Mineralogy of Soils from Different Agraecological Regions of Bangladesh : Region 25 - Level Barind Tract and Region 27 - Noth-eastern Barind Tract

Bangladesh has been divided into 30 Agroecological Regions (AEZs) and the applied agricultural research has currently been conducted on this basis. In context of the lack of enough mineralogical information on the AEZ basis, an attempt has been taken to study mineralogy of important soils from all AEZs of Bangladesh in order to provide basic information for applied research. As a part of this attempt, the mineralogy of twelve soils from AEZ 25, Level Barind Tract, and that of ten soils from AEZ 27, North-eastern Barind Tract, has been reported in this paper. The soils of both AEZs were acidic in nature, had moderate to high amounts of clay, and the texture was medium (silt loam) to heavy (clay). The 2-20μm silt fraction was composed mainly of quartz, with small amounts of mica, plagioclase, K-feldspar and in some cases chlorite. Mica, kaolinite and the interstratified kaolinite-smectite and mica-vermiculite-smectite minerals were predominant minerals in the < 2μm clay fraction. The impact of genesis and weathering on the mineralogy of soils from the two AEZs has been discussed