Integrating Branch- and Soil-Level Flux Measurements to Investigate Carbon Exchange Dynamics in Tea Plantations

Anthropogenic greenhouse gas emissions continue to drive global climate change, highlighting the importance of terrestrial ecosystems in regulating atmospheric carbon. While vegetation acts as a major carbon sink through photosynthetic uptake and biomass accumulation, carbon sequestration research has predominantly focused on forest ecosystems. In contrast, agricultural systems—especially perennial crops—remain comparatively underrepresented despite their extensive land coverage and long-term management.

Tea plantations (Camellia sinensis) are perennial agroecosystems composed of long-lived woody shrubs with repeated harvest cycles and sustained biomass, suggesting a potentially significant but poorly constrained role in terrestrial carbon cycling. In Taiwan, tea is a major commercial crop occupying extensive agricultural land, yet quantitative assessments of plant–soil carbon exchange processes in tea systems remain limited. To better understand carbon exchange processes in tea plantations, this study applies a dual-approach integrating plant- and soil-level greenhouse gas measurements in a managed tea garden in Taiwan.

Field measurements were conducted from January to April 2026. Branch-level photosynthesis and respiration were monitored using branch cuvettes, and gas exchange rates were extrapolated to the plant level using allometric relationships. Concurrently, soil carbon dioxide (CO₂) fluxes were measured using static chamber techniques to characterize soil–atmosphere carbon exchange, with fluxes further extrapolated to the garden scale. Measurements were repeated monthly under fair-weather conditions and supported by laboratory gas chromatography analysis. Ancillary environmental variables and management activities were recorded to support flux interpretation.

Overall, this study provides an integrated, field-based assessment of carbon exchange dynamics in a managed tea plantation by explicitly linking plant- and soil-level gas fluxes with seasonal progression and agricultural practices. By aligning greenhouse gas measurements with farming activities, the results offer insight into how management and phenological stages jointly regulate carbon exchange in perennial agroecosystems. The findings contribute to reducing current uncertainties surrounding the role of tea plantations in terrestrial carbon cycling and provide a scientific basis for future evaluations of carbon management and climate mitigation potential in perennial agricultural systems.