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@ARTICLE{Meyer:820872,
author = {Meyer, Nele and Welp, Gerhard and Bornemann, Ludger and
Amelung, Wulf},
title = {{M}icrobial nitrogen mining affects spatio-temporal
patterns of substrate-induced respiration during seven years
of bare fallow},
journal = {Soil biology $\&$ biochemistry},
volume = {104},
issn = {0038-0717},
address = {Amsterdam [u.a.]},
publisher = {Elsevier Science},
reportid = {FZJ-2016-06136},
pages = {175 - 184},
year = {2017},
abstract = {Decomposition of soil organic matter (SOM) is regulated by
microbial activity, which strongly depends on the
availability of carbon (C) and nitrogen (N). Yet, the
special role of N on soil organic carbon (SOC)
mineralization is still under discussion. The recent concept
of microbial N mining predicts increasing SOC mineralization
under N-deficiency, which is in contrast to the generally
accepted stoichiometric decomposition theory.Following this
concept we hypothesized that spatio-temporal patterns of
microbial activity are controlled by SOC and N contents, but
that microorganisms maintain their functionality to
mineralize C under conditions of N deficiency because of
microbial N mining.To test this hypothesis, we added glucose
to an arable soil that had experienced increasing losses of
C3-derived SOM after one, three, and seven years of bare
fallow and measured spatio-temporal patterns of
substrate-induced respiration (SIR). The SIR measurements
were performed with and without additions of mineral N.
Selected samples were treated with C4 sugar in order to
trace the source of CO2 emissions (sugar vs. SOC-derived) by
natural 13C abundance measurements. Sugar additions were
repeated after the first SIR experiment to derive
information on changing N availability.The results showed
that spatial patterns of SIR were not consistently regulated
by SOC and N. On a temporal scale, the maximum microbial
growth peak declined by $47\%$ from one year bare fallow to
seven years bare fallow but soils often developed a second
growth phase in the 7th year of fallow. Intriguingly, the
maximum microbial growth peak increased again when N was
added together with the glucose and no second growth peak
occurred. A similar effect was observed after repeated sugar
additions but without N additions. The 13C experiment
revealed a slightly higher contribution of SOC-derived CO2
in N-deficient samples $(16.7\%)$ than in N-fertilized
samples $(14.6\%).We$ conclude that the first SIR peak was
related to the supply of immediately available N while the
second growth phase indicated a delayed release of N, due to
N mining from SOM. Hence, microbes were able to compensate
for initial N limitation and there was no significant change
in the overall substrate-induced CO2 release with proceeding
time under fallow.},
cin = {IBG-3},
ddc = {570},
cid = {I:(DE-Juel1)IBG-3-20101118},
pnm = {255 - Terrestrial Systems: From Observation to Prediction
(POF3-255)},
pid = {G:(DE-HGF)POF3-255},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000389555900017},
doi = {10.1016/j.soilbio.2016.10.019},
url = {https://juser.fz-juelich.de/record/820872},
}