Das Projekt "Vorhersage und Erklaerung des Verhaltens und der Belastbarkeit von Oekosystemen unter veraenderten Umweltbedingungen - Teilprojekt S9: Untersuchungen zu Mechanismen und Kinetik der anorganischen Schwefelbindung in Boeden des Fichtelgebirges und Identifizierung der Schwefelfestphasen" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Lehrstuhl für Bodenkunde und Bodengeographie durchgeführt. Inorganic sulfur retention is an important process of acid-base chemistry of acid forest soils, yet the binding forms of retained S are not completely understood. Column experiments with the sand fraction of two rockforming minerals (albite and gibbsite) have been set up to study sulfate-retention-kinetics in water-saturated environments with various pH and various concentrations of Al3+ and SOtief4hoch2-. Temperature is kept constant at 10 degC. We applied several instrumental analytical methods to identify solid phases of inorganic sulfur in acid forest soils. In preliminary experiments we successfully tested: Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and Infrared Spectroscopy (IR). For these experiments we used untreated material and pretreated material that was allowed to react at 100 degC for two hours with 0,1 N sulfuric acid. Additional methods are to be applied: Secondary Ion Mass Spectrometry (SIMS), Differential Thermal Analysis (DTA), X-ray Fluorescence Analysis (XFA), Atomic Force Microscopy (AFM) and Laser Microprobe Mass Analysis (LAMMA).