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1.
N. B. Khitrov 《Eurasian Soil Science》2016,49(2):125-144
Data on clayey swelling soils with gilgai microtopography are systematized. Classifications of gilgai microtopography representing regularly alternating microhighs and microlows are discussed, and its geometric parameters under different landscape conditions are considered. Gilgai microtopography is developed within flat or slightly inclined elements of the mesorelief composed of swelling clays of different geneses. These materials are characterized by the high swelling–shrinking capacity upon wetting–drying cycles owing to the predominance of clay minerals of smectitic group. These processes are especially pronounced under conditions of the impeded surface drainage and contrasting of the wet seasons with strong soil moistening by atmospheric precipitation or surface water and the seasons with deep soil drying under the impact of physical evaporation and transpiration. The areas with gilgai microtopography have complex soil cover patterns composed of Vertisols and vertic soils. Their formation is related to lateral movements of solid material in the soil profiles and along the curved soil surface. The morphological types of soil complexes in such area are systematized. 相似文献
2.
N. B. Khitrov 《Eurasian Soil Science》2016,49(3):257-271
Data on the morphology and spatial distribution of slickensides and cracks, particle-size distribution, the organic carbon content, the content and forms of carbonate concentrations, and physical and physicochemical properties of Vertisols with the gilgai microtopography are systematized. Relatively scarce information on the functioning regimes of gilgai soil complexes (their temperature and moisture conditions, redox potential, vertical and horizontal deformations, and soil density changes) is discussed. Common properties of gilgai soils are the clayey texture of their profiles and the high portion of smectitic minerals specifying the high shrink–swell capacity of the soil material. The most important specificity of soils with the gilgai microtopography is a significant horizontal differentiation of the soil profiles with alternation of bowl-shaped morphostructures with a thick dark layer without carbonates in microlows and diapiric morphostructures composed of the rising material of the lower layers with diverse carbonate concentrations on microhighs. Data on the spatial distribution of soil properties within the gilgai microcatenas can be applied in the studies of the genesis and evolution stages of the gilgai soil complexes. 相似文献
3.
Data on the morphology and radiocarbon ages of humus of dark vertic quasigley nonsaline clayey soils with alternating bowl-shaped (Pellic Vertisols (Humic, Stagnic)) and diapiric (Haplic Vertisols (Stagnic, Protocalcic)) structures are discussed, and the genetic concept for these soils is suggested. The studied soils develop on loesslike medium clay in the bottom of a large closed depression on the Eisk Peninsula in the lowest western part of the Kuban–Azov Lowland. The lateral and vertical distribution of humus in the studied gilgai catena displays a lateral transition of a relatively short humus profile of the accumulative type with a maximum near the surface and with a sharp increase in 14C dates of humus in the deeper layers within the diapiric structure to the extremely deep humus profile with a maximum at the depth of 40–80 cm, with similar mean residence time of carbon within this maximum, and with a three times slower increase in 14C dates of humus down the profile within the bowl-shaped structure. The development of the gilgai soil combination is specified by the joint action of the lateral–upward squeezing of the material of the lower horizons from the nodes with an increased horizontal stress toward the zones a decreased horizontal stress, local erosional loss of soil material from the microhighs and its accumulation in the adjacent microlows, leaching of carbonates from the humus horizons in the microlows, and the vertical and lateral ascending capillary migration of the soil solutions with precipitation of calcium carbonates in the soils of microhighs. 相似文献
4.
Five variants of the distribution of clay (<0.001 mm) and physical clay (<0.01 mm) fractions along the vertical profiles of Vertisols (slitozems) and vertic soils (slitic subtypes of different soil types) from the European part of Russia are distinguished: (1) accumulative, (2) even, (3) regressive, (4) with a maximum in the middle-profile horizon and with their approximately equal contents in the upper and the lower horizons, and (5) eluvial–illuvial. These distribution patterns are related to the lithological specificity of sedimentation and formation of parent materials composed of swelling clays of different geneses and ages. Solonetzic, eluvial- gley, and solodic processes contribute to the development of the eluvial–illuvial and, partly, regressive variants of clay distribution. All the five variants with a predominance of the even distribution pattern can be found in Vertisols. Most of Vertisols in the European part of Russia have a medium clayey or a heavy clayey texture in the entire profile. The regressive distribution pattern is typical of the group of vertic soils. In the upper horizons of Vertisols, where slickensides do not form, the texture is usually heavier than that in the analogous horizons of vertic soils. The middle-profile and lower horizons with slickensides have similar statistical distributions of particle-size fractions in Vertisols proper and in vertic soils. However, in Vertisols, a tendency for a more frequent occurrence of the soils with a higher content of the clay fraction and with a higher portion of this fraction in the physical clay fraction is observed (as compared with the vertic soils). 相似文献
5.
The analytical, mineralogical and micromorphological characteristics of Calcisols are studied here, in order to improve their genesis and influence in soil properties. Two main features stand out: one being of a colluvial nature, consisting molasses and bioclastic molasses (postorogenic marine detrital sediments whose origin is the upper-middle Miocene) over primitive haplic Vertisols, with appearance of subsurface gilgai microrelief, non visible from the ground and, the other, being the appearance of a calcic horizon resulting from the leaching and translocation of carbonates proceeding from the colluvial material. The former Vertisol had suffer an erosion process which removed its A horizon and later was produced new material deposition. The deposited carbonated material was loose, becoming soils in Calcisols. As a result of the vertic movements, the subsurface gilgai in the boundary between the new deposited and former material, which remains buried, show the higher degree of undulation in front of non buried Vertisols, by polynomial equations. 相似文献
6.
Soil organic matter (SOM) was studied in relation to vertic processes (i.e., shrinking/swelling, cracking, vertical turbation,
lateral shearing, gilgai formation) in Vertisols and vertic soils of the North Caucasus in Russia, and Texas and Louisiana
in the USA. Their impact on SOM properties and distribution was analyzed according to various levels of soil organization,
such as soil cover, profile, horizon, and aggregate structure using chemical methods, micromorphology, isotopic analyses,
and physical fractionation. The greatest variations both in the distribution and properties of SOM were found in mature Vertisols
at the level of soil cover including Ctot, organic carbon stocks, stable carbon isotopic composition, and SOM 14C-age, chemical composition. The distribution of SOM at the profile and horizon levels was related to the functioning of Vertisols
during wet-dry cycles. The isotopic and chemical study of densi-granulometric fractions at the aggregate level reflected the
minor role of vertic processes. 相似文献
7.
ZHANGMIN LIULIANG－WU 《土壤圈》1993,3(1):81-88
The ages of organic matter of some dark-colored horizons and calcareous concretions in some Vertisols from tropical,subtropical and warm-temperate zones of China were studied using radiocarbon dating method.The relationship between soil age and genesis of Vertisols was also expounded based on the study of their genetic characteristics and micromorphological features.The results show that although Vertisols have developed for a relatively long time,their weathering and soil forming process are weak and young with little horizonation.This is closely related to their special grochemical soil forming environment.Low-lying terrain,heavy texture,clay minerals dominated by montmorillonites and alternative drying-wetting climate give rise to the vertic features expressed in intense swelling-shrinking and cracking-closing in soils.As a result,the soil development and soil leaching process are resisted,and the climatic effect on the horizonation is impeded.Moreover,pedoturbation eliminates the horizonation in the upper part of soil profile,and postpones their evolution into zonal soils.So vertisols show certain pedogenic inertia and stay at relatively young developmental stage.Therefore,Vertisols are intrazonal soils dominated by local soil forming factors such as the relief and parent materials. 相似文献
8.
Studies on Vertisols of Southwest China show that the distribution of organic matter, mechanical composition, carbonates and spore-pollen in their profiles exhibits a definite differentiation and the radiocarbon age has a functional variation with soil depth, which suggests that pedoturbation model is a kind of incomplete model for genetic study and that the disturbance and inversion of solums of Vertisol are not as rapid and absolute as expected. In further consideration of the characters of swelling pressure and shear strength of Vertisol, vertic soil and other zonal soils, it is speculated that soil mechanics model is more adaptable for interpreting the morphogenesis of Vertisols without any contradiction with soil properties. 相似文献
9.
N. B. Khitrov 《Eurasian Soil Science》2012,45(9):834-842
On the basis of soil studies along routes and on key plots, 35 new areas of soils with definite features of vertigenesis have been identified in Belgorod and Voronezh oblasts and in the northern part of Volgograd oblast (in the Don River basin). Earlier, vertic soils were not noted for these areas. In the studied region, their portion in the soil cover is much less than 1%. All the delineated areas of vertic soils are confined to the outcrops of swelling clay materials of different origins (marine, lacustrine, glacial, and colluvial sediments) and ages (Quaternary or Tertiary) that may be found in four landscape positions: (1) in the deep closed depressions within vast flat watersheds; (2) in the bottoms of wide hollows on interfluvial slopes and, sometimes, on steeper slopes of local ravines; (3) in the hydromorphic solonetzic soil complexes, and (4) on step-like interfluvial surfaces with the outcrops of Tertiary clays. Within the studied areas, soils with different degrees of expression (six grades) of vertic properties are present. These soils belong to the type of dark vertic soils proper and to vertic subtypes of different soil types according to the Russian soil classification system; according to the WRB system, they belong to Vertisols proper and to reference soil units with a Vertic prefix in the groups of Chernozems, Phaeozems, and Solonetzes. Statistical data on the morphometric indices of the vertic properties (the depth and thickness of the soil horizons with slickensides, a wedge-shaped structure, and cracks filled with material from the upper horizons) and the depth and thickness of the Vertic horizon are analyzed. 相似文献
10.
Moralistic soils (vertic and non-vertic black clays) were sampled along a 200 m top sequence in the Transvaal Highveld, South Africa. The Milk wood soil on the upper part of the margalitic top sequence has an Al horizon which lacks both slickensides and self-mulching properties but has strong blocky structure, the others are all self-mulching (i.e. Vertisols). The Vertisols differ in some morphological properties such as the absence (Mngazi series) and presence (Arcadia series) of pedogenic calcite accumulation, both overlying decomposed dolerite, whereas the third member from a red-black centenary sequence is calcareous with a gleyed subsoil horizon. Chemical and XRD analysis suggest that the clays of the Vertisols comprise mainly a partly chloritized iron-rich smectite with Ie > Mg + Al in the octahedral layer (and interlayer positions), while in the upland Milkwood soil intergradient halloysitic clay occurs in addition to a more‘open’structured chloritized iron smectite. The mineralo-chemical results and the geomorphic data suggest that the genesis of these soils is controlled primarily by the internal soil water regime. 相似文献
11.
《CATENA》2001,43(3):231-249
The Purna Valley, a part of the Payanghat Plain, is an oval basin covering an area of about 1.9 Mha in central India. The soils are deep, calcareous, clayey and very dark greyish brown to dark brown in colour, and meet criteria for the Vertisols order of Soil Taxonomy. Cracks extend down to the slickenside zones in soils of the northeastern part of the valley, but cut through the slickenside zones in the soils of the southwestern part. Soils of the southwestern part are strongly alkaline with exchangeable sodium percentages (ESPs) of 5–26, whereas those of the northeastern part are moderately alkaline and have ESP values <5. Despite their similar coefficients of linear extensibility, volumetric shrinkage potentials, clay contents and amounts of fine clay smectite, the plasmic fabric of the slickenside horizons in soils of the northeastern part is porostriated, whereas in soils of the southwestern part, it is stipple-speckled to mosaic-speckled, indicating weak plasma separation. The soils have both pedogenic and nonpedogenic calcium carbonate, but those of the southwestern part have more pedogenic carbonate than those in the northeastern part. The semiarid climate removes Ca2+ ions from the soil solution by precipitating carbonate, and also causes the ESP and sodium absorption ratio to increase with depth. The lack of soil water in soils of the southwestern area is thought to be the reason for weak swelling of smectite, for larger amounts of pedogenic carbonate and for cracks cutting through the slickenside zones. The Vertisols of the southwestern part of the of the Purna Valley are, therefore, polygenetic because they exhibit distinctly different soil properties resulting from increasing aridity in the valley during the late Holocene. 相似文献
12.
13.
I. I. Lebedeva G. S. Bazykina A. M. Grebennikov L. G. Smirnova S. I. Tyutyunov 《Eurasian Soil Science》2016,49(12):1344-1354
Agrochernozems of a catena (local divide, backslope, and footslope positions on a gentle slope of southern aspect) on the fields of Belgorodskoe farm were studied. The soils are developed from lithologically heterogeneous sediments with temporal accumulation of precipitation water above the lithological contact. A close correlation between the morphology and properties of the soils and the character of their water regime in different positions of the catena was found. Agrochernozems of the divide belong to the migrational–mycelial type of forest-steppe chernozems according to their humus profile, water regime, and slightly differentiated distribution of carbonates. Agrochernozems on the backslope with a higher ground moistening have a more contrasting water regime with the topsoil drying in the summer, a sharper decrease in the humus content down the soil profile, and a distinct carbonate-accumulative horizon with a smooth upper boundary, which makes them closer to the type of steppe agrochernozems. The soils of the footslope are characterized by alternation of the percolative and exudative water regimes; these soils are classified as quasigley agrochernozems with a shortened humus horizon and with dispersed and pendant forms of pedogenic carbonates. The character of moistening, morphology, and properties of the studied soils allow us to state that their genesis is controlled by the local ecological conditions with minimal influence of erosional processes on the slope. 相似文献
14.
《Communications in Soil Science and Plant Analysis》2012,43(9-10):1291-1298
Abstract Heavy clay soils with swell‐shrink properties comprise most of the arable land in northern Jordan. These soils are classified as Vertisols. Vertisols occupy a large and important part of the agricultural land in Jordan where rainfed agriculture is practiced. Five sites were selected to represent Vertisols occurring in different precipitation zones. Soil characterization was carried out to provide useful information to understand the genesis and behavior of these soils. Vertisols in northern Jordan occur on flat to gently sloping plains. Clay, silt, and sand fractions were uniformly distributed indicating active pedoturbation. Clay content is moderate to high, and the higher the rainfall the higher the clay content. The high cation exchange capacity (CEC)/clay ratio suggest montmorillonitic and mixed mineralogy. Calcium (Ca) was the most dominant extractable cation followed by magnesium (Mg), sodium (Na), and potassium (K). The similar patterns of distribution for the electrical conductivity values and soluble cations throughout the studied soil sites indicate the low leaching rate, eluviation, and illuviation processes within these studied sites. All soils belong to the Haploxererts soil great group. 相似文献
15.
Studies on Vertisols of Southwes China show that the distribution of organic matter,mechanical compositon,carbonates and spore-pollen in their profiles exhibits a definite differentiation and the radiocarbon age has a functional variation with soil depth,which sugests that pedoturbation model is a kind of incomplete model for genetic study and that the distubance and inversion of solums of Vertisol are not as rapid and absolute as expected.In further consideration of the characters of swelling pressure and shear strength of Vertisol,vertic soil and other zonal soils.it is speculated that soil mechanics model is more adaptable for interpreting the morphogenesis of vertisols without any contradiction with soil properties. 相似文献
16.
M.J. Knight 《Geoderma》1980,23(4):245-283
Gilgai microrelief at an undisturbed site is described. Surface and subsurface structural patterns in a duplex soil (solodic planosol) are analysed using principles and techniques adapted from structural geology. The microrelief is situated on a gently dipping regional slope and some mounds show evidence of surface erosion. Large cracks on the ground surface have an orientational relationship with the strike and dip of the regional slope. Some of the surface cracks may post-date the original time of gilgai formation. Beneath the microrelief surface a lenticular gravel layer of sedimentary origin is folded into a series of anticlines and synclines. Compositional layers also have fold-like geometries. Two-dimensional crack pattern analysis on a vertical section through several mounds, revealed upwards fan-like and concentric-convex patterns, where upwards movement had occurred. Three-dimensional measurements were made on monoliths and on an undisturbed block sample. The mean slickensided shear plane dip below a mound is 43° (standard deviation 9°). There is a statistical decrease in shear plane dip with depth, which is in partial agreement with soil mechanics theory. Shear planes are distributed from 0.3 m below ground surface down to a projected limit of 1.3 m to 1.8 m which is shallower than the limits reported for slickensided cracks in non-gilgai soils of Israel. The mechanism proposed to explain the surface and subsurface structures involves moisture concentrations that focus near, and below pre-gilgai surface cracks and a gravel lens. The moisture interacts with a swelling component and a triaxial state of stress is achieved. Differences between lateral and vertical stresses due to swelling pressures and overburden loads are sufficient to cause small, inclined shear displacements in definable depth zones. Accumulations of vertical movement components arising from the shear displacements, and vertical sliding of blocky non-sheared units nearer the ground surface, cause the gilgai microrelief and fold-like deformations in the soil profile. Zones of possible downward movement are located at the margins of mounds. Mechanical models proposed in the past are assessed in the light of the Boorook findings. Some proposals appear to be mechanically unlikely for the Boorook gilgai. 相似文献
17.
Carbonate nodules and soft masses were studied in a gilgai soil complex in the North Caucasus, South Russia. Microrelief with an amplitude about 30 cm resulted in a wetter environment with stronger leaching in the microlow and a drier pedoenvironment with carbonate accumulation in the microhigh. Various macroforms of carbonate nodules and soft masses were identified in soil pits and sampled for micromorphology, scanning electron microscopy (SEM), and microprobe analyses to better characterize them and elucidate their pedogenesis. Common and unique attributes were described for carbonate pedofeatures depending on loci in gilgai soil complex. The most probable hypothesis for their formation is as follows. Nodules represent early pedogenic products that were initiated before gilgai formation. Modern hydrology resulted in variability of dissolution/recrystallization of the nodules along the gilgai microtopography. The variability in degree of impregnation, aggregation into pellets, and presence of hard nodular cores reflects several generations of soft masses. 相似文献
18.
In the profiles of cryozems (Oxyaquic Turbic Cryosols) developing in tundra of northern Yakutia under conditions of shallow active layer, suprapermafrost horizons of the accumulation of raw organic matter are formed. Taking into account their genesis, stable and regular position in the soil profile, paragenetic links with the overlying horizons and neighboring soil profiles, and a set of diagnostic features and properties, these horizons can be separated as a new type of genetic soil horizons—the organomineral accumulative suprapermafrost horizon (CRO). Its qualitative composition (the ratio of organic and mineral matter in the material) can be reflected at a lower level. In relation to the separation of the new genetic horizon within the framework of the new Russian soil classification system, a new genetic types of soils—cryozem with suprapermafrost accumulation of raw organic matter (suprapermafrost organo-accumulative cryozem)—can be established. Its diagnostic profile has the following horizonation: (O, AO, T)–CR–CRO–┬C. 相似文献
19.
T. A. Arkhangel’skaya M. A. Butylkina M. A. Mazirov M. V. Prokhorov 《Eurasian Soil Science》2007,40(3):237-246
In agrolandscapes of the Vladimir opolie region, the ancient paleocryogenic microtopography is completely buried. However, the pattern of the paleocryogenic soil complex can be deduced from data on the humus content in the plow layer. Under conditions of a leveled surface microtopography, regular differences in the temperature and moisture of soils with different morphologies of their profile are observed; they are explained by the differences in the properties of particular genetic horizons. It is supposed that differences in the regimes of functioning of modern soils of the complex favor the preservation of the relict soilscape. 相似文献
20.
Manganese (Mn) contamination of drinking water may cause aesthetic and human health problems when concentrations exceed 50 and 500 μg l?1, respectively. In the UK, the majority of Mn-related drinking water supply failures originate from unpolluted upland catchments. The source of Mn is therefore soil, but the exact mechanisms by which it is mobilised into surface waters remain unknown. Elevated Mn concentrations in surface waters have been associated with the rewetting of dried upland soils and with conifer afforestation. We investigated these hypotheses in a laboratory experiment involving the drying and rewetting of intact soil cores (1,900 cm3 volume) of horizons of four representative soil type-land use combinations from an upland water supply catchment in southwest Scotland. Although no statistically significant effect of land use or soil type was detected on Mn concentrations in soil water, Mn release occurred from three soil horizons upon rewetting. Soil water Mn concentrations in the moorland histosol H2 (10–30 cm), the histic podzol H and Eh horizons increased from means of 5.8, 6.2 and 0.6 μg l?1 prior to rewetting to maxima of 90, 76 and 174 μg l?1 after rewetting, respectively. The properties of these three horizons indicate that Mn release is favoured from soil horizons containing a mixture of organic and mineral material. Mineral material provides a source of Mn, but relatively high soil organic matter content is required to facilitate mobilisation. The results can be used alongside soil information to identify catchments at risk of elevated Mn concentrations in water supplies. 相似文献