Relationship between Environmental Covariates and Ceylon Tea Cultivation in Sri Lanka

Abstract

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.

Climate Change May Imperil Tea Production in the Four Major Tea Producers According to Climate Prediction Models

“…Annual mean temperature (BIO1) was the key indicator for determining the suitability of tea habitat in Kenya and China ( Figure 1) and ( Table 2). Similar to the findings of previous studies, the highest probability of tea occurrence in the four countries was related to areas having a mean annual temperature around 20 • C [16,58]. Annual precipitation (BIO12) emerged as the strongest range predictor to determine current and future suitable habitats for tea in India and Kenya as precipitation is critical and plays an important role in sustaining tea cultivation [16].…”

“…The monsoonal climate, alternate wet and dry seasons and the high elevation of subtropical mountains in China, India, and Sri Lanka appear to provide above optimal conditions for tea cultivation [15]. A successful tea cultivation is highly dependent on climatic factors [16]. Abrupt climate change has been recognised as the foremost environmental issue for tea systems and the tea plant experiences the multi-decadal impacts of climate change all over the world as it has a long lifespan [17].…”

Quality chemical analysis of crush–tear–curl (CTC) black tea from different geographical regions based on UHPLC‐Orbitrap‐MS

“…Geographical environment has a significant impact on the growth of tea plants, which is mainly influenced by light intensity, light duration, rainfall, etc. (Jayasinghe et al., 2020; Liu et al., 2013). Research has shown that phospholipid content increases with light exposure and thus, when the level of chlorophyll derivatives is lower (Jaakola & Hohtola, 2010).…”

“…Studies have shown that the concentration of caffeine and polyphenol in tea increases with altitude, whereas an increase in light intensity decreases the content of AAD and caffeine (Akiko et al, 2011;Song et al, 2012;Zhang et al, 2014). Temperature, light intensity, and hours of sunlight vary greatly depending on the geographical location and play a vital role in plant growth and quality formation (Jayasinghe et al, 2020;Liu et al, 2013). Kang et al (2019) analyzed the aromas of the world's four most famous black teas and found that methyl salicylate (Ceylon), (E)−2-octenal (Assam), benzeneacetaldehyde (Keemun), and linalool and trans-linalool oxide (furanoid) (Darjeeling) might be the most definitive odorants in the corresponding tea categories.…”

“…Studies have shown that the concentration of caffeine and polyphenol in tea increases with altitude, whereas an increase in light intensity decreases the content of AAD and caffeine (Akiko et al., 2011; Song et al., 2012; Zhang et al., 2014). Temperature, light intensity, and hours of sunlight vary greatly depending on the geographical location and play a vital role in plant growth and quality formation (Jayasinghe et al., 2020; Liu et al., 2013). Kang et al.…”