Estimating heterotrophic and autotrophic soil respiration in a semi-natural forest of Lombardy, Italy

We studied an unmanaged alluvial forest in Northern Italy in order to better understand the soil carbon cycle and in particular the partitioning of soil respiration between autotrophic and heterotrophic respiration. We measured annual fluxes of soil respiration with a mobile chamber system at 16 per-manent collars and sampled soil organic carbon and root density at each collar in order to apply the indirect regression method for partitioning (Rodegheiro and Cescatti, 2006). The soil pool of organic carbon was very high down the 45 cm profile. The annual respiration rates ranged from 0.6 to 6.9 µmol carbon dioxide (CO2) m-2s-1 with an average value of 3.4 (±2.3) µmol CO2 m-2 s-1, and a cumulative flux of 1.1 kg C m-2y-1. The correlation between total soil respiration and soil temperature was high (R2=0.85), whereas the correlation with soil water content was weaker (R2=0.46). The heterotrophic component accounted for 66% of annual CO2 efflux. Soil temperature largely controlled the heterotrophic respiration (R2=0.93), while the autotrophic component followed irradiation. The indirect regression method enabled us to partition the seasonal course of undisturbed autotroph-ic and heterotrophic respiration. The role of photosynthesis in modulating soil respiration needs to be considered in terrestrial carbon cycle models.

FERRE Chiara;  ZENONE Terenzio;  COMOLLI Roberto;  SEUFERT Guenther; 

2013-01-30

ELSEVIER GMBH

JRC66636

0031-4056,   

http://dx.doi.org/10.1016/j.pedobi.2012.05.001,    https://publications.jrc.ec.europa.eu/repository/handle/JRC66636,