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| Titel |
Evaluation and adjustment of description of denitrification in the DailyDayCent and COUP models based on N2 and N2O laboratory incubation system measurements |
| VerfasserIn |
Balázs Grosz, Reinhard Well, Michael Dannenmann, René Dechow, Barbara Kitzler, Kerstin Michel, Jan Reent Köster |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250151486
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| Publikation (Nr.) |
 EGU/EGU2017-16075.pdf |
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| Zusammenfassung |
| Denitrification is an anaerobic key process by microbes where the NO3− is step-by-step
reduced and emitted as NO, N2O and finally N2 gas from the soil. The accurate knowledge of
the reduction of nitrate (NO3−) and nitrite (NO2−) to N2O and molecular N2 is
important because the N2O fraction is further reduced to N2 and constitutes the
main emission source of this greenhouse gas from agricultural soils. Hence, our
understanding and ability to quantify soil denitrification is crucial for mitigating
nitrogen fertilizer loss as well as for reducing N2O emissions. Models can be an
important tool to predict mitigation effects and help to develop climate smart mitigation
strategies.
Ideally, commonly used biogeochemical models could provide adequate predictions of
denitrification processes of agricultural soils but often simplified process descriptions and
inadequate model parameters prevent models from simulating adequate fluxes of N2 and N2O
on field scale. Model development and parametrization often suffers from limited
availability of empirical data describing denitrification processes in agricultural
soils. While in many studies N2O emissions are used to develop and train models,
detailed measurements on NO, N2O, N2 fluxes and concentrations and related soil
conditions are necessary to develop and test adequate model algorithms. Composition of
denitrifying communities, coinciding effects of management and local conditions
on the development of denitrification hotspots are highly variable in space and
time.
To address this issue the coordinated research unit „Denitrification in Agricultural Soils:
Integrated Control and Modelling at Various Scales (DASIM)” was initiated to more closely
investigate N-fluxes caused by denitrification in response to environmental effects, soil
properties and microbial communities.
Data suitable to validate denitrification models are still scarce due to previous technical
and/or methodical limitations of measuring N2 fluxes, but large data-sets are needed in view
of the extreme spatio-temporal heterogeneity of denitrification. DASIM will provide such
data based on laboratory incubations including measurement of N2O and N2 fluxes and
determination of the relevant drivers.
Here, we present how we will use these data to evaluate common biogeochemical process
models (DailyDayCent, Coup) with respect to modeled NO, N2O and N2 fluxes from
denitrification. The models are used with different settings. The first approximation is the
basic “factory” setting of the models. The next step would show the precision in the results of
the modeling after adjusting the appropriate parameters from the result of the measurement
values and the “factory” results. The better adjustment and the well-controlled input and
output measured parameters could provide a better understanding of the probable
scantiness of the tested models which will be a basis for future model improvement. |
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