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2016
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Scheer, C; Meier, R; Bruggemann, N; Grace, P R; M.Dannenmann, An improved 15N tracer approach to study denitrification and nitrogen turnover in soil incubations Journal Article Rapid Communications in Mass Spectrometry, 30 (18), 2016. Abstract | Links | BibTeX | Tags: Rapid Communications in Mass Spectrometry @article{Scheer2016,
title = {An improved ^{15}N tracer approach to study denitrification and nitrogen turnover in soil incubations},
author = {C. Scheer and R. Meier and N. Bruggemann and P. R. Grace and M.Dannenmann},
doi = {10.1002/rcm.7689},
year = {2016},
date = {2016-08-12},
journal = {Rapid Communications in Mass Spectrometry},
volume = {30},
number = {18},
abstract = {"Rationale
Denitrification (the reduction of oxidized forms of inorganic nitrogen (N) to N_{2}O and N_{2}) from upland soils is considered to be the least well-understood process in the global N cycle. The main reason for this lack of understanding is that the terminal product (N_{2}) of denitrification is extremely difficult to measure against the large atmospheric background.
Methods
We describe a system that combines the ^{15}N-tracer technique with a 40-fold reduced N_{2} (2% v/v) atmosphere in a fully automated incubation setup for direct quantification of N_{2} and N_{2}O emissions. The \emph{δ}^{15}N values of the emitted N_{2} and N_{2}O were determined using a custom-built gas preparation unit that was connected to a DELTA V Plus isotope ratio mass spectrometer. The system was tested on a pasture soil from sub-tropical Australia under different soil moisture conditions and combined with ^{15}N tracing in extractable soil N pools to establish a full N balance.
Results
The method proved to be highly sensitive for detecting N_{2} (1.12 μg N h^{−1} kg^{−1} dry soil (ds)) and N_{2}O (0.36 μg N h^{−1} kg^{−1} ds) emissions. The main end product of denitrification in the investigated soil was N_{2}O for both water contents, with N_{2} accounting for only 3% to 13% of the total denitrification losses. Between 90 and 95% of the added ^{15}N fertiliser could be recovered in N gases and extractable soil N pools.
Conclusions The high and N_{2}O-dominated denitrification rates found in this study are pointing at both the high ecological and the agronomic importance of denitrification in subtropical pasture soils. The new system allows for a direct and highly sensitive detection of N_{2} and N_{2}O fluxes from soils and may help to significantly improve our mechanistic understanding of N cycling and denitrification in terrestrial agro-ecosystems. Copyright © 2016 John Wiley & Sons, Ltd."},
keywords = {Rapid Communications in Mass Spectrometry},
pubstate = {published},
tppubtype = {article}
}
"Rationale
Denitrification (the reduction of oxidized forms of inorganic nitrogen (N) to N2O and N2) from upland soils is considered to be the least well-understood process in the global N cycle. The main reason for this lack of understanding is that the terminal product (N2) of denitrification is extremely difficult to measure against the large atmospheric background.
Methods
We describe a system that combines the 15N-tracer technique with a 40-fold reduced N2 (2% v/v) atmosphere in a fully automated incubation setup for direct quantification of N2 and N2O emissions. The δ15N values of the emitted N2 and N2O were determined using a custom-built gas preparation unit that was connected to a DELTA V Plus isotope ratio mass spectrometer. The system was tested on a pasture soil from sub-tropical Australia under different soil moisture conditions and combined with 15N tracing in extractable soil N pools to establish a full N balance.
Results
The method proved to be highly sensitive for detecting N2 (1.12 μg N h−1 kg−1 dry soil (ds)) and N2O (0.36 μg N h−1 kg−1 ds) emissions. The main end product of denitrification in the investigated soil was N2O for both water contents, with N2 accounting for only 3% to 13% of the total denitrification losses. Between 90 and 95% of the added 15N fertiliser could be recovered in N gases and extractable soil N pools.
Conclusions The high and N2O-dominated denitrification rates found in this study are pointing at both the high ecological and the agronomic importance of denitrification in subtropical pasture soils. The new system allows for a direct and highly sensitive detection of N2 and N2O fluxes from soils and may help to significantly improve our mechanistic understanding of N cycling and denitrification in terrestrial agro-ecosystems. Copyright © 2016 John Wiley & Sons, Ltd." |