INFLUENCE OF FIRE ON THE DISTRIBUTION OF ELEMENTS IN THE PEAT DEPOSIT OF THE BOG

The article is devoted to the comparison of the distribution of elements over peat deposits in post-pyrogenic and adjacent bogs. The object of the study is a drained bog located in the interfluve of Bakchar and Iksa, where a fire occurred in August 2016. The studies were carried out at four sites. In the PG1 site, the vegetation was completely burned out, in the PG2 partly, in the RG and PG3 areas, the vegetation was completely preserved. We found that the average concentration values for all elements, except Fe and Cu, are highest on PG1, which was most affected by the fire. In the post-pyrogenic areas, we noted an increase in the content of all considered elements in the upper layers (0-5 cm) of the peat deposit. The increase in the concentration of elements is explained by the presence in these areas of a layer of charred organic matter formed because of the destruction of plants during a fire and an increase in the degree of decomposition of the upper layer of peat. In the areas adjacent to the burned-out ones, in the upper layers, there is not such a sharp increase, but it persists at great depths, reaching the lowest water level. At a depth of approximately 20 to 50 cm, an increase in the concentration of Cu, Fe and Mn is observed. In the sites PG3 and RG, the maximum average content of Cu and Fe is observed in comparison with the burnt out sites. A correlation was found between the content of elements, which indicates the absence of a significant input of elements from external sources. The concentrations of Na, P, K, and Cd are positively correlated with all the considered elements, except for Ca. In Ca, negative correlation is observed only with Zn, Cd and Pb. A high correlation was found for Ca with the degree of decomposition along the depth of the peat deposit in all areas. The change in the content of Mn, Fe and Cu peat deposits with depth turned out to be very similar; they are mutually correlated with each other, and behave similarly with other elements. Zn and Pb correlate with all elements except Mn, Fe and Cu. Mg behaves in the same way (except for the correlation with Na). Synergism in the behavior of Mn, Fe and Cu is observed in each of the considered areas, and is explained by the affinity of all three elements for soluble organic complexes and the ability to bind in an acidic environment with humic and fulvic acids. Thus, in the post-pyrogenic sites with burnt- out vegetation, an increase in the content of all the considered elements in the upper layers of the peat deposit was noted. The increase in the concentration of elements is explained by the presence of a layer of charred organic matter in these areas and the almost complete absence of living plants. In the sites adjacent to the burned-out, in the upper layers, a not so sharp, but more prolonged in depth increase in concentration is observed.