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Effects of Rhizobium- Based Biofertilizer on Nodulation Efficiency and Growth of Black Gram (Vigna mungo L.) and Soybean (Glycine max L.)

2025-01-01T00:00:00Z

Title: Effects of Rhizobium- Based Biofertilizer on Nodulation Efficiency and Growth of Black Gram (Vigna mungo L.) and Soybean (Glycine max L.) Authors: Sathaniga, Y.; Shayanthan, A.; Sritharan, S.; Ekanayake, S.; Seneviratne, G. Abstract: Although inorganic fertilizers enhance crop production, excessive usage reduces soil fertility and causes pollution and health hazards. Biofertilizers could be a sustainable alternative to manage soils without yield reduction. Rhizobium-based biofertilizers have been introduced to Sri Lanka and have been successively applied in some areas where legumes are cultivated. This study was designed to examine the impact of the Rhizobium-based biofertilizers on nodulation and growth of black gram (Vigna Mungo L.) and soybean (Glycine max L.) in Kilinochchi. A pot experiment was conducted at the University of Jaffna, Ariviyal Nagar, Kilinochchi, which falls within the DL3 agroecological region (Flat to Slightly Undulating Low Country Dry Zone), with three treatments: T1 (No fertilizer), T2 (Recommended inorganic fertilizers), and T3 (Rhizobium-based biofertilizer) with five replicates. The measurements of plant height, biomass, nodulation and nutrient uptake were taken. The results indicated that Rhizobium inoculants significantly increased the growth and nutrient uptake in both crops. In black gram, T3 (Rhizobium-based biofertilizer) plants showed significant differences in plant height compared to T2 (Recommended inorganic fertilizers) at 15 days after planting (DAP), but no differences at 30 DAP. In contrast, significant differences were observed only at the later stage in soybean plants. Significantly higher numbers of total and active nodules were observed in T3 (Rhizobium-based biofertilizer) compared to T2 (Recommended inorganic fertilizers) in black gram, while no nodules were observed in soybean. In both plants, T3 (Rhizobium-based biofertilizer) recorded significantly higher plant biomass and nutrient uptake (NPK) than T2 (Recommended inorganic fertilizers). In conclusion, the Rhizobium- based biofertilizers are capable of replacing urea application to black gram and soybean in Kilinochchi soils and require detailed studies to validate their effects under field conditions.

Seasonal incidence of major pests and diseases in the Attakkari rice cultivar in Northern Sri Lanka

2026-01-01T00:00:00Z

Title: Seasonal incidence of major pests and diseases in the Attakkari rice cultivar in Northern Sri Lanka Authors: Anushika, C.M.; Suvanthini, T.; Pratheepkanth, P.; Gajapathy, K.; Kishanthan, A. Abstract: Attakkari, a traditional bold-grained rice cultivar favored by consumers in northern Sri Lanka, continues to be cultivated despite not being a recommended cultivar because of its cooking quality and tolerance to the flooding. Farmers frequently report yield losses due to pests and diseases; however, systematic regional assessments are limited. This study, evaluated the major pests and diseases affecting Attakkari over two growing seasons, Yala 2025 and Maha 2025/2026, across 53 farmer fields. A random sampling method was employed using 1 m × 1 m quadrats in the paddy fields. The incidence and severity of each pest and disease were assessed using the standard evaluation system for rice developed by IRRI, along with environmental parameters, including temperature, rainfall, and relative humidity (RH). During Yala, bacterial blight was severe in Mannar, with 80% incidence and a severity score of 9.0, following high temperatures (>32 °C) and rainfall of 42.5–56.7 mm recorded 2 weeks earlier. Leaf folder incidence reached a severity score of 9.0 in Mannar. Yellow stem borer showed moderate incidence with low severity, while brown spot was widespread at early growth stages. In Maha, fungal diseases were predominated. Brown spot affected all surveyed fields in Jaffna and Mullaitivu, with peak severity (9.0) at Oddusuddan following extreme rainfall and sustained RH. Leaf and panicle blast occurred only in Jaffna, with incidence up to 50% and severity up to 7.0 under cooler temperatures ( 32 °C (r = 0.68, α = 0.05), a negative association between blast and temperature (r = -0.54), and a strong correlation between brown spot and 30- day cumulative rainfall (r = 0.82). Sites with ≥ 10 consecutive days of RH > 85% exhibited 3.2-fold greater brown spot severity. These findings indicate the importance of continued multi-season evaluation and integrated pest and disease management strategies for sustainable cultivation of Attakkari rice.

Palmyrah (Borassus flabellifer L.) as a Strategic Economic Resource in Sri Lanka for Sustainable Development: Opportunities, Challenges and Future Prospects

2026-01-01T00:00:00Z

Title: Palmyrah (Borassus flabellifer L.) as a Strategic Economic Resource in Sri Lanka for Sustainable Development: Opportunities, Challenges and Future Prospects Authors: Pakeerathan, K. Abstract: Palmyrah (Borassus flabellifer L.) so called “Karpakatharu-கற்பகதரு-” is a widely distributed salient crop, and resilient natural resource that abundantly exists in the northern and eastern provinces of Sri Lanka with multiple economic benefits and uses. The Palmyrah tree, from its crown to root, supports rural livelihoods and the national economy by providing raw materials for multiple sectors including food and nutrition, Jaggery & treacle, distillery industry, traditional medicine and Nutraceutical, timber, handicrafts and small-scale industries, etc. Further, multibillion dollar export-oriented business is running all around the world directly associated with the Palmyrah. Due to its drought tolerance and substantial adaptability attributes to climate change, the Palmyrah tree plays an important role in sustainable agriculture. There is a strong believe of palmyrah based fence to hope up with the raising crop-elephant-human conflicts and natural resource management in dry zones of Sri Lanka. Morevoer, a wide range of products, including palm jaggery, palm sugar, toddy, fruit pulp, tubers, fibre, and leaf-based handicrafts, provide considerable opportunities for value addition and rural entrepreneurship in Sri Lanka. However, insufficient investment, political negligence and corruption in the past, lack of value-added technologies and capacity building training, hike in tree felling and land clearance, marketing challenges and low participation of the younger generation are major obstacles to the full development of the palmyrah sector. Therefore, there is great potential to strengthen the rural economy of Sri Lanka by utilizing palmyrah resources through scientific research, technological development, policy support and entrepreneurship development. Researchers identify several high-potential areas for future growth such as organic palm sugar for premium international markets; functional foods and nutraceutical ingredients from palmyrah fruit and sap; climate-resilient agroforestry in dryland regions; Biodegradable packaging and fibre-based products; carbon sequestration and ecosystem-service payments and, eco-tourism centered on traditional palmyrah landscapes and cultural heritage. In conclusion, Palmyrah represents an important yet underexploited economic resource with considerable potential to support sustainable rural development and climate-resilient livelihoods in Sri Lanka. Strategic investments in research and development, value-chain modernization, product diversification, capacity building, and supportive public policies are essential to enhance the competitiveness and long-term sustainability of the palmyrah industry. Strengthening collaboration among government agencies, research institutions, universities, and the private sector will be critical for realizing the full economic potential of this indigenous resource.

Evaluation of Submergence Tolerance in Twenty-two Rice (Oryza sativa L.) Genotypes based on Anaerobic Germination

2026-01-01T00:00:00Z

Title: Evaluation of Submergence Tolerance in Twenty-two Rice (Oryza sativa L.) Genotypes based on Anaerobic Germination Authors: Theepika, K.; Arasakesari, S.J.; Pradheeban, L.; Sritharan, S. Abstract: Flash flooding during germination limits direct-seeded rice in rainfed lowlands. Twenty-two rice genotypes were evaluated for submergence tolerance during germination stage. Materials included improved varieties from Rice Research and Development Institute, Bathalagoda; traditional varieties collected from local farmers; and six genotypes selected from previous studies, representing both red- and white-pericarp genotypes. The experiment was conducted from July to August 2025 at the Crop Farm, Ariviyal Nagar, Kilinochchi District, Agro Ecological Zone DL3 on low-humic gley soils using Completely Randomized Design with three replicates. Seeds were sown in plastic containers filled with puddled soil at the depth of 5 cm and subjected to controlled submergence for 3(T2), 7(T3), 10(T4), and 14(T5) days, with non-submerged seeds as control(T1). Germination percentage, shoot length (cm), root length (cm), and seedling vigor index were recorded 7 days after submergence. Data were analyzed using analysis of variance (ANOVA) with mean comparisons by Duncan’s Multiple Range Test (DMRT) at 5% significance level in SAS 9.4. Rice genotypes were classified as tolerant, moderately tolerant, or susceptible based on germination percentage using the IRRI (2013) descriptor, and cluster analysis. Under seven days of submergence (T3), Pachaiperumal, Bw 372 (red pericarp) showed >75% germination and were identified as tolerant; Mottaikaruppan karainagar, Mottaikaruppan Ariyalai, At 362, Pachaiperumal, Analvariyan, At 307, Mottaikaruppan Karainagar, Bg 379/2 exhibited as moderately tolerant under seven days of submergence (T3) compared to < 25% germination in susceptible genotypes. Mottaikaruppan Ariyalai, Mottaikaruppan Karaiainagar, Bg 400-6, Pachaiperumal, Bw 372 showed >50% germination and identified as moderately tolerant even under fourteen days of submergence (T5). Bw 372, Pachaiperumal and Bg 400-6 were identified as superior submergence tolerant genotypes at germination. Tolerant genotypes exhibited shoot elongation and seedling vigor, enabling better establishment in anaerobic conditions. These are valuable genetic resources for flood-prone direct-seeded rice systems and require multi-location validation.