 |
| Titel |
Validating soil denitrification models based on laboratory N2 and N2O fluxes and underlying processes
derived by stable isotope approaches |
| VerfasserIn |
Reinhard Well, Jürgen Böttcher, Klaus Butterbach-Bahl, Michael Dannenmann, Marianna Deppe, Klaus Dittert, Peter Dörsch, Marcus Horn, Olaf Ippisch, Robert Mikutta, Carsten Müller, Christoph Müller, Mehmet Senbayram, Hans-Jörg Vogel, Nicole Wrage-Mönnig |
| Konferenz |
EGU General Assembly 2016
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250133616
|
| Publikation (Nr.) |
 EGU/EGU2016-14246.pdf |
|
|
|
|
|
| Zusammenfassung |
| Robust denitrification data suitable to validate soil N2 fluxes in denitrification models are
scarce due to methodical limitations and the extreme spatio-temporal heterogeneity of
denitrification in soils.
Numerical models have become essential tools to predict denitrification at different
scales. Model performance could either be tested for total gaseous flux (NO + N2O + N2),
individual denitrification products (e.g. N2O and/or NO) or for the effect of denitrification
factors (e.g. C-availability, respiration, diffusivity, anaerobic volume, etc.). While there
are numerous examples for validating N2O fluxes, there are neither robust field
data of N2 fluxes nor sufficiently resolved measurements of control factors used as
state variables in the models. To the best of our knowledge there has been only one
published validation of modelled soil N2 flux by now, using a laboratory data set to
validate an ecosystem model. Hence there is a need for validation data at both,
the mesocosm and the field scale including validation of individual denitrification
controls.
Here we present the concept for collecting model validation data which is be part of
the DFG-research unit “Denitrification in Agricultural Soils: Integrated Control
and Modelling at Various Scales (DASIM)” starting this year. We will use novel
approaches including analysis of stable isotopes, microbial communities, pores
structure and organic matter fractions to provide denitrification data sets comprising as
much detail on activity and regulation as possible as a basis to validate existing and
calibrate new denitrification models that are applied and/or developed by DASIM
subprojects.
The basic idea is to simulate “field-like” conditions as far as possible in an automated
mesocosm system without plants in order to mimic processes in the soil parts not
significantly influenced by the rhizosphere (rhizosphere soils are studied by other DASIM
projects). Hence, to allow model testing in a wide range of conditions, denitrification control
factors will be varied in the initial settings (pore volume, plant residues, mineral N, pH) but
also over time, where moisture, temperature, and mineral N will be manipulated according to
typical time patterns in the field. This will be realized by including precipitation events,
fertilization (via irrigation), drainage (via water potential) and temperature in the course of
incubations. Moreover, oxygen concentration will be varied to simulate anaerobic
events.
These data will be used to calibrate the newly to develop DASIM models as well as
existing denitrification models. One goal of DASIM is to create a public data base as a joint
basis for model testing by denitrification modellers. Therefore we invite contributions of
suitable data-sets from the scientific community. Requirements will be briefly outlined. |
|
|
|
|
|
|