Application of C-13 NMR Spectroscopy to the Study of Soil Organic Matter: A Review of Publications

Possibilities of NMR spectroscopy with C-13 nuclei application to the study of soil organic matter and its various fractions is considered. This is a non-destructive method, which is particularly valuable in the analysis of various fractions of soil organic matter. It is regarded as a direct method, and, unlike most of indirect methods, it allows one to obtain reliable estimates of the ratio between virtually all groups of carbon atoms in different organic molecules, including those in humus specimens. Owing to impulse technique and high sensitivity, C-13-NMR spectra may be obtained immediately from soil samples without any extraction operations. The modern technique of obtaining spectra, their mathematical processing (Fourier transform), and data interpretation are considered. The results of applying C-13-NMR to the study of humus substances, water-soluble fractions of soil organic matter, and soil litters from different natural zones are discussed.