New insights into organic carbon stabilization in soil macroaggregates: An in situ study by optical microscopy and SEM-EDS technique

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