Evaluation of soil and biomass carbon stock across different land use systems in the Vitalapura sub-watershed, Kadur taluk, Chikkamagaluru district-Karnataka, India

Carbon stock assessment studies at the watershed level remain limited due to the absence of standardized methodologies, leading to inconsistent and incomparable estimates across ecosystems. The present study evaluated carbon stock distribution across major land cover types in the Vitalapura sub-watershed of Kadur Taluk, Chikmagaluru District, using high-resolution QuickBird satellite imagery (0.61 m) combined with ground-truthing. The identified land cover categories included agricultural land (21.82 %), coconut plantation (16.67 %) and forest (0.45 %). Statistical analysis revealed significant variations in biomass and carbon pools among these land covers. Forests recorded the highest above ground biomass (104.29 Mg ha-1), below ground biomass (28.16 Mg ha-1) and total carbon stock (208.29 Mg C ha-1), while agricultural lands showed the lowest values. Soil organic carbon (SOC) was also greatest in forests (146.04 Mg ha-1) and least in agricultural land (77.88 Mg ha-1). Although forests had the highest per-hectare carbon stock, their limited spatial extent restricted their contribution to only 2 % of the total carbon stock. By contrast, coconut plantations and agricultural land, owing to their wider distribution, contributed 56 and 42 % of the total carbon stock, respectively. These findings demonstrate the critical role of land cover in regulating carbon sequestration potential. The study highlights the significance of coconut plantations as a major carbon pool in the sub-watershed and the comparatively reduced contribution of forests due to their limited area. Overall, the results emphasise the need for sustainable land use planning and management strategies that enhance carbon storage, conserve existing forest patches and optimise agricultural and plantation systems for improved carbon sequestration in the region.