TY - JOUR A1 - Walter, Judith A1 - Lück, Erika A1 - Bauriegel, Albrecht A1 - Facklam, Michael A1 - Zeitz, Jutta T1 - Seasonal dynamics of soil salinity in peatlands BT - a geophysical approach JF - Geoderma : an international journal of soil science N2 - Inland salt meadows are particularly valuable ecosystems, because they support a variety of salt-adapted species (halophytes). They can be found throughout Europe; including the peatlands of the glacial lowlands in northeast Germany. These German ecosystems have been seriously damaged through drainage. To assess and ultimately limit the damages, temporal monitoring of soil salinity is essential, which can be conducted by geoelectrical techniques that measure the soil electrical conductivity. However, there is limited knowledge on how to interpret electrical conductivity surveys of peaty salt meadows. In this study, temporal and spatial monitoring of dissolved salts was conducted in saline peatland soils using different geoelectrical techniques at different scales (1D: conductivity probe, 2D: conductivity cross-sections). Cores and soil samples were taken to validate the geoelectrical surveys. Although the influence of peat on bulk conductivity is large, the seasonal dynamics of dissolved salts within the soil profile could be monitored by repeated geoelectrical measurements. A close correlation is observed between conductivity (similar to salinity) at different depths and temperature, precipitation and corresponding groundwater level. The conductivity distribution between top- and subsoil during the growing season reflected the leaching of dissolved salts by precipitation and the capillary rise of dissolved salts by increasing temperature (similar to evaporation). Groundwater levels below 0.38 cm resulted in very low conductivities in the topsoil, which is presumably due to limited soil moisture and thus precipitation of salts. Therefore, to prevent the disappearance of dissolved salts from the rooting zone, which are essential for the halophytes, groundwater levels should be adjusted to maintain depths of between 20 and 35 cm. Lower groundwater levels will lead to the loss of dissolved salts from the rooting zone and higher levels to increasing dilution with fresh rainwater. The easy-to-handle conductivity probe is an appropriate tool for salinity monitoring. Using this probe with regressions adjusted for sandy and organic substrates (peat and organic gyttja) additional influences on bulk conductivity (e.g. cation exchange capacity, water content) can be compensated for and the correlation between salinity and electrical conductivity is high. KW - Peatlands KW - Inland salinization KW - Soil salinity dynamics KW - Electrical conductivity KW - Pore-fluid conductivity Y1 - 2017 U6 - https://doi.org/10.1016/j.geoderma.2017.08.022 SN - 0016-7061 SN - 1872-6259 VL - 310 SP - 1 EP - 11 PB - Elsevier Science CY - Amsterdam ER - TY - JOUR A1 - Walter, J. A1 - Lück, Erika A1 - Heller, C. A1 - Bauriegel, Albrecht A1 - Zeitz, Jutta T1 - Relationship between electrical conductivity and water content of peat and gyttja BT - implications for electrical surveys of drained peatlands JF - Near surface geophysics N2 - The application of electrical resistivity tomography to peatlands supports conventional coring by providing data on the current condition of peatlands, including data on stratigraphy, peat properties and thickness of organic deposits. Data on the current condition of drained peatlands are particularly required to improve estimates of carbon storage as well as losses and emissions from agriculturally used peatlands. However, most of the studies focusing on electrical resistivity tomography surveys have been conducted on natural peatlands with higher groundwater levels. Peatlands drained for agriculture have not often been studied using geophysical techniques. Drained sites are characterized by low groundwater levels and high groundwater fluctuations during the year, which lead to varying levels of water saturation. To validate better electrical resistivity tomography surveys of drained peatlands, the aim of this laboratory study is to investigate the influence of varying water saturation levels on electrical conductivity (reciprocal of resistivity) for a variety of peat and gyttja types, as well as for different degrees of peat decomposition. Results show that different levels of water saturation strongly influence bulk electrical conductivity. Distinct differences in this relationship exist between peat and gyttja substrates and between different degrees of peat decomposition. Peat shows an exponential relationship for all degrees of decomposition, whereas gyttja, in particular organic-rich gyttja, is characterized by a rather unimodal relationship. The slopes for the relationship between electrical conductivity and water content are steeper at high degrees of decomposition than for peat of low degrees of decomposition. These results have direct implications for field electrical resistivity tomography surveys. In drained peatlands that are strongly susceptible to drying, electrical resistivity tomography surveys have a high potential to monitor the actual field water content. In addition, at comparable water saturations, high or low degrees of decomposition can be inferred from electrical conductivity. KW - Electrical conductivity KW - Peat KW - Gyttja Y1 - 2019 U6 - https://doi.org/10.1002/nsg.12030 SN - 1569-4445 SN - 1873-0604 VL - 17 IS - 2 SP - 169 EP - 179 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Walter, J. A1 - Hamann, Göran A1 - Lück, Erika A1 - Klingenfuss, C. A1 - Zeitz, Jutta T1 - Stratigraphy and soil properties of fens: Geophysical case studies from northeastern Germany JF - Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution N2 - The determination of the total carbon storage of peatlands is of high relevance in the context of climate-change mitigation efforts. This determination relies on data about stratigraphy and peat properties, which are conventionally collected by coring. Ground-penetrating radar (GPR) and electrical resistivity imaging (ERI) can support these point data by providing subsoil information in two-dimensional cross-sections. In this study, GPR and ERI were conducted at two groundwater-fed fen sites located in the temperate zone in north-east Germany. The fens of this region are embedded in low conductive glacial sand and are characterised by thick layers of gyttja, which can be either mineral or organic. The two study sites are representative of this region with respect to stratigraphy (total thickness, peat and gyttja types) and ecological conditions (pH-value, trophic condition). The aim of this study is to assess the suitability of GPR and ERI to detect stratigraphy and peat properties under these characteristic site conditions. Results show that GPR clearly detects the interfaces between (i) Carex and brown-moss peat, (ii) brown-moss peat and organic gyttja, (iii) organic- and mineral gyttja, and (iv) mineral gyttja and the parent material (glacial sand). These layers differ in bulk density and the related organic matter content. ERI, however, does not delineate these layers; rather it delineates regions of varying properties. At our base-rich site, pore fluid conductivity and cation.exchange capacity are the main factors that determine peat electrical conductivity (reverse of resistivity), whereas organic matter and water content are most influential at the more acidic site. Thus the correlation between peat properties and electrical conductivity are driven by site-specific conditions, which are mainly determined by the solute load in the groundwater at fens. When the total organic deposits exceed a thickness of 5 m, the depth of investigation by GPR is limited due to increasing attenuation. This is not a limiting factor for ERI, where the transition from organic deposits to glacial sand is visible at both sites. Due to these specific sensitivities, a combined application of GPR and ERI meets the demand for up-to-date information on carbon storage of peatlands, which is, moreover, very site-specific because of the inherent variety of ecological conditions and stratigraphy between peatlands in general and between fens and bogs in particular. (C) 2016 Elsevier B.V. All rights reserved. KW - Fen stratigraphy KW - Peat properties KW - Gyttja KW - Ground penetrating radar KW - Electrical conductivity KW - Electrical resistivity imaging Y1 - 2016 U6 - https://doi.org/10.1016/j.catena.2016.02.028 SN - 0341-8162 SN - 1872-6887 VL - 142 SP - 112 EP - 125 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Tronicke, Jens A1 - Allroggen, Niklas A1 - Biermann, Felix A1 - Fanselow, Florian A1 - Guillemoteau, Julien A1 - Krauskopf, Christof A1 - Lück, Erika T1 - Rapid multiscale analysis of near-surface geophysical anomaly maps BT - application to an archaeogeophysical data set JF - Geophysics N2 - In near- surface geophysics, ground-based mapping surveys are routinely used in a variety of applications including those from archaeology, civil engineering, hydrology, and soil science. The resulting geophysical anomaly maps of, for example, magnetic or electrical parameters are usually interpreted to laterally delineate subsurface structures such as those related to the remains of past human activities, subsurface utilities and other installations, hydrological properties, or different soil types. To ease the interpretation of such data sets, we have developed a multiscale processing, analysis, and visualization strategy. Our approach relies on a discrete redundant wavelet transform (RWT) implemented using cubic-spline filters and the a trous algorithm, which allows to efficiently compute a multiscale decomposition of 2D data using a series of 1D convolutions. The basic idea of the approach is presented using a synthetic test image, whereas our archaeogeophysical case study from northeast Germany demonstrates its potential to analyze and process rather typical geophysical anomaly maps including magnetic and topographic data. Our vertical-gradient magnetic data show amplitude variations over several orders of magnitude, complex anomaly patterns at various spatial scales, and typical noise patterns, whereas our topographic data show a distinct hill structure superimposed by a microtopographic stripe pattern and random noise. Our results demonstrate that the RWT approach is capable to successfully separate these components and that selected wavelet planes can be scaled and combined so that the reconstructed images allow for a detailed, multiscale structural interpretation also using integrated visualizations of magnetic and topographic data. Because our analysis approach is straightforward to implement without laborious parameter testing and tuning, computationally efficient, and easily adaptable to other geophysical data sets, we believe that it can help to rapidly analyze and interpret different geophysical mapping data collected to address a variety of near-surface applications from engineering practice and research. KW - archaeology KW - case history KW - near surface KW - magnetics KW - decomposition Y1 - 2020 U6 - https://doi.org/10.1190/GEO2019-0564.1 SN - 0016-8033 SN - 1942-2156 VL - 85 IS - 4 SP - B109 EP - B118 PB - Society of Exploration Geophysicists CY - Tulsa, Okla. ER - TY - JOUR A1 - Stiller, M. A1 - Lück, Erika A1 - Krawczyk, C. M. T1 - DEKORPïs deep-seismic Transect BASINï96 throught the north german basin : field work and data processing Y1 - 1997 ER - TY - JOUR A1 - Stiller, M. A1 - Krawczyk, C. M. A1 - Lück, Erika T1 - The northern rim of the central european basin system : first results of the offshore-onshore survey BASINï96 Y1 - 1997 ER - TY - JOUR A1 - Lück, Erika A1 - Stiller, M. A1 - Krawczyk, C. M. T1 - Wide angle seismics of Basinï96 Y1 - 1997 ER - TY - JOUR A1 - Lück, Erika A1 - Rühlmann, Jörg A1 - Kirchmann, Holger T1 - Properties of soils from the Swedish long-term fertility experiments VI. Mapping soil electrical conductivity with different geophysical methods JF - Acta agriculturae Scandinavica : Section B, Soil and plant science N2 - Swedish long-term soil fertility experiments were used to investigate the effect of texture and fertilization regime on soil electrical conductivity. In one geophysical approach, fields were mapped to characterize the horizontal variability in apparent electrical conductivity down to 1.5 m soil depth using an electromagnetic induction meter (EM38 device). The data obtained were geo-referenced by dGPS. The other approach consisted of measuring the vertical variability in electrical conductivity along transects using a multi-electrode apparatus for electrical resistivity tomography (GeoTom RES/IP device) down to 2 m depth. Geophysical field work was complemented by soil analyses. The results showed that despite 40 years of different fertilization regimes, treatments had no significant effects on the apparent electrical conductivity. Instead, the comparison of sites revealed high and low conductivity soils, with gradual differences explained by soil texture. A significant, linear relationship found between apparent electrical conductivity and soil clay content explained 80% of the variability measured. In terms of soil depth, both low and high electrical conductivity values were measured. Abrupt changes in electrical conductivity within a field revealed the presence of 'deviating areas'. Higher values corresponded well with layers with a high clay content, while local inclusions of coarse-textured materials caused a high variability in conductivity in some fields. The geophysical methods tested provided useful information on the variability in soil texture at the experimental sites. The use of spatial EC variability as a co-variable in statistical analysis could be a complementary tool in the evaluation of experimental results. KW - Conductivity depth model KW - conductivity map KW - electrical resistivity KW - soil heterogeneity Y1 - 2011 U6 - https://doi.org/10.1080/09064710.2010.502124 SN - 0906-4710 VL - 61 IS - 5 SP - 438 EP - 447 PB - Taylor & Francis Group CY - Oslo ER - TY - JOUR A1 - Lück, Erika A1 - Rühlmann, Jörg T1 - Resistivity mapping with GEOPHILUS ELECTRICUS - Information about lateral and vertical soil heterogeneity JF - Geoderma : an international journal of soil science N2 - GEOPHILUS ELECTRICUS (nickname GEOPHILUS) is a novel system for mapping the complex electrical bulk resistivity of soils. Rolling electrodes simultaneously measure amplitude and phase data at frequencies ranging from 1 mHz to 1 kHz. The sensor's design and technical specifications allow for measuring these parameters at five depths of up to ca. 1.5 m. Data inversion techniques can be employed to determine resistivity models instead of apparent values and to image soil layers and their geometry with depth. When used in combination with a global positioning system (GPS) and a suitable cross-country vehicle, it is possible to map about 100 ha/day (assuming 1 data point is recorded per second and the line spacing is 18 m). The applicability of the GEOPHILUS system has been demonstrated on several sites, where soils show variations in texture, stratification, and thus electrical characteristics. The data quality has been studied by comparison with 'static' electrodes, by repeated measurements, and by comparison with other mobile conductivity mapping devices (VERIS3100 and EM38). The high quality of the conductivity data produced by the GEOPHILUS system is evident and demonstrated by the overall consistency of the individual maps, and in the clear stratification also confirmed by independent data. The GEOPHILUS system measures complex values of electrical resistivity in terms of amplitude and phase. Whereas electrical conductivity data (amplitude) are well established in soil science, the interpretation of phase data is a topic of current research. Whether phase data are able to provide additional information depends on the site-specific settings. Here, we present examples, where phase data provide complementary information on man-made structures such as metal pipes and soil compaction. KW - Proximal soil sensing KW - Electrical conductivity KW - Electrical resistivity KW - Phase angle KW - Mapping KW - Soil stratification Y1 - 2013 U6 - https://doi.org/10.1016/j.geoderma.2012.11.009 SN - 0016-7061 VL - 199 SP - 2 EP - 11 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lück, Erika A1 - Müller, Martin T1 - Special section on the application of geophysics in agriculture : part II ; foreword Y1 - 2009 SN - 1569-4445 ER - TY - JOUR A1 - Lück, Erika A1 - Meyer, M. T1 - Geophysical preparation of an archaeological excavation in the highlands (Mardorf, Hessen) Y1 - 1999 ER - TY - JOUR A1 - Lück, Erika A1 - Herbst, R. T1 - Widerstandskartierung einer Kreisgrabenanlage im Oderbruch bei Quappendorf, Landkreis Märkisch-Oderland Y1 - 1997 ER - TY - JOUR A1 - Lück, Erika A1 - Gebbers, Robin A1 - Ruehlmann, Joerg A1 - Spangenberg, Ulrike T1 - Electrical conductivity mapping for precision farming N2 - Precision farming overcomes the paradigm of uniform field treatment by site-specific data acquisition and treatment to cope with within-field variability. Precision farming heavily relies on spatially dense information about soil and crop status. While it is often difficult and expensive to obtain precise soil information by traditional soil sampling and laboratory analysis some geophysical methods offer means to obtain subsidiary data in an efficient way. In particular, geoelectrical soil mapping has become widely accepted in precision farming. At present it is the most successful geophysical method providing the spatial distribution of relevant agronomic information that enables us to determine management zones for precision farming. Much work has been done to test the applicability of existing geoelectrical methods and to develop measurement systems applicable in the context of precision farming. Therefore, the aim of this paper was to introduce the basic ideas of precision farming, to discuss current precision farming applied geoelectrical methods and instruments and to give an overview about our corresponding activities during recent years. Different experiments were performed both in the laboratory and in the field to estimate first, electrical conductivity affecting factors, second, relationships between direct push and surface measurements, third, the seasonal stability of electrical conductivity patterns and fourth, the relationship between plant yield and electrical conductivity. From the results of these experiments, we concluded that soil texture is a very dominant factor in electrical conductivity mapping. Soil moisture affects both the level and the dynamic range of electrical conductivity readings. Nevertheless, electrical conductivity measurements can be principally performed independent of season. However, electrical conductivity field mapping does not produce reliable maps of spatial particle size distribution of soils, e.g., necessary to generate input parameters for water and nutrient transport models. The missing step to achieve this aim may be to develop multi-sensor systems that allow adjusting the electrical conductivity measurement from the influence of different soil water contents. Y1 - 2009 UR - http://nsg.eage.org/ U6 - https://doi.org/10.3997/1873-0604.2008031 SN - 1569-4445 ER - TY - JOUR A1 - Lück, Erika A1 - Eisenreich, Manfred A1 - Wetzel, G. T1 - Geophysikalische Untersuchungen zur Erkundung der Kreisgrabenanlage bei Dyrotz (Brandenburg) Y1 - 1998 ER - TY - JOUR A1 - Lück, Erika A1 - Eisenreich, Manfred A1 - Wetzel, G. T1 - Magnetische Kartierung einer Kreisgrabenanlage im Oderbruch bei Platkow, Lankreis Märkisch-Oderland Y1 - 1997 ER - TY - JOUR A1 - Lück, Erika A1 - Eisenreich, Manfred A1 - Spangenberg, Ute A1 - Schütte, Marc T1 - Automatisierung der Leckageerkennung an Deponieoberflächenabdichtungen Y1 - 2000 ER - TY - JOUR A1 - Lück, Erika A1 - Eisenreich, Manfred A1 - Spangenberg, Ute A1 - Christl, G. T1 - A note on geophysical prospection of archaeological structures in urban contexts in Potsdam (Germany) Y1 - 1997 ER - TY - JOUR A1 - Lück, Erika A1 - Eisenreich, Manfred A1 - Lochter, F. T1 - Geophysikalische Erkundungen einer neolithischen Doppelkreigrabenanlage im Land Brandenburg Y1 - 1998 ER - TY - JOUR A1 - Lück, Erika A1 - Eisenreich, Manfred A1 - Domsch, Horst A1 - Blumenstein, Oswald T1 - Mapping of soil characteristics using geophysical methods Y1 - 1997 SN - 0943-7266 ER - TY - JOUR A1 - Lück, Erika A1 - Eisenreich, Manfred A1 - Domsch, Horst A1 - Blumenstein, Oswald T1 - Geophysik für Landwirtschaft und Bodenkunde JF - Stoffdynamik in Geosystemen Y1 - 2000 SN - 0949-4731 VL - 4 PB - Selbstverl. der Arbeitsgruppe Stoffdynamik in Geosystemen CY - Potsdam ER -