Soil transformation processes generating N2O and N2 play a key role in the soil N cycle due to their implication for losses of reactive N and emission of gaseous N oxides to the atmosphere. Despite being intensively studied for a long time and numerous recent technological progresses, we still lack a comprehensive, quantitative understanding of denitrification rates in soils. This is in part due to methodical difficulties in measuring N2 production and emission at ambient concentrations of 78%. But also the complexity of the processes itself with their intricate cellular regulation in response to numerous factors varying at a small scale in space and time in the soil matrix prevents robust prediction of gaseous emissions.
The effective control at the field scale and the spatial variability of transformation processes resulting in N2O and N2 on a landscape scale is still not satisfactorily clarified. Due to the lack of suitable data sets, process -based denitrification models have rarely been validated and results of their application on site and regional scales are highly uncertain.
Recent technological improvements of experimental and analytical tools like measurements of N2 fluxes, linking structure and activity of denitrifying microbial communities with denitrification rates, small scale resolution of soil structure, improved numerical methods and computational power offer new opportunities in this area.
We invite contributions from the following fields:
- methodological advances in measuring and modelling of N2O and N2 generating processes in soils;
- measuring N2 and N2O fluxes and controlling factors using methods like incubation under He atmosphere;
- 15N-tracer technique or natural abundance stable isotopes signatures of N2O and N2 fluxes;
- method comparisons;
- process-based modelling of denitrification at various scales;
- linking denitrification rates to parameters of the denitrifying community