Residue-C effects on denitrification vary with soil depth

M Kuntz, NJ Morley, PD Hallett, CA Watson, EM Baggs

Research output: Contribution to journalArticle

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Abstract

A stable isotope (13C-residue, 15N-NO3 e fertiliser) approach combined with measurements of soil pore space gas concentrations was used to investigate spatial and temporal mechanisms of residue carbon (C) affecting denitrification. Whilst relationships between residue addition and N2O fluxes have previously been well characterised, the influence of residues on production and reduction of N2O at depth is less well understood. Here we investigated the relationship between residue-13C addition (0, 1 and 2 mg C g 1 soil) and denitrification (15N-N2O and 15N-N2 production) at 2, 5 and 8 cm soil depths and also fluxes from the soil surface. Hydrophobic probes that equilibrate with the soil gas phase were used to extract gases at soil depth, followed by analysis for 15N-N2O, 15N-N2, 13C-CO2 and O2 concentrations. 15N-N2O and CO2 surface fluxes peaked one day after 14NH4 15NO3 application (1 mg N g 1 soil), with residue application resulting in a more than 20-fold greater 15N-N2O emission rate compared to the non-amended control. Eight days after N application 15N-N2O pore space concentrations had significantly increased 20-fold at 8 cm depth below the residue layer compared to no residue application. However, simultaneous increases in 15N-N2 surface fluxes and profile concentrations showed efficient reduction of the N2O at shallow depth (3e10 cm depth) resulting in surface emission of N2 rather than N2O. Our results have implications for management to lower emissions as denitrifier activity at greater depth, and the greater reduction of N2O to N2, appeared to be indirectly driven by residue addition via the depletion of O2 during aerobic heterotrophic respiration in the surface layer. In contrast, net surface fluxes of N2O were more directly related to the residue addition through substrate provision for denitrification. © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license
Original languageEnglish
Pages (from-to)365 - 375
Number of pages11
JournalSoil Biology & Biochemistry
Volume103
Early online date27 Sep 2016
DOIs
Publication statusFirst published - 27 Sep 2016

Fingerprint

soil depth
denitrification
surface flux
soil gas
fold
pore space
surface layer
soil surface
stable isotope
respiration
soil
probe
effect
fertilizer
substrate
carbon

Bibliographical note

1028812
1030821

Keywords

  • Carbon
  • Dinitrogen
  • Nitrous oxide
  • Residue
  • Soil depth
  • Stable isotope

Cite this

Kuntz, M ; Morley, NJ ; Hallett, PD ; Watson, CA ; Baggs, EM. / Residue-C effects on denitrification vary with soil depth. In: Soil Biology & Biochemistry. 2016 ; Vol. 103. pp. 365 - 375.
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Residue-C effects on denitrification vary with soil depth. / Kuntz, M; Morley, NJ; Hallett, PD; Watson, CA; Baggs, EM.

In: Soil Biology & Biochemistry, Vol. 103, 27.09.2016, p. 365 - 375.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Residue-C effects on denitrification vary with soil depth

AU - Kuntz, M

AU - Morley, NJ

AU - Hallett, PD

AU - Watson, CA

AU - Baggs, EM

N1 - 1028812 1030821

PY - 2016/9/27

Y1 - 2016/9/27

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AB - A stable isotope (13C-residue, 15N-NO3 e fertiliser) approach combined with measurements of soil pore space gas concentrations was used to investigate spatial and temporal mechanisms of residue carbon (C) affecting denitrification. Whilst relationships between residue addition and N2O fluxes have previously been well characterised, the influence of residues on production and reduction of N2O at depth is less well understood. Here we investigated the relationship between residue-13C addition (0, 1 and 2 mg C g 1 soil) and denitrification (15N-N2O and 15N-N2 production) at 2, 5 and 8 cm soil depths and also fluxes from the soil surface. Hydrophobic probes that equilibrate with the soil gas phase were used to extract gases at soil depth, followed by analysis for 15N-N2O, 15N-N2, 13C-CO2 and O2 concentrations. 15N-N2O and CO2 surface fluxes peaked one day after 14NH4 15NO3 application (1 mg N g 1 soil), with residue application resulting in a more than 20-fold greater 15N-N2O emission rate compared to the non-amended control. Eight days after N application 15N-N2O pore space concentrations had significantly increased 20-fold at 8 cm depth below the residue layer compared to no residue application. However, simultaneous increases in 15N-N2 surface fluxes and profile concentrations showed efficient reduction of the N2O at shallow depth (3e10 cm depth) resulting in surface emission of N2 rather than N2O. Our results have implications for management to lower emissions as denitrifier activity at greater depth, and the greater reduction of N2O to N2, appeared to be indirectly driven by residue addition via the depletion of O2 during aerobic heterotrophic respiration in the surface layer. In contrast, net surface fluxes of N2O were more directly related to the residue addition through substrate provision for denitrification. © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license

KW - Carbon

KW - Dinitrogen

KW - Nitrous oxide

KW - Residue

KW - Soil depth

KW - Stable isotope

U2 - 10.1016/j.soilbio.2016.09.012

DO - 10.1016/j.soilbio.2016.09.012

M3 - Article

VL - 103

SP - 365

EP - 375

JO - Soil Biology and Biochemistry

JF - Soil Biology and Biochemistry

SN - 0038-0717

ER -