|Neumann, J; Matzner, E: Contribution of newly grown extramatrical ectomycorrhizal mycelium and fine roots to soil respiration in a young Norway spruce site, Plant Soil, 378, 73-82 (2014), doi:10.1007/s11104-013-2018-0|
Background and aims
Partitioning of soil respiration is a challenging taskwhen resolving the C cycling in forest ecosystems. Our aim was to partition the respiration of newly grown extramatrical ectomycorrhizal mycelium (ECM) and fine roots (and their associated microorganisms) in a young Norway spruce forest.
Ingrowth mesh bags of 16 cm diameter and 12 cm height were placed in the upper soil and left for 12–16 months in 2010 and 2011. The 2 mm mesh size allowed the ingrowth of ECM and fine roots whereas a 45 μm mesh size allowed only the ingrowth of ECM. Themesh bags were filled with either homogenized EA horizon soil, pure quartz sand (QS) or crushed granite (CG, only 2011), each with five replicates. Controls without any ingrowth were established for each substrate by solid plastic tubes (2010) and by 1 μm mesh bags (2011). Fluxes of CO2 from the mesh bags and controls were measured biweekly during the growing season by the closed chamber method.
The contribution of ECMto soil respiration was largest in the QS treatments, reaching cumulatively 1.2 and 2.2 Mg C ha−1 6 months−1 in 2010 and 2011, respectively. For EA and CG treatments, the cumulative respiration from ECM was larger than from controls, however the differences being not statistically significant. The respiration of newly grown fine roots in QS amounted to 1.0 Mg C ha−1 in 2010, but could not be identified in 2011 since fluxes from 2 mm and 45 μm mesh bags were similar. The correlation of total root length in single QS mesh bags to CO2 fluxes was poor. The contribution of fine root respiration was also not detectable in the EA and CG treatment. No correlation was found between the autumnal biomass of newly grown ECM and its cumulative respiration.
Our results suggest a substantial contribution of newly grown ECM to soil respiration. Respiration of ECM might be larger than respiration of fine roots.
Soil respiration . Carbon allocation . Ectomycorrhiza . Picea abies . Fine roots