Showing papers by "Russian State Agricultural University published in 2017"

Characterization, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons in urban soil of Nanjing, China

Abstract: Polycyclic aromatic hydrocarbons (PAHs) are widespread in the urban environment, particularly in urban soil, which are affected by intensive human activities. The purpose of this study was to determine the levels of PAHs in urban areas of Nanjing, China, apportion their sources, and evaluate their health risk. One hundred eighty topsoil samples (0–10 cm) were collected from 180 grids of 1 km × 1 km in the main urban area of Nanjing, China, which was divided into four different land use classes. All the soil samples were analyzed for 16 US Environmental Protection Agency (US EPA) priority PAHs by HPLC. Source of PAHs was explained by isomer ratios and principal component analysis, and health risk of PAHs was assessed by benzo[a]pyrene (BaP) toxic equivalency factors. The average concentration of PAHs ranged from 41.19 to 7016.65 μg kg−1, with an average of 979.59 μg kg−1. PAHs in soil characterized by different land uses, in decreasing order, were as follows: university (UN) > traffic area (TA) > forest park (FP) > residential area (RA). PAHs in FP soils were mainly attributed to biomass combustion, while TA soils exhibited clear traffic emission characteristics. PAHs for UN and RA came from mixed sources. A principle component analysis (PCA) and ordinary kriging map indicated coal combustion and vehicle emissions as the major contributors to PAHs in Nanjing urban soils, respectively. A health risk assessment based on the BaP toxic equivalency approach indicated a potential risk level of PAHs. The mean value of PAH concentrations in UN was the highest. However, the maximum was detected in TA. The PAHs in soil samples originated mainly from coal combustion and petroleum combustion sources. There was a potential health risk level of PAHs in Nanjing urban areas.

Urban Soil’s Functions: Monitoring, Assessment, and Management

Abstract: Urbanization is a key trend of current land-use change, responsible for large environmental changes worldwide. Sustainable functioning of urban ecosystems is a priority goal of today and nearest future. Urban soil is a key component of urban ecosystems. Urban soils are formed and exist under predominant direct and indirect effect of anthropogenic factor. Urbanization was traditionally related to negative impacts on soils, whereas the capacity of urban soils to perform environmental functions is poorly understood. Traditional approaches to assess and standardize soil quality through static parameters and health thresholds give limited information on soil living phase and its dynamics. Quantifying urban soils’ functions directly relates soil quality to the role of soil for environment and society, that is especially relevant in urban ecosystems. This chapter aims to overview existing approaches to monitor and assess soil functions for a specific case of urban soils. Individual functions (i.e., gas exchange and carbon sequestration, bioresources, remediation, etc.) are observed over variety of bioclimatic conditions and for different levels of anthropogenic disturbance. Assessment results are further implemented to develop guidelines and best management practices to construct and treat urban soils for maintaining their functions and quality.

Carbon stocks and CO2 emissions of urban and natural soils in Central Chernozemic region of Russia

Abstract: C-sequestration, as a function of soils, is known to help mitigate climate change. However, the potential of urban soils to be C-sinks or sources, is widely unknown. This study aims to understand the role and significance of urban soils in the C-balance of the region. It reveals several important findings about the C-balance capacities of urban soils and the multiple factors affecting this balance. This two-year study focused on soil organic carbon (SOC) stocks and CO 2 emissions of urban soils in the city of Kursk, located in the Central Chernozemic region of Russia, an area known to have some of the most fertile soils in the world. SOС stocks and emissions were studied in residential, recreational, and industrial functional zones and in comparison to corresponding natural reference soils to analyze the influence of urbanization on C turnover Urban soils were found to store 20 to 50 kg С m − 2 in 1.5 m layer; 10–30% less than in corresponding natural Luvic Chernozems and Chernic Phaeozems, but greater than what has been reported for many other cities. The urban soils with developed cultural layers stored more C in subsoil compared to the natural soils. Emissions of CO 2 in urban soils, however, were higher than from Chernic Phaeozems but comparable to those from Luvic Chernozems. The CO 2 /SOC stocks ratio in urban soils was two–three times higher than in natural soils. These outcomes point to the intensive C turnover and low sustainability of SOC stocks in urban soils. This study found evidence that the recent urbanization of the Chernozemic region has adversely affected the C balance. Natural soils in the region are important C sinks, however they can convert to C sources in result of urbanization.

Assessment of agronomic homogeneity and compatibility of soils in the Vladimir Opolie region

Abstract: Complexes of gray forest soils of different podzolization degrees with the participation of gray forest podzolized soils with the second humus horizon play a noticeable role in the soil cover patterns of Vladimir Opolie The agronomic homogeneity and agronomic compatibility of gray forest soils in automorphic positions (“plakor” sites) were assessed on the test field of the Vladimir Agricultural Research Institute The term “soil homogeneity” implies in our study the closeness of crop yield estimates (scores) for the soil polygons; the term “soil compatibility” implies the possibility to apply the same technologies in the same dates for different soil polygons within a field To assess the agronomic homogeneity and compatibility of soils, the statistical analysis of the yields of test crop (oats) was performed, and the spatial distribution of the particular parameters of soil hydrothermic regime was studied The analysis of crop yields showed their high variability: the gray forest soils on microhighs showed the minimal potential fertility, and the maximal fertility was typical of the soils with the second humus horizon in microlows Soils also differed significantly in their hydrothermic regime, as the gray forest soils with the second humus horizon were heated and cooled slower than the background gray forest soils; their temperature had a stronger lag effect and displayed a narrower amplitude in seasonal fluctuations; and these soils were wetter during the first weeks (40 days) of the growing season Being colder and wetter, the soils with the second humus horizons reached their physical ripeness later than the gray forest soils Thus, the soil cover of the test plot in the automorphic position is heterogeneous; from the agronomic standpoint, its components are incompatible

Monitoring and Assessing Anthropogenic Influence on Soil’s Health in Urban Forests: The Case from Moscow City

Abstract: Urbanization dominates current land-use change with important environmental consequences worldwide. Urban green zones including parks and urban forests provide key functions and services for city dwellers. Most of the urban forests’ functions, including biodiversity maintenance, supporting carbon and nitrogen cycles and climate mitigation are supported by soil. Therefore, urban forests’ soil health and its vulnerability to anthropogenic influence need thorough investigation. In the chapter the anthropogenic influence on soil health was studied for the unique forest experimental station located in Moscow and exposed to urbanization for more than a century. Changes in soil physical (bulk density), chemical (nutrients’ and heavy metals’ concentrations and mobility), and biological features (amount of ammonifiers and soil nitrogen-fixing activity) resulted from continuous urbanization and anthropogenic load were studied. Urbanization effect on soil health and functions was examined through comparison of the recent soil features to the historical data obtained at the same experimental sites prior urbanization, whereas anthropogenic influence gradient was studied based on the proximity to the roads and residential blocks. Substantial anthropogenic influence on soil features, their time dynamics, spatial variability, and profile distribution was found. Urban forest soils’ contamination with heavy metals was more than ten times higher compared to the non-urbanized counterparts. Concentration of heavy metals increased and nutrients’ concentration decreased from the forest core to the boundary zones. Over-compaction of forest topsoil was observed in proximity to the pathway network. Negative changes in soil chemical and physical features resulted in substantial decline in soil health and depletion of important soil functions, like support of a nitrogen cycle. The observed negative trend in forest soil health, resulted from urbanization and anthropogenic pressure, highlights importance to develop strategies of sustainable urban development, integrating green zones into urban areas.

A model for determination of residual stresses in plasma coatings

Abstract: The main reasons for the formation of residual (internal tensile) stresses in thermal spraying methods are the large differences in the temperatures of particles of deposited material on the surface of the substrate, the specific volumes of these particles at the moment of contact with the substrate and in the cooled condition, and also the non-uniformity of the distribution of temperature over the cross-section of the coating. The theory of hereditary elasticity is used to develop a mathematical model of theoretical justification of the process of formation and redistribution of the residual stresses which takes into account the relationship between the stresses and strains in the contact – substrate zone in heating and also the changes of their strength properties. Analytical dependences of controlling the technological parameters, such as the time and heating temperature, are proposed.

Analysis of Carbon Stocks and Fluxes of Urban Lawn Ecosystems in Moscow Megapolis

Abstract: Urbanization results in irreversible transformations of vegetation and soils. Urban lawn is an important part of urban ecosystems, providing several principal ecological functions, including participation in global carbon cycle. Carbon stocks and fluxes in urban lawns are diverse due to the different functional uses (residential, recreational areas, etc.), and different morphogenetic and physico-chemical properties of soil and their components. The research was focused on C stocks and fluxes in urban lawns to assess their function in regulating atmospheric air composition. Soil CO2 emission and CH4 fluxes (summarized for summer period); soil organic C (SOC); below and aboveground biomass were studied. Carbon emission by soil respiration and C sequestration in biomass were considered to estimate C balance.

Stereoselective synthesis of 2-aryl-4-en-1-ols, promising synthons for the preparation of oxygen heterocycles

Abstract: Reactions of arylacetic acids with N-methoxymethanamine afford corresponding Weinreb amides which at alkenylation with methallyl and prenyl bromides in the presence of (Me3Si)2N–Na+ form unsaturated amides ArCHRCONMe(OMe) (R = CH2CMe=CH2, CH2C=CMe2). Amides readily react with BuLi and BnMgCl to give ketones ArCHRCOR' (R' = Bu, Bn). A stereoselective reduction of the latter with LiBH(s-Bu)3 leads to a quantitative formation of syn-isomers of 2-aryl-4-en-1-ols.

Evaluation of Peat Stability Under Various Temperature and Moisture Conditions

Abstract: The study explores relationships between the peat decomposition rate and moisture-temperature conditions. Decomposition was evaluated through studying microbial production of CO2 and CH4. Decomposition of the original peat substrate (peat) was compared to one of the peat-sand mixture from 5 year old urban lawn (mixture). In the research the CO2 and CH4 emissions were studied under following temperatures and moisture conditions: temperature – 5 °C, 10 °C, 15 °C и 40 °C and moisture – 30%, 60%, 120%, 300%. The obtained results showed significant correlations between moisture and temperature conditions and CO2 and CH4 emissions. Differences of moisture and temperature impacts on the soil organic carbon (SOC) decomposition in the peat and peat-sand mixtures were observed as well. The CO2 emissions from the peat-sand mixture were higher compared to the peat, whereas SOC content in both substrates was similar.