Interactive effects of disturbance intensity, seasonality, and soil depth on fine root biomass and carbon and nitrogen content in a tropical dry forest of central India

Baghel, Yamini

JOURNAL OF TROPICAL ECOLOGY

2026

42

Chaturvedi, RK

Disturbance-driven changes in tropical dry forests can alter belowground carbon storage and nutrient dynamics, yet the combined effects of seasonality, soil depth, and root traits on fine-root functioning remain poorly understood. We conducted a factorial field experiment across low, medium, and high disturbance levels. Root samples were collected in five replicates during three seasons from two soil depths (0-10 and 10-20 cm). Fine roots were classified by diameter (<1 and 1-5 mm) and status (live or dead). Biomass and nutrients were analyzed using ANOVA and principal component analysis (PCA). Fine-root biomass, carbon, and nitrogen content significantly declined with increasing disturbance, with strongest reductions during winter. Biomass declined from 1.75 g m(-2) under low disturbance to 1.10 g m(-2) under high disturbance, maximum during the rainy season (2.10 g m(-2)) and minimum during winter. Carbon content ranged from 250 to 400 mg m(-2), whereas nitrogen ranged from 22.5 to 35 mg m(-2). Roots <1 mm had higher nutrient concentrations and greater sensitivity to disturbance. Soil depth had a stronger effect on nitrogen than carbon, with higher carbon and nitrogen contents in surface soil. The C:N ratio increased with disturbance in live roots, suggesting reduced nutrient quality under stress, while dead roots showed greater variability and higher C:N ratios. PCA revealed separation of root traits by season and disturbance level, indicating shifts in belowground resource allocation and nutrient status. Overall, increasing disturbance reduced fine-root biomass and nutrient concentrations, potentially weakening belowground carbon sequestration and nutrient cycling in tropical dry forests.