Present status of soil nutrient and tree stands density of Sundarbans mangrove forest of Bangladesh

The study was conducted in Khulna and Satkhira ranges of western Forest Division to determine the present nutrient status in soils and tree stand density of Sundarbans mangrove forest of Bangladesh during February to May 2016. Sampling was carried out at 46 sites from two locations viz. 23 sampling sites were from Khulna forest range and 23 sites from Satkhira range. The soil samples were collected at two depths viz. surface (0 to 15 cm) and sub-surface (15 to 30 cm) layers of soil. Tree-related data like name of the species, a number of trees/plots were recorded for all the natural trees having a diameter at breast height (dbh) ≥10 cm to calculate the stand density in the study area marked 10 m×10 m quadrate sample plots randomly. The collected soil samples were analyzed in a laboratory to determine the nutrient status. The result revealed that the soils of Sundarbans mangrove forest in Bangladesh were neutral to saline and the pH values (7.6) of surface soils were higher compared to sub-surface soils. The results also indicate that organic matter, total N, available P, Ca, Mg, S, Fe, B and Zn were observed comparatively higher (1.65%, 0.09%, 19.26 ppm, 9.11 meq/ml, 2.92 meq/ml, 169.59 ppm, 22.72 μg/ml, 0.66 μg/ml and 4.22 μg/ml, respectively) in surface soils except for exchangeable K which was higher (1.55 meq/100g) in sub-surface soils. However, the tree stands density in Sundarbans mangrove forest was recorded as 525 trees/ha and 569 trees/ha in Khulna and Satkhira forest ranges, respectively. Therefore, the information of this study would be helped to the researcher and policymaker for better understanding and management of Sundarbans.