Assessment of Temporal Variability of Soil and Water Salinity in the Saline Prone Vicinity of Bangladesh

Abstract

Salinity intrusion is a concerning issue in the coastal vicinity of Bangladesh. This study was conducted to investigate the variability of soil and water salinity at Paikgachha upazila of Khulna district in Bangladesh. Soil samples were collected from inside and outside polder of Bhodra river of Paikgachha upazila and some selected crop fields. Water samples (Deep tube-well water and pond water) were collected periodically from different locations and sites of Paikgachha upazila. The soil and water samples were analyzed for pH and electrical conductivity (EC). Soil pH was determined by using a glass electrode pH meter. Soil EC was measured in soil-water suspension (1:2 and 1:5) using EC meter. The pH of water samples was determined by using pH meter. The EC of collected water samples was determined by inserting the probe of EC meter to the saline water. The findings of the study reveal that polder had a remarkable effect on soil pH, showing that inside polder soil pH value ranged from 5.09-6.58 and outside polder, the pH varied from 7.61-8.14. The EC value recorded at 1:5 soil-water suspension was always lower than that noted at 1:2 soil-water suspension, which was, although not proportional, as due to the dilution effect. Soil pH value of some crop field soil ranged from 4.98 to 7.39. The EC (1:2 soil-water ratio) value varied within a wide range from 2.02 to 14.65 dS/m and these values from 0.49-5.74 dS/m when EC was measured on 1:5 soil-water ratio. The pH value of pond water ranged from 7.07 to 7.90. The EC value varied within a wide range from 0.91 to 33.55 dS/m. The pH value of deep tube-well water ranged from 7.20 to 7.44. The EC value varied within a wide range from 3.38 to 8.87 dS/m. Therefore, this study will provide a better understanding of the temporal variability of soil and water salinity in the saline prone vicinity of Bangladesh.