Ammonia fluxes in relation to cutting and fertilization of an intensively managed grassland derived from an inter-comparison of gradient measurements

C. Milford*, M. R. Theobald, E. Nemitz, K. J. Hargreaves, L. Horvath, J. Raso, U. Dämmgen, A. Neftel, S. K. Jones, A. Hensen, B. Loubet, P. Cellier, M. A. Sutton

*Corresponding author for this work

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Quantification of ammonia (NH3) land-atmosphere exchange is required for atmospheric modelling and assessment of nitrogen deposition, yet flux measurement methods remain highly uncertain. To address this issue, a major inter-comparison of ammonia fluxes over intensively managed grassland was conducted during the GRAMINAE Integrated Experiment held in Braunschweig, Germany. In order to provide a robust dataset of ammonia exchange with the vegetation, four independent continuous flux gradient systems were operated. Three independently operated continuous wet denuders systems (AMANDA) were compared with a Wet Effluent Diffusion Denuder (mini-WEDD) system. Measurements were made at two distances from an adjacent livestock farm, allowing effects of advection to be quantified in a real landscape setting. Data treatment included filtering for instrument failure, disturbed wind sectors and unsuitable micrometeorological conditions, with corrections made for storage and advection errors. The inter-comparison demonstrated good agreement in measured ammonia concentrations and fluxes (relative standard error <20%) for some periods, although the performance of the ammonia analyzers were variable, with much poorer agreement on particular days. However, by using four systems, the inter-comparison was able to provide a robust mean estimate of continuous ammonia fluxes through the experiment. The observed fluxes were: a) small bi-directional fluxes prior to cutting (-64 to 42 ng NH3 m -2 s-1), b) larger diurnally-varying emissions following cutting (-49 to 703 ng NH3 m-2 s-1) and c) much larger emissions following fertilizer application (0 to 3820 ng NH3 m-2 s-1). The results are a salutary reminder of the uncertainty in unreplicated ammonia flux measurements, while the replication of the present study provides a uniquely robust dataset for the evaluation of ammonia exchange processes. It is clear that consistently reliable determination of ammonia concentrations remains the major measurement challenge.

Original languageEnglish
Pages (from-to)819-834
Number of pages16
JournalBiogeosciences
Volume6
Issue number5
DOIs
Publication statusPrint publication - May 2009
Externally publishedYes

Fingerprint

ammonia
grasslands
grassland
flux measurement
advection
comparison
cutting (process)
atmospheric modeling
measurement method
fertilizer application
livestock
experiment
farm
effluent
effluents
atmosphere
vegetation
nitrogen
uncertainty
Germany

Cite this

Milford, C. ; Theobald, M. R. ; Nemitz, E. ; Hargreaves, K. J. ; Horvath, L. ; Raso, J. ; Dämmgen, U. ; Neftel, A. ; Jones, S. K. ; Hensen, A. ; Loubet, B. ; Cellier, P. ; Sutton, M. A. / Ammonia fluxes in relation to cutting and fertilization of an intensively managed grassland derived from an inter-comparison of gradient measurements. In: Biogeosciences. 2009 ; Vol. 6, No. 5. pp. 819-834.
@article{f3b61943e0834c9a9883341b28f599bb,
title = "Ammonia fluxes in relation to cutting and fertilization of an intensively managed grassland derived from an inter-comparison of gradient measurements",
abstract = "Quantification of ammonia (NH3) land-atmosphere exchange is required for atmospheric modelling and assessment of nitrogen deposition, yet flux measurement methods remain highly uncertain. To address this issue, a major inter-comparison of ammonia fluxes over intensively managed grassland was conducted during the GRAMINAE Integrated Experiment held in Braunschweig, Germany. In order to provide a robust dataset of ammonia exchange with the vegetation, four independent continuous flux gradient systems were operated. Three independently operated continuous wet denuders systems (AMANDA) were compared with a Wet Effluent Diffusion Denuder (mini-WEDD) system. Measurements were made at two distances from an adjacent livestock farm, allowing effects of advection to be quantified in a real landscape setting. Data treatment included filtering for instrument failure, disturbed wind sectors and unsuitable micrometeorological conditions, with corrections made for storage and advection errors. The inter-comparison demonstrated good agreement in measured ammonia concentrations and fluxes (relative standard error <20{\%}) for some periods, although the performance of the ammonia analyzers were variable, with much poorer agreement on particular days. However, by using four systems, the inter-comparison was able to provide a robust mean estimate of continuous ammonia fluxes through the experiment. The observed fluxes were: a) small bi-directional fluxes prior to cutting (-64 to 42 ng NH3 m -2 s-1), b) larger diurnally-varying emissions following cutting (-49 to 703 ng NH3 m-2 s-1) and c) much larger emissions following fertilizer application (0 to 3820 ng NH3 m-2 s-1). The results are a salutary reminder of the uncertainty in unreplicated ammonia flux measurements, while the replication of the present study provides a uniquely robust dataset for the evaluation of ammonia exchange processes. It is clear that consistently reliable determination of ammonia concentrations remains the major measurement challenge.",
author = "C. Milford and Theobald, {M. R.} and E. Nemitz and Hargreaves, {K. J.} and L. Horvath and J. Raso and U. D{\"a}mmgen and A. Neftel and Jones, {S. K.} and A. Hensen and B. Loubet and P. Cellier and Sutton, {M. A.}",
year = "2009",
month = "5",
doi = "10.5194/bg-6-819-2009",
language = "English",
volume = "6",
pages = "819--834",
journal = "Biogeosciences",
issn = "1726-4170",
publisher = "European Geosciences Union",
number = "5",

}

Milford, C, Theobald, MR, Nemitz, E, Hargreaves, KJ, Horvath, L, Raso, J, Dämmgen, U, Neftel, A, Jones, SK, Hensen, A, Loubet, B, Cellier, P & Sutton, MA 2009, 'Ammonia fluxes in relation to cutting and fertilization of an intensively managed grassland derived from an inter-comparison of gradient measurements', Biogeosciences, vol. 6, no. 5, pp. 819-834. https://doi.org/10.5194/bg-6-819-2009

Ammonia fluxes in relation to cutting and fertilization of an intensively managed grassland derived from an inter-comparison of gradient measurements. / Milford, C.; Theobald, M. R.; Nemitz, E.; Hargreaves, K. J.; Horvath, L.; Raso, J.; Dämmgen, U.; Neftel, A.; Jones, S. K.; Hensen, A.; Loubet, B.; Cellier, P.; Sutton, M. A.

In: Biogeosciences, Vol. 6, No. 5, 05.2009, p. 819-834.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Ammonia fluxes in relation to cutting and fertilization of an intensively managed grassland derived from an inter-comparison of gradient measurements

AU - Milford, C.

AU - Theobald, M. R.

AU - Nemitz, E.

AU - Hargreaves, K. J.

AU - Horvath, L.

AU - Raso, J.

AU - Dämmgen, U.

AU - Neftel, A.

AU - Jones, S. K.

AU - Hensen, A.

AU - Loubet, B.

AU - Cellier, P.

AU - Sutton, M. A.

PY - 2009/5

Y1 - 2009/5

N2 - Quantification of ammonia (NH3) land-atmosphere exchange is required for atmospheric modelling and assessment of nitrogen deposition, yet flux measurement methods remain highly uncertain. To address this issue, a major inter-comparison of ammonia fluxes over intensively managed grassland was conducted during the GRAMINAE Integrated Experiment held in Braunschweig, Germany. In order to provide a robust dataset of ammonia exchange with the vegetation, four independent continuous flux gradient systems were operated. Three independently operated continuous wet denuders systems (AMANDA) were compared with a Wet Effluent Diffusion Denuder (mini-WEDD) system. Measurements were made at two distances from an adjacent livestock farm, allowing effects of advection to be quantified in a real landscape setting. Data treatment included filtering for instrument failure, disturbed wind sectors and unsuitable micrometeorological conditions, with corrections made for storage and advection errors. The inter-comparison demonstrated good agreement in measured ammonia concentrations and fluxes (relative standard error <20%) for some periods, although the performance of the ammonia analyzers were variable, with much poorer agreement on particular days. However, by using four systems, the inter-comparison was able to provide a robust mean estimate of continuous ammonia fluxes through the experiment. The observed fluxes were: a) small bi-directional fluxes prior to cutting (-64 to 42 ng NH3 m -2 s-1), b) larger diurnally-varying emissions following cutting (-49 to 703 ng NH3 m-2 s-1) and c) much larger emissions following fertilizer application (0 to 3820 ng NH3 m-2 s-1). The results are a salutary reminder of the uncertainty in unreplicated ammonia flux measurements, while the replication of the present study provides a uniquely robust dataset for the evaluation of ammonia exchange processes. It is clear that consistently reliable determination of ammonia concentrations remains the major measurement challenge.

AB - Quantification of ammonia (NH3) land-atmosphere exchange is required for atmospheric modelling and assessment of nitrogen deposition, yet flux measurement methods remain highly uncertain. To address this issue, a major inter-comparison of ammonia fluxes over intensively managed grassland was conducted during the GRAMINAE Integrated Experiment held in Braunschweig, Germany. In order to provide a robust dataset of ammonia exchange with the vegetation, four independent continuous flux gradient systems were operated. Three independently operated continuous wet denuders systems (AMANDA) were compared with a Wet Effluent Diffusion Denuder (mini-WEDD) system. Measurements were made at two distances from an adjacent livestock farm, allowing effects of advection to be quantified in a real landscape setting. Data treatment included filtering for instrument failure, disturbed wind sectors and unsuitable micrometeorological conditions, with corrections made for storage and advection errors. The inter-comparison demonstrated good agreement in measured ammonia concentrations and fluxes (relative standard error <20%) for some periods, although the performance of the ammonia analyzers were variable, with much poorer agreement on particular days. However, by using four systems, the inter-comparison was able to provide a robust mean estimate of continuous ammonia fluxes through the experiment. The observed fluxes were: a) small bi-directional fluxes prior to cutting (-64 to 42 ng NH3 m -2 s-1), b) larger diurnally-varying emissions following cutting (-49 to 703 ng NH3 m-2 s-1) and c) much larger emissions following fertilizer application (0 to 3820 ng NH3 m-2 s-1). The results are a salutary reminder of the uncertainty in unreplicated ammonia flux measurements, while the replication of the present study provides a uniquely robust dataset for the evaluation of ammonia exchange processes. It is clear that consistently reliable determination of ammonia concentrations remains the major measurement challenge.

U2 - 10.5194/bg-6-819-2009

DO - 10.5194/bg-6-819-2009

M3 - Article

AN - SCOPUS:69249144906

VL - 6

SP - 819

EP - 834

JO - Biogeosciences

JF - Biogeosciences

SN - 1726-4170

IS - 5

ER -