IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 176 Travel Awardee Presentations Friday, 28 August 2026 / Hall C TA8 Comparative Elemental and Spectroscopic Evaluation of Humic Acids Extracted from Conventional and Biodynamic Field Spray Preparation Maurizio Marrese1, Muzammal Hoque1, Maria Jerzykiewicz2, Alessandro Piccolo3, Antonio Scopa1, Marios Drosos1 1 University of Basilicata, Department of Agricultural, Forestry, Food and Environmental Sciences (DAFE), Viale dell’Ateneo Lucano 10, Potenza, 85100, Italy. e-mail: maurizio.marrese@studenti.unibas.it 2 Wroclaw University, Faculty of Chemistry, F. Joliot-Curie 14, 50383, Wroclaw, Poland. 3 University of Naples Federico II, Department of Agriculture, Piazza Carlo III 1, NA, Portici, 80055, Italy. Biodynamic field-spray preparation 500 is produced by an anaerobic humification of cow manure inside bovine horns and is reported to yield a humus-like material enriched in condensed aromatic residues arising from only partial lignin degradation [1]. Because anaerobic humification pathways are fundamentally different from the oxidative aerobic mechanisms, this study investigated the molecular characteristics of humic acids (HAs) derived from preparations 500 and compared them to those formed during conventional aerobic composting. All laboratory work followed standardized IHSS procedures for humic substances isolation, purification and characterization [2]. Briefly, after sample homogenization and freeze-drying, 0.5M NaOH was applied to extract natural organic matter, followed by acidification with HCl:H2O (1:1). The isolated HAs were purified until Cl- free and were freeze-dried before being characterized by CHNS/O elemental analysis and solid state 13C-CPMAS-NMR. Elemental ratios of O/C, H/C and C/N were used to evaluate the oxidation state and hydrophobicity of the HAs. HB/HI, A/OA, ARM and LigR indices were calculated as presented in [3]. ARM/LigR ratio was recently found to be a good index of the abundance of free phenolic radicals in HAs [4]. Elemental analysis and solid-state 13C-CPMAS-NMR spectra revealed clear and systematic compositional and structural differences between HAs extracted from biodynamic materials and those from conventional composts. The spectrum of the biodynamic compost HA is mainly aromatic and phenolic (46.4%), in respect to this of the conventional compost HA (23.3%). This is consistent with the high O level that was found by elemental analysis. Hence, it seems that the anaerobic conditions of formation of the biodynamic products are preserving the functional groups of HA. Therefore, biodynamic HA resembles that of a lignite HA, with a lower lignin ratio and a higher
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