Evaluating the role of topsoil properties and climate on the suitability of rubber plantations: A geographical study in Badalkumbura Divisional Secretariat

Abstract

Temperature and rainfall fluctuations, along with soil degradation, significantly impact the distribution, productivity, and economic viability of rubber plantations and farmers. This study examines the combined influence of topsoil characteristics and climate on the suitability of rubber plantations in the Badalkumbura Divisional Secretariat Division. Land Surface Temperature (LST) analysis was conducted in 2014 and 2024 to assess temperature trends, while rainfall and temperature variations from 2011–2024 to assess temperature trends, while rainfall and temperature variations from 2011-2024 were analysed using data from the Department of Meteorology and represented graphically. Soil quality was determined through laboratory analysis of samples collected from 25 Grama Niladhari Divisions, focusing on parameters such as pH, Electrical Conductivity (EC), Moisture Content (MC), and texture. Inverse Distance Weighted (IDW) interpolation was used to generate soil suitability maps. Multiple regression analysis was applied to assess the relationship between climatic and soil variables and rubber plantation patterns. The LST analysis identified a notable increase in land surface temperature from 2014 to 2024. From 2011 – 2024, minimum temperatures consistently met the requirements for rubber, yet maximum temperatures occasionally exceeded 34°C, especially during the Yala seasons, potentially limiting productivity. Rainfall conditions during some Maha seasons were favourable and corresponded with periods of increasing market prices, encouraging plantation expansion. On the basis of pH, EC, MC, and texture, the areas of Hingurukaduwa, Dewathura, Ankada, Ethpattiya, Ranugalla, and Miyanakandura were identified as highly favourable for rubber. These optimal places fall within Badalkumbura V, particularly in "Ihala Kandukaraya". In correlation, temperature, rainfall, and soil quality were found to moderately influence rubber plantation trends in Badalkumbura. Finally, this study provides valuable insights for identifying suitable plantation zones and highlights the importance of integrated climate-soil management and policy support for sustainable rubber cultivation in Badalkumbura.