The study was conducted using soil samples collected from 12 agro-ecological zones (AEZs) of Bangladesh viz., Old Himalayan Piedmont Plain (AEZ 1), Tista Meander Floodplain (AEZ 3), Karatoya- Bangali Floodplain (AEZ 4), Ganges Tidal Floodplain (AEZ 13), Old Meghna Estuarine Floodplain (AEZ 19), Northern and Eastern Piedmont Plain (AEZ 22), Chittagong Coastal Plain (AEZ 23), Level Barind Tract (AEZ 25), North-eastern Barind Tract (AEZ 27), Madhupur Tract (AEZ 28), Northern and Eastern Hills (AEZ 29) and Akhaura Terrace (AEZ 30). The numbers of collected soil samples of the mentioned AEZs were 10, 10, 12, 20, 7, 14, 15, 12, 10, 73, 16 and 7, respectively with a total of 206 soil samples. Soil samples (0–15 cm) were collected from arable land during November to December in both 2017 and 2018 after harvesting of transplanted aman rice using core samplers to determine soil bulk density. A bulk sample from each sampling point was also collected to analyze other soil parameters. The soil samples were air dried, ground and sieved (2mm) and analyzed in the Laboratory of Soil Science Department, BSMRAU, Gazipur. The soil samples were analyzed for bulk density, texture, pH, organic C, Na, K, Ca, Mg and water stable soil aggregates. For aggregates, soil was sieved by four different sized sieves (2, 1, 0.5 and 0.25 mm) and water stable soil aggregates were determined by the wet sieving method. To determine aggregates, 10 g air dried soil sample was taken in 50 ml conical flask and the sample was kept overnight under water. The soaked soil samples were then transferred to sieves of respective sizes. Sieves with soil were taken to agitation rack placed under water in plastic box containing 15 L water and agitated 20 times per 40 seconds. Then sieves were kept in oven at 105 °C for 2 hours. After complete drying, weight of sieves with soil was recorded and again agitated in NaOH solution (1.6 g/L). Again sieves were dried in oven and weight of dried sample with sieve was recorded as mentioned above. Empty sieve weight was also recorded and calculation was done following (Castellanos-Navarrete et al., 2013). Soil texture was determined by the Bouyoucos hydrometer method as described by Gee and Baunder (1986). The collected core samples were oven dried at 105°C for 24 hours and bulk density was calculated (Rowell, 1994). Soil pH was measured by a glass electrode pH meter (Horiba model No. M-8L) using a soil: water ratio of 1:2.5 (Jackson, 1973). The basic cations (Na, K, Ca, and Mg) were determined by the ammonium acetate extraction method (Thomas, 1982) using an atomic absorption spectrophotometer and reading was taken at a 285.2 nm wavelength. Organic C was determined by the wet oxidation method (Walkley and Black, 1934). Sodium adsorption ratio (SAR), monovalent cation adsorption ratio (MCAR) and cations ratio of soil structural stability (CROSS) were determined using procedures proposed by Rengasamy and Marchuk (2011). Soil C stock was calculated using the following equation (Rahman et al., 2016). Soil C stock (t ha-1) = Soil C % × soil bulk density (g/cc) × depth of soil (cm) The data collected on different parameters were subjected to statistical analysis (Gomez and Gomez, 1984). The Microsoft Excel and SPSS 20 software programs were used wherever appropriate to perform statistical analysis. Relationships among the parameters were established through correlation and regression analysis. Mean differences among the treatments were interpreted by using the least significant difference (LSD) test at 5% level of significance.