Characterization and Classification of Soils of Tumkur District, Karnataka Based on Organic Carbon Stocks as an Index of Land Degradation.

The detailed reconnaissance soil survey was carried out in Tumkur district of Karnataka to characterize, classify and study organic carbon stocks of degradation vulnerable soils during 2021-2023 using remote sensing, GIS and field studies. Satellite imageries (Sentinal -2) of three-seasons were used along with soil map to delineate the degraded soils through visual image interpretation. Using this as base map, resource characterization was done. Thirteen soil pedons were studied from Tumkur district covering major soils. Four representative pedons (Kurubarahalli, Koratagere; Huliyurdurga, Kunigal; Chinnenahalli, Sira and Hosahalli forest, Gubbi) to study characterization and classification of soils of Tumkur district, Karnataka based on organic carbon. The granite, gneissic and schistose landform, with dykes and laterized parent material give rise to well, somewhat excessive or moderately well drained soils. The soils were generally deep, non-gravelly to very gravelly with sandy clay loam to clayey texture. Moderately acid to moderately alkaline Specify with low to high organic carbon content were observed. CEC/clay ratio ranged from 0.14 to 0.70 and base saturation varied from 46.31 to 79.98 per cent. The available water holding capacity ranged from 42.84 to 77.55 mm m^-1 with highest organic carbon stock in Hosahalli forest of Gubbi (9.82 kg m^-3) and the least in Kurubarahalli village of Koratagere (1.93 kg m^-3) upto 150 cm. The major taxa of the soil identified at sub-group level of soil taxonomy were Rhodic Kanhaplustalfs, Typic Rhodustalfs, Rhodic Kandiustalfs and Fluventic Haplustepts. Use of remote sensing and GIS techniques along with field studies is ideal for assessing land qualities of Tumkur district. This can help in identifying and encountering problems created by land degradation processes over a period of time along with exposure to adverse climatic conditions, land management and other anthropogenic interventions for ensuring sustainable management of land with enhanced productivity. [ABSTRACT FROM AUTHOR]