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 - Stiller, M. A1 - Krawczyk, C. M. T1 - Wide angle seismics of Basinï96 Y1 - 1997 ER - TY - JOUR A1 - Domsch, Horst A1 - Ehlert, D. A1 - Lück, Erika A1 - Eisenreich, Manfred T1 - Use of the electrical conductivity to reduce the effort of precision farming Y1 - 2000 ER - TY - JOUR A1 - Krawczyk, C. M. A1 - Lück, Erika A1 - Stiller, M. T1 - The structure of the North German Basin - the DEKORP-Experiment BASIN'96 Y1 - 1997 SN - 90-73834-04-X 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 - 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 - 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 - Herbst, R. A1 - Kapp, Ingo A1 - Krummel, H. A1 - Lück, Erika T1 - Seismic sources for shallow investigatons : a field comparison from Northern Germany Y1 - 1998 ER - 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 - 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 -