Features of biogeochemical processes of soils in urban conditions based on the study of ecosystems of Large lysimeters of the soil stationary of MSU

Abstract

The functioning of stationary soil lysimeters is determined by a limited volume of soil in both horizontal and vertical directions. The areal spatial limitation and the proximity of phytocenoses to each other in the large lysimeters at the
Moscow State University Soil Station determines the interbiogeocenotic exchange of plant litter, while the vertical
one excludes the role of groundwater and their influence on soil formation. The absence of lateral runoff, which is
common in natural landscapes, and the increased supply of alkaline earth elements with atmospheric precipitation
and dust, reduces the manifestation of the eluvial-illuvial process. Comparison of lysimetric waters in 1967–1968
and 2014–2015 showed a significant increase over time in the concentration of elements such as calcium, sodium,
magnesium and potassium, and among the anions chloride and sulfate ions. The local spatial geochemical contrast
of lysimetric waters caused by the effect of anti-icing agents, however, does not change the relative migration ability
of elements. According to the level of biogeochemical accumulation of elements in the soil, macroelements form
a series of Ca > K > Al > Mg > Na, and trace elements — Zn > Sr > Cu > Ba, while maintaining the same type on all
types of lysimeters. An increase in the concentration of elements in the soil occurs in the following order: broad
leaf > spruce > mixed > pure fallow. The increased accumulation of elements in the soil profile of spruce forests in
comparison with mixed plantations correlates with the type of humus forming here, which is close to the moder
type, which is due to the combination of coniferous and deciduous litter.