Monoculture vs mixed-species plantation impact on the soil quality of an ecologically sensitive area
Over the past four decades Western Ghats, one of the eight hottest hotspots of biological diversity in the world, has witnessed the transformation of its prime forests into other land-use types mainly monoculture plantations. The present study evaluated the impact of conversion of natural forests to mixed-species (teak) and monoculture (rubber) plantations on the soil quality of the Typic Plinthohumults soil series in the Southern Western Ghats region of Kerala, India. The baseline physicochemical and biological parameters of the different locations were analyzed using standard methods. To comprehend the impact of plantations on the overall soil quality, the soil quality index of the different land-uses was quantified using the forest as the reference land-use Significant variations in different soil physical, chemical, and biological properties of plantation and forest soils were observed in the present study. The overall soil quality index was found to follow the order: forest (1.0) > teak plantations (0.9) > rubber plantations (0.6), thus signifying the negative impact, monoculture rubber plantations had on the soil quality of the study area. The results emphasize the need for the development of better land management practices and mixed-species plantation systems such as the teak plantations in the present study which did not deteriorate the soil quality.