Soil taxonomy, physicochemical characteristics and mineralogy under Syzygium travancoricum a critically endangered and endemic tree species from Kerala part of Western Ghats, India

Soil properties are important indicators of plant growth as well as soil health. Syzygium travncorium is an endangered species as well as an indigenous tree to the South Western Ghats, India on which few studies have been conducted related to the properties of soil under it. The current study was conducted at Kalasamala, a temple grove lying near Kunnamkulam at Thrissur district, Kerala, where the soil taxonomy, physicochemical properties, mineralogy, of soil under two types of vegetation systems viz., Syzygium travancoricum (profile-1) and heterogeneous tree species (profile-2) grown there by taking soil profiles at depth 1.5m. The soils under two types of vegetations were classified under the order ultisol and sub-classified as ustic Palehumults in profile A and typic Haplustolls in profile B. Identification of mineralogy in profile A finds quartz in the sand fractions; chlorite mica, kaolinite, gibbsite and quartz in silt fractions; chlorite, kaolinite, gibbsite and quartz in clay fractions. In contrast profile B, exhibits quartz and feldspars in sand fractions; chlorite, Hydroxy Interlayered Vermiculate, mica, kaolinite, gibbsite, and quartz in silt fractions; chlorite, Hydroxy Interlayered Vermiculate, kaolinite, gibbsite, and quartz in clay fractions. Profile A has three classes of soil textures; sandy loam, sandy clay loam, sandy clay, whereas two textural classes, sandy loam, sandy clay loam were found in profile B. Furthermore, it has been observed that the process of laterization results accumulation of clays at the bottom horizons in these systems, thus enhancing Cation Exchange Capacity (CEC), Total Exchangeable Acidity (TEA) and Soil Organic Carbon (SOC) except the illuvial layer (Bt2) of profile B. This study recognized typical characteristics of tropical humid soils, including leaching, low nutrient levels, and acidity. The decline of Syzygium travancoricum, by low seedling and poor regeneration, may be partly due to these limiting edaphic conditions.