Description: Das Projekt "Quantification of small-scale physicochemical properties of intact macropore surfaces in structured soils" wird vom Umweltbundesamt gefördert und von Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V., Institut für Bodenlandschaftsforschung durchgeführt. In structured soils, the interaction of percolating water and reactive solutes with the soil matrix is mostly restricted to the surfaces of preferential flow paths. Flow paths, i.e., macropores, are formed by worm burrows, decayed root channels, cracks, and inter-aggregate spaces. While biopores are covered by earthworm casts and mucilage or by root residues, aggregates and cracks are often coated by soil organic matter (SOM), oxides, and clay minerals especially in the clay illuviation horizons of Luvisols. The SOM as well as the clay mineral composition and concentration strongly determine the wettability and sorption capacity of the coatings and thus control water and solute movement as well as the mass exchange between the preferential flow paths and the soil matrix. The objective of this proposal is the quantitative description of the small-scale distribution of physicochemical properties of intact structural surfaces and flow path surfaces and of their distribution in the soil volume. Samples of Bt horizons of Luvisols from Loess will be compared with those from glacial till. At intact structural surfaces prepared from soil clods, the spatial distribution (mm-scale) of SOM and clay mineral composition will be characterized with DRIFT (Diffuse reflectance infrared Fourier transform) spectroscopy using a self-developed mapping technique. For samples manually separated from coated surfaces and biopore walls, the contents of organic carbon (Corg) and the cation exchange capacity (CEC) will be analyzed and related to the intensities of specific signals in DRIFT spectra using Partial Least Square Regression (PLSR) analysis. The signal intensities of the DRIFT mapping spectra will be used to quantify the spatial distribution of Corg and CEC at these structural surfaces. The DRIFT mapping data will also be used for qualitatively characterizing the small scale distribution of the recalcitrance, humification, and microbial activity of the SOM from structural surfaces. The clay mineral composition of defined surface regions will be characterized by combining DRIFT spectroscopic with X-ray diffractometric analysis of manually separated samples. Subsequently, the spatial distribution of the clay mineral composition at structural surfaces will be determined from the intensities of clay mineral-specific signals in the DRIFT mapping spectra and exemplarily compared to scanning electron microscopic and infrared microscopic analysis of thin sections and thin polished micro-sections. The three-dimensional spatial distribution of the total structural surfaces in the volume of the Bt horizons will be quantified using X-ray computed tomography (CT) analysis of soil cores. The active preferential flow paths will be visualized and quantified by field tracer experiments. These CT and tracer data will be used to transfer the properties of the structural surfaces characterized by DRIFT mapping onto the active preferential flow paths in the Bt horizons.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Rochen ? Regenwurm ? Organischer Kohlenstoff ? Gerinne ? Infrarotstrahlung ? Röntgenstrahlung ? Wasserstraße ? Anstrich ? Abraum ? Oxid ? Skigebiet ? Tracer ? Verrottung ? Würmer ? Brunnen ? Humus ? Kartographie ? Kationen ? Leitfaden ? Lössboden ? Bodenwasser ? Regressionsanalyse ? Dränwasser ? Sickerwasser ? Spektralanalyse ? Bodenkunde ? Pflanzenwurzel ? Karte ? Austauschkapazität ? Bodenstruktur ? Lehm ? Bodenaustausch ? Gelöster organischer Kohlenstoff ? Pestizidabdrift ? Biologische Aktivität ? Wasserströmung ? Reflexion ? Sorption ? Strömungsfeld ? Ackerland ? Mikroorganismen ? Bewässerung ? Wasser ? Boden ? Glühverlust ? Bodenuntersuchung ? Bohrkern ? Daten ? Tonmineral ? Technik ? Spektrum ? Abdeckung ? Mineral ? Gebiet ? Rückstand ? LEISTUNGSFAEHIGKEIT ? OBERFLAECHE ? VORSCHLAEGE ? PFAD ? BEREICH ? VORSCHLAG ? WAND ? BESCHREIBUNG ? PROBE ? RAEUMLICHE VERTEILUNG ? SPEZIFISCH ? LOESUNG ? Buchgrundstück ? AUSTAUSCHEN ? EXPERIMENT ? STARK ? VERGLEICHEN ? Fluss [Bewegung] ? VERSCHIEBUNG ? KONTROLLE ? VERTEILUNG ? Konzentrat ? VERWANDT ?
Region: Brandenburg
Bounding box: 13.01582° .. 13.01582° x 52.45905° .. 52.45905°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2013-01-01 - 2024-11-29
Accessed 1 times.