Катенарная биогеохимическая дифференциация в южно-таежных ландшафтах (Центрально-Лесной заповедник, Тверская область)

A landscape-geochemical catena with Albic Retisols (Loamic) under coniferous-deciduous forest on loess-like loams underlain by carbonate moraine deposits located in the southern part of the Central Forest Reserve on a gentle interfluve slope was studied to evaluate the migration of trace elements in the soil–plant system. Biogeochemical differentiation of landscapes was analyzed basing on Mn, Fe, Zn, Sr, Cu, Ni, Cr and Pb concentrations in parent rocks, soils and plants. Soils of the catens have near-clarke content of Mn and Pb and lower content of Cu, Fe, Zn, Ni, Sr and Cr. In the upper part of the catena, A and O-horizons are enriched in Pb, Mn and Zn. E-horizon is depleted in Fe, Ni, Sr and Zn. B-horizon has a higher content of Cr, Ni and Cu and a lower content of Sr and Mn. Ash proportions in studied coniferous and broadleaved species of coniferous-decidous forests are 1–4 and 1–8% respectively, while it is 3–12% for the aboveground parts of grasses. The studied plant species contain near-clarke amounts of Cu, Zn and Ni. Branches and bark of woody plants are depleted in Fe and Cr, while sphagnum has lower content of Sr. Within the lower part of catena Fe content in plants decreases and this of Mn increases. Within the upper part of catena where plant leaves and needles accumulate Mn, Cu, Sr and Zn more actively than within its lower part, the element concentrations in plant organs differ slightly. Spatial differentiation of the total content decreases from Mn, Ni and Fe to Zn, Sr and Cu. Trees are the most active in the uptake and turnover of biophilic Mn and Zn while sphagnum and grasses mostly accumulate Fe, Cr and Pb. At the catena (toe)slope grass-shrub plants and tree leaves accumulate Cu. In the landscapes of the upper part of catena metals show more even distribution compared to the lower part where photosynthetic organs of plants accumulate Mn, Cu, Sr and Zn. Concentrations of Mn, Ni and Fe show the highest differentiation along the catena, while Zn, Sr and Cu are evenly distributed. Needles of Picea abies most intensively accumulate Mn in all landscapes (especially in hydromorphic). The photosynthetic organs of Picea abies, Tilia cordata, Salix caprea and Sphagnum have the greatest biogeochemical activity with the main contribution of Mn, Cu, Sr, Zn and Ni. The lowest biogeochemical activity is characteristic of Acer platanoides and Ulmus glabra.