Mineralogical study was carried using XRD analysis of six representative pedons of two horizones (Ap andBw) developed over granitegneissin Kanaginahala subwatershed to describe the mineralogical composition of sand and clay fractions. The slope of the study area ranged from 1 to 3 per cent with moderate to severe erosion, soil colour was dark grayish brown ( Y 4/2) tovery dark gray (10 YR 3/1), texture was clay in all the pedons. The pH was neutral to moderately alkaline (pH to ), with ECnonsaline ( to dSm-1 ) and organic carbon low to high range( to g kg-1 ). CEC was relatively high in all the pedons, it ranged from to (p+ ) kg -1 and ESP was ranged from to . The study revealed that’s mectite was the dominant clay mineral. It varied from to per cent in Ap horizon and to per cent inBw horizon, Vermiculite was ranged from to per cent in surface and to per cent in Bw horizon, followed by kaolin and quartz. Kaolin and quartz varied from to per cent and to per cent, respectively in Ap horizon and to per cent and to per cent, respectively in Bw horizon. In most of the pedons, the smectite content increased while kaolin content decreased with soil depth. Among second minerals, smectite dominated over vermiculite and kaolin. | Studies on sand and clay minerals of Kanaginahala sub-watershed in Gadag district, Karnataka, India
