1Centre for Ecology and Hydrology (CEH), Edinburgh Research Station, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
2University of Manchester (UoM), Oxford Road, Manchester, M13 9PL, UK
3Energy research Centre of the Netherlands (ECN), Postbus 1, 1755 ZG Petten, The Netherlands
4Plant and Soil Science Laboratory, University of Copenhagen (UoC), Faculty of Life Sciences, Thorvaldsensvej 40, 871 Frederiksberg C, Copenhagen, Denmark
5Institut National de la Recherche Agronomique (INRA), UMR Environnement et Grandes Cultures, Thiverval-Grignon, 78850, France
6Agroscope Reckenholz-Tänikon Research Station (formerly: FAL-CH; now: ART), Zürich-Reckenholz, 8046 Zürich, Switzerland
7Hungarian Meteorological Service (HMS), P.O. Box 39 1675 Budapest, Hungary (in association with the Forest Research Institute (FRI) of Hungary), Hungay
8Eötvös Loránd University (ELU), Dept. Meteorology, 1117 Budapest, Hungary
9Research Institute of Soil Science and Agrochemistry of Hungary (RISSAC), Herman Ottó út 15, 1022 Budapest, Hungary
10University of Bonn, Institute for Crop Science and Resource Conservation, INRES-PE, Karlrobert-Kreiten-Str. 13, 53115 Bonn, Germany
11Agrometeorological Research Station of Deutscher Wetterdienst (DVD), Bundesallee 50; 38116 Braunschweig, Germany
12Institut fur Agrarokologie, Bundesforschungsanstalt fur Landwirtschaft (FAL), (now: the von Thunen Institute), Bundesallee 50, 38116 Braunschweig, Germany
*now at: Institute of Earth Sciences "Jaume Almera", CSIC, Lluis Solé i Sabarís, 08028, Barcelona, Spain
**now at: Section for Economy & Technology, Halmstad University, 30118 Sweden
***formerly at: University of Bern, Hochschulstr. 4, 3012 Bern, Switzerland
Abstract. A major international experiment on ammonia (NH3) biosphere-atmosphere exchange was conducted over intensively managed grassland at Braunschweig, Germany. The experimental strategy was developed to allow an integrated analysis of different features of NH3 exchange including: a) quantification of nearby emissions and advection effects, b) estimation of net NH3 fluxes with the canopy by a range of micrometeorological measurements, c) analysis of the sources and sinks of NH3 within the plant canopy, including soils and bioassay measurements, d) comparison of the effects of grassland management options on NH3 fluxes and e) assessment of the interactions of NH3 fluxes with aerosol exchange processes. Additional technical objectives included the inter-comparison of different estimates of sensible and latent heat fluxes, as well as continuous-gradient and Relaxed Eddy Accumulation (REA) systems for NH3 fluxes.
The prior analysis established the spatial and temporal design of the experiment, allowing significant synergy between these objectives. The measurements were made at 7 measurement locations, thereby quantifying horizontal and vertical profiles, and covered three phases: a) tall grass canopy prior to cutting (7 days), b) short grass after cutting (7 days) and c) re-growing sward following fertilization with ammonium nitrate (10 days). The sequential management treatments allowed comparison of sources-sinks, advection and aerosol interactions under a wide range of NH3 fluxes.
This paper describes the experimental strategy and reports the grassland management history, soils, environmental conditions and air chemistry during the experiment, finally summarizing how the results are coordinated in the accompanying series of papers.