title: Chemical and spectroscopic characteristics of humic acids and dissolved organic matter along two Alfisol profiles.
abstract: The aim of this study was to elucidate the heterogeneous structural and functional composition of humic acids (HAs) and dissolved organic matter (DOM) isolated from two Alfisol profiles with different soil texture, in order to develop a better understanding of the organic matter dynamics. Soil samples were collected at different depths from three (Ap, 2AB and 2Bt) and eight (A1, A2, A3, E1, E2, 2Bt1, 2Bt2 and 2Bt3) soil horizons of two Alfisols located in the south (PR1) and north (PR2) of Italy, with a clay texture and a silt loam to loam ones, respectively. Chemical and spectroscopic methods were used to characterize the HAs and the DOM isolated from different soil horizons, including Ultraviolet-Visible (UV-Vis), Fourier Transform Infrared (FTIR), and Fluorescence spectroscopies. The HAs and the DOM isolated from the two Alfisols apparently showed significant differences in their compositional, structural and functional characteristics. In particular, the HAs isolated from the PR1 featured a higher degree of humification and molecular complexity with respect to those isolated from the PR2. On the contrary, the DOM samples isolated from the PR2 showed a more marked aromatic character and polycondensation degree. Both the HAs and the DOM obtained from the PR1 presented a greater qualitative homogeneity with respect to those obtained from the PR2. These results could be reasonably ascribed to the different texture and horizons of the two Alfisols, and to a greater pedogenesis occurred in the PR1.
authors.affiliation: Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, University of Foggia, 71122-Foggia, Italy.
authors.forename: Andreina
authors.initials: A
authors.lastname: Traversa
authors.affiliation: Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari, 70126-Bari, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: D'Orazio
authors.affiliation: Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari, 70126-Bari, Italy.
authors.forename: Giuseppe Natale
authors.initials: GN
authors.lastname: Mezzapesa
authors.affiliation: Dipartimento di Scienze Agrarie, Forestali e Alimentari, University of Torino, 10095-Grugliasco, TO, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Bonifacio
authors.affiliation: Biology and Environmental Indicators, Department of Central Laboratory for Environmental Quality Monitoring (CLEQM), National Water Research Centre (NWRC), Egypt.
authors.forename: Karam
authors.initials: K
authors.lastname: Farrag
authors.affiliation: Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari, 70126-Bari, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Senesi
authors.affiliation: Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari, 70126-Bari, Italy. Electronic address: gennaro.brunetti@uniba.it.
authors.forename: Gennaro
authors.initials: G
authors.lastname: Brunetti
mesh_terms: D004784:Environmental Monitoring; D006812:Humic Substances / Q000032:analysis*; D007558:Italy; D009930:Organic Chemicals / Q000737:chemistry* / Q000302:isolation & purification; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000302:isolation & purification; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D006812:Humic Substances; D009930:Organic Chemicals; D012987:Soil; D012989:Soil Pollutants
keywords: Alfisol; FTIR spectroscopy; Fluorescence spectroscopy; Soil organic matter fractions; Texture