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| Titel |
Modelling the effect of soil moisture and organic matter degradation on biogenic NO emissions from soils in Sahel rangeland (Mali) |
| VerfasserIn |
C. Delon, E. Mougin, D. Serça, M. Grippa, P. Hiernaux, M. Diawara, C. Galy-Lacaux, L. Kergoat |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 11 ; Nr. 12, no. 11 (2015-06-03), S.3253-3272 |
| Datensatznummer |
250117960
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| Publikation (Nr.) |
 copernicus.org/bg-12-3253-2015.pdf |
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| Zusammenfassung |
| This work is an attempt to provide seasonal variation of biogenic NO emission
fluxes in a Sahelian rangeland
in Mali (Agoufou, 15.34° N, 1.48° W) for years 2004, 2005, 2006, 2007 and 2008. Indeed, NO
is one of the most important precursors for tropospheric ozone, and previous studies have shown that arid areas
potentially display significant NO emissions (due to both biotic and abiotic processes). Previous campaigns
in the Sahel suggest that the contribution of this region in emitting NO is no longer considered as negligible.
However, very few data are available in this region, therefore this study focuses on model development.
The link between NO production in the soil and NO release to the atmosphere
is investigated in this modelling study, by taking into account vegetation
litter production and degradation, microbial processes in the soil, emission
fluxes, and environmental variables influencing these processes, using a
coupled vegetation–litter decomposition–emission model. This model includes
the Sahelian Transpiration Evaporation and Productivity (STEP) model for the
simulation of herbaceous,
tree leaf and faecal masses, the GENDEC model (GENeral DEComposition) for the simulation of the buried litter decomposition
and microbial dynamics, and the NO emission model (NOFlux) for the simulation of the NO release to the atmosphere.
Physical parameters (soil moisture and temperature, wind speed, sand
percentage) which affect substrate diffusion and oxygen supply in the soil
and influence the microbial activity, and biogeochemical parameters (pH and
fertilization rate related to N content) are necessary to simulate the NO
flux. The reliability of the simulated parameters is checked, in order to
assess the robustness of the simulated NO flux. Simulated yearly average of
NO flux ranges from 2.09 to 3.04 ng(N) m−2 s−1 (0.66 to
0.96 kg(N) ha−1 yr−1), and wet season average ranges
from 3.36 to 5.48 ng(N) m−2 s−1 (1.06 to 1.73 kg(N) ha−1 yr−1). These results are of the
same order as previous measurements made in several sites where the vegetation and the soil are comparable to the ones
in Agoufou. This coupled vegetation–litter decomposition–emission model could be generalized at the scale of the Sahel
region, and provide information where few data are available. |
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