Invasion impacts of Acacia mearnsii on soil properties of Shola forests in the Western Ghats
Surya Prabha AC, Arulmani K, Velumani R, Senthivelu M, Padmini S
The Australian Black Wattle (A. mearnsii) introduced during the 1960s in State Forest lands located in the upper altitudes of the Palani hills, threatens native habitats by out competing indigenous vegetation for water, soil nutrients and organic matter. The present investigation was undertaken to study the soil properties of shola forests invaded by A. mearnsii plantations in the Western Ghats covering the Kodaikanal. Soil samples were collected from shola forests invaded by A. mearnsii in the Kodaikanal forest range of the Kodaikanal Forest Division. For comparison purpose, soil samples were collected from shola forest, pure A. mearnsii plantation, grass land and pine plantations. The soil organic carbon (5.73%) was highest under shola forest and A. mearnsii invaded shola forest recorded the highest available nitrogen at 0-30 cm depth (465.5 kg ha-1), available phosphorus (29.8 kg ha-1), exchangeable calcium (1.2 meq/100g), magnesium (1.6 meq/100g). A. mearnsii plantation recorded the highest available potassium (490.0 kg ha-1) at 0-30 cm depth and was followed by shola forest (400.0 kg ha-1), and grassland (343.0 kg ha-1). The study has contributed to the understanding of soil characteristics in A. mearnsii invaded shola forests and the baseline data generated can be utilized for undertaking appropriate decision making in the management of forests to control the invasion menace of A. mearnsii thereby improving the soil quality.