BASAVARAJ, BNATARAJA, K C2019-11-082019-11-082003No . of references 112http://krishikosh.egranth.ac.in/handle/1/5810134849Six soil profiles from three sites of North Karnataka viz., Main Agricultural Research Station, Dharwad in Dharwad district, Bheemarayanagudi in Gulbarga district and Mantagani in Haveri district were collected to identify and determine the secondary and primary minerals silt and sand fractions. Identification of primary minerals in silt and sand fractions was made by XRD and petrographic method respectively and determination of secondary minerals in the silt fraction through chemical methods. It was revealed that structure in red and black pedons were predominantly sub-angular blocky and angular blocky in subsurface horizon of Bheemarayanagudi black pedon. Slickensides were common feature in black pedons and their intensity was more in middle of the solumn. Free iron oxides content was more in red pedon compared to the associated black pedon. Among the three study sites, Bheemarayanagudi had low amount of free iron oxides as it was devoid of iron bearing minerals while free calcium carbonate was more at Bheemarayanagudi sites than Main Agricultural Research Station, Dharwad and Mantagani sites. Smectite and vermiculite content was more over other secondary minerals in the silt fraction of all the red and black pedons and little amount of Kaolinite was found in the pedons. Among the primary minerals quartz, mica, potassium and sodium feldspars were dominant as identified by XRD in the silt fractions of all the pedons. Fine sand fraction showed the dominance of light minerals like quartz, biotite mica, Na-Feldspars, K-Feldspars and apatite. The abundance of these minerals is high at the surface layer of Dharwad black pedon compared to its red counterpart indicating more weathering status of the associated red pedon. Whereas, these difference is not much conspicuous in other two sites. However, the presence of weathering resistant minerals like zirconium throughout the depths of both red and black pedons of Mantagani site indicated similar weathering status of the associated red and black pedon.ennullSILT AND SAND MINERALOGY OF SELECTED ASSOCIATED RED AND BLACK SOILS OF NORTH KARNATAKAThesis