Nikolai Andreevich Shnyrev

The results of 60-year research on physical properties of soils in the MSU large lysimeters are discussed. The
questions under study were the elements of soil water balance, soil evolution, soil temperature regime, and transport of various substances in soil profile. The long-term changes in soil texture, soil mineralogy, and organic carbon content were observed. It was shown that the horizon sequence in soil profile affects the intensity of drainage flux and its stabilization in the long-term aspect. It was also found that the amount of the transit transfer of substances in different soil profiles depended both on profile structure and upper boundary conditions.

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.

A comparative analysis of the composition of lysimetric waters for 2021–2022 was carried out. for two groups
of stationary soil lysimeters in the city. Th e fi rst group of lysimeters is formed by the system: fallow — grass
phytocenosis — overgrown fallow — spruce forest — mixed and broad-leaved plantation, developing on the
same type of mantle loam. Th e second group of lysimeters represents soils with diff erent types of tillage: conventional
plowing, extra-deep planting according to Bushinsky, plowing according to Mosolov, deep plowing
according to Kachinsky.
For both groups, the same type of migration of components is shown, in which the most migrating elements are
carbon, mono- and divalent cations, and chloride ion, with minimal migration of iron, manganese, and aluminum.
In the group of lysimeters under various types of vegetation, as the tree canopy develops and, accordingly, the
intensity of the biological cycle increases in migrating waters, the concentration of such important biophilic elements
as magnesium, calcium, potassium, and carbon increases signifi cantly, and among anions, chloride and sulfate ions.
Th is determines, within the framework of the cluster analysis, two diff erent subgroups in terms of the composition of
natural waters: the fi rst one is formed by the fallow-grass phytocenosis — overgrown fallow system, and the second
one combines tree plantations.
In the group of lysimeters with diff erent tillage, a cluster characterizes the composition of water in lysimeters with
reclamation plowing according to Mosolov and deep plowing according to Kachinsky. At the same time, individual
aggregates form lysimeters with conventional plowing and ultra-deep planting according to Bushinsky. This is explained
by the fact that in this group of lysimeters, the initially created soil profi le design is transformed, which is
characterized by the placement of eluvial and illuvial soil horizons in various combinations and at diff erent depths
depending on the type of plowing.

The paper presents the results of experiments to study changes in hydrological properties of soil substrates composing profiles of artificial soils (construktozems) 1-4 years aft er their creation. Constructozems are represented by two variants - layered soils including Ap horizon, lowland peat and quarry sand of the same thickness, and a mixture of these substrates in an identical amount by weight, as for layered constructozems. Water retention curves obtained by capillarimetric method on samples of undisturbed structure were compared. A decrease in the water-holding capacity of the peat layer and an increase in the mixture samples were found a year after their functioning as part of the artificial soils. Laboratory and field experiments showed a statistically significant difference in water filtration rates of the layered constructozems and the mixture. Sharp boundaries between soil horizons contrasting in their properties reduce water migration rates down to zero values. Obtaining breakthrough curves of potassium ions allowed us to establish that the formation of continuous paths of rapid movement of water and dissolved substances is observed after four years of functioning of artificial soils and is most pronounced in constructions with homogeneous soil profile structure.