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1.
Soil pollution with Cr, Cu, Ni, and Pb oxides and with oil products in the Adygea Republic leads to the deterioration of the soil biological properties. According to the degree of deterioration of the biological properties, the soils of Adygea may be arranged into the following sequence: brown forest soils > mountainous meadow (subalpine) soils > gray forest soils > soddy calcareous soils = leached vertic chernozems. With respect to the negative effect of heavy metal oxides on the biological properties of the soils, they form the following sequence: CrO3 > CuO = PbO ≥ NiO.  相似文献   

2.
Model soil contamination with Cr, Cu, Ni, and Pb in the dry steppes and semideserts of southern Russia has worsened the biological soil properties. With respect to the degree of deterioration of the biological properties, the soils can be arranged in the following sequence: dark chestnut soils > chestnut soils > light chestnut soils > brown semidesert soils > sandy brown semidesert soils. The sequence of metal oxides according to the adverse effect on the biological soil properties is as follows: CrO3 > CuO ≥ PbO ≥ NiO.  相似文献   

3.
The effect of soil contamination with black oil added in amounts of 0.1, 0.5, 1.0, 2.5, 5, 10, 25, and 50% of the soil mass on the biological properties of ordinary and leached vertic chernozems, brown forest soils, and gray sands in the south of Russia was studied in a model laboratory experiment. It was shown that the soil contamination causes a drop in the catalase and dehydrogenase activities, the cellulolytic capacity, the number of Azotobacter bacteria, and the characteristics of the plant germination. The ordinary and vertic chernozems were more tolerant toward the contamination than the gray sands and brown forest soils. The changes in the biological soil properties in dependence on the degree of the soil contamination differed considerably for the soils with different properties (the chernozems, brown forest soil, and gray sands) and were similar for the soils with similar properties (the ordinary and vertic chernozems). One soil (the brown forest soil) could be more tolerant toward the contamination than another soil (the gray sands) at a given concentration of black oil (<2.5%) and less tolerant at another concentration of black oil (>2.5%). The ecologically safe levels of the soil contamination with black oil do not exceed 0.7% in the ordinary chernozems, 0.3% in the compact chernozems, 0.1% in the brown forest soils, and 0.06% in the gray sands.  相似文献   

4.
The parameters of adsorption of Cu2+, Pb2+, and Zn2+ cations by soils and their particle-size fractions were studied. The adsorption of metals by soils and the strength of their fixation on the surface of soil particles under both mono- and polyelement contamination decreased with the decreasing proportion of fine fractions in the soil. The adsorption capacity of the Lower Don chernozems for Cu2+, Pb2+, and Zn2+ depending on the particle-size distribution decreased in the following sequence: clay loamy ordinary chernozem ∼ clay loamy southern chernozem > loamy southern chernozem > loamy sandy southern chernozem. According to the parameters of the adsorption by the different particle-size fractions (C max and k), the heavy metal cations form a sequence analogous to that obtained for the entire soils: Cu2+ ≥ Pb2+ > Zn2+. The parameters of the heavy metal adsorption by similar particle-size fractions separated from different soils decreased in the following order: clay loamy chernozem > loamy chernozem > loamy sandy chernozem. The analysis of the changes in the parameters of the Cu2+, Pb2+, and Zn2+ adsorption by soils and their particlesize fractions showed that the extensive adsorption characteristic, namely, the maximum adsorption (C max), was a less sensitive parameter characterizing the soil than the intensive characteristic of the process—the adsorption equilibrium constant (k).  相似文献   

5.
The phenomenon of mineralization (biological mineralization) of organic matter in chernozems has been studied. A decrease in the content of Corg with time can be considered an index of the organic matter mineralization. It is suggested that the humus horizons of modern chernozems contain the pools of organic matter of different ages: easily decomposable organic matter, labile biologically active humus, stable biologically active humus, and relatively inert humus. The composition and mean residence times of these pools and their contribution to the total organic matter content have been estimated. The particular types of the biological mineralization have been determined on the basis of the comparison between the velocities of mineralization (M) and humification (H) processes: total unidirectional mineralization (M ≫ H), equilibrium mineralization (M ∼ H), nonequilibrium mineralization (M> <H), and zero mineralization. The separation of subtypes is based on data on the relative rates (%) of the organic matter mineralization. On the basis of available experimental data on chernozems buried under kurgans and in loess sediments (with the age of up to 800 ka), the quantitative relationship of the humus content in the buried soils on their age has been found; it has an exponential shape. During the first 100 ka after the soil burial, the soil humus content gradually (with a slowing intensity) decreases from 100–75 to 6.5% of its content in the virgin chernozems. Then, 100–1000 ka after the soil burial, the soil humus content remains approximately constant (6.5% of the initial level, or 0.3% of the soil mass). The rates of mineralization have been estimated. It is shown that the elemental composition (C, H, N, O) of humic acids remains relatively stable for a long time due to the regeneration of the chemical structure of humus (matric restoration of humus). It is suggested that several different forms of humus related to pedogenesis should be distinguished in the biosphere. The renewable humus in the equilibrium state with the environment is typical of the open biospheric (soil) systems. The fossil humus, whose content decreases with time, and whose composition remains stable, is typical of the semiclosed and closed systems. With time, it transforms into residual humus, whose content and composition remain stable. The fossilized organic matter in the fossil soils and sediments of the past geological epochs (Mesozoic and Paleozoic) considerably differs from the renewable, fossil, and residual humus.  相似文献   

6.
The trends of the soil-forming process and the changes in the main physicochemical properties of leached chernozems under different phytocenoses (virgin land, cereal-row crop rotation, and sown perennial grasses (Galega + Bromopsis)) were studied. In the cereal-row crop agrocenoses, as compared to the virgin land, the thickness of the humus horizon increased, and the depth of effervescence remained the same. The reaction of the leached chernozems in the phytocenoses did not change, and the sum of exchangeable bases increased in the following sequence: sown perennial grasses < cropland = virgin land. The humus content and its reserves in the 0- to 20-cm soil layer of all the agrophytocenoses were almost the same, and the total nitrogen content decreased in the following sequence: virgin land = cropland > perennial grasses. On the contrary, the total phosphorus content, its mobility, the phosphorus capacity and reserves, and the sum of the mineral phosphates increased in the same order. The highest content of exchangeable potassium was found in the soils of the virgin land and the lowest one, in the soils of the cereal-row crop agrocenosis. The perennial grasses consumed the greatest amounts of potassium and nitrogen and the spring wheat of the cereal-row crop rotation, those of nitrogen. The removal of nitrogen was 1.6–1.8 and 2.3 times greater than the losses of phosphorus and potassium, respectively.  相似文献   

7.
The soil cover of Tra-Tau and Yurak-Tau shikhans (monadnocks) has been examined. Leached and typical medium-deep chernozems are developed on colluvial fans on the footslopes and on the lower parts of slopes, whereas typical calcareous thin slightly and moderately gravelly chernozems are developed on the upper and medium parts of slopes. The leached and typical chernozems of the footslopes correspond to zonal soils of the adjacent plain areas, though they have some specific features related to the local topographic conditions. These soils are somewhat thinner than plain chernozems and are characterized by the perfect granular water-stable structure, the high content of humus of the humate type, the high content of exchangeable cations, strong acid-base buffering, and high enzymatic activity. These features predetermine their high tolerance towards technogenic impacts. The concentrations of highly hazardous substances of the first toxicity class (mercury, arsenic, lead, and cadmium) and of moderately hazardous substances of the second toxicity class (copper, zinc, and nickel), as well as the concentrations of low-hazardous elements (manganese and iron) in these soils do not exceed provisional maximum permissible concentrations of these substances in soils irrespectively of the slope aspect. No changes in the physicochemical and biological properties of the soils under the impact of technogenic loads from Sterlitamak industrial center have been identified.  相似文献   

8.
The degree of soil contamination in the impact zone of the Solnechnyi Tin Ore Processing Plant in the Solnechnyi district of the Khabarovsk region was evaluated. It was shown that the air contamination by the waste products of the ore-processing plant is extremely high with respect to the concentrations of toxic dust and heavy metals. The maximum concentrations of these contaminants exceed the background values by 16–80 times. The bulk contents of Pb, Zn, Cu, As, and Hg in the upper soil horizons within the impact zone exceeded the maximum permissible concentrations and the background values by 2–90 times. Abnormally high concentrations of Zn, As, and Pb were observed not only in the surface 10–cm-thick soil layer but also in the underlying (10–20 cm) horizon. The soil contamination transformed the geochemical sequence of heavy metals typical of the background soils (Zn > Pb > As > Cu > Hg) into a new sequence (As > Pb > Cu > Zn > Hg). The statistical data proved that the intensity of the migration of the heavy metals in the soils decreases with a rise in the soil humus content and a drop in the soil acidity. This should be taken into account in the elaboration of soil-protective measures in the investigated region.  相似文献   

9.
The content of heavy metals in the soils of the Middle CisUrals (the town of Chusovoi and its vicinities) is controlled by both natural and technogenic factors. The enrichment of the parent rocks in Cr, Pb, Zn, and Cu, which influences the chemical composition of the soils, is the most important among the natural factors. Among the other natural factors, the gleying and washing of the alluvial soils with flood water are significant. The technogenic contamination of the urban soils reaches its maximum in the technozems, where the content of Cu, Zn, Pb, and Cr exceeds their clarkes by 4–8 times. The index of technogeneity (the share of technogenic metals referring to their total content) is high for the bulk of metals in technozems, in particular, ranging within 36–97%. The technogeneity sequence is the following for the urban soils: Cr > Zn = Mn > Pb > Cu > Fe. The soil contamination with metals is confined to the depression where the metallurgical plant is operating, and it significantly falls already at a distance of 2–3 km in the settlements located at higher topographic positions.  相似文献   

10.
Minerals of the pedogenic chlorite group were studied in the clay fractions isolated from the mineral horizons of podzolic and gleyic peat-podzolic soils. In the AE and E horizons of the podzolic soil, pedogenic chlorites are thought to develop from vermiculite, whereas in the E horizon of the gleyic peat-podzolic soil, they can be formed from smectite minerals. For estimating the degree of chloritization (the degree of filling of the interlayer space of 2: 1 minerals with Al hydroxides), a numerical criterion was is proposed. The difference between the values of this criterion before and after the treatment of the preparations with NH4F indicated that the degree of chloritization in the pedogenic chlorites decreases in the following sequence: the E horizon of the podzolic soil > the AE horizon of the podzolic soil > the E horizon of the gleyic peat-podzolic soil. Another numerical criterion was proposed to estimate the degree of polymerization of Al-hydroxy complexes in pedogenic chlorites. This criterion was based on the thermal stability of soil chlorites and represented the temperature at which an increase in the intensity of the 1.0-nm peak after heating the K-saturated preparations exceeds 50% of its initial value. According to this criterion, the degree of polymerization of the Al-hydroxy interlayers in pedogenic chlorites decreases in the following sequence: the E horizon of the podzolic soil > the E horizon of the gleyic peat-podzolic soil ≥ the AE horizon of the podzolic soil. The distinct interrelation between the soil properties and the degrees of chloritization and polymerization of the Al-hydroxy interlayers attests to the modern origin of the pedogenic chlorites.  相似文献   

11.
The physical properties of ordinary chernozems and meadow-chernozemic soils under different land management practices (maple, larch, birch, and pine sections of the shelterbelts; continuous (since 1959) fallow; and arable field (since 1952)) were studied in the Kamennaya Steppe. The soils had favorable physicochemical properties, light clayey texture, and high microaggregation independently from the type of land management. The long-term impact of the shelterbelts improved the soil structure in the upper part of the humus horizon: the content of agronomically valuable aggregates increased, the content of coarse aggregates (>10 mm) decreased, the aggregation coefficient increased by 3.7–4.3 times, and the water stability of the aggregates became by 8–12% higher. The soils under the shelterbelts were characterized by minimum values of the bulk density and solid phase density and by maximum values of the total, active, and air porosities. At the same time, no considerable differences between water reserves in the studied range of soils were detected. The ratio of the optimum productive water range to the active (productive) water range (OPWR/AWR) within the upper soil meter varied from 0.42–0.44 to 0.45–0.54. This points to changes in the character of perched water: the content of intra-aggregate capillary-perched water decreases, and content of film perched water increases down the soil profile.  相似文献   

12.
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13.
The study of soils of different ages in different physiographic regions of the Crimean Peninsula made it possible to reveal the main regularities of pedogenesis in the Late Holocene (in the past 2800 years). With respect to the average rate of the development of soil humus horizons, the main types of soils in the studied region were arranged into the following sequence: southern chernozems and dark chestnut soils > mountainous forest brown soils > gravelly cinnamonic soils. In the newly formed soils, the accumulation of humus developed at a higher rate than the increase in the thickness of humus horizons. A sharp decrease in the rates of development of soil humus profiles and humus accumulation took place in the soils with the age of 1100-1200 years. The possibility for assessing the impact of climate changes on the pedogenetic process on the basis of instrumental meteorological data was shown. The potential centennial fluctuations of the climate in the Holocene determined the possibility of pulsating shifts of soil-geographic subzones within the steppe part of the Crimea with considerable changes in the rates of the development of soil humus horizons in comparison with those in the Late Holocene.  相似文献   

14.
According to the present-day ecotoxicologic data, hazardous heavy metals/metalloids form the following sequence in the soil: Se > Tl > Sb > Cd > V > Hg > Ni > Cu > Cr > As > Ba. This sequence differs from the well-known series of the hazardous heavy elements, in which the danger of Pb and Zn is exaggerated, whereas that of V, Sb, and Ba, is underestimated. Tl also should be included in the list of hazardous elements in the soil. At present, the stress is made on the investigation of heavy metals/metalloids in agricultural soils rather than in urban soils, as the former produce contaminated products poisoning both animals and humans. The main sources of soil contamination with heavy metals are the following: aerial deposition from stationary and moving sources; hydrogenic contamination from the industrial sewage discharging into water bodies; sewage sediments; organic and mineral fertilizers and chemicals for plant protection, tailing dumps of ash, slag, ores, and sludge. In addition to the impact on plants and groundwater, heavy metals/metalloids exert a negative effect on the soil proper. Soil microorganisms appear to be very sensitive to the influence of heavy elements.  相似文献   

15.
The susceptibility of soil organic matter (SOM) to mineralization decreases in the following sequence of zonal soils: tundra soil > soddy-podzolic soil > gray forest soil > chestnut soil > dark chestnut soil > chernozem. The content of potentially mineralizable organic matter in the plowed soils is 1.9–3.9 times lower than that in their virgin analogues. The highest soil carbon sequestration capacity (SCSC) is typical of the leached chernozems, and the lowest SCSC is typical of the tundra soil. Taking into account the real soil temperatures and the duration of the warm season, the SCSC values decrease in the following sequence: leached chernozem > dark chestnut soil > chestnut soil ≥ tundra soil > gray forest soil > soddy-podzolic soil. Arable soils are characterized by higher SCSC values in comparison with their virgin analogues.  相似文献   

16.
To calculate the soil loss tolerance for chernozems of the central chernozemic region, a linear modification of Skidmore’s equation was used. The soil loss tolerance values were obtained with due account for the soil type, the degree of erodibility, and the crop rotation pattern. The maximum possible value (10 t/ha per year) was obtained for a typical noneroded chernozem in all the crop rotations. Close values were obtained for noneroded leached and typical chernozems (9.6–9.9 t/ha per year depending on the crop rotation pattern). The soil loss tolerance for the noneroded podzolized chernozem was somewhat lower: 9.1 t/ha per year in the grain-herb-intertilled crop rotation and 6.3 t/ha/year in the grain-intertilled crop rotation. With an increase in the degree of the soil erosion, the soil loss tolerance decreased in all the variants of the experiment with an especially abrupt decrease in the grain-intertilled crop rotation (from 9.9–10.0 to 0.3–2.0 t/ha per year in the, respectively, noneroded and slightly eroded ordinary and typical chernozems). In the grain-herb-intertilled crop rotation, these differences were much smaller: in the slightly eroded typical chernozem the soil loss tolerance was estimated at 9.7 t/ha per year, while, in the slightly eroded typical chernozem, at 8.1 t/ha per year. The moderately eroded chernozems without the addition of manure could only be used in the grain-herb-intertilled crop rotation; the soil loss tolerance was estimated at 9.0 t/ha per year for the typical chernozem and 4.3 t/ha per year for the ordinary chernozem.  相似文献   

17.
The water stability of typical chernozems was studied, as well as the content and composition of the labile humic substances (LHSs) in the structural units of perennial experiment treatments: Corg was 4.68% on an unmown steppe (fallow), 3.55% under continuous winter wheat without fertilizers, and 2.92 and 2.78% in two treatments of permanent black fallow. It was shown that the water stability of the chernozem??s structure depended on the land use; it deteriorated in the following series: fallow > winter wheat > permanent fallow. No clear relationship was found between the content of Corg in the aggregates obtained by dry sieving and the size of these aggregates. At the same time, the content of Corg in the water-stable aggregates was shown to increase with their size. A positive correlation between the size of the water-stable aggregates and their content of LHSs was found for the unmown steppe and continuous winter wheat treatments.  相似文献   

18.
The biological activity of soil samples taken from genetic horizons of plowed and virgin chernozems in the Kamennaya Steppe Reserve was determined as the amount evolved from the soil upon its incubation in laboratory conditions. In the top humus horizons, the biological activity of virgin chernozem was two to three times higher as compared with that in the plowed chernozem. The intensity of biological processes and the microbial biomass in the soil profile was mainly controlled by the quantity and quality of soil organic matter. Long-term agricultural use exerted a weaker effect on the biological properties of chernozems developed on microelevations (blocks) of the paleocryogenic microtopography in comparison with chernozems developed in the microdepressions between the blocks. The factor analysis showed that soil characteristics related to the biological processes comprise more than 50% of the total variance of factor loads and are distinctly differentiated in the soil profile.  相似文献   

19.
Soils of the Arkaim Reserve were studied before the establishment of the reserve and, then, 12 and 18 years after the reservation of this territory. Former pastures and hayfields occupy 70% of the reserve, and former plowlands occupy about 30%. Some of them have been converted into sown meadows. The soil cover of the reserve is composed of chernozems (about 50% of the area), solonetzes and salt-affected soils (32%), meadow-chernozemic soils (7%), and forest soils (1%). In eighteen years of reservation, the Corg content in the upper 20 cm has increased by 0.5–0.8%, or by 14–25% of the initial content with the average rate of 60–100 g C/m2 per year. The accumulation of Corg has been more intensive in the soils of former plowlands than in the soils of former pastures and in the chernozems than in the meadow-chernozemic soils. Self-restoration of most of the soils of the reserve is accompanied the rise in the content of the labile fraction of organic carbon. In some soils, the contents of the labile fraction (0.3%) and light-weight fraction (>25% of Corg) have reached optimum values. After 18 years of reservation, the biomass of microorganisms has reached 500–800 μg/g of soil (or 1.1–1.9% of Corg); the basal respiration has reached 0.7–1.5 μg C-CO2/g per hour. These characteristics are the highest for meadow-chernozemic soils under former pasture and the lowest for postagrogenic chernozems. The rise in the Corg content and changes in the particular forms of soil organic matter under the regime of a reserve greatly depend on the soil type and on the former land use. The role of parent materials is smaller. Many soils of the reserve require a long period of rehabilitation.  相似文献   

20.
A chrono-toposequence of five soils formed in strongly weathered granite in the South Island of New Zealand was described on the basis of soil profile morphology, landscape position, and the degree of weathering of the underlying granite. The sequence contains five progressively younger soils on increasing slopes from crest to backslope formed in a Parent Material of originally uniform mineralogical and chemical composition as Parent Rock under a uniform climate and vegetation. All profiles of the sequence are strongly weathered and leached with the final member of the sequence being considered to represent a terminal steady-state system.Changes in a number of chemical and physical soil properties were described with the increasing soil development (i.e. increasing weathering and leaching) represented in the sequence profiles. Profile soil weights (< 2mm) remained approximately constant, once weathering of stone material (> 2 mm) to fines was completed. An initial increase in profile silt and clay content was followed by a decline in both fractions with a corresponding increase in the sand fraction. Proportions of kaolin/metahalloysite initially increased and 2:1–2:2 Al intergrades decreased, but the final three sequence profiles had similar clay mineralogies with kaolin/metahalloysite being the main component. Profile weights of oxidisable carbon and total nitrogen followed an exponential decline after an initial increase between the first two sequence profiles. Profile cation-exchange capacity, total exchangeable bases, percent base saturation, and exchangeable cations showed no trends with increasing soil development. Depth-gradients of these parameters together with oxidisable carbon and total nitrogen became less pronounced, with the apparent tendency towards a steady-state system in the final sequence profile. Multiple regression analysis indicated that oxidisable carbon was the main contributing factor to cation-exchange capacity followed by clay content.Profile weights of total calcium and potassium were closely correlated and showed an approximately exponential decline with increasing soil development, whereas total magnesium showed a relatively linear decline. Total aluminium and iron both showed an initial increase and then declined. The relative rates of loss of the five total elements studied were in the order: Ca > Mg > K, Fe > Al.  相似文献   

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