Soils of the Sundarbans mangrove forest differ from other inland soils in that they are subjected to the effects of salinity and waterlogging, which naturally affect the vegetation.
- In places soils are semi-solid and poorly consolidated.
- pH ranges widely from 5.3 to 8.0.
- Texture: soil is in general medium textured; sandy loam, silt loam or clay loam. The grain size distribution is highly variable. Silt loam is the dominant textural class. However, Ray et al. 2014 reported a 72-87% silt content in 0-60cm depth for Indian part of Sundarbans.
- Porosity: 0.7 (Ray et al. 2014)
- Sodium and calcium contents of the soil vary from 5.7 to 29.8 meq/100g dry soil, respectively, and are generally low in the eastern region and higher towards the west.
- Available potassium (K) content of the soil is low, 0.3-1.3 meq/100g dry soil.
- Organic matter content varies between 4% and 10% in dry soil.
- Soil salinity increases from 5ppt in east (slight to moderate) to 30ppt in west (highly saline), but the salinity is not uniform from north to south throughout the forest.
- Geology: the area is the result of extensive fluvio-marine deposits of the river Ganges and the Bay of Bengal and the character of the sediment is silty clay. Rajkumar et al. (2012) reported the dominant association of kaolinite with subordinate amount of quartz, illite and chlorite in the clay minerals in the Sundarban mangrove core sediment. The adsorption capabilities result from a net negative charge on the structure of minerals, high surface area and high porosity (Alkan et al. 2004).
Reference: [Source: http://wikimapia.org/1651148/The-Great-Sundarbans-Bangladesh-and-India] Alkan, M., Demirbas, O., Celikcapa, S., Dogan, M., 2004. Sorption of acid red 57 from aqueous solutions onto sepiolite. J. Hazard.Mater. 116, 135–145. Rajkumar,K., Ramanathan,A.L., Behera,P.N., 2012. Characterization of clay minerals in the Sundarban Mangrove River sediments by SEM/EDS. J. Geol. Soc. India 80, 429–434. Ray, R., Majumder, N., Das, S., Chowdhury, C., & Jana, T. K. (2014). Biogeochemical cycle of nitrogen in a tropical mangrove ecosystem, east coast of India. Marine Chemistry, 167, 33–43. http://doi.org/10.1016/j.marchem.2014.04.007