Norbert GÁL¹, Tivadar M. TÓTH², Béla RAUCSIK², Tamás FÖLDES³, & Andrea FARSANG^1
1Department of Physical Geography and Geoinformatics, University of Szeged, Egyetem Street 2–6, Szeged 6722 Hungary, galnorbert@geo.u-szeged.hu;
²Department of Mineralogy, Geochemistry and Petrology, University of Szeged, Egyetem Street 2–6, Szeged 6722 Hungary;
³Institute of Diagnostic Imaging and Radiation Oncology, Kaposvár University, Guba S. Street 40, Kaposvár 7400 Hungary

EFFECTS OF INLAND EXCESS WATER ON BULK DENSITY AND CLAY MINERALOGY OF A CHERNOZEM SOIL USING XRCT AND XRPD TECHNIQUES

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Inland excess water (IEW) is surplus water in the soil, resulting in long lasting (2–3 months) inundation of areas. The aim of this study is to establish a method to detect differences amongst undisturbed soil cores collected in inundated and non-inundated study plots, in order to reveal the potential effects of IEW on bulk density. In the same patch of Chernozem, two intact soil cores (height 28–32 cm, diameter 19 cm) were sampled in PVC cylinders in an inundated area and, as the control, two more in a non-inundated area. X-ray computed tomography (XRCT) measurements were carried out at a spatial resolution of 660 × 660 μm². Higher bulk density, compaction, calculated from the Hounsfield units were recorded by XRCT in the case of the inundated soil columns. As a potential reason for the more remarkable shrinkage observed in the samples affected by inland excess water, the mineralogical composition was analysed by X-ray powder diffraction (XRPD). The measurement confirms the higher proportion of expandable clay mineral phase in the inundated samples compared to the control. Experiments revealed that due to water inundation, secondary clay mineral formation and translocation occurred in the upper horizon of the soil samples, and they can trigger unfavourable structures that enhance the risk of IEW formation.