Application of nitrogen fertilizer to a boreal pine forest has a negative impact on the respiration of ectomycorrhizal hyphae

TY - JOUR

T1 - Application of nitrogen fertilizer to a boreal pine forest has a negative impact on the respiration of ectomycorrhizal hyphae

AU - Vallack, Harry W.

AU - Leronni, Vincenzo

AU - Metcalfe, Daniel B.

AU - Hogberg, Peter

AU - Ineson, Phil

AU - Subke, Jens-Arne

PY - 2012/3

Y1 - 2012/3

N2 - Aims There is evidence that increased N inputs to boreal forests, via atmospheric deposition or intentional fertilization, may impact negatively on ectomycorrhizal (ECM) fungi leading to a reduced flux of plant-derived carbon (C) back to the atmosphere via ECM. Our aim was to investigate the impact of N fertilization of a Pinus sylvestris (L.) forest stand on the return of recently photoassimilated C via the ECM component of soil respiration.Methods We used an in situ, large-scale, C-13-CO2 isotopic pulse labelling approach and monitored the C-13 label return using soil gas efflux chambers placed over three different types of soil collar to distinguish between heterotrophic (R-H), autotrophic (R-A; partitioned further into contributions from ECM hyphae and total R-A) and total (R-S) soil respiration.Results The impact of N fertilization was to significantly reduce R-A, particularly respiration via extramatrical ECM hyphae. ECM hyphal flux in control plots showed substantial spatial variability, resulting in mean flux estimates exceeding estimates of total R-A, while ECM contributions to R-A in N treated plots were estimated at around 30%.Conclusion Significant impacts on soil C cycling may be caused by reduced plant C allocation to ECM fungi in response to increased N inputs to boreal forests; ecosystem models so far lack this detail.

AB - Aims There is evidence that increased N inputs to boreal forests, via atmospheric deposition or intentional fertilization, may impact negatively on ectomycorrhizal (ECM) fungi leading to a reduced flux of plant-derived carbon (C) back to the atmosphere via ECM. Our aim was to investigate the impact of N fertilization of a Pinus sylvestris (L.) forest stand on the return of recently photoassimilated C via the ECM component of soil respiration.Methods We used an in situ, large-scale, C-13-CO2 isotopic pulse labelling approach and monitored the C-13 label return using soil gas efflux chambers placed over three different types of soil collar to distinguish between heterotrophic (R-H), autotrophic (R-A; partitioned further into contributions from ECM hyphae and total R-A) and total (R-S) soil respiration.Results The impact of N fertilization was to significantly reduce R-A, particularly respiration via extramatrical ECM hyphae. ECM hyphal flux in control plots showed substantial spatial variability, resulting in mean flux estimates exceeding estimates of total R-A, while ECM contributions to R-A in N treated plots were estimated at around 30%.Conclusion Significant impacts on soil C cycling may be caused by reduced plant C allocation to ECM fungi in response to increased N inputs to boreal forests; ecosystem models so far lack this detail.

UR - http://www.scopus.com/inward/record.url?scp=84858006168&partnerID=8YFLogxK

U2 - 10.1007/s11104-011-1005-6

DO - 10.1007/s11104-011-1005-6

M3 - Article

VL - 352

SP - 405

EP - 417

JO - Plant and Soil

JF - Plant and Soil

SN - 0032-079X

IS - 1-2

ER -