共查询到20条相似文献,搜索用时 46 毫秒
1.
Changes in the physical, physicochemical, and biological properties of cultivated gray forest soils after their abandoning
and overgrowing with meadow and forest vegetation for 8–10 years are clearly seen in the upper part of the former plow layer.
The organic matter content and the content of available forms of phosphorus and potassium increase; a significant increase
in the root biomass and in the soil biological activity is observed. Changes in the physical properties—an increase in the
degree of soil aggregation and a decrease in the bulk density values—are seen in the upper and middle parts of the former
plow layer. The biological factor is the major factor of transformation of formerly cultivated gray forest soils upon their
abandoning and overgrowing with meadow and forest vegetation. At the same time, a significant role in the improvement of the
structural state of the soils belongs to the physical shrink-swell and freezing-thawing processes. 相似文献
2.
Yu. N. Krasnoshchekov 《Eurasian Soil Science》2010,43(2):117-126
Specific features of the soil formation and soil cover patterns in the mountainous alpine tundra and forest landscapes of
the Central Khangai Range are analyzed. It is shown that the specific mucky grayhumus permafrost-affected soils are only formed
under larch forests within the tundra-alpine and forest zones. Other soils have a wider geographic area. The morphological,
physicochemical, and chemical characteristics of the widespread soils are given. A medium-scale map of the soil cover patterns—soil
complexes, combinations, and mosaics—has been developed for the studied area. 相似文献
3.
The extent of soil degradation and soil pathology in Russia is discussed. The concept of a federal target program “National
System of the Chemical and Biological Security of the Russian Federation (2009–2013)” is examined. A definition is given to
healthy soil of agrocenoses and its main functional characteristic—ecological stability (including balanced biodiversity,
self-cleaning capacity, and suppressive activity of the phytopedocenosis). Urgent applied scientific problems of regional
soil sanitation are formulated. Criteria and modern methods of ecological monitoring and assessment of soil quality and health
are considered. A systems approach to sanitation of soils infected by highly harmful phytopathogens—the causative agents of
root rots of cereal crops—is demonstrated using the induction of soil suppressiveness as an example. 相似文献
4.
V. M. Kolesnikova I. O. Alyabina L. A. Vorob’eva E. N. Molchanov S. A. Shoba V. A. Rozhkov 《Eurasian Soil Science》2010,43(8):839-847
Russia has long needed a world-level soil attribute (profile) information database which should become the basis for creating
a system of monitoring of the state of soils and for developing measures for their conservation and efficient land use. A
unified system of gathering and storing information on soils, which at the same time would be open for general use, is needed.
The present work is devoted to problems of the concept and methodology of creating a soil geographic database (SGDB) of Russia.
The structure and content of the soil attribute database, underlying which is the concept of representative soils profiles,
are given. A list of classifiers for preparing data presentation formats in the SGDB on the basis of existing concepts of
soil morphology and classifiers characterizing the main physicochemical properties of soils is developed. The work underlies
the creation of an information resource—“Soil-Geographic Database of Russia. Project of the Dokuchaev Soil Science Society”—on
the Internet at the address . 相似文献
5.
The diversity of soils within the specially protected natural territory of Pokrovskoe-Streshnevo in Moscow is discussed. The
soils of this large park are not affected by the modern construction activities that delete the features inherited from the
early stages of the anthropogenic transformation of soils in Moscow. They are characterized by the book-like type of soil
memory, which makes it possible to trace several sequences of the anthropogenic soil transformation. The background natural
soils-rzhavozems (Chromic Cambisols)—have been transformed into agrogenic soils (agrosols) and postagrogenic soils (postagrosols)
under abandoned plowlands, into urbo-soils and urbanozems in the areas of former or modern settlements, and into techno-soils
in the areas of active excavation works and engineering reclamation. The change in the character of the land use without the
accumulation of osediments on the surface leads to the development of polygenetic soil horizons. 相似文献
6.
The water-stability of soil and coprolite aggregates in soddy-podzolic soils and the participation of fungi in the formation
of water-stable aggregates from earthworm (Aporrectodea caliginosa) coprolites were assessed. The water stability of the soil and coprolite aggregates in the soils increased in the following
sequence: potato field—mown meadow—mixed forest. The fungal mycelium reserves increased in the same sequence. The water stability
of the coprolite aggregates of Aporrectodea caliginosa inhabiting these soils is 2–2.5 times higher than that of the soil aggregates of the same size (3–5 mm). The inhibition of
the growth of fungi by cycloheximide decreased the water stability of the coprolite aggregates, on the average, by 15–20%. 相似文献
7.
A. A. ShinkarevJr. I. P. Breus S. A. Neklyudov V. A. Breus 《Eurasian Soil Science》2010,43(9):993-1003
The effect of two methods for the preparation of soil samples for sorption experiments—hard (dehydration at 105°C) and mild
(drying over P2O5 at 20°C in vacuum) drying—on the values of the vaporphase sorption of p-xylene was studied depending on the content of organic matter in the soil. It was shown with dark gray forest and chernozemic
soils as examples that the hard drying of soil samples taken from the upper layer of the humus profile with a high content
(>4%) of organic carbon decreased their sorption capacity in the range of 0–5% by 7–81%. Therefore, the method is unsuitable
for these soils. It was also found that the mild method of soil preparation had obvious analytical advantages. 相似文献
8.
N. D. Ananyeva E. A. Susyan I. M. Ryzhova E. O. Bocharnikova E. V. Stolnikova 《Eurasian Soil Science》2009,42(9):1029-1037
In two layers of the humus horizons in soddy-podzolic soils of different biogeocenoses (Kostroma oblast) representing a succession
series, the carbon content in the microbial biomass (Cmic) was determined using the method of substrate-induced respiration and the rate of microbial CO2 production (basal respiration, BR). The Cmic content was from 110 to 755 μg/g soil, and the BR was from 0.40 to 2.52 μg CO2-C/g/h. A gradual increase in the Cmic content and BR was found in the following sequence: cropland—fallow (7-year-old)—young (20- and 45-year-old) forests—secondary
and native (primary) forests (90- and 450-year-old, respectively). In the litter, the Cmic content was higher in the 45-year-old forest than in the secondary and native forests: 10423, 6459, and 4258 μg C/g of substrate,
respectively. The portion of Cmic in the soil organic carbon content in the upper layer of the soils studied varied from 1.3 to 5.4%; its highest value was
in the soils under the secondary and native forests. The pool of microbial biomass carbon and the microbial CO2 production in the upper 25-cm layer of the soils were calculated. 相似文献
9.
V. A. Kholodov A. I. Konstantinov A. V. Kudryavtsev I. V. Perminova 《Eurasian Soil Science》2011,44(9):976-983
The structure of humic acids (HAs) in zonal soil types—soddy-podzolic soils (two samples), gray forest soil (one sample),
and chernozems (two samples)—was quantitatively studied by 13C NMR spectros-copy. In the series considered, the content of unsubstituted carbon in the aromatic fragments of HAs increased,
and the fraction of unsubstituted aliphatic structures decreased. HAs of soddy-podzolic soils were found to be enriched with
carbohydrate fragments compared to HAs of chernozems and gray forest soil. The carbon skeleton of HAs from typical rich chernozem
contained significantly more aliphatic and carbohydrate fragments compared to typical chernozem, which probably reflected
the lower degree of HA transformation in rich chernozem. 相似文献
10.
Harvester ants (Messor spp.) function as an essential link between aboveground resources and below-ground biota such as the microbial community.
We examined changes in soil microbial biomass and functional diversity resulting from harvester ant (Messor spp.) activity in the Negev Desert, Israel. Abiotic and biotic soil parameters were recorded during two seasons—wet and dry—also
representing food availability periods for the ants (low and high seed availability, respectively). Soil samples were collected
monthly from the 0- to 10- and 10- to 20-cm soil layers: (1) near the nest entrance, (2) under chaff piles, and (3) at a 2-m
radius from the nest entrance (control). Harvester ant activity increased the percentage of organic matter, total soluble
nitrogen, and microbial activity in nest-modified soils in comparison to the control soils. Higher CO2 evolution was recorded in the low-seed season in ant nest soils than in the control soils. During the high-seed season, higher
carbon dioxide evolution was recorded only at the nest entrance locations. There were no differences in microbial biomass
between the low- and high-seed seasons, but highest microbial biomass was found under chaff in low-seed season and in nest
soils in high-seed season. Microbial functional diversity was higher in nest-modified soils than in the control soils. This
study suggests that the effect of harvester ant nests on soil fertility is due to increased microbial biomass and microbial
activity in ant nest-modified soils. 相似文献
11.
A. I. Pozdnyakov A. V. Rusakov S. M. Shalaginova A. D. Pozdnyakova 《Eurasian Soil Science》2009,42(11):1218-1228
It is shown that the horizons and profiles of anthropogenically transformed soils of podzolic type—light typical agrozems,
typical texture-differentiated soils developed from glaciolacustrine loamy sands and clays and from noncalcareous mantle loams,
agrosoddy deeply podzolic soils developed from noncalcareous mantle loams, and agrosoddy shallow-podzolic soils developed
from noncalcareous mantle loams and from calcareous loams underlain by ancient glaciolacustrine loams and clays—are characterized
by some anisotropy of most of their properties. The highest anisotropy is typical of the field water content, bulk density,
and total porosity. The coefficients of anisotropy (gradients) calculated for the separate horizons as the ratios between
the values of the properties measured in the horizontal and vertical directions (k = Phoriz/Pvertic) of these properties are much higher than those of other soil properties. The coefficient of anisotropy of the soil profile
(K) is suggested as the coefficient of correlation between the values of a given property determined in the horizontal and vertical
soil sections. For the considered properties, K varies from 0.4 to 0.6. For other soils properties, such as the solid phase density, the electrical resistance determined
in a laboratory and in the field, and the organic carbon content, the coefficients of anisotropy are close to 1.0. The clay
content has an intermediate anisotropy. The values of anisotropy and its direction (gradient) should be taken into account
upon the assessment of the soil physical properties and the processes controlling them; this is particularly important in
the study of soil transformation. The revealed regularities of the soil anisotropy make it possible to suggest a new interpretation
of the data on the distribution of water and energy in soil profiles. 相似文献
12.
Dalia-Marija Brazauskiene Valdas Paulauskas Nomeda Sabiene 《Journal of Soils and Sediments》2008,8(3):184-192
Background, aim, and scope Heavy metal (HM) mobility in soil depends on the HM species in it. Therefore, knowledge of the HM speciation in soil allows
the prediction of HM impact on the environment. HM speciation in soil depends on the metal chemical origin, soil texture,
and other factors such as the origin and level of soil contamination. Recently, the problem of organic waste utilization is
of great importance as the amount of this recyclable material is continually increasing. One of the possible ways of recycling
is the use of processed organic wastes for agricultural needs. In this research, aerobically composted sewage sludge was used,
the utilization of which is of essential importance. But one of the most serious restrictions is HM transfer from such material
to the soil. Therefore, a prediction of HM mobility in soil and its migration in the environment is an important issue when
using sewage sludge compost (SSC) in agriculture. Zn, Cu, and Pb speciation was performed according to the modified methodology
of Tessier et al. (Anal Chem 51:844–851, 1979) in two different (sandy and clay) soils with background HM amounts and in soil samples amended with aerobically digested
SSC to find out the predominant species of the investigated HM and to predict their potential availability.
Materials and methods The modified method of sequential extraction initially proposed by Tessier et al. (Anal Chem 51:844–851, 1979) is designed for HM speciation into five species where HM mobility decreases in the order: F1—exchangeable HM (extracted with 1 M MgCl2 at an initial pH of 7 and room temperature), F2—carbonate-bound HM (extracted with 1 M CH3COONa buffered to pH 5 at room temperature), F3—Fe/Mn oxide-bound HM (extracted with 0.04 M NH2OH·HCl at an initial pH of 2 at 96°C), F4—organic matter-complexed or sulfide-bound HM (extracted with 0.02 M HNO3 and 30% (v/v) H2O2 at a ratio of 1:1 and an initial pH of 2 at 85°C), and F5—the residual HM (digested with HNO3, HF, and HCl mixture). After digestion, HM amounts in solution were determined by atomic absorption spectrometry (AAS ‘Hitachi’).
Mixtures of uncontaminated soils of different textures (clay and sandy) with SSC in ratios 20:1, 10:1, and 5:1 were used to
simulate the land application with SSC. During a period of 7 weeks, changes in Zn, Cu, and Pb content within species were
investigated and compared weekly in soil–SSC mixtures with their speciation in pure soil and in the SSC.
Results Results in the SSC showed that more HM were found as mobile species compared to the soils, and in sandy soil, more were found
in the mobile species than in clay soil. But the HM speciation strongly depended on the metal chemical origin. According to
the potential availability, HM ranked in the following order: Zn>Pb>Cu. Zinc generally occurred in the mobile species (F1
and F3), especially in sandy soils amended with SSC, and changes of the Zn speciation were insignificant at the end of the
experiment. Pb transfer to insoluble compounds (F5) was evident in the SSC–soil mixtures. This confirms that Pb is extremely
immobile in the soil. However, the observed increase of Pb amounts in the mobile species (F1 and F2) during the course of
experiment shows a critical trend of Pb mobilization under anthropogenic influence. Copper in the soil–SSC mixtures had a
trend to form compounds of low mobility, such as organic complexes and sulfides (F4) and nonsoluble compounds (residual fraction
F5). Initially, the amounts of mobile Cu species (F1 and F2) increased in the soils amended with SSC, probably due to the
influence of SSC of anthropogenic origin with lower pH and high organic matter content, but Cu mobility decreased nearly to
the initial level again after 3–4 weeks. Hence, the soil has a great specific adsorption capacity to immobilize Cu of anthropogenic
origin.
Discussion Zn mobility and environmental impact was greater than that seen for Cu and Pb, while mobility of both Cu and Pb was similar,
but variable depending on soil texture and contamination level. The effect on the shift of HM mobility and potential availability
was greater in sandy SSC-amended soils than in clay soils and increased with an increasing amount of SSC.
Conclusions Usage of SSC for land fertilization should be strictly regulated, especially regarding Pb amounts.
Recommendations and perspectives The influence of SSC on Cu and Zn mobility and potential availability was more significant only in the case of sandy soil
with a higher SSC ratio. Nevertheless, this waste product of anthropogenic origin increased Pb mobility in all cases in spite
of only moderate Pb mobility in SSC itself. Therefore, aerobic processing of sewage sludge must be strictly regulated, especially
regarding Pb amounts, and SSC ratios must be in control regarding HM amounts when using it for on-land application. 相似文献
13.
N. V. Mozharova 《Eurasian Soil Science》2010,43(8):935-944
Natural soils with disturbed functioning parameters compared to the background soils with conservative technogenic-pedogenic
features were distinguished on vast areas above the artificial underground gas storages in the zones of spreading and predominant
impact of hydrocarbon gases. The disturbance of the functioning parameters is related to the increase in the methane concentration,
the bacterial oxidation intensity and destruction, and the complex microbiological and physicochemical synthesis of iron oxides.
The technogenic-pedogenic features include neoformations of bacteriomorphic microdispersed iron oxides. The impurity components
consist of elements typical for biogenic structures. New soil layers, horizons, specific anthropogenically modified soils,
and soil-like structures were formed on small areas in the industrial zones of underground gas storages due to the mechanical
disturbance, the deposition of drilling sludge, and the chemical contamination. Among the soils, postlithogenic formations
were identified—chemotechnosols (soddy-podzolic soils and chernozems), as well as synlithogenic ones: strato-chemotechnosols
and stratochemoembryozems. The soil-like bodies included postlithogenic soil-like structures (chemotechnozems) and synlithogenic
ones (strato-chemotechnozems). A substantive approach was used for the soil diagnostics. The morphological and magnetic profiles
and the physical, chemical, and physicochemical properties of the soils were analyzed. The micromorphological composition
of the soil magnetic fraction was used as a magnetic label. 相似文献
14.
Data on the taxonomic and trophic composition, population density, and biomass of invertebrates in the soils of the main mountain
vegetation zones of the Khibiny Mountains—taiga, subalpine, and alpine—are obtained. The degree of similarity between soil
faunal complexes in different vegetation zones within the studied slope is higher than that between zonal biocenoses of Murmansk
oblast. The mountain tundra zone differs from the zonal tundra in a higher population density and taxonomic diversity of invertebrates,
which are similar to those in the northern taiga podzols. At the same time, invertebrate complexes in the mountain taiga zone
are poorer than those in the zonal plain taiga soils. The analysis of invertebrate taxa present in all the studied mountain
vegetation zones demonstrates similar effects of the altitudinal and latitudinal zonality on the species composition of invertebrates.
A conclusion is made about a higher functional activity of saprotrophs in the high-humus soils enriched in biogenic elements
of the Khibiny Mountains in comparison with the functional activity of saprotrophs in the zonal plain podzols. 相似文献
15.
The Quaternary deposits on the Tersk coast of the White Sea are represented by marine deposits (the Tersk sands) enriched
in the sea-sorted eluvium of the red Tersk sandstone. These deposits and the soils developed from them are characterized by
the predominance of the fine sand fraction and the absence of gravel and the coarser fractions. The sediments derived from
the red Tersk sandstone have an impoverished chemical composition (the silica content reaches 75–80%). The iron-illuvial podzols
developed from them are characterized by the slightly pronounced differentiation of the main oxides and by the eluvial-illuvial
redistribution of the amorphous Al and Fe compounds. Sandy soils—psammozems—with undifferentiated soil profiles are developed
from windblown sands subjected to afforestation and from coastal marine sands under a relatively thin natural plant cover.
Iron-illuvial podzols buried under a thin sand layer preserve the Al-Fe-humus type of the profile differentiation. In the
recently deposited sand layer, the eluvial-illuvial redistribution of the chemical elements is absent. 相似文献
16.
V. D. Tonkonogov I. I. Lebedeva M. I. Gerasimova S. F. Khokhlov 《Eurasian Soil Science》2009,42(9):967-975
The factors of soil formation are not directly taken into account in the new profile-genetic Russian soil classification system;
they are not reflected in the names and diagnostics of the soils. At the same time, as well as in many other modern soil classification
systems, including the American Soil Taxonomy and the WRB system, the choice of the diagnostic criteria, the establishment of the relationships between them, and the setting
of the quantitative boundaries between the soil taxa are based on our perception of soil geneses with due account for the
factors of soil formation. In contrast to the ecological-genetic soil classification system of 1977, information on the factors
of soil formation in the new system is encoded in the properties of the soil horizons. In some cases, this is insufficient
for the definite geographic localization of soils and complicates the practical application of the new classification system.
In this context, information on the ecological niches of soil types was included in the field manual on soil correlation-an
abridged version of the soil classification system published in 2008—in the form of special tables developed for native and
agrogenic soils. The analysis of these tables made it possible to outline certain geographic regularities in the distribution
of soil types belonging to the trunk of postlithogenic soils. 相似文献
17.
Background, aim, and scope Exploited gas fields and underground gasholders are specific sources of increasing methane concentration. Methane migrates
into the soils by diffusion and convection through natural and technogenic cracks in geological structures and influences
the function of the soils. Soil cover of gas-bearing area functions as a specific, bilateral, periodically penetrating, geomembrane.
Soils shield, transform, and differentiate migrating fluxes of technogenic-allochthonous methane, preventing its emission
to the atmosphere. Problems of methane’s emission are rather current at the present, as methane is the second in importance
after CO2 greenhouse gas, since its concentration in the atmosphere annually grows by approximately 1%. By global estimations, methane
emissions in the gas industry make about 8% of annual receipt to the atmosphere, equal on the average to 500 Тg per a year
(Cicerone and Oremland, Global Biogeochem Cy 2:299–327, 1988). But these calculations are based on the account of the technological losses making 3–12% from the mining of natural gas.
The contribution of migratory methane fluxes to the atmosphere, as a rule, is not considered. The need for research of soil
cover functioning on gas-bearing areas is explained by the fact that processes of methane oxidation, its transformation in
soils, and emission to the atmosphere at these objects are now practically not being studied. The aim of our study was to
reveal specific processes of soil function and formation on gas-bearing areas by an example of underground gasholder.
Materials and methods The material was sampled in 1998–2003 at the territory of underground gasholder located in Albeluvisol’s zone in Russia. According
to the comparative-geographical method, 51 soil profiles have been studied in similar litologically geomorphological conditions
in various geochemical zones: in the industrial zone, in the zone of gas dissipation, and at the regional background. The
total square of investigated territory is about 60 km2. Six soil profiles were investigated in seasonal dynamics. Samples of soils for physical, chemical, and microbiological analyses
were taken from each horizon of soil profiles (202 samples). Samples of soil air for a definition of methane concentration
were taken from depths of 20, 40, and 60 cm. Methane emission to the atmosphere was measured near soil’s cuts and, in addition,
on all area of the investigated territory at knots of squares network through 700–1,000 m, in total at 32–42 points in May,
July, and November. Years of investigation have been split by technological and hydrothermal conditions. The periods with
the normal and lowered compression of gas in gasholder, dry and warm, and damp and cool years have been allocated. It has
influenced the soil function processes and considered an interpretation of the data received.
Results The changes of functional parameters of soils at a gas-bearing area influenced by methane fluxes migrating from gas deposits,
in comparison with background soils, are revealed. Such functional parameters are methane concentration in the soils, activity
of its bacterial oxidation, methane emission to the atmosphere, and oxidation–reduction potential. Spatial and temporary dynamics
of these parameters at gas-bearing and background territory are investigated.
Discussion Methane interaction with soil’s air is in its ascending (descending) and lateral diffusion and convection in soils. Methane
fluxes dissipate in porous space of soils forming gas anomalies. The technogenic-allochthonous methane concentration strongly
varies in soil’s air on gas-bearing area (1–10,500 ppm) and, on average, exceeds the autochthonous, microbiologically produced
methane at background territories. Migratory methane is deposited on diffusion and sorption barriers. The capacity of diffusion
barrier depends on effective coefficient of diffusion, the attitude of air and general porosity, and granulometric composition
and sharply differs in auto-, semi-hydro-, and hydromorphic soils reaching maximum in hydromorphicity and among the soils
with identical water content—in heavy soils. The capacity of the sorption barrier is defined by abiotic methane absorption
and a specific surface of soils and grows with their increasing intensity in soils to a heavier granulometric composition
or into soils with peat and gleyic horizons. The low sorption capacity leads to an increase of methane concentration in the
soil’s air and decreases its utilization by microorganisms, in which its quantity depends on sorption properties. The central
component of functioning that promotes a number of essential transformations in soils on gas-bearing areas is methane interaction
with the biotic phase. The periods of methane deposition by diffusion and sorption barriers are used for biological methane
oxidation and formation of biogeochemical barriers in soils. The activity of bacterial methane oxidation is characterized
by spatial variability and depends on the entrance of methane, defined by granulometric composition, soil moisture, the attitude
of air and general porosity, Eh, organic matter content, and salinization. During interaction between technogenic-allochthonous
methane and soil on diffusion, sorption, and biogeochemical barriers, its transformation occurs, accompanied by a strengthening
of variability of oxidation–reduction potential and formation of pedogenic, bacteriomorphic, and nanodispersic magnetic oxides
of iron.
Conclusions and perspectives Specificity of soil functioning on a gas-bearing area is in interaction of technogenic-allochtonous methane with solid, liquid,
gaseous, and living substance of the soil system. Spatial laws of soils functioning on gas-bearing area in the Albeluvisol’s
zone are revealed. Distinctions of soil functions depending on litologically geomorphological conditions are shown. The greatest
changes of parameters of functioning under the influence of technogenic-allochthonous methane occur in automorphic soils,
and it is less in semi-hydromorphic soils. Activity of bacterial methane oxidation in soils, emission, and consumption from
the atmosphere and their spatial laws are characterized by the time dynamics depending on hydrothermal and technological conditions
of seasons and years. During oxidation in soils of gas-bearing areas, carbon of methane is concentrated on a biogeochemical
barrier that is shown in the increase of methylotrophic microorganisms’ biomass and leads to a high variability and decrease
of Eh and to the formation of magnetic oxides of iron.
Recommendations Results of research can be used for carrying out ecological monitoring and an estimation of tightness of objects of the gas
industry. Activity of bacterial methane oxidation, Eh, and magnetic oxides of iron can be used as diagnostic parameters of
soils on gas-bearing areas.
This paper has been developed from a presentation at the conference SUITMA-4 (Soils in Urban, Industrial, Traffic, Mining
and Military Areas) Nanjing, China, 2007 相似文献
18.
Structural and functional response of soil microbiota to addition of plant substrate are moderated by soil Cu levels 总被引:1,自引:0,他引:1
Steven Alan Wakelin Guixin Chu Kris Broos K. R. Clarke Yongchao Liang Mike J. McLaughlin 《Biology and Fertility of Soils》2010,46(4):333-342
In soils, the microbially mediated decomposition of plant residue is a key process with wide ranging effects on ecosystem
functioning and stability. Understanding the impact of contamination on this process is of high importance. We investigated
the effects of long-term (6 years) copper exposure on the capacity of soil microbiota to decompose newly added resources;
dried and ground Medicago truncatula stubble. In addition, the effects on the microbial community structure across the three domains were explored using polymerase
chain reaction–denaturing gradient gel electrophoresis rRNA gene profiling. Ecological distances in community structure between
treatments was calculated (Kulczynski) and effects tested using PERMANOVA. Clear dose–response relationships were present
between microbial respiration (CO2 evolution) and soil Cu level in soils receiving medic, but not under basal conditions (i.e., no medic added). These show
that relatively labile forms of C are needed to drive microbial ecotoxicological responses and that microbial adaptation to
the presence of Cu in the soils—after >6 years exposure—was functionally limited. Bacterial, archaeal and fungal communities
showed significant (P < 0.05) levels of structural change in soils across the Cu gradient, demonstrating that species replacement had occurred
following strong selective pressure. Addition of medic resources to the soils caused significant shifts in the bacterial and
archaeal community structure (P < 0.001), which occurred across the entire range of soil Cu levels. For the fungal community, a significant interaction effect
was present between Cu and medic addition (P = 0.002). At low Cu levels, medic addition caused large shifts in community structure, but this was negligible under high
Cu levels. This was reflected in significant changes in the level of community structural dispersion at low compared with
high Cu levels. As such, we show that Cu limits the capacity of soil fungal communities to rapidly respond to new resource
capture. Given the primary role of soil fungi in plant material decomposition, this may have wide ranging impacts on wider
ecosystem processes including nutrient cycling, trophic interactions, food web stability and energy transfer. 相似文献
19.
The spatial distribution of major soil horizons and layers of pyroclastic deposits in Kamchatka was analyzed with the use
of GIS technologies. For this purpose, the attribute soil database and the computer-supported cartographic database were developed.
Their analysis with the help of GIS technologies made it possible to study the dependence of the morphology of soil profiles
on the bioclimatic conditions and on the stratification of ash layers in the particular areas of Kamchatka and to develop
the cartographic model of the areas of soil horizons. The concept of tephra stratotypes—the particular combinations of ash
layers in the profiles of volcanic soils—was verified on the basis of factual materials. It was shown that tephra stratotypes
affect many important soil properties and specify the direction of soil formation in Kamchatka. Several major tephra stratotypes
differing in their morphology and environmentally important features were distinguished in Central Kamchatka. The method of
soil mapping on the basis of the concept of tephra stratotypes with due account for the specificity of surface organic horizons
of soils was developed. It is argued that this method makes it possible to reflect the specificity of soil formation in volcanic
regions. 相似文献
20.
The influence of a fire retardant (Firesorb, an acrylic–acrylamide copolymer) on the microbial community structure determined by phospholipid fatty acid (PLFA) analysis was examined under laboratory conditions using two different textured soils under pine forest. Firesorb was added to unheated and heated soil samples (350°C for 10 min followed by reinoculation, to mimic a forest fire) at three levels of application (none, usual and three times the usual levels), and measurements were made after 12 weeks of incubation. The relative importance of the three factors considered on the PLFA profiles was as follows: soil heating ≫ soil texture ≈ Firesorb treatment. In the unheated soils, Firesorb had a larger effect than soil texture, while the opposite was found in the heated soils. Soil heating reduced the total PLFAs, while Firesorb tended to increase them in both the unheated and heated soils. Soil heating decreased the PLFAs indicative of gram-positive (G+) bacteria and tended to increase the fatty acids associated with gram-negative (G−) bacteria and, to a lesser extent, the PLFA 18:2ω6, considered to be predominantly of fungal origin. Firesorb treatment decreased the G−/G+ bacteria ratio in the heated soils but tended to increase it in the unheated soils, the effect being dose dependent. 相似文献