Fate of humic acids isolated from natural humic substances

Abstract

Composition of humic acids (HA) is a function of plant-derived inputs, degradation processes regulated by microorganisms, organo-mineral interactions and age. Characterization of different origin humic substances is important for evaluation of their contribution to stabile and labile carbon pool in the environment. The relative abundance of chemical components in HA isolated from soils, compost, commercial lignohumates, alginite, acadiane and lignite was studied with aim to quantify content of important biomarkers such as amino acid, lipids and polyphenols. HA were considered as a heterogeneous complex and high concentration of peptides, polyphenols and lipids was determined in acadian-HA to compare with soil-HA. Compost-HA contained much more amino acids to compare with soil-HA samples. Alginite-HA and lignite-HA were similar in biomarkers content to soil-HA. Fourier transform infrared spectroscopy confirmed that chemical composition and functional groups content differs with the origin, humification degree and the age of studied samples. Soil-HA are typically composed of a variety of -OH, COOH-, C-O, C-H-2, (aliphatic and aromatic) groups, quinines, lignin fragments, polysaccharide, monosaccharide and proteins fragments, which are linked together by -O-, -NH-, -H=, >C=O, metal ions and -S- groups. C-13 NMR spectroscopy showed that aromatic carbon content was the highest in lignite-HA and soil-HA.

Keywords

biomarkers; FTIR and C-13 NMR spectroscopy; natural humic substances

Published in

Acta Agriculturae Scandinavica, Section B - Soil and Plant Science
2015, volume: 65, number: 6, pages: 517-528
Publisher: TAYLOR & FRANCIS AS

SLU Authors

• Strålenhielm, Anna

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Soil Science

Publication identifier

• DOI: https://doi.org/10.1080/09064710.2015.1030442

Permanent link to this page (URI)

https://res.slu.se/id/publ/69647