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Author: Anjali M.C. × End date: 2018 × Start date: 2017 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Characterization and Mineralogy of Soils of Kavalur Sub-Watershed (4d4a2p) of Koppal District, North Karnataka
    (University of Agricultural Science, Dharwad, 2017-06) Anjali M.C.; Hebbara, Manjunatha
    An investigation was carried-out by University of Agricultural Sciences, Dharwad to characterize soils and study mineralogy of Kavalur sub-watershed of Koppal district, Karnataka during 2015-17. Twenty two soil pedons representing larger heterogeneity were studied for their morphological, physical and chemical properties. Nine typical pedons, each representing a different soil series were selected for assessing their mineralogical properties. The sub-watershed was nearly level with moderate erosion and drainage conditions. The soils were very shallow to very deep, sandy clay loam to clay in texture and weak to moderate sub-angular blocky structure with many fine roots distributed in surface horizons. The soil consistency was predominantly hard when dry, friable when moist, moderately sticky and moderately plastic when wet. The BD, MWHC and COLE values were higher in black soils as compared to red soils and increased with depth. The pedons were slightly alkaline to alkaline in reaction and non-saline while organic carbon content was low to medium (1.56 to 5.80 g kg-1). The black soil pedons contained more free CaCO3 (58.5 g kg-1) than red pedons (23.4 g kg-1). The cationic dominance was in the order of Ca2+>Mg2+>Na+>K+. The black soil pedons had higher CEC, base saturation and ESP than red soil pedons. Taxonomically, the soils of the study area were classified under the orders Entisol, Inceptisol, Vertisol and Alfisol. The mineralogical composition of sand fraction of soils was dominated by quartz followed by feldspar, olivines, biotite mica and pyroxenes. Quartz followed by mica and feldspar as primary and smectite followed by vermiculite and kaolinite as secondary minerals dominated in silt fraction. Kaolin was dominant among secondary clay minerals followed by smectite in red soil pedons. Kaolin content decreased with depth while, smectite content increased with depth. The black soil pedons showed higher content of smectite than kaolin.