Inhaltszusammenfassung

Proton NMR wideline spectroscopy and low field relaxometry are versatile and non-disturbing tools for investigating soil-water interactions. Relaxometry allows studying properties of water, redistribution within the pore system (wetting), pore size distribution and its time-dependent changes (swelling). Two- dimensional correlations between transversal and longitudinal relaxation times and diffusion coefficients, extends our knowledge by features of molecular mobility of wate...Proton NMR wideline spectroscopy and low field relaxometry are versatile and non-disturbing tools for investigating soil-water interactions. Relaxometry allows studying properties of water, redistribution within the pore system (wetting), pore size distribution and its time-dependent changes (swelling). Two- dimensional correlations between transversal and longitudinal relaxation times and diffusion coefficients, extends our knowledge by features of molecular mobility of water, interconnectivity of pores and entrapment in gel phases. Combination with structural features of liquid water affecting its freezing-melting behavior obtained by thermal analysis, this versatile insight allows to identify gel phases in the organic matter and to understand the role of highly swellable substances (such as extracellular polymeric substances and mucilage) for soil structure, rhizosphere functions and aggregate properties. Proton wideline spectroscopy allows studying molecular interactions between water and soil organic matter segments on a microscopic scale. Mobility of proton-containing material is directly reflected by the linewidth in these cases. Combining the two methods and using information obtained from thermal characterization of the OM matrix rigidity, information on the supramolecular structure and the presence of water molecular bridges (WaMB) are obtained. This method is thus optimal to study labile structures in the soil organic matter matrix.» weiterlesen» einklappen

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