TY  - JOUR
AU  - Scheer, Clemens
AU  - Meier, Rudolf
AU  - Brüggemann, Nicolas
AU  - Grace, Peter R.
AU  - Dannenmann, Michael
TI  - An improved $^{15}$ N tracer approach to study denitrification and nitrogen turnover in soil incubations
JO  - Rapid communications in mass spectrometry
VL  - 30
IS  - 18
SN  - 0951-4198
CY  - New York, NY
PB  - Wiley Interscience
M1  - FZJ-2016-06156
SP  - 2017 - 2026
PY  - 2016
AB  - RationaleDenitrification (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.MethodsWe 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.ResultsThe 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000382976800004
C6  - pmid:27470312
DO  - DOI:10.1002/rcm.7689
UR  - https://juser.fz-juelich.de/record/820892
ER  -