Consecutive 2-year data analysis to assess the soil quality and ecological risk of heavy metals in Tobacco field: a case study in Northern Bangladesh

Abstract

AbstractA successive 2-year (2019 and 2020) field experiment was conducted in northern Bangladesh (Rangpur district) to observe the status of soil quality and heavy metal risk due to tobacco cultivation in this area. Soil samples were collected randomly from four major sub-districts (Rangpur Sadar, Badargonj, Gangachara, and Mithapukur Upazila) where Mithapukur was a non-cultivating tobacco field and the rests were tobacco-growing fields. Along with heavy metal concentrations, physicochemical parameters were analyzed to observe the progressive change in the soil. Results depicted that values of bulk density, particle density, porosity, soil organic matter (SOM), and major nutrients (N, P, K, S) were decreased in the tobacco-growing field from 2019 to 2020, whereas significant improvement was observed in non-tobacco-growing field at successive year analysis. However, exchangeable bases were raised in the tobacco cultivated field from 40.86 to 52.98% compared to the non-tobacco cultivated field which was in a declining trend (43.66–34.33%). Overall, the soil pollution index depicted that Pb was shown a moderate risk of contamination in 2020. The ecological risk analysis also stated that the tobacco field in Rangpur Sadar was at a moderate risk of soil pollution (RI = 126.16), although the non-tobacco field in Mithapukur was at no risk of pollution (RI = 45.23). So, it can be recommended that tobacco cultivation harms the soil health, and thus, it should be prohibited from the agricultural field.