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The purpose of this study was to investigate the in situ characterization of organic matter (OM) within soil macroaggregates, and to assess the relationships between OM characteristics and macroaggregate size indicating different OM stabilization mechanisms. Optical micro-morphological investigations, coupled to SEM-EDS (scanning electron microscopy and energy X-ray spectroscopy) technique, were carried out on thin sections of 1–4 and 0.25–1 mm soil aggregates (coarse and fine macroaggregates, respectively) from 0 to 20 cm soil layer corresponding to A horizon of four different sites in which soil structure were not disturbed by tillage. The intraggregate porosity, measured by image analysis of four different size classes (200 µm), showed that fine macroaggregates were significantly less porous (3.70–6.71% of total porosity) and had higher presence of the finest pore class (

Technosols are soils developed on non-traditional substrates and containing large quantities of materials mostly due to intensive human industrial activity, such as artefacts. The increasing number of sites affected by Technosols and their impact on the environment as growing media for plants or as source of pollutants require an understanding of their functioning and evolution, above all the knowledge on the transport of toxic substances from contaminated technogenic soils to groundwater. A case study on properties, remediation and evaluation of Technosols made up by vitrified fly ash and glass–ceramics in Italy was carried out. Original technogenic soils, classified as Spolic Technosols (ecotoxic), were pedotechnically in situ remediated by adding smectitic marlstone and Ca(OH)2. Chemical analysis on samples from piezometers showed the presence of harmful heavy metals in groundwater. By means of boreholes and soil profiles the new soils generated, after remediation, were physically and chemically characterized and classified as Spolic Technosols (calcaric). Analysis on soil toxicity and leaching tests showed the effectiveness of the remediation and the mobility reduction of some potentially harmful elements according to the environmental Italian regulation.

In bisequal soils a complex combination of pedogenic processes has occurred and the minerals that arise from a specific soil forming process may have been modified by other processes. In this work we investigated the mineralogical composition of the clay fraction and related it to pedogenic processes in three soils of the Russian Taiga. The soils showed evidences of clay translocation, podzolisation, and gleying with different intensities and combinations. Clay translocation was present in all profiles, but better expressed in Profile 2. Evidences of podzolisation were found in Profiles 2 and 3, but in this latter hydromorphic processes have also occurred. In Profile 1 almost permanent water stagnation has lead to the development of a thick sphagnum cover. In all profiles, during the formation of the Alfisol sequa, the transformation of illite into vermiculite or smectite has occurred through the formation of mixed-layered minerals while the pH favoured Al intercalation in the interlayer. When podzolisation started, the presence of HIV/HIS in the E horizon was no longer favoured, because of Al complexation by organic acids, but in the Bs horizons Al-intercalation in the interlayers continued, thus prolonging a mineralogical process that has started during the previous pedogenic phase. The formation of swelling minerals was moderate and related to the cheluviation phase of podzolisation. We found swelling mixed layer minerals only in the surface horizons of Profile 1 and 3, where the vegetation cover was favourable to the production of aggressive organic acids and thus Al may be removed also from the structural sites of phyllosilicates. The reducing conditions acted upon soil minerals, but affected directly only Fe oxi(hydr)oxides. The dissolution of the protective Fe-films from mineral surfaces has, however, favoured the physical disintegration of feldspar grains where the waterlogging conditions were almost permanent.