Some Chemical Properties of Soils from Two Agroecological Regions of Bangladesh : Region 5 : Lower Atrai Basin and Region 6 : Lower Purnabhaba Floodplain

Bangladesh has been divided into 30 Agroecological Regions (AEZs) and the applied agricultural research has currently been conducted on this basis. An experiment was undertaken to elucidate chemical properties of fourteen soils collected from AEZ 5 of the Lower Atrai Basin and six soils from AEZ 6 of the Lower Purnabhaba Floodplain. The soils belonged to five soil series of Laskara, Tarash, Manda, Malanchi and Gangachara in AEZ 5 and one soil series of Jaonia in AEZ 6. Particle-size distribution, pH, active acidity, lime requirement, electrical conductivity (EC), organic carbon and total nitrogen, available sulfur and phosphorus, cation exchange capacity (CEC), exchangeable calcium, magnesium, sodium and potassium, and non-exchangeable potassium were determined following the standard methods. Most of the soils from AEZ 5 were medium-textured (loam to silty loam) except the Tarash-1 and Tarash-2 soils which were in the same category as the soils from AEZ 6 of fine-texture (silty clay loam, silty clay and clay). The fineness of texture was related to the position of soils in the lower elevation and accumulation of clay. The latter group of the soils had, in general, higher values of organic matter, lime requirement, total nitrogen, CEC, and some exchangeable cations. But, the values for pH, EC, available sulfur and phosphorus were not related to the difference between two groups of the soils. Soil test values were compared with the Bangladesh soil standards for crop requirement