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  • Ellerbrock, Ruth H.  (8)
  • Gerke, Horst H.  (8)
  • 1
    Online Resource
    Online Resource
    Interpretation of infrared spectra for OM characterization of soil structural surfaces of Bt‐horizons
    Wiley ; 2016
    In:  Journal of Plant Nutrition and Soil Science Vol. 179, No. 1 ( 2016-02), p. 29-38
    Details
    In: Journal of Plant Nutrition and Soil Science, Wiley, Vol. 179, No. 1 ( 2016-02), p. 29-38
    Abstract: The surfaces of macropores or aggregates can act as hot spots for biogeochemical processes and solute transport during preferential flow. For the characterization of organic matter (OM) at macropore surfaces non‐destructive methods have been applied such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). However, effects of organic components on DRIFT signal intensities are often difficult to distinguish from those of mineral components. Here, DRIFT spectra from intact earthworm burrow walls and coated cracks were re‐evaluated to improve the interpretation of C–H and C=O bands. We compared DRIFT and transmission Fourier transform infrared (FTIR) spectra of entire samples that were from the same pedogenetic soil horizon (Bt) but different in mineral composition and texture ( i.e. , glacial till vs. loess). Spectra of incinerated samples were subtracted from the original spectra. Transmission FTIR and DRIFT spectra were almost identical for entire soil samples. However, the DRIFT spectra were affected by the bulk mode bands ( i.e. , wavenumbers 2000 to 1700 cm −1 ). These bands affected spectral resolution and reproducibility. The ratios between C–H and C=O band intensities as indicator for OM quality obtained with DRIFT were smaller than those obtained from transmission FTIR. The results demonstrated that DRIFT and transmission FTIR data required separate interpretations. DRIFT spectroscopy as a non‐destructive method for analyzing OM composition at intact surfaces in structured soils could be calibrated with information obtained with the more detailed transmission FTIR and complementary methods. Spectral subtraction procedure was found useful to reduce effects of mineral absorption bands. The improved DRIFT data may be related to other soil properties ( e.g. , cation exchange capacity) of hot spots in structured soils.
    Type of Medium: Online Resource
    ISSN: 1436-8730 , 1522-2624
    URL: Issue
    URL: Article
    DOI: 10.1002/jpln.v179.1
    DOI: 10.1002/jpln.201400619
    RVK:
    RA 5430
    Language: English
    Publisher: Wiley
    Publication Date: 2016
    detail.hit.zdb_id: 1481142-X
    detail.hit.zdb_id: 1470765-2
    detail.hit.zdb_id: 200063-5
    SSG: 12
    SSG: 13
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  • 2
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    Correcting Microtopography Effects on DRIFT Mapping Signals of Organic Matter at Intact Soil Aggregate Surfaces
    Wiley ; 2011
    In:  Soil Science Society of America Journal Vol. 75, No. 5 ( 2011-09), p. 1626-1639
    Details
    In: Soil Science Society of America Journal, Wiley, Vol. 75, No. 5 ( 2011-09), p. 1626-1639
    Type of Medium: Online Resource
    ISSN: 0361-5995
    URL: Article
    DOI: 10.2136/sssaj2010.0462
    RVK:
    RA 4845
    Language: English
    Publisher: Wiley
    Publication Date: 2011
    detail.hit.zdb_id: 241415-6
    detail.hit.zdb_id: 2239747-4
    detail.hit.zdb_id: 196788-5
    detail.hit.zdb_id: 1481691-X
    SSG: 13
    SSG: 21
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  • 3
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    Droplet infiltration dynamics and soil wettability related to soil organic matter of soil aggregate coatings and interiors
    Walter de Gruyter GmbH ; 2016
    In:  Journal of Hydrology and Hydromechanics Vol. 64, No. 2 ( 2016-6-1), p. 111-120
    Details
    In: Journal of Hydrology and Hydromechanics, Walter de Gruyter GmbH, Vol. 64, No. 2 ( 2016-6-1), p. 111-120
    Abstract: The organo-mineral coatings of soil aggregates, cracks, and biopores control sorption and macropore-matrix exchange during preferential flow, in particular in the clay-illuvial Bt-horizon of Luvisols. The soil organic matter (SOM) composition has been hypothesized to explain temporal changes in the hydraulic properties of aggregate surfaces. The objective of this research was to find relations between the temporal change in wettability, in terms of droplet infiltration dynamics, and the SOM composition of coated and uncoated aggregate surfaces. We used 20 to 40 mm sized soil aggregates from the Bt2 horizon of a Haplic Luvisol from loess that were (i) coated, (ii) not coated (both intact), and (iii) aggregates from which coatings were removed (cut). The SOM composition of the aggregate surfaces was characterized by infrared spectroscopy in the diffuse reflection mode (DRIFT). A potential wettability index (PWI) was calculated from the ratio of hydrophobic and hydrophilic functional groups in SOM. The water drop penetration times (WDPT) and contact angles (CA) during droplet infiltration experiments were determined on dry and moist aggregate samples of the three types. The decrease in the CA with time was described using the power function (CA( t ) = at −b ). For dry aggregates, the WDPT values were larger for coated as compared to uncoated regions on the aggregate surfaces, and increased with increasing PWI value ( R 2 = 0.75). The a parameter was significantly related to the WDPT ( R 2 = 0.84) and to the PWI ( R 2 = 0.64). The relations between the b parameter and the WDPT ( R 2 = 0.61) and the PWI ( R 2 = 0.53) were also significant. The WDPT values of wet soil aggregates were higher than those of dry aggregates due to high water contents, which limited the droplet infiltration potential. At the wet aggregate surfaces, the WDPT values increased with the PWI of the SOM ( R 2 = 0.64). In contrast to dry samples, no significant relationships were found between parameters a or b of CA( t ) and WDPT or PWI for wet aggregate surfaces. The results suggest that the effect of the SOM composition of coatings on surface wettability decreases with increasing soil moisture. In addition to the dominant impact of SOM, the wettability of aggregate surfaces could be affected by different mineralogical compositions of clay in coatings and interiors of aggregates. Particularly, wettability of coatings could be decreased by illite which was the dominant clay type in coatings. However, the influence of different clay mineral fractions on surface wettability was not due to small number of measurements (2 and 1 samples from coatings and interiors, respectively) quantified.
    Type of Medium: Online Resource
    ISSN: 0042-790X
    URL: Article
    DOI: 10.1515/johh-2016-0021
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2016
    detail.hit.zdb_id: 2503779-1
    SSG: 14
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  • 4
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    Analyzing organic matter composition at intact biopore and crack surfaces by combining DRIFT spectroscopy and Pyrolysis‐Field Ionization Mass Spectrometry #
    Wiley ; 2016
    In:  Journal of Plant Nutrition and Soil Science Vol. 179, No. 1 ( 2016-02), p. 5-17
    Details
    In: Journal of Plant Nutrition and Soil Science, Wiley, Vol. 179, No. 1 ( 2016-02), p. 5-17
    Abstract: In the clay‐illuvial horizons (Bt) of Luvisols, surfaces of biopores and aggregates can be enriched in clay and organic matter (OM), relative to the bulk of the soil matrix. The OM composition of these coatings determines their bio‐physico‐chemical properties and is relevant for transport and transformation processes but is largely unknown at the molecular scale. The objective of this study was to improve the interpretation of spectra from Fourier transform infrared spectroscopy in diffuse reflectance mode (DRIFT) by using thermograms and released ion intensities obtained with pyrolysis‐field ionization mass spectrometry (Py‐FIMS) for a more detailed analysis of the mm‐scale spatial distribution of OM components at intact structural surfaces. Samples were separated from earthworm burrow walls, crack coatings, uncoated cracks, root channels, and pinhole fillings of the Bt‐horizons of Luvisols. The information from Py‐FI mass spectra enabled the assignment of OM functional groups also from spectral regions of overlapping DRIFT signal intensities to specific OM compound classes. In particular, bands from C=O and C=C bonds in the infrared range of wave numbers between 1,641 and 1,605 cm −1 were related to heterocyclic N‐compounds, benzonitrile, and naphthalene. The OM at earthworm burrow walls was composed of chemically labile aliphatic C‐rich and rather stable lignin and alkylaromatic compounds whereas the OM of thick crack coatings and pinholes was dominated by heterocyclic N and nitriles and high‐molecular compounds, likely originating from combustion residues. In combination with Py‐FIMS, DRIFT applications to intact samples seem promising for generating a more detailed mm‐scale spatial distribution of OM‐related sorption and wettability properties of crack and biopore surfaces that may serve as preferential flow paths in structured soils.
    Type of Medium: Online Resource
    ISSN: 1436-8730 , 1522-2624
    URL: Issue
    URL: Article
    DOI: 10.1002/jpln.v179.1
    DOI: 10.1002/jpln.201400620
    RVK:
    RA 5430
    Language: English
    Publisher: Wiley
    Publication Date: 2016
    detail.hit.zdb_id: 1481142-X
    detail.hit.zdb_id: 1470765-2
    detail.hit.zdb_id: 200063-5
    SSG: 12
    SSG: 13
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  • 5
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    Effect of vegetation and its succession on water repellency in sandy soils
    Wiley ; 2018
    In:  Ecohydrology Vol. 11, No. 6 ( 2018-09)
    Details
    In: Ecohydrology, Wiley, Vol. 11, No. 6 ( 2018-09)
    Abstract: Vegetation and its succession can change the parameters of soil water repellency (SWR) due to the change in amount and composition of soil organic matter. This hypothesis was tested in natural and agricultural environments in Germany, Hungary, and Slovakia. The parameters investigated were the extent (determined by the repellency indices RI , RI c , and RI m ) and persistence (determined by the water drop penetration time and water repellency cessation time) of SWR, as well as the potential wettability index of organic matter in sandy soils. The SWR parameters and soil organic carbon (SOC) content increased in the course of primary succession at Mehlinger Heide, Germany, and Sekule, Slovakia. Dye tracer experiments undertaken at Sekule revealed contrasting flow patterns: (a) preferential flow in water‐repellent soil under biological soil crust and grass and (b) piston flow in wettable soil that consists almost of pure quartz sand. The effective flow cross section decreased, and the degree of preferential flow increased in the course of primary succession at Sekule. No consistent trend of the SWR parameters and SOC was observed in the course of secondary succession at Csólyospálos, Hungary. This is the first time that differences between trends in SWR parameters due to primary and secondary successions were observed and related to the composition of SOC and extracellular polymeric substances. It can be concluded that dynamics of soil organic matter composition during the succession controls SWR.
    Type of Medium: Online Resource
    ISSN: 1936-0584 , 1936-0592
    URL: Issue
    URL: Article
    DOI: 10.1002/eco.v11.6
    DOI: 10.1002/eco.1991
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 2418105-5
    SSG: 12
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  • 6
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    DRIFT Mapping of Organic Matter Composition at Intact Soil Aggregate Surfaces
    Wiley ; 2010
    In:  Vadose Zone Journal Vol. 9, No. 2 ( 2010-05), p. 317-324
    Details
    In: Vadose Zone Journal, Wiley, Vol. 9, No. 2 ( 2010-05), p. 317-324
    Abstract: In structured soils, interaction of percolating water and reactive solutes with the soil matrix is often restricted to the outer surfaces of the preferential flow paths. Such surfaces of soil aggregates and biopores are mostly covered by organic matter (OM) that finally controls wettability, sorption, and transfer properties of the flow pathways. However, the local OM properties along such surfaces are largely unknown to date because the coatings are relatively thin and vulnerable. The objective of this study was to determine and compare the local two‐dimensional distribution of soil OM composition at intact aggregate surfaces that serve as preferential flow paths. The Fourier transformed infrared spectroscopy in diffuse reflectance mode (diffuse reflectance infrared Fourier transform, DRIFT) was applied to determine transects and grids of OM functional group data (i.e., CH/CO ratios) on undisturbed and intact surfaces of soil aggregate samples using a DRIFT mapping procedure in 1‐mm steps. The aggregate sample surfaces could be distinguished by DRIFT mapping in areas from earthworm burrows, root channels, and aggregate coatings. The water drop infiltration time of these structural surfaces appeared to correspond with CH/CO ratios for uncoated crack surfaces but less so for earthworm burrows. The results show that coatings at preferential flow‐path surfaces differed locally in terms of OM composition, distribution, and possibly also in wettability, indicating yet unknown implications for preferential movement of water and reactive solutes.
    Type of Medium: Online Resource
    ISSN: 1539-1663 , 1539-1663
    URL: Article
    DOI: 10.2136/vzj2009.0101
    Language: English
    Publisher: Wiley
    Publication Date: 2010
    detail.hit.zdb_id: 2088189-7
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  • 7
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    Online Resource
    Macropore–matrix mass transfer of reactive solutes quantified by fluorescence imaging
    Wiley ; 2020
    In:  Vadose Zone Journal Vol. 19, No. 1 ( 2020-01)
    Details
    In: Vadose Zone Journal, Wiley, Vol. 19, No. 1 ( 2020-01)
    Abstract: A wetting experiment with a reactive and fluorescent dye was performed. Dye concentrations were mapped at intact soil structural surfaces. Millimeter‐scaled Na‐fluorescein mass distribution maps were derived. The method was validated by comparing applied and recovered dye masses.
    Type of Medium: Online Resource
    ISSN: 1539-1663 , 1539-1663
    URL: Issue
    URL: Article
    DOI: 10.1002/vzj2.v19.1
    DOI: 10.1002/vzj2.20078
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2088189-7
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  • 8
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    Spatial Distribution of Organic Matter Compounds at Intact Macropore Surfaces Predicted by DRIFT Spectroscopy
    Wiley ; 2017
    In:  Vadose Zone Journal Vol. 16, No. 9 ( 2017-09), p. 1-11
    Details
    In: Vadose Zone Journal, Wiley, Vol. 16, No. 9 ( 2017-09), p. 1-11
    Abstract: Clay coatings in Bt horizons are enriched in heterocyclic organic matter compounds. The enrichment results from preferential transport in the soil macropore network. These compounds probably originate from long‐term humification and biomass combustion. Py‐FIMS and DRIFT spectroscopy approach enables millimeter‐scale spatial characterization. The illuvial Bt horizon of Luvisols is characterized by coatings of clay and organic matter (OM) at the surfaces of cracks and biopore walls. The occurrence and distribution of OM compounds such as heterocyclic N compounds (NCOMP) and benzonitrile and naphthalene (BN+NA) in macropore coatings could have important effects on preferential transport processes in structured soil. The objective of this study was to estimate the millimeter‐scale distribution of NCOMP and BN+NA at intact surfaces of coated and uncoated cracks, pinholes, and burrow walls. The proportions of NCOMP and BN+NA in OM were determined by pyrolysis–field ionization mass spectrometry (Py‐FIMS) from disturbed material that was manually separated from the intact sample surfaces. Fourier‐transform infrared spectroscopy in diffuse reflectance mode (DRIFT) and partial least squares regression (PLSR) between DRIFT signals and Py‐FIMS data were used to generate millimeter‐scale maps of predicted NCOMP and BN+NA proportions at intact macropore surfaces. The NCOMP and BN+NA proportions were linearly related to C=O and C=C groups from OM and to O–H groups from clay minerals in DRIFT spectra. The millimeter‐scale distribution of NCOMP and BN+NA at intact macropore surfaces could be predicted in terms of relative differences among the macropore types. Increased NCOMP and BN+NA proportions corresponded to the spatial distribution of crack coatings and pinholes. The relative enrichment suggested that pyrogenic OM has been preferentially transported in cracks rather than in biopores and that it was stabilized by clay minerals and prevented from decomposition. The results indicated that preferential transport affects OM turnover processes in the subsoil.
    Type of Medium: Online Resource
    ISSN: 1539-1663 , 1539-1663
    URL: Article
    DOI: 10.2136/vzj2017.05.0111
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 2088189-7
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