Department of Plant Sciences

Therapeutic value of organic and conventional teas in Sri Lanka against microbial agents

2026-05-08T05:56:03Z

Therapeutic value of organic and conventional teas in Sri Lanka against microbial agents Rajapakshaa*, R.W.W.K.A.D.; Warnasooriyaa, W.M.R.S.K.; Benaragamaa, D.I.D.S.; Benaragamaa, D.I.D.S.; Wanasingheb, K.D.K. Due to its naturally occurring medicinal ingredients known as polyphenols, tea attracts the interest of the pharmaceutical and scientific disciplines. Besides the established antioxidant activity, many phenolic compounds in tea exhibit significant antimicrobial activity. Environmental factors and crop management substantially influence the amount and activity of polyphenols available in tea leaves. In Sri Lanka, there are six main agro-ecological regions where tea is grown using either conventional or organic management. Present study focused to determine the effects of tea production system and their growing region on polyphenol content and antimicrobial properties of made tea. Fresh leaf samples were collected from randomly selected tea estates each for organically certified and conventional from major tea growing regions in Sri Lanka. They were manufactured into CTC black tea using a miniature system. Polyphenol content was assessed by ISO standard method, while the anti-bacterial and anti-fungal properties were evaluated using disk diffusion technique against Escherichia coli ATCC 25922 and clinical pathogen of Aspergillus niger. Polyphenol content, anti- bacterial and anti-fungal properties were significantly different (P<0.05) between the tea production systems and among the growing regions, where organic tea had higher polyphenol content, anti- bacterial and anti-fungal properties than conventional teas. The Southern region tea had greater anti-bacterial and anti-fungal properties probably due to the high polyphenol content, while it was the lowest in Uva region. In conclusion, this research presents preliminary evidence that Sri Lankan teas grown and managed organically have superior antimicrobial properties over conventional teas. To confirm the findings, more investigation using time series measurement in all tea-growing regions is suggested.

Growth Performance and Carbon Accumulation of Khaya (Khaya senegalensis) in Sri Lanka

2026-05-08T05:14:34Z

Growth Performance and Carbon Accumulation of Khaya (Khaya senegalensis) in Sri Lanka Warnasooriya*, W.M.R.S.K.; Sivananthawer, T. ABSTRACT: Khaya (Khaya senegalensis) being a new forest plantation species, its growth performance under Sri Lankan conditions has not been evaluated. Further, carbon sequestration by forest plantations, which forms an important option in climate change mitigation, has not gained much attention in Sri Lanka. Hence, the present study aimed at assessing the growth performance and carbon accumulation of Khaya plantations in Sri Lanka. The tree height and tree diameter were measured non-destructively in identified age classes and biomass was estimated with allometric equations. Khaya in Kurunegala division (Intermediate Zone) has achieved 39.98 cm and 18.31 m of dbh and height, respectively, by the age of 18-20 years, whereas in Anuradhapura division (Dry Zone) it was 22.21 cm and 12.41 m, respectively. Significantly higher dbh and tree height (p<0.05) indicates the better site conditions in the Kurunegala division for superior growth of Khaya compared to those in the Anuradhapura division. The dbh and tree height of Khaya showed a strong correlation in both divisions. Significantly higher (p<0.05) biomass of Khaya was recorded in Kurunegala than in Anuradhapura division. The average carbon sequestration of K. senegalensis was 88.98 and 127.92 t/ha in Anuradhapura and Kurunegala divisions, respectively. Khaya plantations in Anuradhapura division (741.92 ha) and Kurunegala division (475.20 ha) have accumulated 21,785 t and 27,969 t of carbon, respectively. Growth performances evaluated in the present study can guide the future decision making process in establishment of forest plantations in Sri Lanka. Regional baseline carbon estimates of Khaya generated by this study could effectively be utilized for carbon budgeting programmes until validated further by increasing the frequency of measurements of variables and developing allometric relationships specific for K. senegalensis.

SUSTAINABLE TEA PRODUCTION: A COMPARATIVE ASSESSMENT OF THE GROWTH, YIELD, AND QUALITY OF TEA UNDER CONVENTIONAL AND ZERO- INPUT ORGANIC MANAGEMENT AT QUEENSBERRY ESTATE, SRI LANKA

2026-05-08T04:48:52Z

SUSTAINABLE TEA PRODUCTION: A COMPARATIVE ASSESSMENT OF THE GROWTH, YIELD, AND QUALITY OF TEA UNDER CONVENTIONAL AND ZERO- INPUT ORGANIC MANAGEMENT AT QUEENSBERRY ESTATE, SRI LANKA Premalal, W.A.K.Y.; Warnasooriya, W.M.R.S.K.; Herath, U.S.; Sandamali, G.G.A. Sri Lanka, a leading global tea producer and a pioneer in organic tea cultivation, holds strong potential for expanding the organic tea sector. Comprehensive scientific validation through systematic assessment of organic and conventional tea management systems can generate evidence to promote the expansion of organic tea in Sri Lanka. Growth, yield, and quality attributes of tea (cultivar DN) were evaluated under organic with zero inputs (T1) and conventional with chemical inputs (T2) at Queensberry Estate, Nawalapitiya, Sri Lanka, using a Randomized Complete Block Design (RCBD) with three replicates. Growth and yield parameters, soil and leaf nitrogen content, and leaf chlorophyll content (measured with SPAD) were recorded. Additionally, the quality of brewed tea was assessed through sensory evaluation by untrained panelists. Growth, yield, and chemical parameters were analyzed using one-way ANOVA in R, while sensory data were evaluated through the Friedman test in Minitab. Results revealed that soil available nitrogen was significantly higher (p<0.05) in conventional treatment (0.090%) compared to organic treatment with zero inputs (0.065%). Similarly, leaf total nitrogen content in T2 (1.145 %) is significantly greater (p<0.05) than in T1 (0.898%). Correspondingly, leaf area, shoot growth rates, and mean shoot length were significantly (p<0.05) higher in T2 (6.60 cm) compared to T1 (4.23 cm). In contrast, the mean number of shoots in 100g was significantly greater (p<0.05) in T1 than in T2. Leaf chlorophyll content and yield were not significantly different (p>0.05), yet greater in T2 than in T1. Sensory evaluation showed no significant quality differences between T1 and T2. In conclusion, conventionally managed tea has superior growth, yield, and quality attributes compared to organically managed tea with zero inputs. A long-term application of organic inputs is recommended to achieve better growth, yield, and quality in organically managed tea.

Evaluation of feed efficiency and growth performance of slow-growing indigenous chicken under different rearing systems

2026-05-06T06:38:34Z

Evaluation of feed efficiency and growth performance of slow-growing indigenous chicken under different rearing systems Kiradurayalage Gedara, Nirosha Harshani; Getamann, Arachchige Kavinda Nimesh Getamann; Madanperuma, Arach- chilage Amali Pubudu Kumari; Wettathperuma, Arachchige Deepthi Nayananjalie; Adikari, Mudiyanselage Jayantha Bandara Adikari; Sharini, Adikari; Sharini, Carol Somasiri Objective: This study aimed to evaluate feed efficiency and growth parameters of slow-growing indigenous chicken raised for meat production under different rearing systems. Material and Methods: Two treatments, pasture-raised system (PRS) (treatment) with six rep- licates and Intensive Rearing System-IS (control) with three replicates, were tested. The birds in the treatment were fed only 80% of the daily feed requirement, while in the control, 100% of the requirement was provided. Birds in both were fed with the same cereal-based starter/grower/ finisher diets, based on age. Daily feed intake and weekly body weight were measured. Daily body weight gain (DBWG), average body weight, feed conversion ratio (FCR), and residual feed intake (RFI) were calculated. Results: The crude protein and metabolizable energy contents of the formulated starter, grower, and finisher diets were 22.74% ± 0.20%, 20.97% ± 0.20%, 20.63% ± 0.20%, and 2,495.94 ± 44.47 kcal/kgDM, 2,909.11 ± 44.47 kcal/kgDM, and 2,927.78 ± 44.47 kcal/kgDM, respectively. The DBWG during the grower and finisher stages of control (18.99 ± 0.66 gm and 16.79 ± 0.66 gm) were sig- nificantly higher (p ˂ 0.05) than the treatment (14.24 ± 0.46 gm and 14.72 ± 0.46 gm). Overall FCR in the treatment (4.28 ± 0.20) and the control (4.62 ± 0.28) was not significantly different. The RFI was significantly lower (p ˂ 0.05) in the treatment in both grower and finisher stages (−0.0206 ± 0.006 and −0.0205 ± 0.010) than the control (0.0474 ± 0.009 and 0.0265 ± 0.014). Conclusion: Considering the ABW and DBWG, slow-growing indigenous chickens fed cereal-based formulated diets under an intensive system are more profitable. However, when assessing RFI, a pasture-raised system proves more efficient than an intensive system. Hence, the farmer could choose either pasture-raised or an intensive management system, depending on t