Litter input promoted dissolved organic carbon migration in karst soil

Litter input is crucial for enhancing carbon sequestration in karst ecosystems. While previous studies have linked litter input to carbon storage in karst soils, the unique conditions of southwest China's karst regions, characterized by high precipitation and rapid groundwater dynamics, pose challenges to understanding dissolved organic carbon (DOC) migration under litter cover. This study investigated how different litter types from karstadapted vegetation affect DOC migration and loss in karst soils, addressing the gaps in carbon sequestration evaluations during vegetation restoration. Artificial soil columns were used to monitor the natural rainfall over one hydrological year. The results indicated that litter cover increased the soil carbon dioxide (CO2) concentration and enhanced DOC leaching and migration, with the highest DOC loss observed in the tree litter treatment (2614.50 mg) and the lowest in the shrub litter treatment (1844.13 mg). These differences were attributed to the synergistic interaction between rainfall and litter characteristics, which accounted for 29.94 % of the variation in soil DOC leaching after litter input. Regression analyses indicated that DOC leaching under litter cover was mainly affected by the soil CO2 concentration, temperature, humidity, rainfall, and litter decomposition duration. In summary, litter cover significantly intensified DOC migration and loss in karst soils. This study provides valuable insights into vegetation restoration and reconstruction, particularly in karst regions.