Abstract
Summary: The structure of some humic acids, fulvic acids and lipid fractions of soil organic matter have been investigated by 13C‐n.m.r. spectroscopy. Signals from aromatic groupings were normally absent in humic and fulvic acids. There were differences in spectra from extracts prepared from different sources or by different techniques. 1 3C‐n.m.r. spectra of lipid fractions were generally similar to each other but there were some distinct differences that may be used to a ‘fingerprint’ the lipids.