Quantitative spectroscopy 13C-NMR of huminic acids of soils from the Selenga river the delta

The structure of the preparations of humic acids extracted from sod humus horizon of forest and meadow soils of the Selenga Delta was investigated by the method of 13C NMR spectroscopy. It is shown that in humic acids of sod forest soils by the broad signal of aromatic carbon number is dominated, and in meadow soils aliphatic part is developed. These data coincide with the results of the elemental composition, the ratio N/S. The differences in the content of carbon atoms included in the structural fragments in the composition of macromolecules of humic acids indicate different conditions of soil formation and humification. The increase in the share of aliphatic structures and the decline in the proportion of aromatic fragments in the composition of humic acids allow to speak about the simplification of the structure of the molecules humic acids, which may be due to lower microbial activity in meadow soil in the conditions of permanent waterlogging.