Soil Properties and Nutrients Availability in Contrasting Natural, Plantation and Deforested Barren Land of Lawachara Forest of Bangladesh

Deforestation has a profound effect on soil properties like soil reaction (pH), organic matter (OM), total nitrogen (N), available phosphorus (P) and potassium (K) contents which are eventually affected by the soil type, management and local climate across eco-regions. Therefore, the present study was conducted with the objective to assess the response of these vital soil physical and chemical properties to changes in land covers arising from the conversion of natural forest of Lawachara National Park (LNP) to deforested barren land and plantation. Vegetative study was conducted with an aim to list and analyze the available species of LNP to have an impression of composition and type of the forest, particularly of the sample plots which were subjected to soil analysis. Jam ( Syzygium spp.) was found as the dominant species for all parts of the natural forest followed by Chapalish ( Artocarpus chama ), while Lohakat ( Xylia dolabriformis ) was the mostly abundant and dominant species followed by Raktan ( Lophopetalum fimbriatam ) in the plantation forest. The mean height and diameter of trees in plantation forest were 9.95 m and 31 cm respectively both of which were higher than the corresponding values of trees in natural forest that were 6.82 m and 21 cm respectively. Results of soil sample analysis revealed a subsequent deterioration in quality of soil resources caused by deforestation in the LNP which were restored by the re-forestation. Contents of soil organic matter and organic carbon were significantly affected, consequently, declination of total N, K and P was found in the deforested barren land in the surface as well as subsurface layers (5-15 cm and 15-30 cm). The other affected soil properties were the increase of particle density, decrease of soil moisture and increasing acidity in the deforested barren land compared to the natural or plantation forest. It can be noted that such declination of soil properties could have rendered soil erosion, reduction of soil fertility and land degradation which subsequently has tremendous implications for sustainable productivity and ecosystem functioning of the LNP.