Vol 51, No 10 (2018)

A review of Russian and foreign approaches to analyze and assess the ecological and socioeconomic role of urban and technogenic soils is made in the context of the two popular concepts: the ecological functions of soils and ecosystem services. The modern definitions, classification, and evaluation of ecosystem services and their relationships with soil functions are considered both in general and in relation to urban and technogenic soils. Despite some methodological differences, the work shows that the concepts are closely related, and their joint use is highly promising. Three practical examples for the cities of Moscow, Hangzhou, and Hong Kong show a consistent transition from the analysis of soil properties and functions to the assessment of ecosystem services and decision making in engineering, urban improvement, and sustainable urban development.

This study focused on characterization of salt-affected organic soils with thin surface mineral layers affected by waste of soda industry in the Inowrocław city area, Poland. The obtained results pointed out that the eolian supply of mineral material from waste ponds and locally, its transport by surface runoff can effect formation of layers contained up to 43% of carbonates. In addition, it was shown that these seemingly small transformations in the soil morphology can have a significant impact on functioning of the studied soils in the landscape. In this regard, the most important were deterioration of water properties and reduction of plant growth due to the salinization and sodification. Specific features of the studied soils could be well reflected in the WRB soil name as Eutric Murshic Histosols (Akromineralic, Salic, Sodic, Prototechnic). However, in the Author’s opinion, the introduction of the new qualifier defining the artifact type in the name (i.e. Calcitechnic) would be advisable.

Transformation of water-soluble organic substances entering mineral horizons of podzol from the forest litter was studied in a model column experiment. The concentration of organic matter in the solution after its interaction with the E horizon increased by 10–44% due to the release of native soluble organic matter. This was accompanied by changes in the quality of water-soluble organic matter: the portion of hydrophobic components increased, the coefficients of extinction at 254–280 nm decreased, and the portion of low-molecular-weight compounds slightly decreased with a corresponding increase in the portion of high-molecular-weight compounds. Upon the interaction of water-soluble organic substances with the E horizon, the pH values first decreased and then slightly increased, which could be due to sequential desorption of organic acids of different strengths. Dissolved organic substances from the E horizon were partly sorbed in the BF horizon at the rate of about 65 mg С/100 g, or 22% of C_org in the BF horizon. The sorption resulted in the removal of mainly hydrophobic medium- and high-molecular-weight (>7000 Da) organic substances from the solution. As judged from the coefficients of extinction in the UV area, the sorbed substances were characterized by a higher aromaticity in comparison with the substances remaining in the solution. The sorption of organic substances in the BF horizon was accompanied by the rise in the pH of the solution, which corresponded to binding of organic anions on the surface of iron hydroxides according to the mechanism of ligand exchange with OH ions.

To investigate the impacts of different fertilization on characteristics of organic carbon (OC) changes in brown earth (Hapli-Udic Cambisol), an experiment was conducted with long-term located fertilization experiment from 1979–2015. The experiment field divided into chemical fertilization group, low levels of organic manure group and high levels of organic manure group. The results showed that: the OC was mainly stored in >1.0 mm size aggregates. As the organic fertilizers application grew, the mass percentage of the water-stable aggregates (WSA) for >1.0 mm aggregates significantly increased by 2.3–30.1 times and when the organic and inorganic fertilizers were combined to be applied, the mass percentage of >2.0 mm aggregates and carbon preservation capacity (CPC) increased significantly. Over 37 years of fertilization, the organic carbon concentration, stock and rate of change in brown soil presented the following rank: high-levels of organic manures group > low-levels of organic manures group> chemical fertilization group. Based on the experimental data over the last 37 years, we examined the relationship between total carbon input and the change of organic carbon stock, and constructed a curve: y = 0.153x–0.129.

Coupled studies of pore space and rheological behavior of undisturbed samples from soddypodzolic soils (Albic Glossic Retisols (Loamic, Aric, Cutanic)) of Moscow oblast under forest and under cropland and from typical chernozems (Haplic Chernozems (Loamic, Aric, Pachic)) of Kursk oblast under oak forest, shelterbelt, and cropland were conducted. Soil pore space was investigated using a Bruker SkyScan 1172 G (Belgium) microtomograph, and 3D models of pore space were constructed. The total pore space (in percent of the volume of analyzed samples) and the volumes of open and closed pores were determined from these models. The nondestructive tomographic method made it possible to analyze the rheological properties of soils for the same samples using the amplitude sweep method on an MCR-302 (Anton Paar, Austria) rheometer. The following parameters of the rheological behavior were determined: storage modulus in the range of linear viscoelastic behavior, the range of linear viscoelastic behavior, and the range of plastic behavior. A joint analysis of the rheological properties and morphometric characteristics of the undisturbed samples of soddy-podzolic soils and chernozems demonstrated the dependence of the rheological behavior of these soils on their physicochemical properties and pore space structure reflecting the differences in the genesis and physical and chemical properties of soil horizons. The correlation analysis attested to direct (positive) relationships between the values of the total and open tomographic porosities, the range of linear viscoelastic behavior, and the deformation upon the destruction of soil structure. Negative relationships were found between the values of open and total porosity and the structural strength of the soil monoliths. A hypothesis about an increase in the range of plastic behavior of soils and a decrease in the strength of soil structure with an increase in porosity was suggested.

The water retention curve (WRC), density, botanical composition, and ash contents were determined for high-ash lowmoor peat soils (Rheic Sapric Histosols) developing on the floodplain of the Yakhroma River (Moscow oblast) from the herb–hypnum and hypnum peat enriched in carbonates, agromineral peat soils (Rheic Drainic Sapric Histosols (Mineralic)), and peat soils developed from woody peat underlain by herb, sedge, and woody peat layers (Rheic Sapric Histosols (Lignic)). The WRC was determined by capillarimetric method in the range of water pressure from 0 to 80–90 кPa. For the studied peat soils, the WRC represents a close to linear dependence of the water content on the water pressure in semilogarithmic scale. In contrast to mineral soils, a characteristic point of the air-entry pressure is virtually absent on the WRC of peat soils. The WRC of peat largely depended on their density: denser peat samples were characterized by a higher water content at the same water pressure, which attests to the increased water retention capacity. An increase in the degree of decomposition of peat and its ash content also leads to the rise in the water retention capacity, but the effect of these factors is considerably smaller than the effect of peat density.

Because soil hydraulic properties are indispensable for determining soil water retention and soil solute movement, their input for simulation models is essential. Many of these parameters cannot be estimated directly at the scale of interest, but can only be derived through inverse modeling. During this process, the parameters are generally adjusted using least-squares approach with Levenberg–Marquardt (LM) algorithms in which numerically simulated models are fitted to measured data. In this study we used a new inverse method to estimate the unsaturated soil hydro-dispersive properties from in-situ experiments. The method employs complex-variable-differentiation method (CVDM) to accurately predict of the hydraulic properties of the van Genuchten–Mualem models (θ_r, θ_s, α, k_s, n). To the knowledge of the authors, it is first study use CVDM in soil physics. The optimization procedure was performed by using a continuous data set of daily in situ soil water content and bromide concentration measurements. Estimated parameters during the inversion showed high correlation (R² = 0.88, RMSE = 0.013 and the model efficiency CE = 0.77) by using the CVDM-methods with the actual field measurements, compared with the traditional LM-algorithm (R² = 0.81, RMSE = 0.021 and CE = 0.626). The results show that the new inverse analysis in the present work has the high accuracy, validity, uniqueness, and higher inversion efficiency. Meanwhile, the convergence and stability of the modified LM-algorithm are improved. Overall, it was concluded that the CVDM is promising method to estimate hydro-dispersive parameters in soil physics.

An investigation of the effect of aquic conditions on Fe-oxides distribution and magnetic susceptibility (χ_lf) was conducted on selected soils from Southern Iran. Seven pairs of adjacent soil pedons with different soil moisture regimes (aquic and non-aquic), were selected. The average concentrations of poorly crystalline Fe (Fe_o) and total free Fe (Fe_d) in aquic soils were 0.2 and 0.07% respectively, and 0.45 and 0.9% in non-aquic soils, respectively. The ratio of Fe_o/Fe_d varied from 0.03 to 0.64. χ_lf ranged from 1.8 to 113 × 10⁻⁸ m³ kg⁻¹ in the soil studied. The variation of χ_fd ranged from 0.0 to 9.65%. The χ_fd values observed in non-aquic soils were larger than in aquic soils (4.00% vs. 1.37%). Positive correlations were observed between χ and clay contents in both aquic and non-aquic soils; however, non-aquic soil samples showed a larger coefficient of determination. A positive correlation existed between χ_fd and χ in aquic and non-aquic soils. Higher values of χ_fd were observed at the soil surface of non-aquic soil samples than at deeper levels, suggesting a greater proportion of ultrafine grains. Of the soil properties that were assessed, clay, cation exchangeable capacity (CEC), Fe_d, Fe_o/Fe_d ratio, χ_lf and χ_fd contents, changed significantly in response to the aquic condition.

Technosol construction is an emergent technology that uses an assemblage of technogenic materials for the ecological reclamation of derelict land and waste recycling. Knowledge about the colonisation of Technosols by soil biota is limited, despite the latter’s central role in ecosystem functioning. In this four-year field (2008 to 2011) study, we characterized the development over time of the diversity and the abundance of soil nematodes in two types of Technosols in North-Eastern France. We also studied the nematode community structure, abundance of taxa and functional groups in both Technosol profiles in the third year of the study. Samples were collected from the top soil layer (0–20 cm) each year in the spring (April), on a one ha. field experiment that had spatially divided in 24 sampling areas. For soil profiles, three samples were collected in three horizons within six pits (three pits per Technosol). Nematodes were extracted from soil and identified at the family or genus level and then classified into functional feeding guilds. In the first year, the community was dominated by opportunistic bacterial feeders. The taxonomic and functional nematode diversity increased with time, with a dominance of non-opportunistic bacterial feeders after four years, but also the significant presence of fungal feeders, omnivorous and carnivorous, as well as plant parasites and insect parasites. No significant difference was observed between the two Technosols. Each layer showed distinct communities, with nematode diversity and abundance decreasing with depth. Abundance and diversity, coupled with the analysis of several indexes, commonly used for nematodes, including Maturity index (MI), Enrichment index (EI), Structure index (SI) and Nematode channel ratio (NCR), lead to the conclusion that the high organic matter content, particularly in the upper horizon of both Technosols, guaranteed nematode colonization and progressive diversification, and is likely to be the key for successful biodiversity reclamation.