Assessing the variations of soil microbial biomass carbon and labile carbon pools across different forest types of Mizoram, India

This study investigated Soil Organic Carbon (SOC) pools and Soil Microbial Biomass Carbon (SMBC) across three forest types in Mizoram, India: Secondary Moist Bamboo Brakes (SMBB), East Himalayan Moist Mixed Deciduous Forest (EHMMDF), and Cachar Tropical Semi-Evergreen Forest (CTSEF). SOC is crucial for global biogeochemical cycles, influencing nutrient availability and ecosystem resilience. The study highlights the impact of forest type on SOC dynamics and microbial activity. The SMBB exhibited an Active Pool (Very Labile Carbon [VLC] + Labile Carbon [LC]) of 1.21% and a Passive Pool (Less Labile Carbon [LLC] + Non-Labile Carbon [NLC]) of 0.78%, resulting in overall TOC of 1.99%, of which SOC (Walkley–Black C) was 1.58% and SMBC of 340.72 mg/kg, indicating a balanced microbial presence. The EHMMDF had relatively higher SOC (2.49%) and SMBC (352.31 mg/kg), suggesting increased microbial activity and faster carbon turnover. The CTSEF recorded the highest SOC (2.51%) and significant SMBC (348.73 mg/kg), with the highest VLC at 1.06%. Additionally, Dehydrogenase Activity (DHA), a key indicator of microbial metabolic activity, was highest in the EHMMDF (6.42 µg TPF/g/h) and lowest in the SMBB (5.62 µg TPF/g/h). Correlations between SMBC and SOC pools were weak, with VLC and LC showing significant positive relationships with Total Organic Carbon (TOC) (r = 0.636 and 0.693). These findings underscore the importance of forest type in shaping SOC and microbial dynamics, with implications for sustainable land management and carbon sequestration strategies in tropical forests.