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1.
N. N. Kashirskaya T. E. Khomutova T. S. Demkina V. A. Demkin 《Eurasian Soil Science》2009,42(5):536-542
The total microbial biomass (TMB) was assessed in the chestnut and light chestnut soils and in the paleosols under burial mounds (steppe kurgans) in the Lower Volga region on the basis of data on the organic carbon content in the extracted microbial fraction supplemented with the data on the extraction completeness as a conversion coefficient. The completeness of the microbial fraction extraction was determined by direct counting of the microbial cells and colony-forming units (on plates with soil agar). The total microbial biomass varied from 400 to 6600 μg of C/soil. Its values in the buried soils were 3–5 times lower than those in the surface soils. The TMB distribution in the buried chestnut soil profile was close to that in its modern analogue (with the minimum in the B1 horizon). In the buried light chestnut paleosols, the TMB values usually increased down the profile; in the recent light chestnut soils, the maximum TMB values were found in the uppermost horizon. 相似文献
2.
N. N. Kashirskaya T. E. Khomutova V. V. Dmitriev V. I. Duda N. E. Suzina V. A. Demkin 《Eurasian Soil Science》2010,43(10):1140-1149
The morphology of microbial cells was studied, and the biomass of microorganisms was estimated in the modern steppe soils
and paleosols buried under kurgans in the Lower Volga region with the methods of electron microscopy. The shape and ultrastructure
of the cells in the modern soils and paleosols were similar, though their average volumes differed (0.37 and 0.28 μm3, respectively). The portion of cells with a volume above 1 μm3 in the surface soils and paleosols reached 10.9 and 9.2%, respectively, and the portion of cells with a volume less than
0.01 μm3 in the surface soils was 10% lower than that in the buried paleosols. It was found that the cells of the microorganisms have
an external organomineral layer, which increases the cell volume by 4.9 times, and this fact was taken into account in the
calculation of the microbial biomass. In the chestnut and light chestnut paleosols, the latter comprised 1500 and 230 μg of
C/g soil, respectively. 相似文献
3.
The microbial communities were studied in the modern and buried under kurgans (1st century AD) soils of solonetzic complexes on the dry steppes of the northern part of the Yergeni Upland. It was found that the changes in the numbers of microorganisms from different trophic groups and in the biomass of the fungal mycelium along the profiles of the modern and buried solonetzic chestnut soils and solonetzes do not differ significantly. The quantitative estimate of the impact of the solonetzic process on the spatial variability of the microbiological parameters of the soils was given on the basis of the ANOVA. As a rule, the values of the microbiological parameters in all the horizons of the modern and buried chestnut soils were 1.2–2.8 times higher than those in the modern and buried solonetzes. The influence of the degree of solonetzicity of the buried paleosols on the microbiological parameters manifested itself in the entire profile, though in each particular horizon it was only seen in the numbers of some particular trophic groups of microorganisms. The comparison between the mean weighted values of the microbiological parameters in the entire soil profiles (the A1 + B1 + B2 horizons) demonstrated an inverse relationship between the population density of the microorganisms utilizing easily available organic matter and the degree of solonetzicity of the buried paleosols. The maximum biomass of the fungal mycelium was found in the solonetzic chestnut paleosol; it exceeded the biomass of the fungal mycelium in the other paleosols (which did not differ significantly in that parameter from one another) by 1.5–1.6 times. 相似文献
4.
The structural state of modern and buried chestnut soils on the Privolzhskaya Upland (Volgograd oblast) was studied in order to determine changes in the soil structure in dependence on the time of soil burying. The soils buried 3500, 1700, and 700 years ago and modern background chestnut soils were examined. The structural state of soils was determined via their fractionation on a set of sieves (10–0.25 mm) in the air-dry state. We determined the contents of coarse aggregates, total aggregates, disperse soil matter, aggregation coefficient, and the degree of differentiation of the soil profiles. It was found that the structure of buried soils is preserved for 3500 years after the soil burying. The structural state of the studied soils changed with time depending on the climatic conditions that existed at the moment of soil burying. In humid periods, the amount of coarse aggregates (lumps) decreased, and the content of aggregated fractions increased; the reverse processes took place in arid epochs. Thus, it was shown that the aggregate composition of soils is specific for each period of soil formation and depends on the degree of climatic humidity. It is preserved in the buried soils independently on the duration of their existence in the buried state. We determined the impact of aggregate size on the Corg tolerance toward mineralization processes. It was shown that the content of organic carbon and its physical protection from mineralization are determined by different mechanisms of its fixing in aggregates of different sizes and depend on the conditions for the development of soil structure before burying and on the duration of the soil existence in the buried state. The results obtained in this study can be used as a retrospective basis for predicting changes in the physical properties of soils under conditions of changing climate. 相似文献
5.
The contents of phospholipids and carbon of the total microbial biomass were determined in the modern chestnut soil and in
the paleosols buried under mounds of the Bronze and Early Iron Ages (5000–1800 years ago) in the dry steppe of the Lower Volga
River basin. Judging from data on the ratio between the contents of phospholipids and organic carbon in the microbial cells,
the carbon content of the living microbial biomass was calculated and compared with the total microbial biomass and total
organic carbon in the studied soils. In the background chestnut soil, the content of phospholipids in the A1, B1, and B2 horizons
amounted to 452, 205, and 189 nmol/g, respectively; in the paleosols, it was 28–130% of the present-day level. The maximum
content was measured in the paleosols buried 5000 and 2000 years ago, in the periods with an increased humidity of the climate.
In the background chestnut soil, the total microbial biomass was estimated at 5680 (the A1 horizon), 3380 (B1), and 4250 (B2)
μg C/g; in the paleosols, it was by 2.5–7.0 times lower. In the upper horizons of the background soil, the portion of the
living microbial biomass in the total biomass was much less than that in the paleosols under the burial mounds; it varied
within 8.5–15.3% and 15–81%, respectively. The portion of living microbial biomass in the total organic carbon content of
the background chestnut soil was about 4–8%. In the paleosols buried in the Early Iron Age (2000 and 1800 years ago), this
value did not exceed 3–8%; in the paleosols of the Bronze Age (5000–4000 years ago), it reached 40% of the total organic carbon. 相似文献
6.
N. P. Chizhikova I. V. Kovda A. V. Borisov N. I. Shishlina 《Eurasian Soil Science》2009,42(10):1179-1189
The development of the solonetzic process in paleosols buried under kurgans and in the modern surface soils has been studied
on the basis of the analysis of the clay (<1 μm) fraction. The revealed changes in the textural differentiation of the soils
and the mineralogical composition of the clay fraction during 4500 years are assessed from the viewpoint of the “memory“ of
the solid-phase soil components. The mineralogical characteristics show that the solonetzic process in the modern background
soil is more developed. The mineralogical approach allows us to reveal the long-term changes in the soil status; it is less
useful for studying the effect of short-term bioclimatic fluctuations. In the latter case, more labile soil characteristics
should be used. The mineralogical method, combined with other methods, becomes more informative upon the study of soil chronosequences.
Our studies have shown that the data on the clay minerals in the buried paleosols may contain specific information useful
for paleoreconstructions that is not provided by other methods. 相似文献
7.
Modern light chestnut and chestnut soils and their analogues buried under steppe kurgans in the southeastern part of the Russian
Plain were studied in order to determine the rates of the CO2 production by these soils under the native (with the natural moisture content) and moistened (60% of the total water capacity)
conditions. It was found that the rates of the CO2 production by the soil samples in the native state are relatively close to one another and vary from 0.3 to 1.4 μg of C/100
g of soil/h. The rates of the CO2 production in the moistened state increased by two orders of magnitude for the modern surface soils and by an order of magnitude
for the buried soils. 相似文献
8.
T. S. Demkina T. E. Khomutova N. N. Kashirskaya E. V. Demkina I. V. Stretovich G. I. El-Registan V. A. Demkin 《Eurasian Soil Science》2008,41(13):1439-1447
Chestnut paleosols buried under steppe kurgans about 4800, 4000, and 2000 years ago and their background analogues were studied
in the dry steppe zone on the Volga-Don interfluve. Morphological, chemical, microbiological, biochemical, and radiocarbon
studies were performed. Paleoclimatic conditions in the region were reconstructed on the basis of paleosol data. The ages
of microbial fractions isolated from the buried and surface soils were determined using the method of 14C atomic mass-spectrometry. It reached 2100 years in the A1 horizon of the buried paleosol, which corresponded to the archaeological
age of the kurgan (1st century AD). The ages of microbial biomass isolated from the B2 horizons of the buried paleosol and
the background surface soil comprised 3680 ± 35 and 3300 ± 30 years, respectively. The obtained data confirmed our assumption
about preservation of microorganisms of the past epochs in the paleosols buried under archaeological monuments. It is ensured
by various mechanisms of adaptation of soil microbial communities to unfavorable environmental conditions (anabiosis, transformation
of bacteria into nanoforms, etc.). The possibility to stimulate germination of the ancient dormant microbial pool isolated
from the buried paleosols by 2–3 orders of magnitude with the use of β-indolyl-3-acetic acid as a signal substance was demonstrated. 相似文献
9.
The reconstruction of soil, vegetation, and climatic conditions for the Srubnaya cultural epoch (3660 ± 40 (date wood), 3860 ± 120 (bones date) was performed on the basis of palynological and paleosol studies with radiocarbon dating of bones and wood fragments from two kurgans in the Cis-Ural forest-steppe of the Republic of Bashkortostan. Morphological features and chemical properties of the modern background soils, the soils formed on the surface of burial mounds (kurgans), and the soils buried under them were characterized. According to palynological data, the climate of this territory in the period of construction of these kurgans was more humid than the modern climate. The paleovegetation of the Srubnaya epoch was represented by mesophilic herbaceous steppes with a lower participation of xerophytic species as compared to the modern steppe and by small forest groves composed of birch and pine trees with some admixture of lime trees. The temperature conditions were close to those at present, or somewhat cooler, which is evidenced by the lower content of pollen of the broadleaved trees. The modern background soils and the soils buried under the kurgans are classified as thin light loamy typical calcareous chernozems; they have similar morphologies and physicochemical properties. However, the reconstructed organic matter content in the upper 50 cm of the buried paleosols is higher than that in the modern soils. This attests to more favorable climatic conditions during the Srubnaya epoch and is in agreement with palynological data. 相似文献
10.
T. S. Demkina T. E. Khomutova T. V. Kuznetsova A. A. Kontoboitseva A. V. Borisov 《Eurasian Soil Science》2016,49(1):56-69
Microbial communities of recent surface soils and the soils buried beneath the rampart of the Tsaritsyn Defense Line (1718–1720) in the Little Ice Age were studied. The contribution of the time factor to the variability in the number of microorganisms from different trophic groups was shown to be minor (0.2–0.3%), although significant. In the upper horizon of the paleosols reflecting the environmental conditions intrinsic to the period of the rampart construction, the lower (by two times) content of live microbial biomass, the lower metabolic activity of the microbial community, and the more contrasting changes in the microbiological parameters as compared to these characteristics in the recent soils were found for all the elements of the local topography. The stabilities of the microbial communities in the buried and recent soils were almost the same. The ecological–trophic structure of the microbial communities in the buried soils evidences that, the climate of the 18th century in the southern Privolzhskaya Upland was more humid than now. At the same time, temperature conditions of the Little Ice Age did not prevent the development of steppe vegetation and corresponding soil microbial communities in this area. Our data on the morphology and physicochemical properties of the soils confirm the assumption about more humid climatic conditions at the beginning of the 18th century in the studied area. 相似文献
11.
《CATENA》2001,43(3):203-215
The carbonate profiles of Chernozems bear important information on soil processes and can be successfully used for paleoenvironmental reconstruction. In the Northern Caucasus region, Russia, carbonate profiles of Chernozems were compared under anthropogenic (irrigation) and natural changes of moisture regime. The results for irrigation served as the basis for understanding the response to natural climatic changes. A soil chronosequence, consisting of soils buried under archaeological mounds dated to >5000, 3800–4000 and 1600–1700 BP and modern surface soils, was studied in a similar way. The soils buried >5000 and 3800–4000 BP had distinctive migrational and segregational carbonate accumulations (CAs). The migrational forms occurred in the surface horizons and contained 89–92% calcite with the highest dissociation temperatures. In the soils buried 1600–1700 BP the carbonate profile was clearly defined in terms of migrational CAs; they occurred only in the deeper horizons, had no clear boundaries and were diffused throughout the soil mass. In the modern surface soils the migrational CAs have almost disappeared, and the segregational CAs have the largest halos of recrystallised carbonates. The values of δ13C for CAs in the soils buried >5000 and 3800–4000 BP were lighter than in the soils buried 1600–1700 BP and the modern surface soils (−10.6‰ to −9.9‰ and −9.6‰ to −8.8‰, respectively). We conclude that the climate of the region during the second half of the Holocene changed from relatively dry and warm in the Atlantic period (>5000 BP) to more humid and cooler in the early Subboreal (5000–4000 BP). Since 4000 BP the climatic conditions have remained relatively stable with some changes in moisture regime resulting from human activities in recent centuries. 相似文献
12.
Periodical forest fires are typical natural events under the environmental and climatic conditions of central and southern Yakutia and Transbaikal region of Russia. Strong surface fires activate exogenous geomorphological processes. As a result, soils with polycyclic profiles are developed in the trans-accumulative landscape positions. These soils are specified by the presence of two–three buried humus horizons with abundant charcoal under the modern humus horizon. This indicates that these soils have been subjected to two–three cycles of zonal pedogenesis during their development. The buried pyrogenic humus horizons accumulate are enriched in humus; nitrogen; total and oxalate-extractable iron; exchangeable bases (Са+2 and Mg+2); and the fractions of coarse silt, physical clay (<0.01 mm), and clay (<0.001 mm) particles in comparison with the neighboring mineral horizons of the soil profile. The humus of buried pyrogenic horizons is characterized by the increased content of humic acids, particularly, those bound with mobile sesquioxides (HA-1) and calcium (HA-2) and by certain changes in the type of humus. 相似文献
13.
The characteristics of the respiration activity of leached chernozems under different land uses were studied. The use of soil-conservation
technologies of crop cultivation led to an increase in the basal and substrate-induced respiration and in the content of the
carbon of the microbial biomass. With respect to the microbial activity and the sustainability of the microbial pool, the
soils were arranged into the following order: virgin soils → soils treated with soil-conservation technologies → soils treated
with traditional methods. 相似文献
14.
The in situ net nitrogen mineralization (Nnet) was estimated in five agricultural soils under different durations of organic farming by incubating soil samples in buried bags. Simultaneously, soil microbial C and N was determined in buried bags and in bulk soil under winter wheat and after harvest. The aim was to check for variations in soil microbial biomass contents and microbial C:N ratios during the incubation period, and their importance for Nnet rates. Microbial C and N contents were highest in soils that had been organically farmed for 41 years, whereas Nnet rates were highest in a short‐term organically managed soil that had been under grassland use until 36 years ago. The mean coefficient of variation in the bulk soil for microbial C estimates ranged from 5 to 12 %. Microbial N contents were similar inside buried bags and in the bulk soil at the end of the incubation periods. Under winter wheat during the incubation period until harvest, microbial C contents and microbial C:N ratios (in 10—27 cm depth only) decreased more strongly inside buried bags than in the bulk soil. Following harvest of winter wheat and ploughing, microbial biomass increased while in situ Nnet decreased, presumably due to N immobilization. The Nnet rates were not correlated with microbial N contents or changes in microbial N contents inside buried bags. At the end of the vegetation period of winter wheat, Nnet rates were negatively correlated with microbial C:N ratios. Because these ratios concurrently decreased more inside buried bags than in the bulk soil, the Nnet estimates of the buried bag method may differ from the Nnet rates in the bulk soil at that time. 相似文献
15.
T. E. Khomutova T. S. Demkina A. V. Borisov I. I. Shishlina 《Eurasian Soil Science》2017,50(2):229-238
The size and structure of microbial pool in light chestnut paleosols and paleosolonetz buried under kurgans of the Middle Bronze Age 4600–4500 years ago (the burial mound heights are 45–173 cm), as well as in recent analogues in the desert-steppe zone (Western Ergeni, Salo-Manych Ridge), have been studied. In paleosol profiles, the living microbial biomass estimated from the content of phospholipids varies from 35 to 258% of the present-day value; the active biomass (responsive to glucose addition) in paleosols is 1?3 orders of magnitude lower than in recent analogues. The content of soil phospholipids is recalculated to that of microbial carbon, and its share in the total soil organic carbon is determined: it is 4.5–7.0% in recent soils and up to three times higher in the remained organic carbon of paleosols. The stability of microbial communities in the B1 horizon of paleosols is 1.3–2.2 times higher than in the upper horizon; in recent soils, it has a tendency to a decrease. The share of microorganisms feeding on plant residues in the ecological–trophic structure of paleosol microbial communities is higher by 23–35% and their index of oligotrophy is 3–5 times lower than in recent analogues. The size of microbial pool and its structure indicate a significantly higher input of plant residues into soils 4600–4500 years ago than in the recent time, which is related to the increase in atmospheric humidity in the studied zone. However, the occurrence depths of salt accumulations in profiles of the studied soils contradict this supposition. A short-term trend of increase in climate humidity is supposed, as indicated by microbial parameters (the most sensitive soil characteristics) or changes in the annual variation of precipitation (its increase in the warm season) during the construction of the mounds under study. 相似文献
16.
《CATENA》2001,43(3):251-265
The soils of Galicia, NW Spain, developed on gabbro often include one or more buried profiles. In the modern overlying soil, gibbsite is common and the Fe oxyhydroxides include maghemite. In the buried soil interstratified kaolinite–smectite is abundant, gibbsite is present in traces and the Fe oxyhydroxides are mostly formed by goethite. Chemical and mineralogical data show that the modern soil has developed under strongly leaching conditions that contrast with those in which the buried soil formed. We suggest that the interstratified kaolinite–smectite is a relict mineral that helps reconstruction of the pedogenetic history of these soils. 相似文献
17.
S. N. Gorbov O. S. Bezuglova K. N. Abrosimov E. B. Skvortsova S. S. Tagiverdiev I. V. Morozov 《Eurasian Soil Science》2016,49(8):898-907
Physical properties of natural and anthropogenically transformed soils of Rostov agglomeration were examined. The data obtained by conventional methods and new approaches to the study of soil physical properties (in particular, tomographic study of soil monoliths) were used for comparing the soils of different functional zones of the urban area. For urban territories in the steppe zone, a comparison of humus-accumulative horizons (А, Asod, Ap, and buried [A] horizons) made it possible to trace tendencies of changes in surface soils under different anthropogenic impacts and in the buried and sealed soils. The microtomographic study demonstrated differences in the bulk density and aggregation of urban soils from different functional zones. The A horizon in the forest-park zone is characterized by good aggregation and high porosity, whereas buried humus-accumulative horizons of anthropogenically transformed soils are characterized by poor aggregation and low porosity. The traditional parameters of soil structure and texture also proved to be informative for the identification of urban pedogenesis. 相似文献
18.
Alessandra Lagomarsino Anna Benedetti Sara Marinari Letizia Pompili M. Cristina Moscatelli Pier Paolo Roggero Roberto Lai Luigi Ledda Stefano Grego 《Biology and Fertility of Soils》2011,47(3):283-291
Five soils characterised by different agro-forest managements, typical of Mediterranean environment and with increasing human
impact were chosen in Sardinia (Italy): two vineyards with different management systems, a rotation hay crop-pasture and a
forest (Quercus suber L.). The study aimed to investigate the relationships between C storage and microbial functionality in soil under different
managements. Pools of total organic C and microbial biomass C were determined, as well as the loss of organic C due to microbial
respiration (basal and cumulative) and several microbial indices (metabolic, mineralization, and microbial quotient) as indicators
of the microbial efficiency in the use of energy and the degree of substrate limitation for soil microbes. Enzymes were chosen
on their relevance in the C (β-cellobiohydrolase, N-acetyl-β-glucosaminidase, β-glucosidase, α-glucosidase), N (leucine aminopeptidase), S (arylsulphatase) and P (acid phosphatase)
cycling and were used as indicators of functional diversity in soil. Organic C pools and enzyme activities on average increased
noticeably in soils with a lower human impact showing the highest values in forest and the lowest in the vineyards, following
the trend of organic matter availability. The trend in functional diversity reflected the increase of microbial pool and organic
C availability: the vineyards showed a lower Shannon’s diversity index, whilst pasture and forest sites reached the maximum
levels of functional diversity. These soils showed an increase of microbial efficiency in the use of available resources and
the decrease of substrate limitation for soil microbes. 相似文献
19.
A comparative analysis of the state of microbial communities in kurgans, paleosols buried under them, and background surface soils in the dry steppe zone of the Lower Volga region has been performed. It is shown that the population density of microorganisms of various trophic groups in the kurgans is an order of magnitude lower than that in the A1 horizon of the corresponding buried paleosols and background surface soils within the areas of chestnut, light chestnut, and solonetzic soils. The respiration activity of the microbial communities in the upper layer of the kurgans is comparable with that in the A1 horizons of the background surface soils; it decreases in the deeper layers of the kurgans. In the A1 horizon of the buried paleosols, the respiration activity is approximately the same as in the deep layers of the kurgans. In the buried paleosols, the spatial variability in the numbers of soil microorganisms is approximately the same or somewhat higher than that in the background surface soils. The spatial variability in the respiration activity of the buried paleosols is two to four times higher than that in the background surface soils. 相似文献
20.
This study examines the effects of atrazine on both microbial biomass C and C mineralization dynamics in two contrasting agricultural
soils (organic C, texture, and atrazine application history) located at Galicia (NW Spain). Atrazine was added to soils, a
Humic Cambisol (H) and a Gleyic Cambisol (G), at a recommended agronomic dose and C mineralization (CO2 evolved), and microbial biomass measurements were made in non-treated and atrazine-treated samples at different time intervals
during a 12-week aerobic incubation. The cumulative curves of CO2–C evolved over time fit the simple first-order kinetic model [Ct = Co (1 − e
−kt
)], whose kinetic parameters were quantified. Differences in these parameters were observed between the two soils studied;
the G soil, with a higher content in organic matter and microbial biomass C and lower atrazine application history, exhibited
higher values of the total C mineralization and the potentially mineralizable labile C pool than those for the H soil. The
addition of atrazine modified the kinetic parameters and increased notably the C mineralized; by the end of the incubation
the cumulative CO2–C values were 33–41% higher than those in the corresponding non-added soils. In contrast, a variable effect or even no effect
was observed on the soil microbial biomass following atrazine addition. The data clearly showed that atrazine application
at normal agricultural rates may have important implications in the C cycling of these two contrasting acid soils. 相似文献