Partitioning of respiratory CO2 fluxes in a managed C3 turfgrass field

Abstract

To evaluate the respiration and temperature dependence of each component of a managed C3 coolseason turfgrass (Kentucky bluegrass, Poa pratensis) field and to elucidate the characteristics of the carbon budget, respiratory CO2 fluxes from leaves, non-assimilatory organs, and decomposition (soil heterotrophic respiration) were measured using a closed dynamic chamber method. Analysis of temperature dependence using the Arrhenius function was performed for partitioning of the components of ecosystem respiration. The activation energy for respiration was 40,200 J mol -1 for non-assimilatory organs, 41,600 J mol -1 for leaves, and 69,800 J mol -1 for heterotrophic respiration. , respectively, in August 2007. A large proportion of non-assimilatory organ respiration coincided with the non-assimilatory organ biomass. At the study site, soil respiration as the sum of non-assimilatory organ and heterotrophic respiration formed 78-81 of the total ecosystem respiration, and the proportion of autotrophic respiration (non-assimilatory organ respiration) to total soil respiration was 64-66 . The total ecosystem respiration and soil respiration were very large in comparison with the values reported for other ecosystems.