Nitrous oxide fluxes and denitrification sensitivity to temperature in Irish pasture soils

M Abdalla, M Jones, P Smith, M Williams

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Nitrous oxide (N2O) emissions from grazed pastures constitute approximately 28% of total global anthropogenic N2O emissions. The aims of this study were to investigate the effect of inorganic N fertilizer application on fluxes of N2O, quantify the emission factors (EFs) for a sandy loam soil which is typical of large areas in Ireland and to investigate denitrification sensitivity to temperature. Nitrous oxide flux measurements from a cut and grazed pasture field for 1 year and denitrification laboratory incubation were carried out. The soil pH was 7.3 and had a mean organic C and N content at 0-20 cm of 44.1 and 4.4 g/kg dry weight, respectively. The highest observed peaks of N2O fluxes of 67 and 38.7 g N2O-N per hectare per day were associated with times of application of inorganic N fertilizer. Annual fluxes of N2O from control and fertilized treatments were 1 and 2.4 kg N2O-N per hectare, respectively. Approximately 63% of the annual flux was associated with N fertilizer application. Multiple regression analysis revealed that soil nitrate and the interaction between soil nitrate and soil water content were the main factors controlling N2O flux from the soil. The derived EF of 0.83% was approximately 66% of the IPCC default EF value of 1.25% as used by the Irish EPA to estimate greenhouse gases (GHGs) in Ireland. The IPCC-revised EF value is 0.9%. A highly significant exponential regression (r2 = 0.98) was found between denitrification and incubation temperature. The calculated Q(10) ranged from 4.4 to 6.2 for a temperature range of 10-25 degrees C and the activation energy was 47 kJ/mol. Our results show that denitrification is very sensitive to increasing temperature, suggesting that future global warming could lead to a significant increase in soil denitrification and consequently N2O fluxes from soils.

Original languageEnglish
Pages (from-to)376-388
Number of pages13
JournalSoil Use & Management
Volume25
Issue number4
Early online date28 Aug 2009
DOIs
Publication statusPublished - Dec 2009

Keywords

  • nitrous oxide
  • soil denitrification
  • grazed pasture
  • acetylene inhibition technique
  • filled pore-space
  • agricultural soils
  • emission factors
  • carbon-dioxide
  • N2O fluxes
  • seminatural grassland
  • fertilized grassland
  • spatial variability
  • seasonal-variation
  • temporal variation

Cite this

Nitrous oxide fluxes and denitrification sensitivity to temperature in Irish pasture soils. / Abdalla, M; Jones, M; Smith, P; Williams, M.

In: Soil Use & Management, Vol. 25, No. 4, 12.2009, p. 376-388.

Research output: Contribution to journalArticle

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abstract = "Nitrous oxide (N2O) emissions from grazed pastures constitute approximately 28{\%} of total global anthropogenic N2O emissions. The aims of this study were to investigate the effect of inorganic N fertilizer application on fluxes of N2O, quantify the emission factors (EFs) for a sandy loam soil which is typical of large areas in Ireland and to investigate denitrification sensitivity to temperature. Nitrous oxide flux measurements from a cut and grazed pasture field for 1 year and denitrification laboratory incubation were carried out. The soil pH was 7.3 and had a mean organic C and N content at 0-20 cm of 44.1 and 4.4 g/kg dry weight, respectively. The highest observed peaks of N2O fluxes of 67 and 38.7 g N2O-N per hectare per day were associated with times of application of inorganic N fertilizer. Annual fluxes of N2O from control and fertilized treatments were 1 and 2.4 kg N2O-N per hectare, respectively. Approximately 63{\%} of the annual flux was associated with N fertilizer application. Multiple regression analysis revealed that soil nitrate and the interaction between soil nitrate and soil water content were the main factors controlling N2O flux from the soil. The derived EF of 0.83{\%} was approximately 66{\%} of the IPCC default EF value of 1.25{\%} as used by the Irish EPA to estimate greenhouse gases (GHGs) in Ireland. The IPCC-revised EF value is 0.9{\%}. A highly significant exponential regression (r2 = 0.98) was found between denitrification and incubation temperature. The calculated Q(10) ranged from 4.4 to 6.2 for a temperature range of 10-25 degrees C and the activation energy was 47 kJ/mol. Our results show that denitrification is very sensitive to increasing temperature, suggesting that future global warming could lead to a significant increase in soil denitrification and consequently N2O fluxes from soils.",
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N2 - Nitrous oxide (N2O) emissions from grazed pastures constitute approximately 28% of total global anthropogenic N2O emissions. The aims of this study were to investigate the effect of inorganic N fertilizer application on fluxes of N2O, quantify the emission factors (EFs) for a sandy loam soil which is typical of large areas in Ireland and to investigate denitrification sensitivity to temperature. Nitrous oxide flux measurements from a cut and grazed pasture field for 1 year and denitrification laboratory incubation were carried out. The soil pH was 7.3 and had a mean organic C and N content at 0-20 cm of 44.1 and 4.4 g/kg dry weight, respectively. The highest observed peaks of N2O fluxes of 67 and 38.7 g N2O-N per hectare per day were associated with times of application of inorganic N fertilizer. Annual fluxes of N2O from control and fertilized treatments were 1 and 2.4 kg N2O-N per hectare, respectively. Approximately 63% of the annual flux was associated with N fertilizer application. Multiple regression analysis revealed that soil nitrate and the interaction between soil nitrate and soil water content were the main factors controlling N2O flux from the soil. The derived EF of 0.83% was approximately 66% of the IPCC default EF value of 1.25% as used by the Irish EPA to estimate greenhouse gases (GHGs) in Ireland. The IPCC-revised EF value is 0.9%. A highly significant exponential regression (r2 = 0.98) was found between denitrification and incubation temperature. The calculated Q(10) ranged from 4.4 to 6.2 for a temperature range of 10-25 degrees C and the activation energy was 47 kJ/mol. Our results show that denitrification is very sensitive to increasing temperature, suggesting that future global warming could lead to a significant increase in soil denitrification and consequently N2O fluxes from soils.

AB - Nitrous oxide (N2O) emissions from grazed pastures constitute approximately 28% of total global anthropogenic N2O emissions. The aims of this study were to investigate the effect of inorganic N fertilizer application on fluxes of N2O, quantify the emission factors (EFs) for a sandy loam soil which is typical of large areas in Ireland and to investigate denitrification sensitivity to temperature. Nitrous oxide flux measurements from a cut and grazed pasture field for 1 year and denitrification laboratory incubation were carried out. The soil pH was 7.3 and had a mean organic C and N content at 0-20 cm of 44.1 and 4.4 g/kg dry weight, respectively. The highest observed peaks of N2O fluxes of 67 and 38.7 g N2O-N per hectare per day were associated with times of application of inorganic N fertilizer. Annual fluxes of N2O from control and fertilized treatments were 1 and 2.4 kg N2O-N per hectare, respectively. Approximately 63% of the annual flux was associated with N fertilizer application. Multiple regression analysis revealed that soil nitrate and the interaction between soil nitrate and soil water content were the main factors controlling N2O flux from the soil. The derived EF of 0.83% was approximately 66% of the IPCC default EF value of 1.25% as used by the Irish EPA to estimate greenhouse gases (GHGs) in Ireland. The IPCC-revised EF value is 0.9%. A highly significant exponential regression (r2 = 0.98) was found between denitrification and incubation temperature. The calculated Q(10) ranged from 4.4 to 6.2 for a temperature range of 10-25 degrees C and the activation energy was 47 kJ/mol. Our results show that denitrification is very sensitive to increasing temperature, suggesting that future global warming could lead to a significant increase in soil denitrification and consequently N2O fluxes from soils.

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KW - grazed pasture

KW - acetylene inhibition technique

KW - filled pore-space

KW - agricultural soils

KW - emission factors

KW - carbon-dioxide

KW - N2O fluxes

KW - seminatural grassland

KW - fertilized grassland

KW - spatial variability

KW - seasonal-variation

KW - temporal variation

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JO - Soil Use & Management

JF - Soil Use & Management

SN - 0266-0032

IS - 4

ER -