Submitted to: Agronomy Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 11/1/2003
Publication Date: 11/1/2003
Citation: Hayes, M., Clapp, C.E., Pedrosa, B., Ferreira, J., Song, G., Mao, J., Schmidt-Rohr, K., Millori, D., Jongales, P.M. 2003. Chemistry of humic substances in irish soils. Agronomy Abstracts. Paper No. S02-hayes959722-Oral. Interpretive Summary:
Technical Abstract: Humic substances (HS) were isolated at pH 7, 10.5, and 12.5 from different Irish soil types. Humic acids (HAs), fulvic acids (FAs) and XAD-4 acids were isolated using XAD-8 and XAD-4 technologies. Elemental, sugar and amino acid analyses and spectroscopic studies using ESR, fluorescence, and NMR were carried out. Some differences were observed in the relative abundances of amino acids and sugars in the different samples, and there was a clear relationship between fluorescence ratios (I470/I360), free radical contents, and extents of humification. NMR provided further evidence for molecular associations in the HA fractions. Only about 30% of the organic matter could be isolated, indicating that up to 70% of the SOM materials can be classified as humin.