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| Titel |
Laboratory measurements of nitric oxide release from forest soil with a thick organic layer under different understory types |
| VerfasserIn |
A. Bargsten, E. Falge, K. Pritsch, B. Huwe, F. X. Meixner |
| 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 ; 7, no. 5 ; Nr. 7, no. 5 (2010-05-06), S.1425-1441 |
| Datensatznummer |
250004763
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| Publikation (Nr.) |
 copernicus.org/bg-7-1425-2010.pdf |
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| Zusammenfassung |
| Nitric oxide (NO) plays an important role in the photochemistry of the
troposphere. NO from soil contributes up to 40% to the global budget of
atmospheric NO. Soil NO emissions are primarily caused by biological
activity (nitrification and denitrification), that occurs in the uppermost
centimeter of the soil, a soil region often characterized by high contents
of organic material. Most studies of NO emission potentials to date have
investigated mineral soil layers. In our study we sampled soil organic
matter under different understories (moss, grass, spruce and blueberries) in
a humid mountainous Norway spruce forest plantation in the Fichtelgebirge
(Germany). We performed laboratory incubation and flushing experiments using
a customized chamber technique to determine the response of net potential NO
flux to physical and chemical soil conditions (water content and
temperature, bulk density, particle density, pH, C/N ratio, organic C, soil
ammonium, soil nitrate). Net potential NO fluxes (in terms of mass of N)
from soil samples taken under different understories ranged from
1.7–9.8 ng m−2 s−1 (soil sampled under grass and moss cover),
55.4–59.3 ng m−2 s−1 (soil sampled under spruce cover), and
43.7–114.6 ng m−2 s−1 (soil sampled under blueberry cover) at
optimum water content and a soil temperature of 10 °C. The water content
for optimum net potential NO flux ranged between 0.76 and 0.8 gravimetric
soil moisture for moss covered soils, between 1.0 and 1.1 for grass covered
soils, 1.1 and 1.2 for spruce covered soils, and 1.3 and 1.9 for blueberry
covered soils. Effects of soil physical and chemical characteristics on net
potential NO flux were statistically significant (0.01 probability level)
only for NH4+. Therefore, as an alternative explanation for the
differences in soil biogenic NO emission we consider more biological factors
like understory vegetation type, amount of roots, and degree of
mycorrhization; they have the potential to explain the observed differences
of net potential NO fluxes. |
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