Partitioning Sources of Ecosystem and Soil Respiration in an Alpine Meadow of Tibet Plateau Using Regression Method

Partitioning sourćes of ecosystem and soil respiration (R eco and Rs) is important for understanding how climate change affects carbon cycling. Plant and microbial biomass analyses and daytime measurements of Reco and Rs were performed for 25 plots in an alpine meadow at elevation 4313 m on the Tibetan Plateau. Plant and microbial biomass were determined by harvesting method and the chloroform fumigation-extraction method, respectively. Respiration fluxes were measured by an automated CO2 flux system (LI-8100, LI-COR Biosciences, Lincoln, NE, USA). Soil respiration can be estimated by a linear or exponential relationship between Reco and aboveground plant biomass (AGB). Microbial respiration (Rm) can be estimated by a linear or exponential relationship between Rs and belowground plant biomass (BGB) or by a multiple relationship between Reco and AGB and BGB. Soil respiration (or Rm) is respiration flux when AGB (or BGB) is extrapolated to zero for the linear and exponential regression methods. Similarly, Rm is respiration flux when both AGB and BGB are zero for the multiple regression method. Our findings suggest that the exponential regression method to partition sources of Reco and R s may be more appropriate compared to other methods for this alpine meadow of Tibet.