Characterization and Mineralogy of Soils of Kavalur Sub Watershed 4d4a2p of Koppal District North Karnataka

Abstract

An investigation was carried-out by University of Agricultural Sciences, newlineDharwad to characterize soils and study mineralogy of Kavalur sub-watershed of newlineKoppal district, Karnataka during 2015-17. Twenty two soil pedons representing larger newlineheterogeneity were studied for their morphological, physical and chemical properties. newlineNine typical pedons, each representing a different soil series were selected for assessing newlinetheir mineralogical properties. The sub-watershed was nearly level with moderate newlineerosion and drainage conditions. The soils were very shallow to very deep, sandy clay newlineloam to clay in texture and weak to moderate sub-angular blocky structure with many newlinefine roots distributed in surface horizons. The soil consistency was predominantly hard newlinewhen dry, friable when moist, moderately sticky and moderately plastic when wet. The newlineBD, MWHC and COLE values were higher in black soils as compared to red soils and newlineincreased with depth. The pedons were slightly alkaline to alkaline in reaction and nonsaline newlinewhile organic carbon content was low to medium (1.56 to 5.80 g kg-1). The black newlinesoil pedons contained more free CaCO3 (58.5 g kg-1) than red pedons (23.4 g kg-1). The newlinecationic dominance was in the order of Ca2+gtMg2+gtNa+gtK+. The black soil pedons had newlinehigher CEC, base saturation and ESP than red soil pedons. Taxonomically, the soils of newlinethe study area were classified under the orders Entisol, Inceptisol, Vertisol and Alfisol. newlineThe mineralogical composition of sand fraction of soils was dominated by newlinequartz followed by feldspar, olivines, biotite mica and pyroxenes. Quartz followed by newlinemica and feldspar as primary and smectite followed by vermiculite and kaolinite as newlinesecondary minerals dominated in silt fraction. Kaolin was dominant among secondary newlineclay minerals followed by smectite in red soil pedons. Kaolin content decreased with newlinedepth while, smectite content increased with depth. The black soil pedons showed newlinehigher content of smectite than kaolin. newline