Assessing the carbon management index across land use changes in Kolli Hills, Eastern Ghats, Tamil Nadu

Alterations in land patterns in Kolli Hills(KH) of the Eastern Ghats, Tamil Nadu, transitioning from native ecosystems to various land uses, have notably diminished soil carbon concentrations. To measure this reduction, the Carbon Management Index (CMI) was evaluated across key land-use categories, including Agricultural System (AS), Horticultural System (HS), Plantation System (PS), Thorn Forest (TF), Deciduous Forest (DF), and Evergreen Forest (EF). The analysis focused on Total Organic Carbon (TOC), Total Carbon (TC), Total Inorganic Carbon (TIC), and carbon pools with varying degrees of lability, including less labile carbon (LLC), labile carbon (LC), very labile carbon (VLC), and non-labile carbon (NLC). The findings indicated that EF's carbon pools were markedly higher (p < 0.05) than AS and HS. The contribution of LC, VLC, LLC, and NLC to TOC was highest in EF and DF, while it was lowest in AS and HS. The TOC at 15 cm depth was highest in the surface soils of EF (106.17 g kg-1), with a gradual decline in concentration with increasing depth. This highlights carbon pool degradation from land-use change, quantified by the CMI. When EF was used as the reference ecosystem, the CMI was higher in DF (51.93) and TF (45.69) at a 30 cm depth, while AS (10.75) and HS (12.46) showed a much lower CMI. These findings highlight the need to implement effective carbon management strategies in KH to restore soil vitality and safeguard biodiversity.