Shifts in soil quality from degradation to early phase of forest restoration: Evidence from Rohingya refugee camps, Cox's Bazar, Bangladesh

Abstract

Rohingya influx in Bangladesh destructed about 3200 ha of the reserved forest of Cox's Bazar South Forest Division for the construction of housing, other utilities, and firewood collection. To reduce soil erosion, the degraded sites were intervened with different slope management initiatives (without terrace, earthen terrace, bamboo terrace). Restoration initiatives were intensified in 2019 and 291.90 ha of degraded forest areas were brought under plantation. A soil quality baseline study was conducted in 2020. The present study monitored the changes in soil properties (bulk density, organic carbon, electrical conductivity, total nitrogen, available phosphorus, and potassium) after four years in the restored sites. Comparatively, higher bulk density (1.61±0.03 g/cm3) and organic carbon (2.45±0.09 %) were observed for the control site soil and bamboo terrace, respectively. Similar pH (4.94±0.07 to 5.14±0.14) and Electrical Conductivity (EC) (109.99±38.17 µS/cm to 122.60±13.13 µS/cm) were observed for the soil of all slope management interventions. In the case of nutrients, higher concentrations of total nitrogen (0.09 %) and available potassium (94.79±22.63 µg/g) were detected for the soil of the bamboo terrace. Similar concentrations of available phosphorus were observed for all slope management interventions. The present study showed a significant (P(T<=t) two-tail) higher content of organic carbon and EC than the baseline study. At the same time, phosphorus and potassium concentrations dropped significantly (P(T<=t) two-tail) compared to the baseline.