title: Modelling the influence of ectomycorrhizal decomposition on plant nutrition and soil carbon sequestration in boreal forest ecosystems.
abstract: Tree growth in boreal forests is limited by nitrogen (N) availability. Most boreal forest trees form symbiotic associations with ectomycorrhizal (ECM) fungi, which improve the uptake of inorganic N and also have the capacity to decompose soil organic matter (SOM) and to mobilize organic N ('ECM decomposition'). To study the effects of 'ECM decomposition' on ecosystem carbon (C) and N balances, we performed a sensitivity analysis on a model of C and N flows between plants, SOM, saprotrophs, ECM fungi, and inorganic N stores. The analysis indicates that C and N balances were sensitive to model parameters regulating ECM biomass and decomposition. Under low N availability, the optimal C allocation to ECM fungi, above which the symbiosis switches from mutualism to parasitism, increases with increasing relative involvement of ECM fungi in SOM decomposition. Under low N conditions, increased ECM organic N mining promotes tree growth but decreases soil C storage, leading to a negative correlation between C stores above- and below-ground. The interplay between plant production and soil C storage is sensitive to the partitioning of decomposition between ECM fungi and saprotrophs. Better understanding of interactions between functional guilds of soil fungi may significantly improve predictions of ecosystem responses to environmental change.
authors.affiliation: Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, Uppsala, SE-750 07, Sweden.
authors.forename: Preetisri
authors.initials: P
authors.lastname: Baskaran
authors.affiliation: Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, Uppsala, SE-750 07, Sweden.
authors.forename: Riitta
authors.initials: R
authors.lastname: Hyvönen
authors.affiliation: Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, Uppsala, SE-750 07, Sweden.
authors.forename: S Linnea
authors.initials: SL
authors.lastname: Berglund
authors.affiliation: Department of Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, Uppsala, SE-750 07, Sweden.
authors.forename: Karina E
authors.initials: KE
authors.lastname: Clemmensen
authors.affiliation: Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, Uppsala, SE-750 07, Sweden.
authors.forename: Göran I
authors.initials: GI
authors.lastname: Ågren
authors.affiliation: Department of Soil and Environment, Swedish University of Agricultural Sciences, Box 7014, Uppsala, SE-750 07, Sweden.
authors.forename: Björn D
authors.initials: BD
authors.lastname: Lindahl
authors.affiliation: Department of Physical Geography, Stockholm University, Stockholm, SE-106 91, Sweden.|Bolin Centre for Climate Research, Stockholm University, Stockholm, SE-106 91, Sweden.
authors.forename: Stefano
authors.initials: S
authors.lastname: Manzoni
mesh_terms: D002244:Carbon / Q000378:metabolism; D057965:Carbon Sequestration; D008954:Models, Biological; D038821:Mycorrhizae / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D010944:Plants / Q000382:microbiology*; D012987:Soil; D066188:Taiga
chemical_list: D012987:Soil; D002244:Carbon; D009584:Nitrogen
keywords: carbon (C) sequestration; ectomycorrhizal (ECM) decomposition; mutualistic-parasitic continuum; nitrogen (N) availability; optimal C allocation; plant growth