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• 1
Article
Language: English
In: Geoderma, May 2013, Vol.199, pp.90-98
Description: Gamma-ray spectrometry is a fast and cost-efficient tool for carrying out spatial mapping of physical parameters related to soil properties. Therefore there is a rising interest in the method for application in digital soil mapping (DSM). However, the concentration of detected radioactive nuclides, gamma K (gK), U and Th, can be influenced by mineralogy and texture as well as further chemical properties, such as pH or organic carbon content (C ). In many existing studies, the main influencing property of measured gamma-ray concentration in soils is the texture. Our investigation focuses on a field site with homogeneous texture at the Static Fertilizer Experiment in Bad Lauchstädt. However, the plot is characterized by high range in C and plant-available potassium (paK) due to specific long-time fertilization. In our study we tested gamma-ray spectrometry as a potential method for mapping C and paK at a test site with very low variation in texture in dependency of pH value. The survey was realised using stop-and-go measurements with a mobile gamma-ray spectrometer. We found a negative correlation between pH value and Th for pH 〈 7. Above this value no correlation can be observed. We have seen no relationship between gK and U/K with C as well as between gK and paK, as found in previous studies. A negative correlation for C and paK content with Th at pH 〈 7 was observed. A pH of 7 was found to be a threshold. Above this pH level we found no correlations. We show that gamma-ray data can be used as indicator for mapping of C in areas with low variations in texture below a pH of 7. In our study gK and U were influenced by soil water content, which is important to be considered for interpretation of data measured at different time steps in humid climates. Our study shows the complexity of relationships between gamma-ray nuclides and soil properties, even for a field site with homogenous texture. In general, we recommend for application of gamma-ray spectrometry in DSM, e.g. at catchment scale, it is necessary to record the pH and the soil water content at the time of measurement. ► Gamma-ray measurements applied on field with homogeneous texture. ► Field site is characterized by high range in C , paK and P. ► Gamma-ray can be used for mapping of C , depending on pH. ► Recording pH and soil moisture during survey for application in DSM is required.
Keywords: Mobile Gamma-Ray Spectrometry ; Static Fertilizer Experiment ; Plant Available Potassium ; Organic Carbon Content ; Agriculture
ISSN: 0016-7061
E-ISSN: 1872-6259
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• 2
Article
Language: English
In: Water Research, 01 March 2018, Vol.130, pp.185-199
Description: Nitrate contamination in ground- and surface water is a persistent problem in countries with intense agriculture. The transition zone between rivers and their riparian aquifers, where river water and groundwater interact, may play an important role in mediating nitrate exports, as it can facilitate intensive denitrification, which permanently removes nitrate from the aquatic system. However, the in-situ factors controlling riparian denitrification are not fully understood, as they are often strongly linked and their effects superimpose each other. In this study, we present the evaluation of hydrochemical and isotopic data from a 2-year sampling period of river water and groundwater in the riparian zone along a 3rd order river in Central Germany. Based on bi- and multivariate statistics (Spearman's rank correlation and partial least squares regression) we can show, that highest rates for oxygen consumption and denitrification in the riparian aquifer occur where the fraction of infiltrated river water and at the same time groundwater temperature, are high. River discharge and depth to groundwater are additional explanatory variables for those reaction rates, but of minor importance. Our data and analyses suggest that at locations in the riparian aquifer, which show significant river water infiltration, heterotrophic microbial reactions in the riparian zone may be fueled by bioavailable organic carbon derived from the river water. We conclude that interactions between rivers and riparian groundwater are likely to be a key control of nitrate removal and should be considered as a measure to mitigate high nitrate exports from agricultural catchments.
Keywords: Riparian Zone ; Nitrate Contamination ; Nitrate Stable Isotopes ; River-Groundwater Interaction ; Denitrification ; Engineering
ISSN: 0043-1354
E-ISSN: 1879-2448
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• 3
Article
Language: English
In: Geoderma, 2013, Vol.199, pp.90-98
Description: Gamma-ray spectrometry is a fast and cost-efficient tool for carrying out spatial mapping of physical parameters related to soil properties. Therefore there is a rising interest in the method for application in digital soil mapping (DSM). However, the concentration of detected radioactive nuclides, gamma K (gK), U and Th, can be influenced by mineralogy and texture as well as further chemical properties, such as pH or organic carbon content (Cₒᵣg). In many existing studies, the main influencing property of measured gamma-ray concentration in soils is the texture. Our investigation focuses on a field site with homogeneous texture at the Static Fertilizer Experiment in Bad Lauchstädt. However, the plot is characterized by high range in Cₒᵣg and plant-available potassium (paK) due to specific long-time fertilization. In our study we tested gamma-ray spectrometry as a potential method for mapping Cₒᵣg and paK at a test site with very low variation in texture in dependency of pH value. The survey was realised using stop-and-go measurements with a mobile gamma-ray spectrometer. We found a negative correlation between pH value and Th for pH〈7. Above this value no correlation can be observed. We have seen no relationship between gK and U/K with Cₒᵣg, as well as between gK and paK, as found in previous studies. A negative correlation for Cₒᵣg and paK content with Th at pH〈7 was observed. A pH of 7 was found to be a threshold. Above this pH level we found no correlations. We show that gamma-ray data can be used as indicator for mapping of Cₒᵣg in areas with low variations in texture below a pH of 7. In our study gK and U were influenced by soil water content, which is important to be considered for interpretation of data measured at different time steps in humid climates. Our study shows the complexity of relationships between gamma-ray nuclides and soil properties, even for a field site with homogenous texture. In general, we recommend for application of gamma-ray spectrometry in DSM, e.g. at catchment scale, it is necessary to record the pH and the soil water content at the time of measurement. ; p. 90-98.
Keywords: Fertilizers ; Soil Ph ; Soil Water Content ; Radionuclides ; Texture ; Watersheds ; Mineralogy ; Gamma Radiation ; Humid Zones ; Carbon ; Potassium ; Soil Surveys ; Spectroscopy
ISSN: 0016-7061
Source: AGRIS (Food and Agriculture Organization of the United Nations)
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• 4
Article
Language: English
In: Environmental Earth Sciences, 2013, Vol.69(5), pp.1719-1732
Description: Geophysical methods are widely applied to soils for resolving different tasks in precision agriculture, pollution evaluation, erosion estimation, etc. Environmental magnetic methods were applied in our study on a collection of soil samples from area near Rosslau (Germany), which was gathered on the basis of a field electromagnetic induction study. Magnetic laboratory analyses include magnetic susceptibility, isothermal remanent magnetization (IRM), anhysteretic remanent magnetization (ARM), thermomagnetic analyses for determination of the kind of magnetic minerals present in soils. The results reveal the presence of statistically significant inverse correlations between magnetic susceptibility, as well as remanent magnetizations ARM and IRM, and conductivity values. This maybe ascribed to influence of topography and water regime on the iron oxide forms in soil and the influence of soil moisture on soil conductivity. Magnetic measurements on soil cores showed close correspondence between soil horizons outlined in 1 m-long cores, and depth changes in mass-specific magnetic susceptibility. Existing relationships between magnetic characteristics, soil reaction pH, and nutrients’ content (total nitrogen, carbon and sulphur) have been explored by cluster analysis and general regression model statistics. The results reveal the presence of significant correlations between nutrients’ content, magnetic susceptibility and the grain size sensitive ratio ARM/χ. These are expressed by numerical equations, representing pedotransfer functions, which predict the content of Nitrogen, Carbon and Sulphur through combination of magnetic parameters and soil pH. The obtained pedotransfer functions for the particular case of Gley soils and Fluvisols studied could be used for application of magnetic methods in agricultural practice as a fast and inexpensive proxy evaluation of the content of these nutrition elements.
Keywords: Soil ; Magnetic susceptibility ; Conductivity ; Environmental magnetism ; Pedotransfer functions
ISSN: 1866-6280
E-ISSN: 1866-6299
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• 5
Article
Language: English
In: Geoderma, May, 2013, Vol.199, p.90(9)
Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.geoderma.2012.10.017 Byline: Claudia Dierke, Ulrike Werban Keywords: Mobile gamma-ray spectrometry; Static Fertilizer Experiment; Plant available potassium; Organic carbon content Abstract: Gamma-ray spectrometry is a fast and cost-efficient tool for carrying out spatial mapping of physical parameters related to soil properties. Therefore there is a rising interest in the method for application in digital soil mapping (DSM). However, the concentration of detected radioactive nuclides, gamma K (gK), U and Th, can be influenced by mineralogy and texture as well as further chemical properties, such as pH or organic carbon content (C.sub.org). In many existing studies, the main influencing property of measured gamma-ray concentration in soils is the texture. Our investigation focuses on a field site with homogeneous texture at the Static Fertilizer Experiment in Bad Lauchstadt. However, the plot is characterized by high range in C.sub.org and plant-available potassium (paK) due to specific long-time fertilization. In our study we tested gamma-ray spectrometry as a potential method for mapping C.sub.org and paK at a test site with very low variation in texture in dependency of pH value. The survey was realised using stop-and-go measurements with a mobile gamma-ray spectrometer. We found a negative correlation between pH value and Th for pH〈7. Above this value no correlation can be observed. We have seen no relationship between gK and U/K with C.sub.org, as well as between gK and paK, as found in previous studies. A negative correlation for C.sub.org and paK content with Th at pH〈7 was observed. A pH of 7 was found to be a threshold. Above this pH level we found no correlations. We show that gamma-ray data can be used as indicator for mapping of C.sub.org in areas with low variations in texture below a pH of 7. In our study gK and U were influenced by soil water content, which is important to be considered for interpretation of data measured at different time steps in humid climates. Our study shows the complexity of relationships between gamma-ray nuclides and soil properties, even for a field site with homogenous texture. In general, we recommend for application of gamma-ray spectrometry in DSM, e.g. at catchment scale, it is necessary to record the pH and the soil water content at the time of measurement. Article History: Received 7 September 2011; Revised 28 September 2012; Accepted 15 October 2012
Keywords: Gamma Rays -- Chemical Properties ; Soil Moisture -- Chemical Properties ; Fertilizers -- Usage ; Fertilizers -- Chemical Properties
ISSN: 0016-7061
Source: Cengage Learning, Inc.
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• 6
Article
Language: English
In: Geomorphology, Nov 1, 2013, Vol.201, p.335(9)
Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.geomorph.2013.07.009 Byline: Jorg Hausmann, Hannes Steinel, Manuel Kreck, Ulrike Werban, Thomas Vienken, Peter Dietrich Abstract: Using geophysical methods for the geomorphological characterization of subsurface features has numerous advantages over traditional exploration methods, because of their noninvasive and rapid nature. In this study, we compared the results of four geophysical methods with each other. We also discuss their possibilities and limitations in a geomorphological investigation. Electrical resistivity tomography (ERT), refraction seismic (RS), ground penetrating radar (GPR), and multichannel analysis of surface waves (MASW) methods were applied at an abandoned meander in northern Saxony to map a predefined structure. By combining these methods, we were able to characterize and delineate subsurface features of the abandoned meander, including a point bar, a channel, and a cutbank. Core samples obtained from sonic drilling were used to validate the findings of both seismic methods. However, we found that electrical resistivity tomography and ground penetrating radar lacked penetration depth and could only be used to resolve shallower subsurface layers. The ERT, GPR, RS, and MASW can be used to gather images of subsurface structures. The MASW in particular provides supplementary information about the channel's internal structure (with respect to lateral and vertical resolution). Besides fluvial-morphological features, we also detected inverse velocity structures within the channel. This allowed us to characterize the abandoned meander using information about its layer distribution and material composition. However, we were only able to characterize and delineate the subsurface features of the abandoned meander by combining all of the aforementioned methods. Article History: Received 24 August 2012; Revised 4 July 2013; Accepted 6 July 2013
Keywords: Geomorphology -- Methods ; Geomorphology -- Chemical Properties ; Geomorphology -- Analysis ; Geomorphology -- Electric Properties ; Ground Penetrating Radar -- Methods ; Ground Penetrating Radar -- Chemical Properties ; Ground Penetrating Radar -- Analysis ; Ground Penetrating Radar -- Electric Properties
ISSN: 0169-555X
Source: Cengage Learning, Inc.
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• 7
Article
Language: English
In: Journal of Applied Geophysics, July, 2012, Vol.82, p.129(8)
Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jappgeo.2012.03.002 Byline: Claudia Schutze, Thomas Vienken, Ulrike Werban, Peter Dietrich, Anthony Finizola, Carsten Leven Keywords: Fault delineation; Direct Push; Seismic refraction; Electrical resistivity tomography; Carbon dioxide; Radon Abstract: This study provides an example of fault structure delineation using both geophysical measurements and soil-gas surveys. Seismic refraction and electrical resistivity tomography investigations were performed in combination with Direct Push (DP) soil gas concentration measurements, with the main objective being the characterization of an assumed permeable fault structure which is covered by sediments that are over 20m thick. Geophysical methods were used to locate a potential fault zone and to provide an insight into the structural features of the covering sediments. Methods for quantifying the soil-gas concentration were applied to evaluate the permeability of the fault zone. The positioning of gas sampling points was based on results of a geophysical survey undertaken beforehand. Gas sampling was performed using DP-technology to obtain concentration profiles for the inert gas Radon-222 and its carrier gas CO.sub.2 along the profile at different depths. Joint interpretation of the spatial distribution of geogenic gases and results from the geophysical survey allowed us to produce a representative model image of the fault structure consisting of two fault branches. Based on this image, it was possible to interpret the observed gas concentration patterns. Article History: Received 11 October 2011; Accepted 6 March 2012
Keywords: Permeability -- Methods
ISSN: 0926-9851
Source: Cengage Learning, Inc.
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• 8
Article
In: Near Surface Geophysics, December 2014, Vol.12(6), pp.731-737
Description: Pseudo‐2D surface wave profiling (MASW) has become a powerful state‐of‐the‐art tool for the characterization of near‐surface features in recent years. The rapid gathering and interpretation of surface wave data, i.e. Rayleigh waves, that this method offers is applicable to many investigations and environments. However, most studies only perform unidirectional active surface wave profiling, i.e. without data evaluation by measuring the same profile in the opposite direction. Uncertainties arising from using the MASW method are connected to the one‐dimensional inversion of a two‐dimensional subsurface. Moreover, the occurence of lateral inhomogeneities and dipping layers distort the flat‐layered 1D assumption used in surface wave inversion. In this study, we present data from two different MASW surveys. For both locations, we reveal shot‐geometrical effects and prove the necessity of bidirectional profiling, especially since these check shots can be implemented with only little extra effort. The results of this investigation show that, in general, more attention should be paid to data evaluation.
Keywords: Applied Geophysics ; Baden ; Baden-Wurttemberg Germany ; Central Europe ; Characterization ; Crust ; Elastic Waves ; Europe ; Geophysical Methods ; Geophysical Profiles ; Geophysical Surveys ; Germany ; Guided Waves ; Lauswiesen Germany ; Multispectral Analysis ; Neckar Germany ; Rayleigh Waves ; Reliability ; Seismic Methods ; Seismic Profiles ; Seismic Waves ; Shallow Depth ; Surface Waves ; Surveys ; Two-Dimensional Models ; Velocity Structure;
ISSN: 1569-4445
E-ISSN: 1873-0604
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• 9
Article
Language: English
In: Journal of Environmental & Engineering Geophysics, 09/2017, Vol.22(3), pp.291-297
Description: In areas with an unknown geology, boreholes are usually placed either at the planned location of buildings and infrastructure or following a semiregular pattern. The number of boreholes is typically limited by installation cost, especially the number of boreholes to be used for geophysical testing, such as those used for downhole, crosshole, or tomographic analyses. An alternative approach to conventional drilling is the use of mobile pushing devices, i.e., direct-push procedures. By placing geophysical tools into the pushing rods, geophysical methods become more flexible and adaptive during drilling, and investigation techniques can be implemented more expeditiously. From a geoengineering perspective, the in-situ tests are relatively efficient because they generate near continuous data and are considerably more accurate in comparison to laboratory consolidation tests. In this paper we present a combination of a direct-push system with seismic crosshole measurements as a cost effective alternative to standard investigation techniques. The new methodology was successfully tested at the site for Technical Safety (TTS) in Horstwalde, Germany. A complete crosshole dataset of P-, SV- and SH-waves was acquired between previously installed PVC cased boreholes and the direct-push borehole. Furthermore, the in-situ profiles of paired shear wave velocity profiles (SH and SV) were used to evaluate the stress history of the soils.
Keywords: Engineering Geology ; Applied Geophysics ; Body Waves ; Boreholes ; Brandenburg Germany ; Buildings ; Central Europe ; Clastic Sediments ; Cone Penetration Tests ; Crosshole Methods ; Dynamic Loading ; Dynamic Properties ; Elastic Waves ; Europe ; Field Studies ; Foundations ; Geophysical Methods ; Geophysical Profiles ; Geophysical Surveys ; Germany ; Horstwalde Germany ; Loading ; Monitoring ; Penetration Tests ; Piles ; Risk Assessment ; S-Waves ; Sand ; Sediments ; Seismic Methods ; Seismic Profiles ; Seismic Waves ; Sh-Waves ; Soil Mechanics ; Stress ; Structures ; Surveys ; Sv-Waves;
ISSN: 1083-1363
E-ISSN: 1943-2658
Source: CrossRef
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• 10
Article
Language: English
In: Environmental Earth Sciences, 2016, Vol.75(11), pp.1-21
Description: Color data are a useful proxy for soil/sediment parameterization since they reflect material characteristics. We introduce direct push color logging for real-time and depth-resolved, in situ colorimetric record of colors in unconsolidated sediments in terrestrial environments. Until now, no routines exist on how to handle highly resolved (mm-scale) data. To develop such routine, we transform colorimetric data (CIE XYZ ) into color surrogates of selected color spaces (CIE xyZ , $${\text{CIE}}L^{*} a^{*} b^{*}$$ CIE L ∗ a ∗ b ∗ , $${\text{CIE}}L^{*} c^{*} h^{*}$$ CIE L ∗ c ∗ h ∗ , sRGB ). We obtain interpretable color logs over depth by filtering with Haar and Daublet4 wavelet functions. We verify the approach, according to repeatability of in situ sediment color measurements, with related lithological determination gathered by state-of-the-art direct push-based cone penetration testing and soil sampling data. The developed routine is appropriate for unambiguous transformation of color data into interpretable color surrogates and filtering small-scale variability. We observe that soil color logs are repeatable and proved to correlate with lithological/chemical changes. Thus, the technique allows enhanced profiling by means of providing a reproducible high-resolution parameter for analysis of soil/sediment characteristics. This opens potential new areas of application and new outputs for in situ-obtained colorimetric data in and beyond geotechnical site characterization.
Keywords: Color logging tool ; In situ ; Soil color ; Direct push ; Colorimeter
ISSN: 1866-6280
E-ISSN: 1866-6299
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