Soil organic carbon pools and carbon management index of the tropical moist deciduous forests in Indian Eastern Ghats

The labile carbon is an important constituent of soil organic carbon (SOC) that is impacted not only by the geoclimatic elements but also the vegetation. We investigated the SOC (active and passive carbon) pools at three soil depths (0–15, 15–30 and 30–45 cm) and carbon management index and vegetation characteristics in Pure Sal (PSF), Sal Dominated Moist Deciduous (SDMDF) and Moist Deciduous Forest without Sal (MDFWS) forests. Our results showed the SOC concentration in the order of PSF > SDMDF > MDFWS and it declined as soil depth increased in different C fractions. Very labile C fraction stock (VLSC) was highest (53.73 Mg C ha−1) in PSF and lowest (19.87 Mg C ha−1) in MDFWS community and it decreased linearly with percentage decrease of sal vegetative parts in annual litter input (56.83% in PSF to 5.85% in MDFWS). The SOC stock (0–45 cm) was noticeably greater in PSF (111.45 Mg C ha−1). The carbon management index (CMI) value decreased linearly with decrease in sal density with lower value (29.31) in MDFWS. The species composition and dominance of S. robusta significantly influenced the annual litter input as well as to the active and passive carbon pools. The study indicates that the sal forests can be a potential soil carbon sink to aid climate change mitigation in its natural zone.