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Ms. Sadeeka Jayasinghe
University of New England

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Research Keywords & Expertise

0 Agriculture
0 Agronomical Sciences
0 Agriculture and environment monitoring
0 Camellia sinensis, Climate change, Climate suitability, Global climate models, MaxEnt
0 Climate modeling, Tea cultivation, Crop modeling, GIS and Spatial analysis

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Original paper
Published: 29 March 2021 in International Journal of Biometeorology
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Understanding the interactive effects and relationships between biochemical elements of tea leaves and the related factors, particularly climatic, cultivar, and geographic, is key for high-quality Ceylon tea production. The objectives of this study were to (1) investigate the effects of season × cultivar × agro-ecological regions (AERs) on the four tested biochemicals in fresh tea leaves, total polyphenol content (TPC), free sugar, protein, and theanine; (2) determine the relationships between, and develop a model to estimate, the biochemicals and their related factors; and (3) project the potential concentrations and distributions of four tested biochemicals in tea leaves with respect to the current and future climate. This study primarily uses inferential statistics via the Statistical Package for the Social Sciences (SPSS), cross-validation using R software, and the inverse distance weighting (IDW) approach in ArcGIS. The results demonstrate that the season, cultivar (Ceylon tea cultivars of TRI 2025 and TRI 4053), and AER and their interactions on biochemicals have significant effects (p < 0.05). The models derived in the regression analysis demonstrate the strong relationships between the independent variables and the biochemicals, with multiple correlation coefficients (R) around 0.8 and coefficient of determination (R2) around 0.6. The low standard deviation of error of prediction (SDEP < 0.1) and the high correlation coefficient of leave-one-out cross-validation (Q2) for all four biochemicals ranged from 0.56 to 0.61, which signifies the predictive ability of the models. The future projections show a considerable increase in the thresholds of all tested biochemicals. The distribution category with ‘very high’ concentrations of TPC and theanine is predicted to increase in the future by averages of 10% and 14%, respectively, while reducing the classes of protein and free sugar by 14% and 12%, respectively. Overall, the changing concentrations of the thresholds of relevant biochemicals and their distribution will negatively affect the final quality of tea, and these variations indicate that climate change has started to diminish Ceylon tea quality.

ACS Style

Sadeeka Layomi Jayasinghe; Lalit Kumar; Ewon Kaliyadasa. The future of high-quality Ceylon tea seems bleak in the face of climate change. International Journal of Biometeorology 2021, 1 -18.

AMA Style

Sadeeka Layomi Jayasinghe, Lalit Kumar, Ewon Kaliyadasa. The future of high-quality Ceylon tea seems bleak in the face of climate change. International Journal of Biometeorology. 2021; ():1-18.

Chicago/Turabian Style

Sadeeka Layomi Jayasinghe; Lalit Kumar; Ewon Kaliyadasa. 2021. "The future of high-quality Ceylon tea seems bleak in the face of climate change." International Journal of Biometeorology , no. : 1-18.

Review
Published: 24 March 2021 in Agronomy
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Even though climate change is having an increasing impact on tea plants, systematic reviews on the impact of climate change on the tea system are scarce. This review was undertaken to assess and synthesize the knowledge around the impacts of current and future climate on yield, quality, and climate suitability for tea; the historical roots and the most influential papers on the aforementioned topics; and the key adaptation and mitigation strategies that are practiced in tea fields. Our findings show that a large number of studies have focused on the impact of climate change on tea quality, followed by tea yield, while a smaller number of studies have concentrated on climate suitability. Three pronounced reference peaks found in Reference Publication Year Spectroscopy (RYPS) represent the most significant papers associated with the yield, quality, and climate suitability for tea. Tea yield increases with elevated CO2 levels, but this increment could be substantially affected by an increasing temperature. Other climatic factors are uneven rainfall, extreme weather events, and climate-driven abiotic stressors. An altered climate presents both advantages and disadvantages for tea quality due to the uncertainty of the concentrations of biochemicals in tea leaves. Climate change creates losses, gains, and shifts of climate suitability for tea habitats. Further studies are required in order to fill the knowledge gaps identified through the present review, such as an investigation of the interaction between the tea plant and multiple environmental factors that mimic real-world conditions and then studies on its impact on the tea system, as well as the design of ensemble modeling approaches to predict climate suitability for tea. Finally, we outline multifaceted and evidence-based adaptive and mitigation strategies that can be implemented in tea fields to alleviate the undesirable impacts of climate change.

ACS Style

Sadeeka Jayasinghe; Lalit Kumar. Potential Impact of the Current and Future Climate on the Yield, Quality, and Climate Suitability for Tea [Camellia sinensis (L.) O. Kuntze]: A Systematic Review. Agronomy 2021, 11, 619 .

AMA Style

Sadeeka Jayasinghe, Lalit Kumar. Potential Impact of the Current and Future Climate on the Yield, Quality, and Climate Suitability for Tea [Camellia sinensis (L.) O. Kuntze]: A Systematic Review. Agronomy. 2021; 11 (4):619.

Chicago/Turabian Style

Sadeeka Jayasinghe; Lalit Kumar. 2021. "Potential Impact of the Current and Future Climate on the Yield, Quality, and Climate Suitability for Tea [Camellia sinensis (L.) O. Kuntze]: A Systematic Review." Agronomy 11, no. 4: 619.

Journal article
Published: 09 October 2020 in Agronomy
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The threat of accelerating climate change on species distribution now and in the future is a topic of increasing research interest. However, little work has been undertaken to assess how shifting climates will affect the suitability of tea cultivation. Therefore, we used MaxEnt modelling to project the impact of current and future climatic scenarios on the potential distribution of tea across the four tea-producing countries of China, India, Kenya and Sri Lanka. Projections were made for the years 2050 and 2070 with three Representative Concentration Pathways (RCPs) using seven bioclimatic predictors under three global circulation models (GCMs). The current and future habitat suitability for tea predicted by the models produced a high accuracy rate, with high areas under the receiver operating characteristic curve (AUCs) for all tested RCPs under the three GCMs for the four countries. The mean true skill statistic (TSS) values for tea in Sri Lanka, Kenya, India and China were 0.80, 0.91, 0.91, and 0.74, respectively. The kappa values (k) of the current and future models for all four countries ranged from 0.40 to 0.75, which indicates that the overall performance of the model was good. The precipitation seasonality and annual precipitation were found to be the most influential variables in Sri Lanka and India, respectively, while annual mean temperature was the most effective contributor for determining the suitability of habitat for tea in Kenya and China. An important proviso is that some existing tea-growing areas will face reduced suitability for future tea cultivation suggesting that by 2050 there will be a drastic reduction in the optimal suitability by averages of 26.2%, 14%, and 4.7% in Kenya, Sri Lanka and China, respectively. The optimal suitability will be reduced by 15.1%, 28.6% and 2.6% in Kenya, Sri Lanka and China, respectively, by 2070. India displays an advantage in projected future climates as it gains optimal suitability areas of 15% by 2050 and 25% by 2070.

ACS Style

Sadeeka Layomi Jayasinghe; Lalit Kumar. Climate Change May Imperil Tea Production in the Four Major Tea Producers According to Climate Prediction Models. Agronomy 2020, 10, 1536 .

AMA Style

Sadeeka Layomi Jayasinghe, Lalit Kumar. Climate Change May Imperil Tea Production in the Four Major Tea Producers According to Climate Prediction Models. Agronomy. 2020; 10 (10):1536.

Chicago/Turabian Style

Sadeeka Layomi Jayasinghe; Lalit Kumar. 2020. "Climate Change May Imperil Tea Production in the Four Major Tea Producers According to Climate Prediction Models." Agronomy 10, no. 10: 1536.

Journal article
Published: 30 March 2020 in Agronomy
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How the current distribution of tea cultivation is influenced by specific environmental conditions in Sri Lanka is yet to be explored. Therefore, this study aims to assess the differences between tea and non-tea growing areas with respect to climatic and topographic covariates, and to determine the major covariates that control tea distributions. Climatic data of temperature and rainfall were extracted from WorldClim-Global Climate Data; the elevation, slopes, and aspects were obtained from Global Multi-resolution Terrain Elevation Data; and the solar radiation data was computed using a clear-sky solar radiation model. Random points were created on rasterised environmental layers for tea-growing and non-tea growing areas, stratified into low, mid, and high regions, using ArcGIS version 10.4.1 (Environmental Systems Research Institute: ESRI Redlands, CA, USA).Correlations were derived between covariates and tea and non-tea growing areas. According to the logistic regression analysis, there was no significant influence of the south-west, west, and north-west aspect compared to the north aspect when all other covariates were held constant. The odds ratio indicated that an area with a one-unit higher solar radiation was 1.453 times more likely to be a tea growing area. Similarly, a per unit increase in slope increases the likelihood of an area being suitable for tea cultivation by 1.039 times. When the annual mean temperature increased, the suitability of tea cultivation decreased, but an increased rainfall had increased the suitability of an area for tea cultivation. Areas with a north facing slope had the highest suitability for tea cultivation. This research demonstrated that tea growing could be expanded into a variety of locations as long as these variables are either found or managed in order to obtain the critical levels. In addition, it is proposed that the results of this study could be utilised in the assessment of the climate or/and land suitability for tea.

ACS Style

Sadeeka Layomi Jayasinghe; Lalit Kumar; Kamrul Hasan. Relationship between Environmental Covariates and Ceylon Tea Cultivation in Sri Lanka. Agronomy 2020, 10, 476 .

AMA Style

Sadeeka Layomi Jayasinghe, Lalit Kumar, Kamrul Hasan. Relationship between Environmental Covariates and Ceylon Tea Cultivation in Sri Lanka. Agronomy. 2020; 10 (4):476.

Chicago/Turabian Style

Sadeeka Layomi Jayasinghe; Lalit Kumar; Kamrul Hasan. 2020. "Relationship between Environmental Covariates and Ceylon Tea Cultivation in Sri Lanka." Agronomy 10, no. 4: 476.

Discussion
Published: 16 December 2019 in Sustainability
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Climatic and non-climatic stressors, such as temperature increases, rainfall fluctuations, population growth and migration, pollution, land-use changes and inadequate gender-specific strategies, are major challenges to coastal agricultural sustainability. In this paper, we discuss all pertinent issues related to the sustainability of coastal agriculture under climate change. It is evident that some climate-change-related impacts (e.g., temperature and rainfall) on agriculture are similarly applicable to both coastal and non-coastal settings, but there are other factors (e.g., inundation, seawater intrusion, soil salinity and tropical cyclones) that particularly impact coastal agricultural sustainability. Coastal agriculture is characterised by low-lying and saline-prone soils where spatial competition with urban growth is an ever-increasing problem. We highlight how coastal agricultural viability could be sustained through blending farmer perceptions, adaptation options, gender-specific participation and integrated coastal resource management into policy ratification. This paper provides important aspects of the coastal agricultural sustainability, and it can be an inspiration for further research and coastal agrarian planning.

ACS Style

Tharani Gopalakrishnan; Kamrul Hasan; A T M Sanaul Haque; Sadeeka Jayasinghe; Lalit Kumar. Sustainability of Coastal Agriculture under Climate Change. Sustainability 2019, 11, 7200 .

AMA Style

Tharani Gopalakrishnan, Kamrul Hasan, A T M Sanaul Haque, Sadeeka Jayasinghe, Lalit Kumar. Sustainability of Coastal Agriculture under Climate Change. Sustainability. 2019; 11 (24):7200.

Chicago/Turabian Style

Tharani Gopalakrishnan; Kamrul Hasan; A T M Sanaul Haque; Sadeeka Jayasinghe; Lalit Kumar. 2019. "Sustainability of Coastal Agriculture under Climate Change." Sustainability 11, no. 24: 7200.

Journal article
Published: 08 July 2019 in Agriculture
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The potential land suitability assessment for tea is a crucial step in determining the environmental limits of sustainable tea production. The aim of this study was to assess land suitability to determine suitable agricultural land for tea crops in Sri Lanka. Climatic, topographical and soil factors assumed to influence land use were assembled and the weights of their respective contributions to land suitability for tea were assessed using the Analytical Hierarchical Process (AHP) and the Decision-Making Trail and Evaluation Laboratory (DEMATEL) model. Subsequently, all the factors were integrated to generate the potential land suitability map. The results showed that the largest part of the land in Sri Lanka was occupied by low suitability class (42.1%) and 28.5% registered an unsuitable land cover. Furthermore, 12.4% was moderately suitable, 13.9% was highly suitable and 2.5% was very highly suitable for tea cultivation. The highest proportion of “very highly suitable” areas were recorded in the Nuwara Eliya District, which accounted for 29.50% of the highest category. The model validation results showed that 92.46% of the combined “highly suitable” and “very highly suitable” modelled classes are actual current tea-growing areas, showing the overall robustness of this model and the weightings applied. This result is significant in that it provides effective approaches to enhance land-use efficiency and better management of tea production.

ACS Style

Sadeeka Layomi Jayasinghe; Lalit Kumar; Janaki Sandamali. Assessment of Potential Land Suitability for Tea (Camellia sinensis (L.) O. Kuntze) in Sri Lanka Using a GIS-Based Multi-Criteria Approach. Agriculture 2019, 9, 148 .

AMA Style

Sadeeka Layomi Jayasinghe, Lalit Kumar, Janaki Sandamali. Assessment of Potential Land Suitability for Tea (Camellia sinensis (L.) O. Kuntze) in Sri Lanka Using a GIS-Based Multi-Criteria Approach. Agriculture. 2019; 9 (7):148.

Chicago/Turabian Style

Sadeeka Layomi Jayasinghe; Lalit Kumar; Janaki Sandamali. 2019. "Assessment of Potential Land Suitability for Tea (Camellia sinensis (L.) O. Kuntze) in Sri Lanka Using a GIS-Based Multi-Criteria Approach." Agriculture 9, no. 7: 148.

Journal article
Published: 10 April 2019 in Agricultural and Forest Meteorology
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Knowledge of potential distributions and habitat preferences of tea (Camellia sinensis) under current and future climate conditions are vital for policy makers and stakeholders to develop suitable adaptation measures to mitigate against any detrimental effects of climate change. Without broad awareness of climate suitability and potential changes in distributions of tea growing areas, efforts of expanding the productivity of tea would remain ineffective. This study aimed to model the climate suitability of tea in Sri Lanka in response to the current and future climate change scenarios using the correlative habitat suitability model MaxEnt. Three representative concentration pathways were used under MIROC5 and CCSM4 global climate models for the year 2050 and 2070. The MaxEnt model projected current habitat suitability for tea based on existing datasets with a mean AUC of 0.92. The TSS value with a mean 0.847 ± 0.007 signifies high accuracy of predicting suitability habitats while the maximum kappa value (k) of the current and future models was around 0.454, indicating the overall performance of the model was good. In relation to the current time, areas of 6090 km2 (9.3%), 5769 km2(8.8%), and 5086 km2 were projected as potential areas of having optimal, medium, and marginal climate suitability for tea, respectively. Results show that most of the optimal and medium suitability areas in the low elevation areas would be lost to a greater extent in comparison to the high elevation areas for all tested RCPs by 2050 and 2070 under both GCMs of MIROC5 and CCSM4. The comparison of the current and future distributions of suitable tea growing areas revealed a decline of approximately 10.5%, 17% and 8% in total 'optimal', 'medium', and 'marginal' suitability areas respectively, implying that climate would have a negative effect on the habitat suitability of tea in Sri Lanka by 2050 and 2070.

ACS Style

Sadeeka Layomi Jayasinghe; Lalit Kumar. Modeling the climate suitability of tea [Camellia sinensis(L.) O. Kuntze] in Sri Lanka in response to current and future climate change scenarios. Agricultural and Forest Meteorology 2019, 272-273, 102 -117.

AMA Style

Sadeeka Layomi Jayasinghe, Lalit Kumar. Modeling the climate suitability of tea [Camellia sinensis(L.) O. Kuntze] in Sri Lanka in response to current and future climate change scenarios. Agricultural and Forest Meteorology. 2019; 272-273 ():102-117.

Chicago/Turabian Style

Sadeeka Layomi Jayasinghe; Lalit Kumar. 2019. "Modeling the climate suitability of tea [Camellia sinensis(L.) O. Kuntze] in Sri Lanka in response to current and future climate change scenarios." Agricultural and Forest Meteorology 272-273, no. : 102-117.