Mineralogy of soils from different agroecological regions of Bangladesh: Region 29- northern and eastern hills

Bangladesh has been divided into 30 Agro-ecological Regions (AEZs) based on which applied agricultural research has currently been conducted. Due to the unavailability of sufficient mineralogical information of soils of those AEZs, there was an initiative to study mineralogical composition of major soils of different AEZs of the country. One of the parts of such attempt, the mineralogy of eight soils from five soil scries (Pritimpasha, Varella, Pahartali, Mirsarai and Borkal) from AEZ 29, Northern and Eastern Hills, has been reported in this manuscript. The soils of the AEZ were medium textured, non-saline and slightly acidic to strongly acidic in nature. The average content of <2;∗m clay fraction was 17.9% and it varied from 7.9 to 32.5%. The 2-20m silt fraction lied between 14.1 to 28.7% with an average of 21.5%. The clay fraction was dominated with mica, chlorite, kaolinite, quartz in all the soils studied. Presence of two interstratified minerals namely, vermiculite-chlorite intergrade and interstratified mica-chlorite minerals were evident in some samples. The findings of the present study do not support the proposed mineralogical suits of mica- kaolinite-vermiculite and kaolinite-mica for this AEZ.