55531
2017
2017
eng
109
118
10
1
10
article
Copernicus
Göttingen
1
2017-01-06
2017-01-06
--
A simple calculation algorithm to separate high-resolution CH4 flux measurements into ebullition- and diffusion-derived components
Processes driving the production, transformation and transport of methane (CH4 / in wetland ecosystems are highly complex. We present a simple calculation algorithm to separate open-water CH4 fluxes measured with automatic chambers into diffusion-and ebullition-derived components. This helps to reveal underlying dynamics, to identify potential environmental drivers and, thus, to calculate reliable CH4 emission estimates. The flux separation is based on identification of ebullition-related sudden concentration changes during single measurements. Therefore, a variable ebullition filter is applied, using the lower and upper quartile and the interquartile range (IQR). Automation of data processing is achieved by using an established R script, adjusted for the purpose of CH4 flux calculation. The algorithm was validated by performing a laboratory experiment and tested using flux measurement data (July to September 2013) from a former fen grassland site, which converted into a shallow lake as a result of rewetting. Ebullition and diffusion contributed equally (46 and 55 %) to total CH4 emissions, which is comparable to ratios given in the literature. Moreover, the separation algorithm revealed a concealed shift in the diurnal trend of diffusive fluxes throughout the measurement period. The water temperature gradient was identified as one of the major drivers of diffusive CH4 emissions, whereas no significant driver was found in the case of erratic CH4 ebullition events.
Atmospheric measurement techniques : an interactive open access journal of the European Geosciences Union
10.5194/amt-10-109-2017
1867-1381
1867-8548
wos:2017
WOS:000391281800002
Hoffmann, M (reprint author), Leibniz Ctr Agr Landscape Res ZALF eV, Inst Soil Landscape Res, Eberswalder Str 84, D-15374 Muncheberg, Germany., mathias.hoffmann@zalf.de
2022-07-08T12:06:01+00:00
sword
importub
filename=package.tar
9b328647b24bfed1463cf31e69731615
false
true
Mathias Hoffmann
Maximilian Schulz-Hanke
Juana Garcia Alba
Nicole Jurisch
Ulrike Hagemann
Torsten Sachs
Michael Sommer
Jürgen Augustin
Geowissenschaften
Institut für Geowissenschaften
Referiert
Import
54312
2017
2017
eng
255
266
12
175
article
Elsevier
Amsterdam
1
2017-10-03
2017-10-03
--
Maize carbon dynamics are driven by soil erosion state and plant phenology rather than nitrogen fertilization form
Carbon (C) stored in soils represents the largest C pool of terrestrial ecosystems and consequently plays a crucial role in the global C cycle. So far, it is widely unclear to what extent different land uses and land use change influence soil C storage. The hummocky ground moraine landscape of northeastern Germany is characterized by distinct small-scale soil heterogeneity on the one hand, and intensive energy crop cultivation on the other. Both factors are assumed to significantly influence gaseous C exchange; as such, they likely drive soil organic carbon (SOC) stock dynamics in terrestrial agricultural ecosystems. To date, it is not clear to what extent N fertilization forms, which are associated with energy crop cultivation (e.g., application of biogas fermentation residues) and soil type relative to soil erosion state, influence soil C dynamics, nor is it clear whether one of these factors is more important than the other. To investigate the influence of soil erosion state and N fertilization form on soil C dynamics, we present dynamic and seasonal net ecosystem carbon balances (NECB) as a proxy for changes in soil organic carbon stocks. Measurements were conducted for maize (Zea mays L.) at five sites in the "CarboZALF-D" experimental field during the 2011 growing season. Measurement sites represent different soil erosion states (non-eroded Albic Luvisols, extremely eroded Calcaric Regosols and depositional Endogleyic Colluvic Regosols) and N fertilization forms (100% mineral fertilizer, 50% mineral and 50% organic fertilizer, and 100% organic fertilizer). Fertilization treatments were established on the Albic Luvisol. Net ecosystem CO2 exchange (NEE) and ecosystem respiration (R-eco) were measured every four weeks using a dynamic flow-through non-steady-state closed manual chamber system. Gap filling was performed based on empirical temperature and PAR dependency functions and was used to derive daily NEE values. In parallel, daily above-ground biomass production (NPFshoot) was estimated using a logistic growth equation, fitted on periodic biomass samples. Finally, C dynamics were calculated as the balance of daily NEE and NPPshoot based on the initial C input due to organic fertilization. Resulting NECB varied from pronounced soil C losses at the Endogleyic Colluvic Regosol (592 g C m(-2)) to soil C gains at the Calcaric Regosol (-124 g C m(-2)). Minor to modest C losses were observed for the Albic Luvisol. Compared to N fertilization forms, soil erosion states generally had a stronger impact on derived NECB. However, interannual variations in plant phonology and interactions between soil erosion states and fertilization forms might result in different NECB values over multiple years. Hence, long-term measurements of different fertilization treatments on characteristic soil landscape elements are needed.
Soil & tillage research : an international journal on research and development in soil tillage and field traffic, and their relationships with soil environment, land use and crop production
10.1016/j.still.2017.09.004
0167-1987
1879-3444
wos:2018
WOS:000414816800026
Hoffmann, M; Pohl, M (reprint author), Leibniz Ctr Agr Landscape Res ZALF, Eberswalder Str 84, D-15374 Muncheberg, Germany., mathias.hoffmann@zalf.de; madlen.pohl@zalf.de
Brandenburg Ministry of Infrastructure and Agriculture (MIL); Federal Agency for Renewable Resources (FNR) [22021008 (08NR210)]; interdisciplinary research project "CarboZALF"
2022-03-14T12:18:26+00:00
sword
importub
filename=package.tar
12aa2a0bb84035deea86c46a4be54397
Hoffmann, Matthias
Pohl, Madlen
false
true
Matthias Hoffmann
Madlen Pohl
N. Jurisch
Anne-Katrin Prescher
E. Mendez Campa
Ulrike Hagemann
R. Remus
G. Verch
Michael Sommer
J. Augustin
eng
uncontrolled
Soil erosion
eng
uncontrolled
Net ecosystem carbon balance (NECB)
eng
uncontrolled
Closed chamber measurements
eng
uncontrolled
Biogas fermentation residues
eng
uncontrolled
Plant phenology
Geowissenschaften
Institut für Geowissenschaften
Import
40818
2015
2019
eng
16
496
postprint
1
2019-01-17
2019-01-17
--
Dynamic C and N stocks
The drainage and cultivation of fen peatlands create complex small-scale mosaics of soils with extremely variable soil organic carbon (SOC) stocks and groundwater levels (GWLs). To date, the significance of such sites as sources or sinks for greenhouse gases such as CO2 and CH4 is still unclear, especially if the sites are used for cropland. As individual control factors such as GWL fail to account for this complexity, holistic approaches combining gas fluxes with the underlying processes are required to understand the carbon (C) gas exchange of drained fens. It can be assumed that the stocks of SOC and N located above the variable GWL - defined as dynamic C and N stocks - play a key role in the regulation of the plant- and microbially mediated CO2 fluxes in these soils and, inversely, for CH4. To test this assumption, the present study analysed the C gas exchange (gross primary production - GPP; ecosystem respiration - R-eco; net ecosystem exchange - NEE; CH4) of maize using manual chambers for 4 years. The study sites were located near Paulinenaue, Germany, where we selected three soil types representing the full gradient of GWL and SOC stocks (0-1 m) of the landscape: (a) Haplic Arenosol (AR; 8 kg C m(-2)); (b) Mollic Gleysol (GL; 38 kg C m(-2)); and (c) Hemic Histosol (HS; 87 kg C m(-2)). Daily GWL data were used to calculate dynamic SOC (SOCdyn) and N (N-dyn) stocks.
Average annual NEE differed considerably among sites, ranging from 47 +/- 30 g C m(-2) yr(-1) in AR to -305 +/- 123 g C m(-2) yr(-1) in GL and -127 +/- 212 g C m(-2) yr(-1) in HS. While static SOC and N stocks showed no significant effect on C fluxes, SOCdyn and N-dyn and their interaction with GWL strongly influenced the C gas exchange, particularly NEE and the GPP : R-eco ratio. Moreover, based on nonlinear regression analysis, 86% of NEE variability was explained by GWL and SOCdyn. The observed high relevance of dynamic SOC and N stocks in the aerobic zone for plant and soil gas exchange likely originates from the effects of GWL-dependent N availability on C formation and transformation processes in the plant-soil system, which promote CO2 input via GPP more than CO2 emission via R-eco.
The process-oriented approach of dynamic C and N stocks is a promising, potentially generalisable method for system-oriented investigations of the C gas exchange of groundwater-influenced soils and could be expanded to other nutrients and soil characteristics. However, in order to assess the climate impact of arable sites on drained peatlands, it is always necessary to consider the entire range of groundwater-influenced mineral and organic soils and their respective areal extent within the soil landscape.
Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
key factors controlling the C gas exchange of maize in heterogenous peatland
urn:nbn:de:kobv:517-opus4-408184
1866-8372
online registration
Biogeosciences 12 (2015), pp. 2737-2752 DOI: 10.5194/bg-12-2737-2015
<a href="http://publishup.uni-potsdam.de/opus4-ubp/frontdoor/index/index/docId/39337">Bibliographieeintrag der Originalveröffentlichung/Quelle</a>
CC-BY - Namensnennung 4.0 International
Madlen Pohl
M. Hoffmann
Ulrike Hagemann
M. Giebels
E. Albiac Borraz
Michael Sommer
Jürgen Augustin
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
496
eng
uncontrolled
soil organic-matter
eng
uncontrolled
Zea-mays L.
eng
uncontrolled
term management impacts
eng
uncontrolled
carbon-dioxide exchange
eng
uncontrolled
net ecosystem exchange
eng
uncontrolled
nitrogen-fertilization
eng
uncontrolled
water-table
eng
uncontrolled
northeast germany
eng
uncontrolled
CO2 fluxes
eng
uncontrolled
mineral fertilization
Geowissenschaften
Biowissenschaften; Biologie
open_access
Mathematisch-Naturwissenschaftliche Fakultät
Referiert
Open Access
Copernicus
Universität Potsdam
https://publishup.uni-potsdam.de/files/40818/pmnr496.pdf
41665
2017
2017
eng
109
118
10
604
postprint
1
2019-02-14
2019-02-14
--
A simple calculation algorithm to separate high-resolution CH4 flux measurements into ebullition- and diffusion-derived components
Processes driving the production, transformation and transport of methane (CH4) in wetland ecosystems are highly complex. We present a simple calculation algorithm to separate open-water CH4 fluxes measured with automatic chambers into diffusion- and ebullition-derived components. This helps to reveal underlying dynamics, to identify potential environmental drivers and, thus, to calculate reliable CH4 emission estimates. The flux separation is based on identification of ebullition-related sudden concentration changes during single measurements. Therefore, a variable ebullition filter is applied, using the lower and upper quartile and the interquartile range (IQR). Automation of data processing is achieved by using an established R script, adjusted for the purpose of CH4 flux calculation. The algorithm was validated by performing a laboratory experiment and tested using flux measurement data (July to September 2013) from a former fen grassland site, which converted into a shallow lake as a result of rewetting. Ebullition and diffusion contributed equally (46 and 55 %) to total CH4 emissions, which is comparable to ratios given in the literature. Moreover, the separation algorithm revealed a concealed shift in the diurnal trend of diffusive fluxes throughout the measurement period. The water temperature gradient was identified as one of the major drivers of diffusive CH4 emissions, whereas no significant driver was found in the case of erratic CH4 ebullition events.
Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
10.25932/publishup-41665
urn:nbn:de:kobv:517-opus4-416659
1866-8372
online registration
Atmospheric Measurement Techniques 10 (2017) 1, pp. 109–118 DOI 10.5194/amt-10-109-2017
<a href="http://publishup.uni-potsdam.de/55531">Bibliographieeintrag der Originalveröffentlichung/Quelle</a>
CC-BY - Namensnennung 4.0 International
Mathias Hoffmann
Maximilian Schulz-Hanke
Juana Garcia Alba
Nicole Jurisch
Ulrike Hagemann
Torsten Sachs
Michael Sommer
Jürgen Augustin
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
604
eng
uncontrolled
water methane emissions
eng
uncontrolled
chamber system
eng
uncontrolled
CO2
eng
uncontrolled
lake
eng
uncontrolled
fen
eng
uncontrolled
exchange
eng
uncontrolled
mechanism
eng
uncontrolled
turbulence
eng
uncontrolled
transport
eng
uncontrolled
reservior
Geowissenschaften
open_access
Mathematisch-Naturwissenschaftliche Fakultät
Referiert
Open Access
Universität Potsdam
https://publishup.uni-potsdam.de/files/41665/pmnr604.pdf