Dr. GANAPATHIAPURVA, VDr. K.T. GURUMURTHY2020-06-192020-06-192017-07-15http://krishikosh.egranth.ac.in/handle/1/5810147746An investigation was undertaken at, Department of Soil Science and Agricultural Chemistry, College of Agriculture, UAHS, Shivamogga to know Carbon Sequestration potential of areca nut based cropping systems of coastal and hilly zones of Karnataka.The study area coveredthe soils of Mangaloreand Udupidistrict of coastal (zone-10) and Chikkamagalur, Kodugu and Shivamogga district of hilly (zone-9 ).Representative soil samples were collected from 0-30 cm, 30-90 cm and 60-90 cm depth from areca nut Sole, arecanut + banana, arecanut+cocoa, arecanut+pepper, arecanut+mixed, arecanut+coffee and areca nut +orangefrom 2 location.The results revealed that soil pH were acidic to neutral with normal EC and Sandy loam to sandy clay loamin texture. TheSOC contents were medium to high ranged and decreases with depth. Among the cropping systems studied, arecanut+mixed recorded higher mean potassium permanganate oxidizable organic carbon(1387.33mg kg-1), cold water extractable carbon (409.06mg kg-1), total carbon (29.39g kg-1), total organic carbon (18.70g kg-1),total inorganic carbon (0.2136g kg-1) andsoil microbial biomass carbon (370.33mg kg-1) fractionsas compared to other cropping systems and decreases with lower depth. Among different areca nut based cropping system E4/E6 values were higher in areca nut +mixed (1.166).Carbon fractions were higher in 0-30cm soil depth and decreases in lower depth of areca nut based cropping systems. Humic acid was higher in areca nut +mixed (5.35) and fulvic acid was higher in arecanut+ coffee (5.01).Correlation study showed that the various carbon fractions were positively and significantly correlated amongst themselves and with pH, clay and CaCO3 (%) content of the soils.ennullThesis