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1.
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
2.
The studies of recent soils and paleosols buried under kurgans created in the periods of long-term aridization (3000–2000 BC) and climatic optimum (13th–14th centuries AD) were performed in steppes of the southeastern part of the East European Plain (Privolzhskaya Upland and Caspian Lowland) in order to determine the rate of carbon dioxide production by the soil samples at the natural moisture and after moistening up to 60% of the total moisture capacity. The CO2 emission from the samples of paleosols corresponding to the period of climatic aridization in the Lower Volga River at their natural moisture status was lower than that from the samples of background surface soils, whereas the CO2 emission from the samples of paleosols buried under optimum climatic conditions was higher than that from the samples of background surface soils. After moistening of the samples, the increase in the CO2 emission from the paleosol samples depended on the actual humidity of the climate in the corresponding period. 相似文献
3.
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
4.
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
5.
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
6.
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
7.
Microbiological and biochemical investigations of chestnut soils and solonetzes were conducted in the dry steppe of the southern
Privolzhskaya and northern Ergeni uplands. The living biomass of the microbial communities in the soils was estimated based
on the content of phospholipids in the soils. Significant correlations were revealed between the contents of phospholipids
and the main soil properties (the contents of humus, r = 0.66, P = 0.999; clay, r = −0.41, P = 0.95; physical clay, r = −0.57, P = 0.99; and pH, r = −0.59, P = 0.99). The content of phospholipids varied from 69 to 192 nmol/g of soil in the A1 horizons; with depth it decreased down
to 36–135 in the B1 horizon and to 26–79 nmol/g of soil in the B2 horizon. The microbial biomass in the solonetzes was lower
by 5 to 38% than that in the chestnut soils. A trend of the decreasing of the microbial biomass in the soils from the north
to the south was revealed. Based on the content of phospholipids, the number of living microbial cells was assessed; the weighed
averages of their number varied from 0.7–3.2 × 1010 to 7.5–13.6 × 1010. 相似文献
8.
T. S. Demkina T. E. Khomutova N. N. Kashirskaya I. V. Stretovich V. A. Demkin 《Eurasian Soil Science》2010,43(2):194-201
Microbiological studies of the paleosols of archeological monuments (burial mounds) of the Neolithic, Bronze, Early Iron,
and Middle Ages (the fourth millennium BC to the fourteenth century AD) located in the dry and desert steppe of the Lower
Volga River basin were conducted. The microbial communities that existed at the time of creating the burial mounds were shown
to be preserved up to the present time. This fact was confirmed by the regularities of the distribution of the microorganisms
in the “mound-buried soil” system and by the data on the determination of the age for the microbial fraction of the paleosols
using the method of 14C atomic mass spectrometry. The total biomass of the microbial communities in the paleosols amounted to 20–40% of the microbial
biomass in their background analogues. In all the paleosols, a special pool of viable microorganisms was present. In the microbial
community of the paleosols, the biomass of the active microorganisms corresponded to 0.30–41.0% of the biomass in the present-day
soil; the content of mycelium of microscopic fungi composed 43–50% of that in the recent soil. In the mycelium structure in
the paleosols, the share of the dark-colored mycelium increased to 98–100%. The microbiological parameters that give a contrasting
characterization of the state of the microbial communities in the soils during the arid and humid climatic periods were revealed.
The changes of the arid and humid climatic epochs were reflected in the structure of the microbial communities in the paleosols
at the ecological-trophic, metabolic, and genetic levels. 相似文献
9.
A new soil-ecological definition of the maximal permissible concentration (MPC) of heavy metals in soils is suggested that
regulates the sampling in contaminated territories. Instead of the shallow pits usually used for collecting surface samples
for soil-hygienic and other investigations, it is proposed to fulfill a detailed analysis along the entire soil profile including
not only the determination of the heavy element content in certain horizons but also the soil density in these horizons. For
the polyelemental contamination Zc (according to the Saet equation) based on the background (clarke) excess, the established
Zc values ranging from 1 to 128, may reach absurd values of 800–900 upon taking into consideration only one surface layer.
At the same time, the use of the weighted average content of the metals in the soil profile adjusts the Zc values for the
existing natural conditions. Upon aerial impact, the consideration of the heavy metal contents along the soil profile instead
of their contents in the surface horizon only leads to a decrease in the indices of the soil contamination degree. Upon the
hydrogenic impact, the transition from the heavy metal contents in the surface horizon to their contents in the soil profile
gives higher values of the soil contamination. 相似文献
10.
The chemical and mineralogical compositions and the contents and properties of the organic matter were studied in the paleosols of different ages buried under the kurgan group “Kalmykia” in the southern part of the Ergeni Upland. The investigated sequence of soils included profiles developed on the given territory about 5100, 4410, 4260, 4120, 3960, and 600 yrs ago. The background light chestnut soil was also examined. The results of our study showed that the earlier established climate changes in this area during the second half of the Holocene are reflected in the chemical and mineralogical compositions of the soils. These characteristics can be used as indicators of the paleoclimatic conditions together with some petrophysical characteristics, such as the magnetic susceptibility of the soil samples. The study of the mineralogical composition of the clay fraction of the paleosols attests to the transformation of the smectitic phase, accumulation of illites, and destruction of chlorites manifested at different degrees. It is argued that the geochemical indices—CIA, Al2O3/(CaO + MgO + K2O + Na2O), Rb/Sr, and Ba/Sr—are sensitive to climate changes and reflect the transformation of the mineral soil mass and the soil genesis. 相似文献
11.
Spatial changes of soil fungal and bacterial biomass from a sub-alpine coniferous forest to grassland in a humid, sub-tropical region 总被引:7,自引:0,他引:7
Fungal and bacterial biomass were determined across a gradient from a forest to grassland in a sub-alpine region in central
Taiwan. The respiration-inhibition and ergosterol methods for the evaluation of the microbial biomass were compared. Soil
fungal and bacterial biomass both significantly decreased (P<0.05) with the shift of vegetation from forest to grassland. Fungal and bacterial respiration rates (evolved CO2) were, respectively, 89.1 μl CO2 g–1 soil h–1 and 55.1 μl CO2 g–1 soil h–1 in the forest and 36.7 μl CO2 g–1 soil h–1 and 35.7 μl CO2 g–1 soil h–1 in the grassland surface soils (0–10 cm). The fungal ergosterol content in the surface soil decreased from the forest zone
(108 μg g–1) to the grassland zone (15.9 μg g–1). A good correlation (R
2=0.90) was exhibited between the soil fungal ergosterol content and soil fungal CO2 production (respiration) for all sampling sites. For the forest and grassland soil profiles, microbial biomass (respiration
and ergosterol) declined dramatically with depth, ten- to 100-fold from the surface organic horizon to the deepest mineral
horizon. With respect to fungal to bacterial ratios for the surface soil (0–10 cm), the forest zone had a significantly (P<0.05) higher ratio (1.65) than the grassland zone (1.05). However, there was no fungal to bacterial ratio trend from the surface
horizon to the deeper mineral horizons of the soil profiles.
Received: 30 March 2000 相似文献
12.
Soil-released carbon dioxide from microbial biomass carbon in the cultivated soils of karst areas of southwest China 总被引:1,自引:0,他引:1
Soil microbial biomass and the emission of CO2 from the soil surface were measured in yellow soils (Ultisols) of the karst areas of southwest China. The soils are relatively
weathered, leached and impoverished, and have a low input of plant residues. The measurements were made for a 1-year period
and show a reciprocal relationship between microbial biomass and surface CO2 efflux. The highest (42.6±2.8 mg CO2-C m–2 h–1) and lowest (15.6±0.6 mg CO2-C m–2 h–1) CO2 effluxes are found in the summer and winter, respectively. The cumulative CO2 efflux is 0.24 kg CO2-C m–2 year–1. There is also a marked seasonal variation in the amount of soil microbial biomass carbon, but with the highest (644±71 μg
C g–1 soil) and lowest (270±24 μg C g–1 soil) values occurring in the winter and summer, respectively. The cumulative loss of soil microbial biomass carbon in the
top 10 cm of the soil was 608 μg C g–1 year–1 soil over 17 sampling times. The mean residence time of microbial biomass is estimated at 105 days, suggesting that the carbon
in soil microbial biomass may act as a source of the CO2 released from soils.
Received: 13 July 1999 相似文献
13.
A sequence of five paleosol units (with seven individual paleosol profiles) buried in the Late Pleistocene (20–40 ka) deposits
was studied at the Kostenki 14 (K14) key section in Voronezh oblast with the use of a set of morphological, physicochemical,
and instrumental methods. The upper-lying paleosols differed from the lower-lying paleosols in the less pronounced gley features,
stronger aggregation of the soil material, more significant accumulation of carbonates, and higher percentage of calcium humates
and fulvates. These features attested to the higher aridity of the paleoclimate and the development of the upper-lying paleosols
under grassy vegetation. Within the studied paleosol sequence, the most developed profiles were typical of the soils that
formed 27–32 ka ago during the Bryansk interstadial. The good aggregation, the presence of features left by the soil fauna
activity, the high magnetic susceptibility, and the morphology of the secondary carbonates in the studied paleosols suggest
that they were formed under meadow-steppe vegetation in well-drained positions and resembled modern cryoarid soils. 相似文献
14.
V. A. Demkin B. N. Zolotareva T. S. Demkina T. E. Khomutova N. N. Kashirskaya M. V. El’tsov S. N. Udal’tsov 《Eurasian Soil Science》2012,45(2):119-131
Paleosols buried under kurgans of the Early (2nd-1st centuries BC), Middle (1st-2nd centuries AD) and Late (2nd-IV centuries
AD) Sarmatian epochs were studied in dry steppes and desert steppes of the Lower Volga region (the Privolzhskaya and Ergeni
Uplands and the Caspian Lowland). It was found that temporal variations in the morphological, chemical, microbiological, and
magnetic properties of the paleosols in the interval of 2200–1600 BP were characterized by the cyclic pattern related to secular
dynamics of climatic humidity with changes in the mean annual precipitation of ±30–50 mm. These climate changes did not transform
chestnut paleosols and paleosolonetzes at the type or subtype taxonomic levels. However, they led to certain changes in the
humus, carbonate, and salt profiles of the soils; in the character of solonetzic horizon B1; and in the state of microbial
communities. According to these data, the Sarmatian time was characterized by alternation of micropluvial and microarid stages
lasting fro about 100–200 years. In particular, the stages of humidization were observed in the 1st century BC-1st century
AD and in the 4th century AD; the most arid conditions were observed in the second half of the 2nd and the first half of the
3rd century AD. 相似文献
15.
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
16.
Thermal diffusivity of the upper horizons of leached meadow-chernozemic soils varies in dependence on the soil water content
within the following limits: 1.20–4.11 × 10−7 m2/s for the Ap horizon, 1.21–3.85 ×10−7 m2/s for the A1 horizon, and 1.35–3.73 × 10−7 m2/s for the A1B horizon. The relationships between the thermal diffusivity and the soil water content are described by S-shape
curves with a long gently inclined segment within the range of water contents of <0.20 cm3/cm3, a distinct rise in thermal diffusivity within the water contents from 0.20 to 0.30–0.35 cm3/cm3, and a flattened or somewhat declining segment in the area with the high (>0.30–0.35 cm3/cm3) water contents. The thermal diffusivity of air-dried soil samples correlates with the physical clay (<0.01 mm) content.
The Pearson correlation coefficient for these two variables equals −0.67 and is statistically significant at the significance
level of 0.05. Regression equations allowing one to calculate the thermal diffusivity of the investigated soil horizons on
the basis of data on the soil water content have been obtained. 相似文献
17.
Determination of the soil microbial biomass carbon using the method of substrate-induced respiration
Specific features of determining the carbon content in the soil microbial biomass using the method of substrate-induced respiration
(MBSIR) were studied as related to the conditions of the incubation (the glucose concentration and temperature) and pre-incubation
(the duration and temperature) of the soil samples collected in the summer (tundra gley and soddy-podzolic soils and chernozems)
and in different seasons (for the gray forest soil). The glucose concentration providing the highest substrate-induced respiration
(SIR) in the soils studied was shown to be 2–15 mg/g. The MBSIR in the soil samples collected in summer and in the soils pre-incubated for 10 and 22°C (7 days) did not significantly differ.
The MBSIR in the gray forest soil pre-incubated at 3, 6, and 10°C (winter, spring/autumn, and summer, respectively) and at 22°C (recommended
by the authors of the SIR method) was similar for the cropland in all the seasons. For the meadow, it was the same in the
winter, summer, and autumn, and, in summer, it did not differ only for the forest. For the comparative assessment of the MBSIR, soil samples from different ecosystems are recommended to be collected in the autumn or in the summer. Soil samples of 100–500
g should be pre-incubated for 7 days at 22°C and moisture of 60% of the total water capacity; then, 1-2 g soil should be incubated
with glucose (10 mg/g) at 22°C for 3–5 hours. 相似文献
18.
Effects of increasing periods under intensive arable vegetable production on biological, chemical and physical indices of soil quality 总被引:6,自引:0,他引:6
The effects on soil condition of increasing periods under intensive cultivation for vegetable production on a Typic Haplohumult
were compared with those of pastoral management using soil biological, physical and chemical indices of soil quality. The
majority of the soils studied had reasonably high pH, exchangeable cation and extractable P levels reflecting the high fertilizer
rates applied to dairy pasture and more particularly vegetable-producing soils. Soil organic C (Corg) content under long-term pasture (>60 years) was in the range of 55 g C kg–1 to 65 g C kg–1. With increasing periods under vegetable production soil organic matter declined until a new equilibrium level was attained
at about 15–20 g C kg–1 after 60–80 years. The loss of soil organic matter resulted in a linear decline in microbial biomass C (Cmic) and basal respiratory rate. The microbial quotient (Cmic/Corg) decreased from 2.3% to 1.1% as soil organic matter content declined from 65 g C kg–1 to 15 g C kg–1 but the microbial metabolic quotient (basal respiration/Cmic ratio) remained unaffected. With decreasing soil organic matter content, the decline in arginine ammonification rate, fluorescein
diacetate hydrolytic activity, earthworm numbers, soil aggregate stability and total clod porosity was curvilinear and little
affected until soil organic C content fell below about 45 g C kg–1. Soils with an organic C content above 45 g C kg–1 had been under pasture for at least 30 years. At the same Corg content, soil biological activity and soil physical conditions were markedly improved when soils were under grass rather
than vegetables. It was concluded that for soils under continuous vegetable production, practices that add organic residues
to the soil should be promoted and that extending routine soil testing procedures to include key physical and biological properties
will be an important future step in promoting sustainable management practices in the area.
Received: 18 November 1997 相似文献
19.
A vertical sequence of seven buried paleosols composing the Klimovsk pedocomplex was studied in the basin of the Sukhona River
(Vologda oblast). These paleosols were formed according to the accumulative model of pedogenesis (pedosedimentation model).
They had monogenetic profiles with eluvial-gley, structural, and carbonate-illuvial types of differentiation. The set of elementary
pedogenic processes responsible for the development of these soils included gleyzation in the surface horizon and around the
roots, the inter- and intrahorizon translocation and segregation of iron, structuring, humification, weathering, lessivage,
the migration and segregation of carbonates, and the synthesis of palygorskite and analcime. The studied paleosol profiles
make it possible to reconstruct seven pedogenetic stages; each of them lasted for about n × 102–103 years. The paleosols were formed on a flat lacustrine-alluvial plain with drying lakes and temporary streams. The stages
of inundation and water stagnation on the surface alternated with the stages of drying of the territory. The climate was warm,
with well-pronounced wet and dry seasons. Against this general climatic background, arid climatic epochs marked by the development
of calcic paleosols alternated with humid climatic epochs marked by the development of noncalcareous paleosols. 相似文献
20.
Karoline D’Haene Annemie Van den Bossche Jeroen Vandenbruwane Stefaan De Neve Donald Gabriels Georges Hofman 《Biology and Fertility of Soils》2008,45(2):213-217
The effect of reduced tillage (RT) on nitrous oxide (N2O) emissions of soils from fields with root crops under a temperate climate was studied. Three silt loam fields under RT agriculture
were compared with their respective conventional tillage (CT) field with comparable crop rotation and manure application.
Undisturbed soil samples taken in September 2005 and February 2006 were incubated under laboratory conditions for 10 days.
The N2O emission of soils taken in September 2005 varied from 50 to 1,095 μg N kg−1 dry soil. The N2O emissions of soils from the RT fields taken in September 2005 were statistically (P < 0.05) higher or comparable than the N2O emissions from their respective CT soil. The N2O emission of soils taken in February 2006 varied from 0 to 233 μg N kg−1 dry soil. The N2O emissions of soils from the RT fields taken in February 2006 tended to be higher than the N2O emissions from their respective CT soil. A positive and significant Pearson correlation of the N2O–N emissions with nitrate nitrogen (NO3
−–N) content in the soil was found (P < 0.01). Leaving the straw on the field, a typical feature of RT, decreased NO3
−–N content of the soil and reduced N2O emissions from RT soils. 相似文献