, 0.1mg/L NAA, 0.5 mg/L BAP, 0.3mg /L IBA and 0.1mg/L and Calcium panthothenate. It was even lesser (<5%)>


P B R Weeraratne¹, M P Jayatilleke¹ & G K K Priyantha Kumara²
¹Dept. of Crop Science, Faculty of Agriculture, University of Ruhuna
²Green Farm Ltd. Pahala Walahapitiya Rodd, Marawila

Croton is one of the exportable type foliage species in Sri Lanka. However, wilting of the leaves is a major problem raised in the export of these foliage species. In order to full fill the demand in world market, it is essential to overcome such problems.
In this study, seven experiments were conducted at Green Farms (Pvt) Ltd. Marawila, to maintain the vase life of Codiaeum varigatum cv. ‘Batik’, ‘Pictum’, and ‘gold star’ cut decorative shoots and to retain their export quality characters. Sugar (0, 1, 2, 4 & 5%), NiCl2 (250, 500, 750 & 1000ppm), combination of sugar (2%) + KMnO4 2ppm and glycerol (1, 5 and 10%) were tested as treatments (vase solutions) in separate experiments. Treatments were arranged in complete randomized design with 3 replicates each. Data were analyzed using SAS statistical method with analysis of variances. Mean separation was done using LSD on parametric procedures.
Croton had ability to maintain vase life up to 3 weeks in preliminary studies. To comparison of different packing methods for vase life of croton, wet paper packing showed higher vase life and higher leaf freshness for croton. Sugar treatments applied to “Pictum” and “Gold star” were maintained 21 days of vase life. “Batik” showed only 17 days vase life (C.V. =7.750323). NiCl2 gave 18 days of vase life for “Batik” (CV = 11.04419) however it is harmful to human. According to the re-cutting & water changes, 4 days cutting interval and 2 days water change was the best. Combination of sucrose & KMnO4 was maintained vase life vase life up to 14 days. Combination of Sucrose 2% + KMnO4 2 ppm & Cotton plug was best among all sugar concentrations (C.V. = 10.90617). For this could maintain export quality up to 19 days. “Pictum” & “Gold Star” were tolerant cultivars. Pure glycerol gave negative effects. All dilute glycerol concentrations (1, 5 and 10%) were good post harvest treatments. Among those, 5% could maintain export quality of “Batik” cuttings up to 20 days. Combination of wax + KMnO4 + sucrose treatment gave negative effect. Pure wax with commercial preservatives did not enhance the quality.

Monday, September 11, 2006


G D G Chaturani & S Subasinghe
Department of Crop Science, Faculty of Agriculture, University of Ruhuna

Hardening of regenerated plantlets for successful field transfer is considered to be a major obstacle in clonal micro-propagation of cinnamon. In-vitro induced roots are rarely functional, lack of root hairs, fragile and are generally damaged during transfer to the soil. Therefore, objectives of present experiments were to develop an appropriate acclimatization procedure and to select a suitable potting media for successful field establishment of Cinnamon plantlets.

In-vitro rooted stem cuttings were transferred in to four different potting media of Soil, Coir dust, Sand: Coir dust – (1:1) and Soil: Sand – (1:1) Sealed containers with sterilized potting media were used to maintain >80 % Relative humidity for 2 weeks and then gradually acclimatized to field conditions. Three different procedures (1) lid removed and kept in shade after 2 weeks of transplanting (2) lid removed only at nights after 2 weeks of transplanting, and (3) lid removed after 4 weeks of transplanting were used as treatments.
At the end of 4th week, plantlets in coir dust medium showed the highest survival rate (87.5 %). Higher number of new leaf formation was observed in coir dust medium and overall appearance of the plantlets was very good. Most plantlets in soil medium were dead at the end of the 4th week, and remaining plantlets were very weak. Acclimatization procedure did not significantly affect on growth or overall appearance of plantlets. Results revealed that coir dust medium provided with two weeks of humid conditions is the best for successful acclimatization of in-vitro Cinnamon plantlets.


W D Samarakkody & I R Palihakkara
Department of Crop Science, Faculty of Agriculture, University of Ruhauna

Tsunami was the worst disaster happened to coastal region of Sri Lanka. Due to tsunami, salinity levels were increased in affected areas, therefore selection of salt tolerant tree species are timely important. But the studies conducted on selection of suitable salt tolerant timber species are rather limited. So this study was conducted to select four suitable salt tolerant species in tsunami affected areas.

Four separate pot experiments were conducted at the faculty of Agriculture University of Ruhuna, Mapalana during mid May to October 2005 to study the effect of different levels of salinity (0.13, 2, 4, 6, 8, 12 mscm –1) on growth performances of four selected tree species (Melia azedarach, Artocarpus heterophyllus, Swietenia mahogany, and Accacia mangium). The experimental design was RCBD with 10 replicates. Six-month-old seedlings of each species were used for the experiment. After root establishment, treatments were started. Number of leaves, plant height, were measured two weeks intervals by non-destructive method, and total fresh weight, total biomass yield, number of roots were measured in once a month by destructive method. Data were statistically analyzed by using ANOVA and means were separated by using DMRT.

According to the study, Melia azedarach, Swietenia mahogany, Accasia mangium are suitable for tsunami-affected areas. Salinity level tolerance of Melia azedarach, artocarpus heterophyllus, Swietenia mahogany, and Acacia mangium are 4 ms/cm, 0.13 ms/cm, 8ms/cm, and 12ms /cm respectively. Normal soil salinity level 0.46ms/cm. Levels of salinity 6ms/cm is the best for Accasia among the treatments. Level of salinity 2ms/cm is the best for the Melia azedarach among the treatments. Normal salinity level of soil (0.46 ms/cm) gives the best performances for Artocarpus heterophyllus and Swietenia mahogany.


R R S Ariyawansa, S Subasinghe & K M C Fernando
Department of Crop Science, Faculty of Agriculture, University of Ruhuna

Vanilla is an orchid spice originated in Mexico It is climbing, branching, and terrestrial orchid growing on trees and shrubs. There is good potential for the vanilla pods in Sri Lanka. At present, 1-2 m long mature Vainila cuttings were used for propagation but demand cannot meet since it is used long cuttings (1-2m) as planting material. Therefore it is important to get more number of cuttings per unit length of the Vanila to meet the existing demand. In this regard, present study was conducted to investigate the effect of cutting length and growing media on growth performances of Vanila. In experiment 01 (Pot experiment), four potting media (coir dust, sand: coir dust 1:1, sand: coir dust: top soil 1:1:1, sand: topsoil: organic matter 1:1:1) and four cutting lengths (one nodded cuttings, two nodded cuttings, three nodded cuttings, four nodded cuttings) were used for the study in the nursery. Experimental design was factorial CRD with 4 replicates. In experiment 02 (field experiment), plants taken from the cuttings with two maturity stages (mature and immature) and three cutting lengths (one nodded cuttings, two nodded cuttings, three nodded cuttings) were used for the field establishment. The experimental design was RCBD with six replicates. Data (Number of leaves, Number of roots and Leaf area) were measured once in three weeks in the nursery and once in four weeks in the field. Data were statistically analyzed by using ANOVA and means were separated by DMRT. In experiment 01, sand: top soil: organic matter 1:1:1 potting media gives good growth performances. Four nodded cuttings are more suitable than others. Maturity and cutting length are significantly affected on growth of Vanilla. Mature cuttings with two nodes shows higher growth performance followed by mature cuttings with three nodes, mature cuttings with one node, immature cuttings with three nodes, immature cuttings with two nodes, and immature cuttings with one node. Therefore potting media of sand: top soil: organic matter 1:1:1 is suitable for filling the poly bags to grow vanilla cuttings in nursery and mature cuttings with two nodes are shown better growth performance in the field.


S T J Rupika¹, M P Jayatilleke¹ & G K K Priyantha Kumara²
¹Department of Crop Science, Faculty of Agriculture, University of Ruhuna
²Green Farm Ltd. Pahala, Walahapitiya Road, Marawila

Wilting and color change of Dracaena leaves are major post harvest problems in exportation. This study is an attempt to overcome these problems and to improve vase life of Dracaena cut stems. Experiments were done at Green Farms Ltd. Marawila to investigate post harvest handling of Dracaena reflexa to maintain export quality and freshness. Series of experiments were conducted to investigate management practices; effect of glycerol solution (pure glycerol in 1, 3 & 5hrs); effect of immersing one hour (using KMnO4 2, 5 & 10pmm); effect of sucrose solution (2, 5 & 10%); effect of KMnO4 (2, 5 & 10ppm) for cultivars of Dracaena reflexa “Reflexa Green”, “Song of Jamaica” and “Song of India”. Treatments were arranged in complete randomized design with 4 replicates each. Data were analyzed using SAS statistical programme with analysis of variances. Mean separation was done using LSD on parametric procedures.

The results revealed that wilting, color change and rotting, of Dracaena reflexa cultivars were not significantly affected by post harvest solutions of KMnO4 and sucrose compared to the control (tap water). However, pure glycerol (dipped for 1hr) and tap water maintained vase life of “Song of Jamaica” for 21days. Damaged cuttings showed Erwinia infection after 10-12 days during vase period (CV = 05.628813). Results in general show avoiding injury to specimens, and this helps to maintain the quality of the products. Many infections can be avoided by keeping the specimens dry. Experiments proved that maximum vase life of Dracaena cuttings could be achieved by maintaining proper management practices and sanitation conditions in a cold room.


G D G Chaturani & M P Jayatilleke
Department of Crop Science, Faculty of Agriculture, University of Ruhuna

Dragon fruit (Hylocereus undatus) is a well-popularized fruit species in countries like Thailand, China and have a great potential for cultivation in semi-arid regions of Sri Lanka. Plant propagation studies have not been carried out in Sri Lanka, and hence objective of this research was to study the in-vivo and in-vitro germination of Dragon fruit seeds and to select a suitable media for in-vitro establishment. Wet filter papers, wet sand, and wet coir dust were used to study the in-vivo germination and Hormone free, MS medium, Anderson’s Rhododendron medium, and McCown Woody Plant medium incorporated with 1 g/l of activated charcoal was used to study in-vitro germination. In-vitro germination percentage was higher (100 % in Anderson, 98.5 % in MS, and 96 % in WP) when compared to seeds germinated in in-vivo conditions (50 %in Filter paper method, 45 % in Sand, and 35 % in Coir dust). Seedlings germinated in in-vitro conditions showed healthy vigorous growth and 15, 14, and 11 mm seedling heights were observed with fully opened cotyledons at the end of second week in Anderson, MS, and WP medium respectively. Though similar plant heights (15±2 mm) were observed, appearance of the seedlings was very weak, and cotyledons had not fully opened under in-vivo conditions. In both in-vivo and in-vitro conditions root system development was similar and root formation was observed within 6 days with 4±2 mm root length. Germination, plant height, and appearance of plants were best in Anderson medium. Results revealed that seeds could be successfully germinated in in-vitro conditions using Anderson medium supplemented with 1 mg/l activated charcoal as the establishment medium.

Wednesday, September 06, 2006


E S Munasinghe & V H L Rodrigo
Rubber Research Institute of Sri Lanka, Dartonfield, Agalawatta, Sri Lanka

Being an industrial crop, rubber (Hevea brasilensis) is having a consistent demand and grown in smallholdings under different environmental conditions providing an economically viable (in terms of both latex and timber production) and socially acceptable system. Also in terms of the environmental benefits, rubber helps to mitigate climate change through the fixing of atmospheric carbon and reducing the carbon emission form nonrenewable resources. Therefore, the present study aimed to assess the genotypic differences in carbon fixing capability of field grown mature rubber cultivations with two specific objectives, 1) to quantify the potential carbon fixation of the mature rubber plantations through the CO2 assimilation and 2) to establish the genotypic differences of rubber in fixing atmospheric carbon.

The experiment was conducted in the Dartonfield estate of the Rubber Research Institute at Agalawatte. Two promising genotypes i.e. RRIC 100 and RRIC 121 at maximum productivity (i.e. in mature stage; 12 years old) were selected for the study. The assessment of the carbon fixation capability of rubber tree was based on measurements on leaf level photosynthesis, leaf area distribution and light attenuation of the rubber canopy. CO2 assimilation rates in rubber leaves under varying light levels were monitored with a portable infra red gas analyzer after dividing the canopy into three strata and then, the parameters of light response curve of photosynthesis were estimated using a quadratic function. Leaf area distribution was assessed by physical counting with point quadrats and the available light for the photosynthesis in different canopy levels was estimated using existing ecophysiological models and then, canopy photosynthetic rates were calculated.

In general, mature rubber was capable of sequestering 22 MT of carbon per hectare annually. Monthly values of carbon fixed differed according to the number of sunny and dull days. The highest rate of carbon sequestering was given in the month of March, whilst November has shown the lowest rate. The value estimated for the whole economic lifecycle of rubber was 660 MT/ha. The genotype, RRIC 121 was superior (160% greater) to RRIC 100 in fixing atmospheric carbon with annual rates of 31.8 and 12.2 MTha-1, respectively. Differences in the capacity of photosynthetic apparatus and canopy architecture were identified as the reasons for the genotypic differences in carbon sequestering.


D L Perera
Auyrvedic Medical Council Nawinna, Maharagama

Recently Applied Ethnobotany is recognized as a fascinating field for research which enables an interdisciplinary approach to development that helps to explore Indigenous Knowledge (IK) and its capacity to effect change in Biodiversity Conservation and Natural Resource Management (NRM). This research aimed an ethnobotanical analysis on ecological perspective of cultural and spiritual implications of forest nomenclature in rural communities, which can be defined in terms of conservation. For this study 43 village localities from 5 areas with different geo-ecological and socio-cultural backgrounds were selected. 616 local informants selected from various impact groups were interviewed and data collected by the participatory action research methodologies during the period of 18 months.

Total number of forest areas reported in all the areas is 834 out of which, 766 forest areas bear suffixes describing vegetation type or habitat features or floristic characteristics of the forest. That is 91.8% as a percentage. Total number of species used for this nomenclature is 161 out of which 105 (65.2%) are playing ecologically very important role in conservation. These species are playing remarkably vital role in ecosystem as biodiversity generative, keystone and flagship species that up keep sustainable survival of the ecosystem being vital indicators of micro-ecological changes of the natural habitat. Out of total forest areas, 279 (33.4%) forest areas are named after a floristic source. Out of total species 121 (75.1%) are registered for any kind of cultural, ritualistic, religious use by the community and have become more sacred or venerable. The average percentage of culturally and spiritually important plant species is 75.8% and 92.9% of threatened plants are culturally important as perceived by the community.

Key Words: Applied Ethnobotany, Indigenous Knowledge, Forest Nomenclature, Natural Resource Management, Biodiversity Conservation, Keystone Species


J H Weerarathne, B M P Singhakumara and P R Attygalle
Department of Forestry & Environmental Science, University of Sri Jayewardenepura
River Basin Planning Division, Mahaweli Authority of Sri Lanka

Dipterocarpus zeylanicus is an endemic tree found in lowland rain forests in Sri Lanka. D. zeylanicus plantations have been established in several districts in Sri Lanka by the Forest Department. The Hora plantation in Kirigala, Ingiriya, and the present study site was established in 1940 by the Forest Department. This study aims to investigate the stand dynamics of D. zeylanicus and its regeneration trends.

The 31 main plots of 10m x 10m, subplots of 5m x 5m and 2m x 2m that were used in 1998 to record the trees, saplings & seedlings numbers and the stand parameters were used in this study as well in 2003.

The results show 515 trees, 789 saplings and 551 seedlings. It is less than that what was recorded in 1998, except the number of trees has increased by approximately seven percent. The mean height, diameter at breast height and basal area of D. zeylanicus within the study site were 22 m, 31.4 cm and 0.0103m2 respectively. A significant increase in height of D. zeylanicus trees and a reduction in seedlings were observed. Ochlandra stridiula is gradually invading the plantation and affecting the stand dynamics of the D. zeylanicus.

J H Weerarathne, B M P Singhakumara - Department of Forestry & Environmental Science, University of Sri Jayewardenepura
Mahaweli Authority of Sri Lanka -River Basin Planning Division


H P Beddage & A J Mohotti
Plant Physiology Division, Tea Research Institute of Sri Lanka, Talawakele

Tea (Camellia sinensis) is a shade loving plant, which is usually grown as a mono crop, under a canopy of shade trees throughout its life. Various physiological functions of tea are facilitated by shade, leading to sustain its vigour, yield and quality of the final produce. The ‘tea - shade tree’ ecosystem is manipulated to possess a microenvironment resembling forest characteristics. Of the four different tea growing agro-climatic regions in Sri Lanka, the recommended shade trees are confined to eight species: Grevillea robusta, Albizzia moluccana and Albizzia chinensis as high shade and Acacia pruinosa, Acacia decurrens, Erythrina lithosperma, Calliandra calothrysus and Gliricidia sepium as medium shade. One species each from the two categories is usually grown at each location; pollarding and periodic lopping of high and medium shade respectively are practiced to ascertain the optimal shade levels of 10-40%. In order to achieve ecological, environmental and economic stability of the system and sustainable productivity per unit area over monocultural systems, exploitation of more number of species is of vital importance. This also imparts direct benefits of harbouring natural enemies of pests, moisture retention, nutrient and energy trapping, soil erosion control, biomass energy and organic matter addition and indirect benefits of C sequestration and opportunities for ‘fair trade labeling’ and eco tourism, biodiversity improvement, floral and aesthetic values and income generation.

The present exercise explored the alternative species considering climatic suitability and natural habitat, growth rate, plant height, root characteristics, pollarding/ lopping ability, stem and branching characteristics, canopy architecture, leaf characteristics such as angle, size, shape, orientation and shedding. In addition, competitiveness with tea for water and nutrients, biomass production, nitrogen fixation, availability of information on propagation and other silvicultural practices, harbouring pests and diseases of tea, food, timber, fuel wood values etc. were considered. Initial database resulted in over 230 potential species with native and introduced origins excluding trees for intercropping and diversification purposes. The most probable species identified in the initial exercise were Adenenthera pavonina, Adina cordifolia, Albizzia odorissima, Alstonia macrophylla, Alstonia scholaris, Bauhinia racemosa, Bauhinia variegata, Berrya cordifolia, Bhesa zeylanica, Cananga odorata, Canthium montanum, Carallia brachiata, Cassia javanica, Cassia spectabilis, Cedrella odorata, Chukrasia tabularis, Dalbergia sissoo, Elaecarpus amoenus, Elaeocarpus glandulifer, Enterolobium cylocarpum, Erythrina edulis, Erythrina fusca, Erythrina poeppigiana, Erythrina variegata, Filicium decipiens, Khaya senegalensis, Macademia ternifolia, Mallotus tetraeocevs, Mangifera zeylanica, Michelia champaca, Muntingia calabura, Parkinsonia aculeata, Paulownia fortunei, Peltophorum dasyrachis, Pentaclethra macroloba, Pongamia pinnata, Pterocarpus indicus, Sapindus emarginatus, Tecoma stans, Ternstroemia gymnanthera and Trema orientalis, which belong to the families Anonaceae, Apocynaceae, Bignonaceae, Elaeocarpaceae, Euphorbiaceae, Fabaceae, Magnoliaceae, Meliaceae, Paulowinaceae, Proteaceae, Rhizophoraceae, Rubiaceae, Sapindacea, Theaceae, Tiliaceae and Ulmaceae.

The species will be exposed to further screening processes and pilot scale field evaluations at the Tea Research Institute and different tea growing areas respectively, prior to releasing the most promising selections for field use.


T M E Nanayakkara
Department of Wildlife Conservation, No: 18, Gregory's Road, Colombo 7

Wasgomuwa National Park was initially declared as a Strict Nature Reserve in 1938, and became a National Park with the commencement of the Accelerated Mahaweli Development Program in 1984. It possesses rich diversity of fauna and flora.

The average poverty level of the communities who are living close to Wasgomuwa National Park is generally much higher than that of the national average. Lack of employment opportunities, land tenure insecurity, low prices for agricultural and farm produce etc. have also contributed for the depressed rural economy and poverty, which is directly linked with the dependency on park resources, causing rapid depletion of resource base. Therefore activities such as encroachments, cattle grazing, poaching, gemming, illicit tree felling is common. Human-elephant confrontations are also severe near the southern boundary of the park. Dunuwilapitiya and Rathtotayaya villages being located in this area are constantly subjected to elephant attacks.

Community Outreach concept which promotes proactive involvement of buffer zone communities in protected area management was used to address the issues of the communities in Dunuwilapitiya & Rathtotayaya villages. By using this community centered participatory approach, village action plans/micro-plans for the two villages were formulated. Two new community based organizations (CBOs) were established as a result of the institutional analysis.

Provision has been made under the Protected Area Conservation Fund to finance environment friendly livelihood improvement initiatives and projects focused on the reduction of dependency of park resources that are originating through the micro-planning process. Community managed grassland of 70ha is presently being developed by the villagers of Dunuwilapitiya while an irrigation canal rehabilitation project was also launched by the same community recently. The Rathtotayaya community is implementing an electric fencing project as a measure to reduce human-elephant conflict. A community based social monitoring system has also been introduced for monitoring progress of related activities.

With the introduction of the participatory development approach and the community empowerment process, improved interaction between the park management and the community is evident while the dependency on park resources is in the process of being reduced.


W Rathnayake
Department of Wildlife Conservation, No: 18, Gregory's Road, Colombo 7

Habitat degradation due to invasive plant species is identified as one of the major threats in several protected areas managed by Department of Wildlife Conservation in Sri Lanka. Bundala National Park, covering an area of 6216 ha is located about 250 km Southeast of Colombo (06008’ – 06014’ N, 81008’ – 81018’). The Bundala National Park is Sri Lanka’s first Wetland of International importance declared under the Ramsar Convention. The park consists of mainly dry thorny scrubland and lagoons, which are shallow brackish water lagoons. They harbours a rich bird life including several species of migratory waterfowls. It also contains key nesting sites for five species of marine turtles. Arid and semiarid terrestrial habitats shelter a wide range of species, including elephants and other mammals, reptiles, amphibians and fish species. The introduced Prosopis julifolia, a tree species native to Central and South America as a fuel wood in home gardens by the Forest Department has expanded its distribution and has invaded the Bundala National Park. There are large stands of Prosopis julifolia that prevents the growth of other indigenous species. Furthermore it invades the lagoon and as a result the area covered by the lagoon is also being reduced. Opuntia stricta var. dillenii, which is also a plant native to Central America, is used mainly as a hedge species around human dwellings and from there it may have invaded wetland habitats in Bundala National Park.

The spread of these invasive alien plant species has resulted in the progressive deterioration of wildlife habitats and native biodiversity in the park, and hence warranting immediate management to curtail their spread. The general methodology adopted for the invasive plant management programme in Sri Lanka is based on adaptive management techniques. Adaptive management is a process that involves planning, management and monitoring to provide a framework for testing assumptions, adaptation and learning. Invasive species were eradicated manually and mechanically. Lack of a planned systematic research programme to compile field observations in areas subjected to invasive plant management is a major constraint. In addition, views of non-scientific public and lack of funds for adaptive management techniques are the major constraints


C J Gagaweera, G A Chandana & R T Seresinhe
Faculty of Agriculture, University of Ruhuna

A short-term field experiment was conducted to study the effects of different vegetation covers on the soil fertility status. Soil samples were taken from several fields from Mapalana farm. The treatments were grass x legume mixed sward (T1), grass monoculture (T2), legume monoculture (T3), vegetable (T4), coconut field with natural vegetation (T5), forest land (T6), bare land (T7) and cover crop grown with rubber (T8).

Each field was divided in to 20 x 20 m four blocks and four random samples from each block were taken at 0-10 cm depth. Soil samples were passed through 0.2 mm sieve and finely ground for subsequent analysis. Samples were analysed to determine the pH and organic matter content. Soil nitrogen percentage was analysed by the Kjeldhal method. Bulk density was determined using the soil core method and oven drying at 1050 C until a constant weight was obtained.

Soil organic matter content ranged from 3.622 % ± 0.819 (grass x legume mixed sward) to 1.433 % ± 0.833 (vegetable). Grass, legume, forest and coconut land had medium organic matter contents. Vegetable land had the least organic matter content may be due to chemical fertilizer application. Soil nitrogen percentage was also highest in mixed culture (0.1812 % ± 0.0016) followed by the legume crop (0.162 % ± 0.0089) showing the benefits of nitrogen fixation and transfer in increasing soil organic matter and nitrogen. The nitrogen content of coconut land was also higher (0.1384 % ± 0.0157) due to nitrogen recycling via buffalo manure. Similarly nitrogen percentage of the soil was lowest in vegetable cultivation (0.0571 % ± 0.0088).

In contrast, soil bulk density was higher (p<0.05) in coconut land (1.491 g/cm3 ± 0.1037). This may be due to the soil compactions occurred by long-term buffalo grazing. Undisturbed lands such as forest cover, cover crop with rubber plantation etc. had lower bulk densities (1.257 g/cm3 ± 0.369 and 1.255 g/cm3 ± 0.033 respectively). Highest value (P<0.05) of pH was observed in grass monoculture (6.3933 ± 0.311). Mild acidic conditions of soils were shown in mix culture (4.84 ± 0.29), vegetable (4.59 ± 0.22), bare land (4.89 ± 0.20) with cover crop grown with rubber (5.12 ± 0.25)

The study concluded that the grass x legume mix culture showed benefits of nitrogen fixation and transfer associated with higher total nitrogen and organic matter content in soil. Positive impact on soil nitrogen status on buffalo grazing showed negative impact on soil bulk density. Human intervention such as chemical fertilizer application etc also affect on soil characteristics.