Particle-Size,Microaggregate-Size,and Aggregate-Size Distributions in Humus Horizons of the Zonal Sequence of Soils in European Russia

Eurasian Soil Science - Experimental data on size distribution of micro- and macroaggregates and primary soil particles were obtained by laser diffraction analysis of the samples of humus horizons...     

果园土壤中结合态腐殖质组成特征

通过化学分析方法研究延边地区典型苹果梨园盛果期土壤剖面中结合态腐殖质的空间分布特征.结果表明:(1)A1层(0-22 cm)松结态腐殖质含量表现为苹果梨园＞荒地,高出荒地42.61％,至A2层(22-53 cm)2种土壤松结合态腐殖质含量下降幅度分别60.79％,36.45％;苹果梨园土壤A1层的松结态腐殖质表聚现象比荒地土壤剧烈;在A1、A2层,松结态FA含量表现为苹果梨园＜荒地,HA/FA比以苹果梨园明显高于荒地.(2)苹果梨园稳结态腐殖质含量随土壤深度增加而下降,荒地土壤呈先升后降再升趋势;A1、A2层稳结态腐殖质含量表现为苹果梨园＜荒地;苹果梨园稳结态FA含量随土壤深度增加呈现升一降一升趋势;苹果梨园稳结态HA含量随土壤深度加深而减小,且A2层稳结态FA含量表现为苹果梨园明显小于荒地;A2层HA/FA比表现为荒地＞苹果梨园.(3)2种土壤紧结态腐殖质含量均随土层深度增加而减小;A1层表现为苹果梨园＜荒地,A2层表现为苹果梨园＞荒地.(4)A1层松结态腐殖质相对含量表现为苹果梨园＞荒地,A2层相反;A1、A2层稳结态腐殖质含量表现为苹果梨园＜荒地;紧结态腐殖质含量相当.苹果梨园松结态腐殖质含量表现为A1＞A2,稳结态腐殖质含量表现为A1＜A2.松/紧比在A1层表现为苹果梨园＞荒地,A2层表现为苹果梨园＜荒地;苹果梨园土壤A1层松结态∶稳结态∶紧结态为3.4∶2.0∶4.6,A2层为2.1∶3.2∶4.7.     

Humus Forms in Forest Soils: Concepts and Classifications

The concepts and classifications of humus forms developed since the time of scientific pedology formation are critically discussed. The concept of humus forms (types) relates to the classification of a set of topsoil organic and organomineral horizons, which reflects morphologically distinct phases of plant litter and soil organic matter decomposition, but not to the fractions of soil organic matter. Humus forms reflect various types of transformation and accumulation of organic matter in the soil. The stages of development and modern classifications of humus forms abroad are described. The taxonomy of humus forms in Russian literature and its application for the mapping and evaluation of forest soils are considered, as well as its use for the mathematical simulation of soil organic matter mineralization and humification. Prospects for the development of the classification of humus forms in combination with the basic soil classification of European Russia are discussed. A call for an understanding and a common language in soil science at the international level is underlined.     

Diagnostic Horizons in the Classification System of Russian Soils: Version 2021

Eurasian Soil Science - Updating the classification system of Russian soils as a preliminary procedure to the development of its new version is provided by new data, extensive testing of the system...     

Biological Activity of Soils in Mountain Tundra Ecosystems under Postpyrogenic Restoration

The dynamics of the content and microbiological transformation of carbon and nitrogen compounds in the surface horizons of mountain tundra soils are considered in the postpyrogenic succession. The contents of total and labile carbon and nitrogen increase in the course of postpyrogenic soil evolution. At the same time, in the surface organic horizons, the carbon reserves, as compared to the nitrogen ones, are restored faster. The aerobic transformation of carbon compounds prevails at all the stages of the succession. The tolerance of soil organic matter toward mineralization increases as the ecosystem recovers after fire. However, this parameter reaches the values characteristic of the control soils no earlier than 60 years after the fire. The microbial communities of the podburs (Folic Podzols, Haplic Podzols) restore their functional activity fast enough after the fire (about three years). In the remote future, the effect of fire leads to an increase in the availability of soil nitrogen and in the soil ability to fix atmospheric nitrogen. Despite the temporary increase in the availability of mineral nitrogen (including nitrates) at early stages of the postpyrogenic restoration of soil systems, denitrification does not play a significant role in the biogeochemical cycle of nitrogen.     

Influence of Texture on Humus Accumulation in Soils of Dry Steppes of Tuva

Eurasian Soil Science - The article is aimed to assessing the potential for humus accumulation in soils of dry steppes of the Central Tuva and Turan–Uyuk basins of Tuva. The research into...     

Polycyclic Aromatic Hydrocarbons Content in Contaminated Forest Soils with Different Humus Types

The aim of the study was to determine polycyclic aromatic hydrocarbon (PAH) content in different forest humus types. The investigation was carried out in Chrzanów Forest District in southern Poland. Twenty research plots with different humus types (mor and mull) were selected. The samples for analysis were taken after litter horizons removing from a depth of 0–10 cm (from the Of- and Oh-horizon total or A-horizon). pH, organic carbon and total nitrogen content, base cations, acidity, and heavy metal content were determined. In the natural moisture state, the activity of dehydrogenase was determined. The study included the determination of PAH content. The conducted research confirms strong contamination of study soil by PAHs and heavy metals. Our experiment provided evidence that different forest humus types accumulate different PAH amounts. The highest content of PAHs and heavy metals was recorded in mor humus type. The content of PAHs in forest humus horizon depends on the content and quality of soil organic matter. Weaker degradation of hydrocarbons is associated with lower biological activity of soils. The mull humus type showed lower content of PAHs and at the same time the highest biological activity confirmed by high dehydrogenase activity.     

Formal Criteria for the Humus Status of Mountainous Peat Soils in Altitudinal Zones

Eurasian Soil Science - Cryogenic oligotrophic (Hyperdystric Cryic Fibric Histosols), oligomesotrophic (Dystric Fibric Histosols), mesoeutrophic (Oligeoeutric Fibric Histosols), and eutrophic...     

Changes in the Ratio of Aggregate Fractions in Humus Horizons of Chernozems in Response to the Type of Their Use

Eurasian Soil Science - Data on the aggregate-size distribution (dry sifting method) in humus horizons of chernozems were processed by principal components analysis (PCA) with the centered logratio...     

Bacterial Diversity in Peat Soils of Forest Ecosystems and Oil Palm Plantation

Eurasian Soil Science - Bacteria play a crucial role in regulating biogeochemical cycles in peatlands. Most of the studies on soil bacteria focus mainly on the peat surface and bacteria that exist...     

Distribution of Organic Carbon in the Humic Fractions of Diagnostic Horizons from Brazilian Soils

Abstract

This study was developed on 52 soil profiles, 61 surface diagnostic horizons, and 26 subsurface diagnostic horizons classified according to the Soil Taxonomy and Brazilian Soil Classification System (SiBCS) as Mollisols (Chernossolos), Spodosols (Espodossolos), Entisols (Gleissolos), Oxisols (Latossolos), and Histosols (Organossolos). The objective was to quantify the carbon (C) in organic matter fractions and to correlate it with soil chemical attributes. Soil organic matter was fractionated into fulvic acids (C‐FAF), humic acids (C‐HAF), and humin (C‐HUM), and the ratios C‐HAF/C‐FAF and AE (alkaline extract)/C‐HUM were calculated. Humin was the predominant fraction in Mollisols and Oxisols, which showed values of AE/C‐HUM and C‐HAF/C‐FAF lower than 1.0. The humin fraction was also predominant in surface horizons of Spodosols and Entisols, whereas a higher content of C‐FAF and C‐FAH was observed in the subsurface horizons, with values higher than 1.5 for the AE/C‐HUM ratio. C‐HAF was predominant in the Histosols, and C‐HAF/C‐FAF ratio values were higher than 2.0. The highest correlation values with soil attributes were observed for C‐HAF, C‐HUM, and total organic C with pH, sum of bases, and cation exchange capacity. The differences in humic substances distribution was a useful parameter to characterize soil orders in the Brazilian soil classification system and to understand pedogenic processes.     

Transformation of Nitrogen Compounds in Soils of Mountain Tundra Ecosystems in the Khibiny

Eurasian Soil Science - The content of nitrogen compounds and processes of nitrogen mineralization and nitrification were studied in the soils of four tundra ecosystems in the Khibiny Mountains....     

Nitrogen Isotopes in Soils and Plants of Tundra Ecosystems in the Khibiny Mountains

Eurasian Soil Science - The isotopic composition of nitrogen in soils and plants may be an indicator of transformation of its compounds and sources of N nutrition of plants. Natural 15N abundance...     

云南省森林土壤腐殖质组分特征及影响因素

云南省森林生态系统在全球碳循环及平衡中具有不可替代的作用,但其森林土壤腐殖质组分特征及其影响因素尚不十分清楚。基于云南省不同林区采集的88个表层土样,通过描述性统计和回归分析量化了海拔、土壤类型、坡向和坡度、年均温和年降水量对土壤腐殖质组分分布影响的相对重要性,探讨云南省森林土壤腐殖质组分分布特征。结果表明:云南省森林土壤表层有机碳含量为8.40～199.73 g·kg^–1,平均含量为51.37 g·kg^–1,土壤可提取腐殖质碳含量为2.54～84.02 g·kg^–1,平均含量为24.52 g·kg^–1;胡富比均值小于1,土壤腐殖质聚合度较低;土壤腐殖质组分分布特征总体表现为滇西北、滇东北部较高,滇中、滇南部较低;土壤类型、海拔、年均温是影响云南省森林土壤腐殖质组分含量的主导因子,各因素的贡献程度总体呈现为土壤类型最高,其次是年均温、海拔,这说明土壤类型对森林表层土壤腐殖质的积累起重要作用。     

Trace Elements in Soils of Urban Areas

Urban soils are an essential element of the city environment. However, studies on urban soils are scattered in terms of geographical distribution, sampling pattern, analytical dataset, etc. One of the major issues arising from the studies on this ecosystem is the diffusion of its contamination. In cities, in fact, the proximity to humans may cause a serious danger for citizens. In the present study, results from the literature about trace elements in urban soils are presented to compare methodologies and results and to offer a basis for the harmonization of investigation approaches and establishment of remediation thresholds. A total of 153 studies on the urban ecosystem published in the last 10 years were collected and data on trace elements in soils of 94 world cities were compared and discussed. Data highlights the discrepancies among different studies (sampling strategies, analytical procedures) and the extreme variability of urban soils. Most cities are contaminated by one or more trace elements, revealing the environmental relevance of the urban soil system. While Pb is still one of the major concerns in many locations, new contaminants are on the rise and would deserve more attention from the researchers. While in fact some contaminants are almost ubiquitous in world cities and could be used as tracers for urban contamination, some traffic-related elements such as platinum, rhodium, and palladium, whose reactivity and toxicity is still unknown, are becoming of concern. Collation of literature data highlights the need for the harmonization of sampling, analytical, and rendering procedures for regulatory purposes and provides a useful dataset for environmental scientists dealing with the urban ecosystem and for city planners. A sampling design adapted to local urban patterns, a prescribed sampling depth, and a minimum set of elements that deserve to be measured could be the core of a common methodology.     

Microbiological Indicators of Heavy Metals and Carbon-Containing Preparations Applied to Agrosoddy-Podzolic Soils Differing in Humus Content

Eurasian Soil Science - The response of the microbial community (microbial biomass carbon (Cmic), basal respiration (BR), and functional diversity (FD)) of agrosoddy-podzolic soil (Albic Glossic...     

Physical Properties of Urban Soils in Rostov Agglomeration

Transformation of particle-size composition, structure, and density of soils upon urbopedogenesis is considered for Rostov agglomeration. Various soils are compared by horizons. It is found that the share of sand fractions increases in upper and middle horizons of migration–segregation chernozems (Calcic Chernozem (Hyperhumic, Loamic)), above all, at the expense of particles of 0.05—0.001 mm in size; with the coarse medium sand fraction 1–0.25 mm being diagnostic for urbopedogenesis. The reason is the introduction of sandy particles upon urban construction, arranging water conduits and other utility lines, as well as the use of icing-control sandy mixtures. The Dolgov-Bakhtin schedule appears to be the most appropriate for assessing the structure of urban soils. Dry sieving testified to the decreasing amount of agriculturally valuable aggregates in all compared pairs of horizons in the sequence of urban soils: under forest vegetation → under steppe vegetation → in the buried massif of urbosoils. The water stability of aggregates decreases in the sequence: soils under steppe vegetation → buried horizons of urbosoils → soils under forest vegetation. The following sequence of urbic horizons (UR and RAT) shows a decrease in the share of agriculturally valuable fractions and an increase in their water stability: heavy-textured UR → light-textured UR → RAT. The density of natural soils varies insignificantly within the city territory, with its urbostratified soils (Calcic Chernozem Novic (Technic Loamic) in residential areas often manifesting the maximal density.     

The Diversity of Bacterial Communities in Urban Soils

Urbanozems (Urbic Technosols) contaminated by heavy metals and polychlorbiphenyls (Urbic Technosols Toxic) and intruzems (Urbic Technosols Toxic) were studied in Moscow; additionally, we studied recreazems (Urbic Technosols Thaptohumic) and culturozems (Urbic Technosols Pantohumic) on the territory of the Botanical Garden of Moscow State University (Aptekarskii Ogorod, the Apothecaries’ Garden). In the soils contaminated with heavy metals and oil products, the number of viable cells of bacteria decreased, whereas the content of filterable forms of bacteria increased. The taxonomic structure of saprotrophic bacterial complexes in contaminated urban soils was transformed towards an increase in the diversity of bacterial taxa atypical of natural undisturbed soils. Rhodococci (Rhodococcus genus) predominated in the soils contaminated with oil and polychlorbiphenyls, enterobacteria (Escherichia, Enterobacter, and Klebsiella genera) predominated in the soils contaminated with municipal wastes, and Arthrobacter genus was dominant in the soils contaminated with cement dust. Soils of both Botanical Gardens of Moscow State University were characterized by the high population density and specific distribution of bacteria in the profile; the structure of their saprotrophic bacterial complex had some similarity with that in the soils of more southern regions. The obtained data on the bacterial diversity of urban soils attest to considerable transformation of bacterial communities both in the contaminated urban soils and in the soils of botanical gardens.