EGUsphere

Copernicus Publications

Göttingen, Germany

10.5194/egusphere-2026-5494

Ammonia measurements over multiple fertilisation campaigns using eddy covariance and the integrated horizontal flux method

Kukowski

Sina

https://orcid.org/0000-0002-5784-6539

¹ Kemmann

Björn

https://orcid.org/0000-0001-6154-4149

² ⁵ Wintjen

Pascal

³ Schmidt

Paul

⁴ Piepho

Hans-Peter

⁴ Rüffer

Jeremy

¹ Jüdt

Jens-Kristian

¹ Saul

Melanie

¹ Götze

Hannah

¹ ⁶ Pacholski

Andreas

https://orcid.org/0000-0003-1615-5122

¹ Flessa

Heinz

¹ Brümmer

Christian

https://orcid.org/0000-0001-6621-5010

Thünen Institute of Climate-Smart Agriculture, 38116 Braunschweig, Germany

Institute for Ecology, Chair of Soil Science, Technische Universität Berlin, 10587 Berlin, Germany

Environmental Modelling, Sensing & Analysis, TNO, 1755LE Petten, The Netherlands

Biostatistics Unit, Institute of Crop Science, University of Hohenheim, 70593 Stuttgart, Germany

now at: Institute of Bio and Geo Sciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany

now at: Institute for Biotechnology and Environmental Research, Faculty of Supply Engineering, Ostfalia University of Applied Sciences, 38302 Wolfenbüttel, Germany

14 09 2026

2026 1 41

2026

This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/

This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-5494/

The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-5494/egusphere-2026-5494.pdf

Quantifying field-scale ammonia emissions following nitrogen fertilisation remains challenging, and estimates may differ substantially between measurement methods. We compared quantum cascade laser-based eddy covariance (QCL-EC) with the integrated horizontal flux method using Adapted Low-cost Passive High Absorption (ALPHA) samplers (ALPHA-IHF) during eight urea fertilisation campaigns in winter wheat (2021–2023). Both approaches identified post-fertilisation emission periods and captured similar dynamics, but paired interval estimates differed. Only 62% of intervals yielded ALPHA-IHF flux estimates, mainly because irregular or weak concentration profiles prevented robust calculation. QCL and ALPHA concentrations were positively correlated, but QCL concentrations were, on average, 31% higher, whereas QCL-EC emission estimates were 23% lower than ALPHA-IHF estimates. Median campaign emission factors were 1.6% for QCL-EC and 3.2% for ALPHA-IHF, respectively. QCL-based estimates were more precise, and differences between the methods varied with short-term ammonia concentration variability, air temperature, friction velocity and ALPHA profile quality. The contrasting results show that concentration-level patterns do not translate directly into flux estimates and that differences between methods vary with field conditions. QCL-EC resolved short-term net exchange but required turbulence-based quality filtering, whereas ALPHA-IHF yielded time-integrated emission estimates only when the fitted concentration profile met the quality criteria. Without an independent reference, systematic over- or underestimation could not be assigned to either method. Assessments of fertiliser-induced emissions must consider method-specific data coverage and differences in flux representation. The greater precision of QCL-based estimates and high temporal resolution of QCL-EC make it promising for detecting subtle emission differences under low-emission conditions, while improved concentration precision and resolution of weak gradients could broaden ALPHA-IHF applicability.

Landwirtschaftliche Rentenbank

grant number 892976