Assessment of Potential Land Suitability for Tea (Camellia sinensis (L.) O. Kuntze) in Sri Lanka Using a GIS-Based Multi-Criteria Approach

Abstract

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.

Relationship between Environmental Covariates and Ceylon Tea Cultivation in Sri Lanka

“…Land with a slope between 15-25 • is considered as having a very highly suitable class, while a gentle slope (>5-7 • ) is regarded as being highly suitable for tea. The class of "very steep slope" (>35 • ) is considered as being unsuitable for tea [19]. Thus, more flatlands in low-country and steeper slopes (>35 • ) in up-country are best avoided because flatlands will increase water logging conditions while steeper slopes provide a major risk of soil erosion and landslides, which is undesirable for tea growth [47,55].…”

“…The elevations at which tea grows greatly affects the quality and quantity of tea [15,18]. It is advisable to avoid flatter and steeper slopes for tea, as steeper slopes pose a significant risk of soil erosion and landslide, whereas flatlands increase water-logging conditions, which are undesirable for tea production [19]. Aspects have a strong influence on solar radiation and temperature and impact the distribution of tea [17,20].…”

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

“…For modeling purposes, the set of bioclimatic variables available on the WorldClim website has been widely used [23,36,37]. Generally, the 'current' climate data sourced from the WorldClim use the years 1950-2000 to calculate climatic averages.…”

Use of GIS Tools in Sustainable Heritage Management—The Importance of Data Generalization in Spatial Modeling

“…The processing functions include transforming, analyzing, aggregating, and generalizing. GIS software allows spatial analysis using a variety of methods, the most popular include: overlay analysis, spatial interpolation, spatial data exploration, hot spot analysis, or kernel density estimation; this type of research finds application in a number of areas, e.g., bathymetry [29], spatial planning [30], location selection [31,32], environmental protection and disaster reduction capability [33][34][35][36][37], spatial and distribution patterns [38][39][40][41], demography [42], as well as many others. Using GIS software, the data can be visualized using many cartographic visualization methods, such as: cartogram, cartodiagram, range method, dot map, etc.…”