Influence of hydrological conditions on the group composition of the bog peat of the European North of Russia

The aim of the work was to study the group composition of peat deposits in the drained and undisturbed areas of bogs in the European North. The studies were carried out in the Primorsky district of the Arkhangelsk region on the territory of the Ilas bog system located 30 km from the Arkhangelsk in the northern taiga zone. The object of the study was bog peat sampled in the summer of 2020 from several sites of the Ilas bog system - drained and natural (undisturbed) areas. Laboratory studies included determination of the type of peat, the degree of decomposition, moisture content, ash content and group chemical composition. The group composition of peat was determined according to the author's certified method based on the sequential isolation of peat components by solvents of various natures and their subsequent determination by the gravimetric method based on the residue. In each investigated area of the bog the peat has a homogeneous plant composition - to its entire depth it is composed of sphagnum mosses with an admixture of cotton grass, shrubs and pine wood. The degree of decomposition of the upper horizons in all areas is low (less than 10 %). All peat samples are characterized by low ash content that is typical of bog peat. A slight increase of the ash content is observed with an increase in the depth of peat, which is quite logical, given the course of the processes of mineralization of organic matter. The content of water-soluble substances is low, slightly varies in the studied samples and practically does not change with the depth. The bituminous content of peat in the upper layers of natural and drained areas practically does not differ (3.3-4.4 %), but in the lower layer of the drained area it significantly increases and reaches 10 %. The content of biopolymers of humic nature also differs slightly for the upper layers (19.9-20.1 %) and increases in the lower layers of the drained area (up to 36.7 %). This trend is also observed for humic acids. The proportions of easily and difficult hydrolysable substances and lignin of the upper layers of the observed areas are comparable with each other while in peat with a higher degree of decomposition the proportion of easily and difficult hydrolysable substances decreases and the lignin content increases. All this results testifies rather to the intensification of transformation processes in the peat strata than to the effect of drainage. Thus, despite anthropogenic interference, the group composition of the organic part of peat of the same degree of decomposition of both natural and drained areas of the same bog system differs insignificantly which is statistically confirmed using the Mann-Whitney test.

Keywords

Authors

References