Dynamics of ammonia exchange with cut grassland: Synthesis of results and conclusions of the GRAMINAE Integrated Experiment

Abstract

Improved data on biosphere-atmosphere exchange are fundamental to understanding the production and fate of ammonia (NH3) in the atmosphere. The GRAMINAE Integrated Experiment combined novel measurement and modelling approaches to provide the most comprehensive analysis of the interactions to date. Major intercomparisons of micrometeorological parameters and NH3 flux measurements using the aerodynamic gradient method and relaxed eddy accumulation (REA) were conducted. These showed close agreement, though the REA systems proved insufficiently precise to investigate vertical flux divergence. Grassland management had a large effect on fluxes: emissions increased after grass cutting (-50to 700 ngm-2 s-1 NH 3) and after N-fertilization (0 to 3800 ngm-2 s -1) compared with before the cut (-60 to 40 ngm-2 s -1). © Author(s) 2009.