JournalTOCs

Tropical Agricultural Research and Extension
Number of Followers: 2

This is an Open Access Journal

Open Access journal
ISSN (Print) 1391-3646
Published by Sri Lanka Journals Online

[71 journals]

The Status of Bactrocera dorsalis as an Emerging Predominant Pest in the
Commercial Fruit Industry in Sri Lanka
- Abstract: Fruit flies (Diptera: Tephritidae) are considered as the most virulent insect pest group in the fruit industry worldwide. However, there are no sufficient previous studies and information on their severity and dominance levels in the fruit industry of Sri Lanka. Hence, the present study aimed to access their abundance and dominance level and, based on the present findings, the potential risk of B. dorsalis is presented herein further. The study was carried out using randomly selected eight (08) fruit stalls as two stalls from each bio-climatic zone. Adult fruit flies were collected using methyl-eugenol field traps from fruit stalls. Trapped flies were identified using standard taxonomic keys. Simpson Population Dominance Index and the Abundance Index for recorded fruit flies were calculated. Four Bactrocera fruit flies; B. dorsalis, B. kandiansis, B. correcta and B. latifrons were recorded. Among them, Bactrocera dorsalis showed the highest percentage abundance in all selected fruit stalls and also in all bio-climatic zones (P
Stem Cuttings as Propagules for Vegetative Propagation of Cashew
(Anacardium occidentale L.)
- Abstract: Due to the existing variability among the populations and the inability of meeting the current demand for planting materials for large-scale cultivation, cashew (Anacardium occidentale L.) requires a promising vegetative propagation method. Stem cuttings is the best propagule and need to induce germination. Wiping of gum secreted onto the cut surface of the stem with three solvents, water, acetone, and kerosene just after and after 5, 10, and 15 min of making the cut was tested to remove the gum. The effect of the presence of apical buds and leaves on the stem cuttings and the application of different types of rooting hormones containing IBA onto the cut surface was tested using three commercial varieties, WUCC-13, WUCC-19, and WUCC-21. Data were analysed using CATMOD or ANOVA procedure. The results denoted a significant effect of gum solvent for maintaining the cutting viability by giving rise to shoots and callus production (p
Management of Whiteflies (Bemisia tabaci. Gennadius) Using Amblyseius
swirskii Athias-Henriot (Swirski-Mite) in Chilli Crop
- Abstract: Whitefly (Bemisia tabaci ) is an important pest of chilli in Sri Lanka. Whiteflies are also vectors of viral diseases in many crops. Indiscriminate use of insecticides leads to resistant development, high residue levels, health hazards and environmental pollution. The laboratory experiment was conducted using the biological agent, Amblyseius swirskii Athias- Henriot, imported from Koppert Biological Systems, Netherlands, for the control of chilli whiteflies. Results indicated A.swirskii reduced the white fly population significantly after two weeks of introduction. The reduction of the population of A.swirskii was statistically significant after the 04th week. The survival of Swirskii mites and whiteflies at the end of the 6th week in the experiment was 25 % and 26.6 % respectively. A.swirskii effectively controlled whiteflies in chilli, though the biological agents did not multiply in the experiment even with the provision of bee's honey as an alternate food source, hence seasonal augmentation releases are necessary. Published on 2023-03-28 00:00:00
Decision Support System Enabled Digital Mobile Platform to Assist Farmers
Towards Agricultural Production Sustainability in Sri Lanka
- Abstract: Various issues in crop production and related industries pose significant impediments to economic growth and food security in Sri Lanka. The key issue identified in the agriculture sector is the lack of access to relevant and timely information in a format that is actionable and context-specific. However, information and communication technology (ICT) has the potential to address these gaps and revolutionise agriculture, as it has done in many other countries. The study employed the Design Science Research (DSR) approach to develop innovative artefacts that provide vital information to farmers during crop production. This paper demonstrates various iterative steps in the artefact construction and evaluation processes and shows how context-specific, relevant and actionable information represented through the user interfaces of two mobile applications: “Govi-Nena Farmer” and “Govi-Nena Home Gardening”. The study further elaborates how the key challenges were addressed and how the conceptual solution was proven to work in a real-world scenario with the evidence of knowledge satisfaction analysis using the 5-point Likert scale method with 32 app users. The works initially modelled crop and variety selection based on agro-ecological regions (AERs), seasons, and pre-planting and cultivation activities of the farming life cycle. Packages of practice (PoP) workbooks were then developed, tailored to the farmer’s context using these models. The analysis of PoP knowledge revealed that every user was satisfied (p<0.05) with the information provided in the app, especially data accuracy (Z=4.221), fertilizer application guidelines (Z=4.170) and information quality (Z=3.785), all of which reached a very high level of satisfaction. Hence, the PoP enabled decision support system has been embedded into the ontological crop knowledge base of the mobile-based systems to assist farmers in making timely quality decisions to achieve target goals. Published on 2023-03-28 00:00:00
Growth Performances and Grain Yield Response of Rice Varieties (Oryza
sativa L.) Established at Different Seed Broadcasting Rates in Irrigated
Fields of Low Country Dry Zone of Sri Lanka
- Abstract: Seed broadcasting rate has an enormous influence on rice plant density and the competition of the crop stands, tiller number, time taken to maturity and grain yield. Relatively low plant densities due to inappropriate sowing methods are the most significant aspects of agronomic restrictions for obtaining higher grain yields and weed competitiveness. A research study was conducted in Maha 2019/20 and Maha 2020/21 seasons to study the effect of different seed broadcasting rates on the yield and weed competitiveness of rice. The experiment was established with 3 different seed broadcasting rates 100, 150 and 200 kg ha-1 for the rice variety At 362 (Long grain) and 75, 112.5 and 150 kg ha-1 for the rice variety At 307 (Intermediate grain). The experiment was conducted under the irrigated condition of the low country dry zone of Sri Lanka in imperfectly drained reddish brown and low humic gley soils at the Rice Research Station (RRS), Ambalantota. Parallel to the research field experiment, recommendation and farmer practiced seed broadcasting rates (100 and 150 kg ha-1) were evaluated at farmers’ fields using rice variety At 362. Grain yield, plant height, tiller count, filled and unfilled grain per panicle, spikelet count per panicle, 1000 grains weight and weed performance were determined. Results of this experiment have shown that elevated seed rates beyond 100 kg ha-1 do not improve the tiller count, effective panicles or the grain yield of two rice varieties At 362 and At 307. Diseases like sheath blight may affect the rice crop more severely causing significant yield losses in favourable weather with increased populations (150 kg ha-1). Therefore, a 100 kg ha-1 seed broadcasting rate can be recommended as the best seed rate for farmer field cultivation where better weed management practices are adopted. Finally, the results of this experiment reconfirmed that exceeding the recommended seed broadcasting rates of 100 kg ha-1 or 75 kg ha-1 for At 362 or At 307 respectively will not be effective to get a higher yield response from paddy under irrigated conditions in the dry zone. Recommended seed application rate of 100 kg ha-1 for long grain rice and 75 kg h-1 for intermediate grain rice in the paddy farming system had been recorded as cost effective seed broadcasting rates. Published on 2023-03-28 00:00:00
An Assessment of Power Distance and Leadership Styles in Agro-Based
Small-Medium Enterprises in Sabaragamuwa Province, Sri Lanka
- Abstract: Organizational culture is a key in developing traits and skills in business enterprises. Organizational culture affects employee performance thereby the business success. Amidst many other models, Geert Hofstede introduced a model to evaluate the cultural influence in business organizations over four dimensions, namely power distance, uncertainty avoidance, individuality, and masculinity. Despite many scholars have researched on organizational culture using this four-dimensional approach, an in-depth study has not been carried out in Sri Lanka, particularly on the relationship between power distance and employee performance. Thus, this study attempts to answer the question; how has the level of power distance influenced on employee performance in small-medium agro-based enterprises (SME) and the leadership styles' Agro-based SMEs over four product categories including dairy, tea, plant production (ornamental and timber plant), and agro-input supply in Sabaragamuwa Province, Sri Lanka were considered. Secondary data was obtained through published documents and primary data was gathered through a questionnaire survey, which elicited questions enveloping both quantitative and qualitative data. Simple random sampling technique was employed to draw a sample of 100 operational-level staff from 10 agro-based SMEs obtained from the lists of Sabaragamuwa Chamber of Commerce. Northouse leadership questionnaire was adopted to investigate the leadership styles. Every variable was rated at a five-point Likert scale from 1 to 5 (1- strongly agree and 5- strongly disagree). Democratic leadership style was prominent in all SMEs with moderate employee performance. Encouraged teamwork culture, collaborative problem solving, and high employee engagement, open discussions are noticeable. A modest power distance has been reported by all the entities in a range of 50-68 (PDI dairy= 68.71; PDI tea= 50.52; PDI plant= 66.21; PDI agro-input= 50.24). It indicates a harmonious relationship between superiors and workers. Despite Sri Lanka has been classified as a country with a high-power distance (80) in 2011, the findings reveal a moderate power distance (58.92) in agro-based SMEs in the Sabaragamuwa Province. Published on 2023-03-28 00:00:00
Development of In-Vitro Protocol to Enhance Mass Production of Turmeric
(Curcuma longa L.)
- Abstract: Conventionally, turmeric (Curcuma longa L.) is propagated through rhizomes. However, its multiplication rate is very low where a single turmeric rhizome approximately produces 6-8 lateral buds and nearly 20-25% of the harvest should be retained as planting materials for the next season. Therefore, the study focuses on the development of an in vitro regeneration protocol of turmeric for the year-round provision of disease-free planting material. Commercially grown sprouted rhizome buds were surface sterilized with fungicide followed by 70% ethanol, and with different concentrations of Clorox (10, 20, 30 and 40%). Different exposure times (5, 10, 15 and 20 minutes) were tested to develop the best sterilization procedure. MS medium supplemented with different concentrations of hormones BAP (2.0, 3.0, 4.0 and 5.0 mg/l) and NAA (0.25 and 0.5 mg/l) for shoot regeneration, and IBA (1.0, 2.0, 3.0 and 4.0 mg/l) for root regeneration to find the best combination. The results showed that 30% Clorox and 20 minutes exposure time is suitable for surface sterilization of buds about 1.5-2.0 cm long. Shoot regeneration was the highest when the media were treated with 4.0 mg/l of BAP and 0.5 mg/l NAA. The best IBA concentration that gives the highest number of roots in the least number of weeks is 2.0mg/l. Additionally, 58.33% of the plantlets survived after field acclimatization. The study concluded that the protocol can be used for in vitro propagation of turmeric using rhizome buds for large-scale production of plant materials. Published on 2023-03-28 00:00:00
Effect of the Rate and Split Application of Albert’s Fertilizer on
Growth and Yield Performances of Cabbage Under the Protected House in the
Low Country Wet Zone of Sri Lanka
- Abstract: In Sri Lanka the demand for fresh vegetables has been increasing all over the country. Therefore, up country vegetable cultivation should be promoted in low and mid country areas. However, there is no proper fertilization pattern to enhance the growth and yield of cabbage grown in the low country. Thus, an experiment was performed in a protected house located in the low country wet zone of Sri Lanka from October 2021 to January 2022 to evaluate the effect of the rate and split application of Albert’s fertilizer on the growth and yield parameters of Cabbage (Brassica oleracea L. var Green Coronet). The study was carried out in a two-factor factorial (2 x 3) Completely Randomized Design with four replicates. The two factors tested were, the rate of fertilizer; A1 (1.0 g/plant/day), A2 (1.5 g/plant/day), A3 (2.0 g/plant/day) and the number of split applications of fertilizer; F1 (1 time/plant/day), F2 (2 times/plant/day), F3 (3 times/plant/day). Treatments were applied daily. The average day temperature inside the protected house was 32.5 °C and the average night temperature inside the protected house was 27°C. As growth parameters plant height, the number of loose leaves per plant and canopy diameter were measured once a fortnight while cabbage heads and total biomass yield were measured as yield parameters, 100 days after transplanting. Measured data were analyzed using ANOVA. Subsequently, means were separated by least significant difference (LSD) at 5% probability level. There is no significant effect of the split of Albert’s fertilizer and no interaction effect between the rate and split of fertilizer. Plant height, the number of loose leaves per plant and canopy diameter were significantly influenced by the rate of fertilizer. 2.0 g/plant/day treatment gave significantly higher values for the above growth parameters with compared to the treatments of 1 and 1.5 g/plant/day. Even though, no significant difference was recorded in total biomass yield, the significantly highest head yield was recorded in 1.0 g of Albert’s fertilizer/plant/day treatment. When considering the economic yield, it can conclude that the treatment of 1.0 g/plant/day is the best fertilizer rate for cabbage grown under protected houses in the low country wet zone of Sri Lanka. Also, fertilizer application at once a day can be recommended when considering energy use efficiency since there is no significant effect of split application of fertilizer. Published on 2023-03-28 00:00:00
Plant growth, foliage senescence and rhizome yield of turmeric (Curcuma
domestica L.) as affected by inorganic and organic fertilizers
- Abstract: Integrated plant nutrient management is one of the key components of sustainable agriculture. It reduces the cost of production while enhancing the revenue of growers. The present study was conducted to examine the effect of sole and combine applications of inorganic fertilizer and organic fertilizers on plant growth, foliage senescence and rhizome yield of turmeric (Curcuma domestica L.) in container gardening. Eight treatments comprise sole applications of different types of organic fertilizers including vermicompost, compost and matured cow dung, and inorganic fertilizer schedule recommended by the Department of Export Agriculture, Sri Lanka together with combinations of inorganic and organic fertilizers. Sand: topsoil: partially burned paddy husk (1:1:1 v/v) were used to fill the black plastic pots with 30 cm in diameter. Due to the variation of shade of the experimental site, the experiment was setup as a randomized complete block design with three replicates. The number of leaves per shoot, leaf length (cm), leaf width (cm), height of the pseudo stem (cm), number of shoots per pot were taken five months after planting while the number of primary fingers/clump, number of secondary fingers/clump, fresh and dry weight of rhizomes/pot (g) were taken at harvest. Foliage senescence as visual senescence score was recorded from 32 weeks after plant establishment until foliage became dry. All measured quantitative parameters were significantly different between treatments, where the greater values were recorded when plants were treated with equal proportions of inorganic fertilizer and vermicompost as an organic fertilizer while the foliage senescence took a longer period in the same treatment when compared to other treatments. This might be due continuous supply of nutrients through an integrated approach of nutrient management and modification of physical and microbiological properties of the growth substrate by vermicompost application. Poor plant growth, early senescence and low fresh and dry yield of rhizomes were reported when plants were grown without inorganic or organic fertilizers may be due to an insufficient supply of nutrients to fulfil the demand of plant growth and development. Combine application of vermicompost and inorganic fertilizer could be considered as a promising combination of fertilizers for the growth and yield of turmeric under integrated plant nutrient management. Published on 2022-12-29 00:00:00
Evaluation of phytotoxicity of composts produced from spent mushroom
substrate using seed germination bioassay of Raphunus sativus L.
- Abstract: present study, a seed germination test was conducted to evaluate the possible phytotoxic effect of SMS compost. Aqueous extracts from compost produced by SMS, amending different N sources (green leaves and urea) with and without an inoculum as 25%, 50%, and 100% were tested against seed germination of radish (Raphanus sativus L). According to the results, the lowest Germination index (GI%) was observed in 100% compost aqueous extractions while the highest GI% was observed in 25% compost aqueous extracts. GI% of inoculated compost has positive significant correlations with both relative seed germination (RSG%) and relative root growth (RRG%) [r=0.600, p=0.05 and r=0.965, p=0.01, respectively]. The regression of GI% and EC values in inoculated (r2=0.7064) and non-inoculated (r2=0.6009) extracts showed negative linear relationship. Moreover, the EC was significantly correlated with all extractable tested ions except Cu2+ and Ni2+ in inoculated treatments. pH values in all aqueous extracts recorded in the range of 6.27 to 8.08. Extractable elements Cu2+ (r=0.645, p=0.01) and Zn2+ (r=0.577, p=0.05) had positive correlation with pH. The water extractable NH4+ concentration was significantly higher (p