DONA: Understanding drivers and origins of N₂O fluxes in agroecosystems

Context

Agriculture is at the core of many global societal challenges, and thus needs to contribute to their solutions. In particular, nitrogen (N) management of arable systems such as precision N fertilization is highly relevant for developing climate-smart strategies, which aim at reducing nitrous oxide (N₂O) and nitrate (NO₃^-) losses from manure management and agricultural soils to the environment. However, the magnitude of such reductions, particularly for N₂O fluxes, under real-world settings still remains unknown. Thus, understanding drivers and origins of N₂O losses to the atmosphere, besides NO₃^- leaching, is a prerequisite for identifying the best N management option(s) for climate-smart agriculture.

Project aims

To achieve the overarching project goal - to understand drivers and the origins of N₂O losses to the atmosphere, besides NO₃^- leaching to identify the best N management option(s) for climate-smart agriculture - we work at the long-term flux measurement site Oensingen and on existing arable field trials located on farms in the cantons of Solothurn, and Schaffhausen/Thurgau and on a farm in the canton of Vaud.

We aim to

1. quantify N₂O fluxes of cropland and identify their drivers,
2. determine the origin of N₂O,
   
3. quantify NO₃^- leaching, and 
4. evaluate precision N fertilization options, applied by farmers.

Methods

We will be using a mobile tower to measure greenhouse gas fluxes with the eddy-covariance technique, use stable nitrogen isotope analysis to determine the origin of N₂O, use self-integrating accumulators for nitrate leaching, and use a participatory approach to develop recommendations for arable farming.