Articles

For the anniversary of the Faculty of Soil Science of Moscow State University, the author examines the issues that have remained unresolved in the field of classical genetic soil science over the past half century, and offers a list of tasks that need to be solved in the near future. It is noted that against the background of decreased interest in pedogenetic research, problems are accumulating in related fields that require a clear understanding of the genesis of soils: soil classification, digital soil mapping, paleopedology and soil assessment. One of the unsolved issues remains the estimation of the rates of soil-forming processes, without which it is difficult both to reconstruct the evolution of soils in the past and to predict the behavior of soil systems in the future. The mechanisms of textural differentiation have not been deciphered both in temperate regions and in the tropics; in many cases, soils clearly differentiated by the content of the clay fraction are adjacent to soils with a profile homogeneous in texture. The mechanisms of deep illuviation of humus are unknown in the absence of signs of spodic or natric properties. There is no clear understanding of the mechanisms of formation of compacted subsurface horizons of soils (fragipan) and horizons cemented with opal (duripan). It is proposed to create a bank of unresolved soil-genetic issues that require analysis and solution.

X-ray fluorescence, electron microscopic, sedimentation analyses and laser diffractometry methods were used to study the composition of bottom sediments of surface watercourses of the Malmyzhskaya Ridge section allocated for the construction of a mining and processing plant (Khabarovsk region, Russia). It is established that the bottom sediments of the coastal zone of the watercourses of the studied area are characterized by a similar gross composition and physical and chemical properties (pH, solid phase density, total carbon content, wetting edge angle CAW). They are mainly represented by fine earth with a high proportion of suspended sediments, in which the fraction of coarse silt prevails (particle size <2,0 mm, <0,1 mm and 0,01–0,05 mm, respectively). It is shown that deforestation in the sources of watercourses accompanied by soil erosion leads to a significant increase in the dispersion of sediments (an increase in the proportion of suspended sediments up to 90%) in the upstream. Downstream, with the distance from the felling sites, the influence of deforestation on the dispersion of deposits fades. The content of suspended sediment is reduced to values characteristic of watercourses in the catchment area of which deforestation has not been carried out. Significant microaggregation of suspended sediments of watercourses was revealed, the participation of microbiota (testate amoebas of xenosome taxa, diatoms and Fe-reducing bacteria) in the formation of microaggregates was diagnosed. The latter are involved in the formation of vivianite on the surface of ferruginous-clay microaggregates with an increased content of phosphates after fires. The mechanism of formation of toroidal microforms of vaterite in bottom sediments with the participation of cyanobacteria of the Spirulinaceae family is proposed.

Th e purpose of this work was to study the acidity of degraded agricultural soils. Th e main objectives of the research
were to study the actual and potential soil acidity of agricultural lands of the Donetsk Peoples Republic on the example
of agricultural farms in the northern part of the Shakhtyorsky district. It was established that the studied model sites
are characterized by a slightly acidic, neutral or slightly alkaline medium reaction, which creates favorable conditions
for the formation of crops and plant growth. When studying the exchangeable acidity of soils, the ambiguity
of changes in its values was established, depending on the location of the model sites, the system of soil content in
the crop rotation, the horizon, and other factors. The most exceeding the control values of the exchange acidity are
characteristic of the slope surfaces of sites where the intensity of erosion processes reaches a maximum (exceeding
the indicator compared to the control by average of 8,6%). In the future, increased values of exchangeable acidity
may adversely aff ect the formation of crop yields. Changes in the values of hydrolytic acidity of soils follow the same
regularity as the variation in the indices of exchangeable acidity. The most signifi cant excess of the hydrolytic acidity
index in comparison with the control was recorded on the slope sites of the fi elds (increase by 11–17%). The conducted
studies confi rm the need for constant agroecological monitoring of these lands with the regulation of mineral
fertilizers to increase the absorption capacity of soils due to increased values of exchangeable and hydrolytic acidity.

The mechanical characteristics of soils of the same genesis and diff erent land use of Syktyvkar are studied: agrodernovo-
podzolic urban-stratifi ed soil within the city, post-frost park soil, podzolic soil of suburban territory. The analysis of their relationship with the content of organic matter and granulometric composition is carried out. In
agrodern-podzolic urban-stratifi ed soil, the strength properties are largely due to the content of large granulometric
fractions (> 0.25 mm), and in podzolic soil — the content of organic matter. Rows of soils were built according
to the values of rheological parameters. The strength of structural bonds, estimated by the parameter of the initial
modulus of elasticity, is greatest in podzolic soil, a wide range of linear viscoelastic state distinguishes the horizons
of agroderno-podzolic urban-stratified soil. Both post-frost and podzolic soil have the same average values of the
starting point of the viscous flow region.

Due to the need to develop technologies for reducing carbon dioxide emissions and increasing the C-absorption
capacity of natural and anthropogenic ecosystems, the possibility of using mineral fertilizers to regulate microbial
respiration and CO2 emissions from urban lawn soils was evaluated. Th e studies were carried out on the territory of
the Botanical Garden of Moscow State University on the Lenin Hills in a small-plot experiment with the fractional
application of four types of complex fertilizers (NPKS 27:6:6:2, NPKS 21:10:10:2, NPK 15:15:15 and NPK 18:18:18
+ 3 MgO + trace elements (TE)) at doses of 60 and 120 kg N ha-1 during the growing season. Th e carbon content
of microbial biomass (Cmic) using substrate-induced respiration was studied, the basal respiration (BR) of soils was
estimated, and the emission of CO2 from soils using closed static chambers was determined. Тhe Cmic content in the
soil of the control plot in the summer period varied within 1300–1450 μg·g-1. Th e application of NPKS 21:10:10:2
and NPK 18:18:18 + 3 MgO + TE at a low dose increased the Cmic content by 12–35% for two weeks, then it decreased.
Th e application of all fertilizers for a short period increased basal respiration of soils and CO2 emission,
maximum on the 6th day. After two weeks, the increase in the intensity of BR and CO2 emission decreased or it
reached the control values (1,5 μg C-CO2·g-1·h-1 and 500 mg·CO2 ·m-2·h-1 respectively) or less. In the short term,
the lowest intensity of CO2 emission and a surge in basal respiration, along with an increase in microbial biomass,
were observed with the addition of fertilizer NPKS 21:10:10:2. The greatest change in the functioning of the soil
microbial community, revealed by the maximum qCO2, occurred with the introduction of NPKS 27:6:6:2. The dynamics
of CO2 emission from the soils of the small-plot experiment from April to October correlated with the soil
temperature (rS = 0.66, p<0.05, n=135). In all periods of the study, the minimum CO2 emissions were noted for the
plot with NPKS 21:10:10:2 fertilizer.

The influence of oil pollution and concomitant salinization of chernozem typical in a field experiment has been studied. It is shown that the oil intake of 2 and 3 g·kg-1 with or without sodium chloride 1 g·kg-1 does not have a
negative effect. It was found that under the influence of salinization, the content of mobile forms of heavy metals
increases by an average of 1.5 times. The analysis of the content of heavy metals in crops cultivated on the territory
of the Republic of Bashkiria (Pisum sativum L., Triticum aestivum L.) aft er contamination with oil and sodium chloride was carried out both individually and jointly in a field experiment. The content of mobile forms of heavy metals in the soil under the infl uence

In the paper, the features of the biological cycle of 90Sr in the birch forests of the Bryansk region in the remote period
aft er the Chernobyl fallout are discussed. Specific activity and inventories of 90Sr in soil, diff erent structures and types
of tree and herbaceous-shrubby stories, higher fungi, and litter are given. It is shown that at present the major part
of 90Sr in the contaminated birch forests of the Bryansk Polesie is accumulated in the soil (82,3%), of which about
71% is in the mineral soil horizons. The biota contains only 17,7% of the total radionuclide inventory with maximum
values in the tree story. Th e contribution of herbaceous-shrubby vegetation and higher fungi is small, <0,5%. In birch
forests 3,07 kBq·m-2 90Sr is involved in the biological cycle, which is about 3% of its total stock in the ecosystem and
approximately corresponds to the radioactive decay of this radionuclide. The main part of the 90Sr goes for formation
of annual growth of the stand, while the contribution of higher fungi to the cycle exceeds the contribution of the
herbaceous-shrubby layer. Th e 90Sr return to soil is lower (48,2%) than its fi xation in annual biomass growth (51,8%).

The results of a vegetation experiment on the humus horizon of soddy-podzolic sandy loamy soil (Albic Retisol),
which was contaminated with heavy metals as a re sult of sewage sludge as a fertilize r, are presented. Th e soil was
used for growing vegetables and forage grasses but has been abandoned for the last 10 years. In the experiment, the
eff ect of rhizospheric bacteria of the genus Pseudomonas on biomass and the entry of micro- and heavy metals into
the vegetative organs and root system of spring wheat plants was studied. Under the infl uence of inoculation with
bacteria, the biomass of wheat plants increased by 10–12% and the content of the main macro- and microelements
in plants changed. Th e content of Ca, K, Mg, Na and P decreased by 1,5–2 times in the vegetative part of wheat plants
inoculated with P. fl uorescens 21 and P. putida 23. The content of macroelements in wheat roots changed little, but the
ratio between the content of elements increased in roots and vegetative parts of plants. Th e distribution of the content
of trace elements and HMs was much more contrasting: the content of Cd in the roots of wheat plants exceeded that
in the vegetative part of plants by 9 times without treatment with bacteria and by 18 and 11 times aft er inoculation
with P. fl uorescens 21 and P. putida 23, and in variants with P. fl uorescens 20 by 7 times. A decrease in the content of
Cd in the vegetative part of wheat plants was noted, by 2 times upon inoculation with P. fl uorescens 21 and by 1,5
times for variants with P. putida 23. Th e content of Zn in the aerial parts of plants also decreased upon inoculation
with P. fl uorescens 21 and by 1,8 times for variants with and P. putida 23 by 1,4 times. An increase in the ratio of the
content of elements in the roots and vegetative mass of plants indicates an increase in the resistance of plants to the
toxic eff ect of heavy metals and the barrier function of the roots.

Bacteria are a sensitive indicator of the state of the soil contaminated with oil and oil products. Aft er the introduction
of ameliorants, the oil content in the soil changes, which aff ects the number of bacteria. Th e aim is to
estimate the number of bacteria in petroleum hydrocarbons contaminated Haplic Chernozem aft er amelioration.
Biochar, sodium humate, nitroammophos, and microbiological fertilizer «Baikal EM-1» were added to petroleum
hydrocarbons-contaminated Haplic Chernozem (5% petroleum hydrocarbons by weight of soil). Aft er 90 days
of the experiment, the number of bacteria in the soil was estimated by the total number of bacteria, determined
by the method of luminescent microscopy, the number of actinomycetes, amylolytic and ammonifying bacteria,
determined by the method of inoculation on solid nutrient media. Th e integral indicator of the number of bacteria
(IINB) of the soil was calculated before and aft er the application of ameliorants. When introducing biochar, it is
possible to use the total number of bacteria to assess the ecological state of the soil, with nitroammophoska — the
number of ammonifying bacteria, sodium humate — the number of actinomycetes, «Baikal EM-1» — the number
of amylolytic bacteria. According to the IINB of soils, the most eff ective dose for remediation with nitroammophoska,
biochar, and Baikal EM-1 is D0.5, and for remediation with sodium humate, D2. It is advisable to use the
results of the study in biodiagnostics and monitoring the state of petroleum hydrocarbons contaminated Haplic
Chernozem aft er amelioration.