TY  - JOUR
A1  - Kaiser, Michael
A1  - Zederer, Dan P.
A1  - Ellerbrock, Ruth H.
A1  - Sommer, Michael
A1  - Ludwig, Bernard
T1  - Effects of mineral characteristics on content, composition, and stability of organic matter fractions separated from seven forest topsoils of different pedogenesis
JF  - Geoderma : an international journal of soil science
N2  - Mineral topsoils possess large organic carbon (OC) contents but there is only limited knowledge on the mechanisms controlling the preservation of organic matter (OM) against microbial decay. Samples were taken from the uppermost mineral topsoil horizon (0 to 5 cm) of seven sites under mature deciduous forest showing OC contents between 69 and 164 g kg(-1) and a wide range in mineral characteristics. At first, organic particles and the water-extractable OM were removed from the soil samples. Thereafter, Na-pyrophosphate extractable organic matter (OM(PY)), assumed to be indicative for OM bound via cation mediated interactions, and the OM remaining in the extraction residue (OM(ER)), supposed to be indicative for OM occluded in mechanically highly stable micro-aggregates, were sequentially separated and quantified. The composition of OM(PY) and OM(ER) was analyzed by FTIR and their stability by C-14 measurements. The OC remaining in the extraction residues accounted for 38 to 59% of the bulk soil OC (SOC) suggesting a much larger relevance of OM(ER) for the OM dynamic in the analyzed soils as compared with OM(PY) that accounted for 1.6 to 7.5% of the SOC. The FUR analyses revealed a lower relative proportion of C=O groups in OM(ER) compared to OM(PY) indicating differences in the degree of microbial processing between these fractions. Correlation analyses suggest an increase in the stability of OM(PY) with the soil pH and contents of Na-pyrophosphate soluble Fe, Al, and Mg and an increase in the stability of OM(ER) with the soil pH and the contents of clay and oxalate-soluble Fe and Al. Despite the detected influence of soil mineral characteristics on the turnover of OM(PY) and OM(ER), the Delta C-14 signatures indicated mean residence times less than 100 years. The presence of less stabilized OM in these fractions can be derived from methodological uncertainties and/or the fast cycling compartment of mineral-associated OM. (C) 2015 Elsevier B.V. All rights reserved.
KW  - Forest mineral topsoil
KW  - Organic matter stabilization
KW  - Na-pyrophosphate soluble organic matter
KW  - Micro-aggregates
KW  - Infrared spectroscopy
KW  - C-14 analyses
Y1  - 2016
U6  - https://doi.org/10.1016/j.geoderma.2015.08.029
SN  - 0016-7061
SN  - 1872-6259
VL  - 263
SP  - 1
EP  - 7
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Wehrhan, Marc
A1  - Rauneker, Philipp
A1  - Sommer, Michael
T1  - UAV-Based Estimation of Carbon Exports from Heterogeneous Soil Landscapes-A Case Study from the CarboZALF Experimental Area
JF  - SENSORS
N2  - The advantages of remote sensing using Unmanned Aerial Vehicles (UAVs) are a high spatial resolution of images, temporal flexibility and narrow-band spectral data from different wavelengths domains. This enables the detection of spatio-temporal dynamics of environmental variables, like plant-related carbon dynamics in agricultural landscapes. In this paper, we quantify spatial patterns of fresh phytomass and related carbon (C) export using imagery captured by a 12-band multispectral camera mounted on the fixed wing UAV Carolo P360. The study was performed in 2014 at the experimental area CarboZALF-D in NE Germany. From radiometrically corrected and calibrated images of lucerne (Medicago sativa), the performance of four commonly used vegetation indices (VIs) was tested using band combinations of six near-infrared bands. The highest correlation between ground-based measurements of fresh phytomass of lucerne and VIs was obtained for the Enhanced Vegetation Index (EVI) using near-infrared band b(899). The resulting map was transformed into dry phytomass and finally upscaled to total C export by harvest. The observed spatial variability at field- and plot-scale could be attributed to small-scale soil heterogeneity in part.
KW  - VI
KW  - soil landscape
KW  - carbon export
KW  - agriculture
KW  - multispectral
KW  - UAV
Y1  - 2016
U6  - https://doi.org/10.3390/s16020255
SN  - 1424-8220
VL  - 16
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Gerke, Horst H.
A1  - Rieckh, Helene
A1  - Sommer, Michael
T1  - Interactions between crop, water, and dissolved organic and inorganic carbon in a hummocky landscape with erosion-affected pedogenesis
JF  - Macromolecular rapid communications
N2  - Hummocky soil landscapes are characterized by 3D spatial patterns of soil types that result from erosion-affected pedogenesis. Due to tillage and water erosion, truncated profiles have been formed at steep and mid slopes and colluvial soils at hollows, while intact profiles remained at plateau positions. Pedogenetic variations in soil horizons lead to spatial differences in the soil water balance at hillslope positions. Here, possible interactions between erosion affected soil properties, the water balances, and the crop growth and feedback effects of erosion on the leaching rates were assumed. The hypothesis was tested by water balance simulations comparing uniform with hillslope position-specific crop and root growths for soils at plateau, flat mid slope, steep slope, and hollow using the Hydrus-1D program. The boundary condition data were monitored at the CarboZALF-D experimental field site, which was cropped with perennial lucerne (Medicago sativa L.) in 2013 and 2014. Crop and root growth at the four hillslope positions was assumed proportional to observed leaf area index (LAI). Fluxes of dissolved organic and inorganic carbon (DOC, DIC) were obtained from simulated water fluxes and measured DOC and DIC concentrations. For the colluvic soil at hollow, the crop growth was initially highest and later limited by an increasing water table; here the predominately upward flow led to a net input in DIC and DOC. For the truncated soils at steep slopes, simulations support the hypothesis that reduced crop growth caused an increase in percolation and DIC leaching from the subsoil horizons, which in turn led to accelerated soil development and more soil variations along eroding hillslopes in arable soil landscapes. (C) 2015 Elsevier B.V. All rights reserved.
KW  - Hydrus-1D
KW  - LAI
KW  - Eroded soil types
KW  - Hillslope pedosequence
KW  - Soil C leaching
KW  - DOC vs. DIC
KW  - Soil water balance simulation
KW  - Root water uptake
KW  - Rooting depth
Y1  - 2016
U6  - https://doi.org/10.1016/j.still.2015.09.003
SN  - 0167-1987
SN  - 1879-3444
VL  - 156
SP  - 230
EP  - 244
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - GEN
A1  - Sommer, Michael
A1  - Augustin, Jürgen
A1  - Kleber, M.
T1  - Feedbacks of soil erosion on SOC patterns and carbon dynamics in agricultural landscapes-The CarboZALF experiment
T2  - Journal of real-time image processing
Y1  - 2016
U6  - https://doi.org/10.1016/j.still.2015.09.015
SN  - 0167-1987
SN  - 1879-3444
VL  - 156
SP  - 182
EP  - 184
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Doetterl, Sebastian
A1  - Berhe, Asmeret Asefaw
A1  - Nadeu, Elisabet
A1  - Wang, Zhengang
A1  - Sommer, Michael
A1  - Fiener, Peter
T1  - Erosion, deposition and soil carbon: A review of process-level controls, experimental tools and models to address C cycling in dynamic landscapes
JF  - Earth science reviews : the international geological journal bridging the gap between research articles and textbooks
N2  - The role of soil erosion in terrestrial carbon (C) sequestration and release remains one of the most important uncertainties in our attempts to determine the potential of soils to mediate climate change. Despite its widely recognized importance for terrestrial C sequestration, to date, no Earth System Model (ESM) implements soil erosion effects on carbon cycling in sufficient detail. So far, available studies have mostly investigated the magnitude of erosional C transport and in-situ measurements of vertical C fluxes on the catchment or regional scale. Recognizing the need to adequately represent C erosion processes and controls in ESMs, we provide a comprehensive cross-disciplinary review on lateral C redistribution in the landscape and discuss the implications for bio-geochemical cycling of carbon. We present current knowledge on the role of erosional C distribution in controlling the stabilization and release of C in soils, taking into consideration the important geomorphic, ecological, hydrologic, pedologic and micro-climatic processes and controls that affect soil organic carbon (SOC) stock, fluxes, and persistence in dynamic landscapes. Further, we provide an overview on latest experimental and modelling approaches that are being used to investigate the role of erosion in the carbon cycle. Finally, to advance our understanding of the role of soil redistribution in biogeochemical cycles of essential elements, we discuss the most promising topics for future research in this field. (C) 2015 Elsevier B.V. All rights reserved.
KW  - Soil erosion
KW  - Soil deposition
KW  - Carbon redistribution
KW  - Terrestrial C sink
Y1  - 2016
U6  - https://doi.org/10.1016/j.earscirev.2015.12.005
SN  - 0012-8252
SN  - 1872-6828
VL  - 154
SP  - 102
EP  - 122
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Premke, Katrin
A1  - Attermeyer, Katrin
A1  - Augustin, Jürgen
A1  - Cabezas, Alvaro
A1  - Casper, Peter
A1  - Deumlich, Detlef
A1  - Gelbrecht, Jörg
A1  - Gerke, Horst H.
A1  - Gessler, Arthur
A1  - Großart, Hans-Peter
A1  - Hilt, Sabine
A1  - Hupfer, Michael
A1  - Kalettka, Thomas
A1  - Kayler, Zachary
A1  - Lischeid, Gunnar
A1  - Sommer, Michael
A1  - Zak, Dominik
T1  - The importance of landscape diversity for carbon fluxes at the landscape level: small-scale heterogeneity matters
JF  - Wiley Interdisciplinary Reviews : Water
N2  - Landscapes can be viewed as spatially heterogeneous areas encompassing terrestrial and aquatic domains. To date, most landscape carbon (C) fluxes have been estimated by accounting for terrestrial ecosystems, while aquatic ecosystems have been largely neglected. However, a robust assessment of C fluxes on the landscape scale requires the estimation of fluxes within and between both landscape components. Here, we compiled data from the literature on C fluxes across the air–water interface from various landscape components. We simulated C emissions and uptake for five different scenarios which represent a gradient of increasing spatial heterogeneity within a temperate young moraine landscape: (I) a homogeneous landscape with only cropland and large lakes; (II) separation of the terrestrial domain into cropland and forest; (III) further separation into cropland, forest, and grassland; (IV) additional division of the aquatic area into large lakes and peatlands; and (V) further separation of the aquatic area into large lakes, peatlands, running waters, and small water bodies These simulations suggest that C fluxes at the landscape scale might depend on spatial heterogeneity and landscape diversity, among other factors. When we consider spatial heterogeneity and diversity alone, small inland waters appear to play a pivotal and previously underestimated role in landscape greenhouse gas emissions that may be regarded as C hot spots. Approaches focusing on the landscape scale will also enable improved projections of ecosystems’ responses to perturbations, e.g., due to global change and anthropogenic activities, and evaluations of the specific role individual landscape components play in regional C fluxes. WIREs Water 2016, 3:601–617. doi: 10.1002/wat2.1147
Y1  - 2016
U6  - https://doi.org/10.1002/wat2.1147
SN  - 2049-1948
SN  - 2049-1948
VL  - 3
SP  - 601
EP  - 617
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Puppe, Daniel
A1  - Höhn, Axel
A1  - Kaczorek, Danuta
A1  - Wanner, Manfred
A1  - Sommer, Michael
T1  - As time goes by-Spatiotemporal changes of biogenic Si pools in initial soils of an artificial catchment in NE Germany
JF  - Applied soil ecology : a section of agriculture, ecosystems & environment
KW  - Biogenic silica
KW  - Diatom frustule
KW  - Testate amoeba shell
KW  - Sponge spicule
KW  - Initial ecosystem
Y1  - 2016
U6  - https://doi.org/10.1016/j.apsoil.2016.01.020
SN  - 0929-1393
SN  - 1873-0272
VL  - 105
SP  - 9
EP  - 16
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Wanner, Manfred
A1  - Seidl-Lampa, Barbara
A1  - Höhn, Axel
A1  - Puppe, Daniel
A1  - Meisterfeld, Ralf
A1  - Sommer, Michael
T1  - Culture growth of testate amoebae under different silicon concentrations
JF  - European journal of protistology
N2  - Testate amoebae with self-secreted siliceous shell platelets ("idiosomes") play an important role in terrestrial silicon (Si) cycles. In this context, Si-dependent culture growth dynamics of idiosomic testate amoebae are of interest. Clonal cultures of idiosomic testate amoebae were analyzed under three different Si concentrations: low (50 mu mol L-1), moderate/site-specific (150 mu mol L-1) and high Si supply (500 mu mol L-1). Food (Saccharomyces cerevisiae) was provided in surplus. (i) Shell size of four different clones of idiosomic testate amoebae either decreased (Trinema galeata, Euglypha filifera cf.), increased (E. rotunda cf.), or did not change (E. rotunda) under the lowest Si concentration (50 mu mol Si L-1). (ii) Culture growth of idiosomic Euglypha rotunda was dependent on Si concentration. The more Si available in the culture medium, the earlier the entry into exponential growth phase. (iii) Culture growth of idiosomic Euglypha rotunda was dependent on origin of inoculum. Amoebae previously cultured under a moderate Si concentration revealed highest sustainability in consecutive cultures. Amoebae derived from cultures with high Si concentrations showed rapid culture growth which finished early in consecutive cultures. (iv) Si (diluted in the culture medium) was absorbed by amoebae and fixed in the amoeba shells resulting in decreased Si concentrations. (C) 2016 Elsevier GmbH. All rights reserved.
KW  - Amoebal silicon
KW  - Sommer et al. 2006
KW  - Biosilicification
KW  - Consumption
KW  - Culture growth dynamics
KW  - Euglyphida
KW  - Terrestrial Si cycle
Y1  - 2016
U6  - https://doi.org/10.1016/j.ejop.2016.08.008
SN  - 0932-4739
SN  - 1618-0429
VL  - 56
SP  - 171
EP  - 179
PB  - Royal Society of Chemistry
CY  - Jena
ER  - 
TY  - GEN
A1  - Wehrhan, Marc
A1  - Rauneker, Philipp
A1  - Sommer, Michael
T1  - UAV-Based estimation of carbon exports from heterogeneous soil landscapes
BT  - a case study from the CarboZALF experimental area
T2  - Sensors
N2  - The advantages of remote sensing using Unmanned Aerial Vehicles (UAVs) are a high spatial resolution of images, temporal flexibility and narrow-band spectral data from different wavelengths domains. This enables the detection of spatio-temporal dynamics of environmental variables, like plant-related carbon dynamics in agricultural landscapes. In this paper, we quantify spatial patterns of fresh phytomass and related carbon (C) export using imagery captured by a 12-band multispectral camera mounted on the fixed wing UAV Carolo P360. The study was performed in 2014 at the experimental area CarboZALF-D in NE Germany. From radiometrically corrected and calibrated images of lucerne (Medicago sativa), the performance of four commonly used vegetation indices (VIs) was tested using band combinations of six near-infrared bands. The highest correlation between ground-based measurements of fresh phytomass of lucerne and VIs was obtained for the Enhanced Vegetation Index (EVI) using near-infrared band b(899). The resulting map was transformed into dry phytomass and finally upscaled to total C export by harvest. The observed spatial variability at field- and plot-scale could be attributed to small-scale soil heterogeneity in part.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 451 
KW  - VI
KW  - soil landscape
KW  - carbon export
KW  - agriculture
KW  - multispectral
KW  - UAV
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-407706
ER  -