University of Sri Jayewardenepura: Journals & Proceedings
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Effect of Anaerobic Soil Disinfestation System on Soil Carbon and Nitrogen Mineralization of Tea Nursery Soils in Up Country Wet Zone
No full textAnaerobic Soil Disinfestation (ASD), is a promising pre-treatment method that can alter the chemical methods by disinfecting the soil, creating an anaerobic condition. This method is implemented by incorporating soil with easily decomposable organic amendments and covering it with air-impermeable polythene. However, the dynamics of Carbon and Nitrogen contents in the ASD system has not been clearly defined yet. Therefore, this study was conducted to determine the dynamics of Carbon and Nitrogen using different organic amendments in this system. Easily decomposable organic matters were selected such as Tithonia diversifolia, Gliricidia sepium, cabbage crop residues, poultry litter and cattle manure and their combinations. Treatments were applied at a 5 t/ha rate to both aerobic and anaerobic systems and analysed for soil organic carbon, NO3--N, NH4+-N, pH and redox potential on day-35 and a comparison was done between aerobic and anaerobic systems. Further, an incubation study was conducted for 35 days to determine C and N mineralisation by each treatment under the aerobic condition. After 35 days, redox potential has been noticeably reduced until -50 mV in some anaerobic-treated soils confirming the anaerobic condition. The organic carbon content in treated soil under anaerobic conditions was higher than the aerobic conditions. Higher carbon content in anaerobic condition was observed in soil incorporated with cabbage crop residue (16.551%±2.93) and the poultry litter 40%+Gliricidia 60% combination (18.85%±6.25). The highest carbon content (14.73%±6.26) was observed in the soil treated with cabbage residue in aerobic conditions. There were no considerable changes shown in anaerobic NO3--N mineralization compared to aerobic treatments. However, in aerobic condition, poultry litter 40%+Gliricidia 60% combination and cabbage crop residue treatments showed significantly higher NO3--N production. The highest NH4+-N production was observed in Tithonia (41.15±1.63 ppm), cabbage crop residue (42.89±1.30 ppm), and the combination of cattle manure 40%+Gliricidia 60% (43.69±0.158 ppm) treatments in anaerobic conditions. Poultry litter 40%+Gliricidia 60%, poultry litter 40%+cabbage 60% and cattle manure 40%+Gliricidia 60% which showed a higher NH4+-N yield content in aerobic conditions. The highest CO2-C was obtained in Cabbage crop residue at day-35 of aerobic incubation (1423 mg/kg). There was a positive and significant increase in carbon (p<0.05) and NH4+-N (p<0.05) in the ASD system compared to aerobic conditions by nourishing and reconditioning the soil using incorporated organic amendments under an anaerobic environment.
Keywords: Aerobic, Anaerobic soil conditions, Gliricidia, Organic matter, Poultry litte
Investigation of the Locomotory Behaviours of Water Striders (Gerrini)
No full textThough the locomotion of water striders of tribe gerrini has been extensively studied, many if not all of these studies focus on the mechanical and physical aspects of the water strider’s ability to reside and locomote atop the surface film of water bodies, and do not investigate the functionality and behavioral aspects of its locomotion. This study utilizes existing knowledge on the mechanics of water strider locomotion to build a more comprehensive understanding of the locomotory behaviors of water striders belonging to tribe gerrini. Observations were made on a population of water striders in a freshwater pond in Homagama, Western Province, Sri Lanka. Initial observations were made ad-libitum with the naked eye, and further observations were made by analyzing photographs and slow-motion videos. Through such analysis, two novel locomotory behaviors were identified: diagonal gliding, and reverse gliding and reorientation. These behaviors, both of which are comparatively complex and consist of several distinct movements, were observed to be utilized as the water strider navigated confined spaces. Furthermore, locomotory behavioral responses to extrinsic stimuli, specifically escape behaviors in response to potential threats (significant disturbances atop the water surface) were observed, and it was noted that water striders nominally responded to such stimuli with rapid successive gliding or leaping movements, the dynamics of which appear to be as described in existing literature. It is also notable that the water striders under study were habituated to the presence of freshwater fish, as well as humans who were regularly in proximity to the study site.
Keywords: Water strider Locomotion, Gerrin
Effective In-Vitro Culture Medium for Multiplication of Phalaenopsis cv. Pink Lip via Protocorm-like Bodies
No full textPhalaenopsis are the most commercialized cut or pot flowers due to their long-lasting and varied flower morphology. At present, the technique of plant tissue culture has been used as the most effective and widely used way to overcome the limitations of conventional cultivation and for the rapid mass propagation of high-value Phalaenopsis plants. In tissue culture, the plantlets produced from protocorm-like bodies (PLBs) are genetically identical to the parent plant and important for the rapid multiplication of plants with desirable traits. PLBs need to be transferred to a nutrient-rich growth medium for rapid multiplication. Therefore, the selection of an effective culture medium for the multiplication of PLB is crucial to the enhancement of in-vitro propagation of Phalaenopsis. The objective of the present research was to identify an effective in-vitro culture medium for the multiplication of Phalaenopsis cv. Pink lip via PLBs. Initially, PLBs (0.5 g) were transferred to selected three culture media, such as 1⁄2 MS, VW, and Hyponex media separately. Cultures were maintained for four months, and growth performance was evaluated. A significant difference in the mean fresh weight increment of PLBs grown in 1⁄2 MS, VW, and Hyponex media was observed after four months of incubation. The highest fresh weight increase of PLBs was observed in 1⁄2 MS medium compared to VW and Hyponex. After identifying that the 1⁄2 MS medium was highly supported for PLB multiplication, the 1⁄2 MS medium was modified by adding BAP (6- Benzylaminopurine) to enhance the rate of multiplication of PLBs. A series of 1⁄2 MS media supplemented with various concentrations of BAP [0 mg/L(control), 1.0mg/L, 2 mg/L, 3.0 mg/L, 4 mg/L, 5 mg/L, 6 mg/L, 7 mg/L], were prepared. PLBs (0.5g) were transferred to media series separately and were maintained for three months. The increase of fresh weight of PLBs was observed in all 1⁄2 MS media with different concentrations of BAP, compared to the control. The highest increment of fresh weight of PLBs was observed in 1⁄2 MS medium with 3.0 mg/L BAP. In conclusion, 1⁄2 MS with 3.0 mg/L BAP medium is the highly supported effective in-vitro culture medium for the multiplication of PLBs of Phalaenopsis cv. Pink lip.
Keywords: Phalaenopsis, Protocorm Like Bodies (PLBs), In-vitro culture medium, Half-strength Murashige and Skoog (1/2 MS), BAP(6-Benzylaminopurine
A Comprehensive Butterfly Checklist and Conservation Assessment at Baddagana Wetland Area, an Urban Ecosystem in Sri Lanka
Get PDFButterflies are obtrusive creatures of the nature belonging to Class Insecta, Order Lepidoptera in biodiversity classification hierarchy. The primary objectives of this study were valuating the diversity of butterfly species found in the Baddagana wetland, assessing their current conservation status, and proposing conservation action to protect these enigmatic creatures in their unique habitats. Data was collected in Baddagana wetland area from August to October 2023. In order to maximise sampling effort, three sessions per day were allocated for the visual encounter survey, which was carried out between 8:00 am, and 6.00 pm at pre-determined locations. Thus, most of the butterfly species were observed 8:00 am to 11.00 am and 12.00pm to 02.00pm. Field notebooks were used for documenting comprehensive observations. The identification of butterfly species was based on field guides. Throughout the study, observations showed that 15 butterfly species, belonging to 4 families, were present. 30 butterflies were the average per day. Most common and frequent species were Psyche (Leptosia nina), Glassy Tiger (Parantica aglea), Common Crow (Euploea core), and White-four ring (Euploea core) in the wetland habitat. On the other hand, the Lime Butterfly (Papilio demoleus) and Great Eggfly (Hypolimnas bolina) were noted as uncommon or rare species in the area according to the study. Of the species of butterflies that were observed, one was classified as vulnerable (Blue Glassy Tiger/Ideopsis vulgaris) and 14 were considered least concerned according to the 2012 Red List assessment. These finding shed light on the basic understanding of the diversity of butterflies that inhabit the Baddagana Wetland. The butterflies observed in this area emphasise how crucial this unique habitat is for conservation efforts as most of the species were absent or less common outside the wetland habitat. In order to increase butterfly populations while promoting the conservation of these creatures, this study suggest growing appropriate feeding and host plants in the wetland area. The dataset created by this study will be starting point for future research and plan future habitat enrichment in this area.
Keywords: Butterfly diversity, Lepidoptera, Baddagana wetland, Conservation, Urban ecolog
Assessment of Groundwater Quality in Attaragoda Grama Niladhari Division in Galle, Sri Lanka
Get PDFInsufficient quality can make water unfit for a range of human purposes. As a result, water is becoming scarcer globally as population growth continues. Water quality assessment is essential for effective water resource management. The present research fills the gap in scientific knowledge and information regarding the groundwater quality status in Attaragoda Grama Niladhari (GN) Division in Galle, Sri Lanka. Randomly selected 33 groundwater samples were collected from 142/A Attaragoda GN division monthly from November 2021 to March 2022. Together, 13 selected general water quality parameters, including temperature, pH, total dissolved solids, electrical conductivity, salinity, dissolved oxygen, biological oxygen demand, total nitrate, total phosphate, total alkalinity, total hardness, ammonia, and fluoride, were measured once a month during the study period using standard methodologies. Additionally, four metals, including Iron, Calcium, Magnesium, and Sodium, were analysed for the randomly selected 15 locations during the study period. Statistical analysis was done using Minitab 17 and MS Excel 13. Weighted Arithmetic Water Quality Index (WQI) was calculated using electrical conductivity, TDS, pH, hardness, phosphate, alkalinity, and nitrate parameters in Attaragoda GND. Results indicated that, except for Fe, none of the tested parameters exceeded the maximum permissible levels for drinking water throughout the study. Accordingly, all locations were categorized as good for drinking purposes. For a more precise evaluation of water quality, the WQI can be improved by future research focusing on heavy metal and microbial contaminants.
Keywords: Groundwater, Water quality, Weighted arithmetic water quality index
 
Investigation on Efficacy of Azolla with Different Organic Fertilizers as Plant Growth Enhancer on Chili (Var.Super)
No full textChili is one of the widely used spices all around the world. Over usage of inorganic fertilizer to satisfy ever growing demand for food leads to detrimental impacts on human health and environment. Therefore, this study was intended to investigate the efficiency of azolla with different organic fertilizer on growth and yield of chili, variety Super. A field experiment was carried out with five different treatments, T1-Azolla+Compost, T2-Azolla+Vermicompost, T3- Azolla+Panchagowvya, T4-Azolla+Vermitea, and T5-Control with five replicates and laid in randomized complete block design. The prepared organic fertilizers were applied from two weeks of transplanting and continued for 12 weeks in one week interval. Then the growth parameter such as mean plant height, number of leaves per plant, leaf width, number of flowers, pod length, pod diameter, pod weight and total yield were measured in different time duration according to the type of measurement. According to the results, T2 showed better performance in terms of mean plant height (45 cm), number of leaves per plant (43 cm), leaf width (2.8 cm), pod length (4.34 cm), individual pod weight (6.94 g), and total yield (176.8 g) whereas comparatively lower performance was observed in control. Considering the significant differences recorded in the statistical analysis for all the parameters other than the mean number of flowers, it can be concluded that the application of Azolla solution with vermicompost improves the growth performance and yield of chili. Therefore, it is recommended to adapt this combination as an organic fertilizer among the farmers to reduce the usage of inorganic fertilizers.
Keywords: Azolla solution, Demand, Growth parameters, Inorganic fertilize
Analytical Methods for Extraction of Microplastics from Compost in Sri Lanka
Get PDFMicroplastics (MP) are the plastics with 1 μm-5 mm dimensions. Meanwhile, compost has been identified as a major source of MP in the soil, although compost is a great plant nutrient source, and it provides tremendous benefits for crops. This is primarily ascribed to most of the compost being produced through Municipal Solid Waste Management projects. However, due to the detrimental impacts on soil’s biological, physical, and chemical health, together with the high accumulation probability of MP caused by repeated application of compost, regulations should be implemented on the limitation of MP in compost. Even though there are a few different methods available in the literature for MP extraction and quantification in organic matter (OM)-rich matrices, like compost, sludge, and sediments, a properly validated, routine analytical procedure is missing in Sri Lanka Standards (SLS). Therefore, in this project, the effectiveness of four different MP extraction methods in the literature were compared and validated for compost, to implement an MP analysis method suitable for compost specifications in the SLS. The methodologies included MP extraction by density separation using NaCl or ZnCl2 solutions followed by digestion of OM using 30% KOH: NaOCl solution or Fenton’s reagent. The common MP analysis method for the four protocols was staining with the hydrophobic, fluorescent stain Nile Red, and visual observation. Digestion efficiency of OM and spike recovery of Polystyrene (PS), Polyvinyl Chloride (PVC), Polyethylene terephthalate (PET), High-Density Polyethylene (HDPE), and Polypropylene (PP) microplastics in 1-2 mm dimension by the four MP extraction methods were compared for the validation. T-tests (confidence level=95%) were carried out to determine the significant difference between the OM digestion efficiency in each of the four methods. Each of the combinations compared was significantly different from the other except for ZnCl2/Fenton and NaCl/30% KOH:NaOCl comparison. Meanwhile, the OM removal by ZnCl2/Fenton and NaCl/30% KOH:NaOCl excluding the density separation step also was not significantly different. The spike recovery analysis showed ZnCl2/Fenton combination as the best out of the tested combinations with above 95% recovery percentages for PS, PVC, PP and 100 for HDPE and PET by particle count. However, precipitate formations in the ZnCl2/Fenton combination might cause false negative or positive results for spike recovery when applied to the real samples with smaller MP. The extraction reagents, NaCl was not an ideal solution and ZnCl2 was a good solution for the MP types used. Moreover, in this project, double digestion of OM with NaCl/30% KOH:NaOCl before and after the density separation with ZnCl2 is suggested as a novel and more effective OM digestion protocol before Nile Red staining, and further validations are suggested prior to its final implementation.
Keywords: Microplastics, Compost, Extraction, Organic matte
Effect of pH and Light Intensity on the Growth of Dunaliella Salina
Get PDFDunaliella salina is a unicellular halophilic green alga dominantly found in salt lakes, and high saline ponds in slatterns all over the world. A rigid cell wall is absent in D. salina while the cells are covered by mucous materials that are enclosed by a thin elastic plasma membrane. This species has both environmental and economic validity as they are capable of producing β–carotene during photosynthesis. Synthesis of β–carotene in D. salina is a function of environmental factors, and thus, the present study was designed to study the effect of pH of the medium and light intensity on the growth of D. salina. The Algae sample was collected from a crystalizing pond of Hambantota Saltern, Sri Lanka, and a monoculture was maintained under suitable laboratory conditions. The seawater sample with pH 7.66 was used to prepare a series of pH using sodium carbonate anhydrous. These cultures were exposed to a series of pH (7.66, 8.0, 8.50, and 9.0) at two light intensities (885 lux and 200 lux). All experimental setups were maintained at 25oC with the photoperiod of 12h light and 12h dark. Four replicates of each pH medium were arranged into a 4×4 setup of flasks for each light intensity and the experiment was conducted for four weeks. At the end of the fourth week, the pH level of all flasks ranged from 8.27 to 8.53 due to the self-adjustment of the pH level in the culture medium in parallel to algal growth. The maximum growth was reflected by the highest absorbance of 1.46 at 750 nm. Taken together, our findings revealed that the optimum pH range and light intensity for culturing D. salina is 8.27-8.53 and 885 lux respectively. This study recommends further research on culturing of D. salina for extracting the bioproduct of β -carotene at various light intensity levels.
Keywords: Cell density, β –carotene, Light intensity, Self-adjuste
Potassium Solubilizers, Aspergillus sp. and Trichoderma sp. Promote Growth in Tomato
Get PDFPotassium (K) is the third most significant plant macronutrient that plays a crucial role in growth and development of plants. K is abundant in soil, but 90-98% of K exists as insoluble minerals and only 1-2% becomes available to the plants. Certain microbes, K solubilizing microbes (KSMs), can solubilize unavailable forms of K and making it available to plants. The objective of the current study was to evaluate the growth promotion ability of two previously (2019) isolated KSMs, Aspergillus sp. and Trichoderma sp in-vitro and under greenhouse conditions using feldspar as the K source. Khandeparkar‘s selection ratio calculated based on K solubilizing assay on Alexandrov medium showed that Aspergillus (1.72+0.16) has a higher and faster K solubilization ability than Trichoderma (1.0+0.16). Effect of KSMs was assayed in a Tomato seed germination assay carried out in Petri plates with KSMs treated and non-treated soils. Both Aspergillus (58%) and Trichoderma (72%) showed enhanced percentage germination of tomato seeds under in vitro conditions compared to that of controls (Aspergillus sp.: 24%, 14%, 22.7%, 51.3%, 39.3%, Trichoderma sp.: 22%, 12%, 13%, 59%, 51%) which was statistically significant (Aspergillus, P=0.026; Trichoderma, P=0.003) at 0.05 confidence level. Seedling length (P=0.102, P=0.028) and root length (P=0.453, P=0.002) of tomato were enhanced when raised in non-autoclaved natural soil than autoclaved natural soil inoculated with Aspergillus and Trichoderma respectively. The greenhouse experiment was carried out with same experimental set up as an in vitro assay. No significant difference was observed in shoot length, number of leaves and length of leaves of tomato plants planted in soil treated with Aspergillus (P=0.093, P=0.906, P=0.260) and Trichoderma (P=0.334, P=0.239, P=0.243) respectively in comparison to controls during the vegetative stage (2 months after sawing). However, flowering was started four days early in plants planted in non-autoclaved soil treated with Aspergillus sp. suggesting that the impact of Aspergillus sp. starts to become visible in the reproductive stage. The results suggest that K solubilizing ability of Aspergillus sp. and Trichoderma sp. seem to show a positive effect on germination ability of tomato, however, only Aspergillus sp. seems to have a positive effect on the later stages of plant growth where K is mainly needed for flower and fruit development. Therefore, Aspergillus sp. can be a potential candidate to be used in up scaling the natural K fertilizers such as feldspar after intensive future experimentation.
Keywords: Plant Growth Promoting Microbes (PGPMs), Growth promotion, K deficienc
Journal of Business Research and Insights Volume 10 Issue 01 June 2024 - Full Journal
No full textJournal of Business Research and Insights Volume 10 Issue 01 June 2024 - Full Journa