Genesis of a polycyclic Terra Rossa (Chromic Cambisol on Rhodic Nitisol) at the Poggio del Comune in Central Italy

A polycyclic Terra Rossa (Chromic Cambisol on Rhodic Nitisol) was studied with the aim of characterizing pedogenetic processes and relating the most evolved term of a previously defined catena with its parent material. Results obtained by field, chemical, micromorphological, sedimentological and mineralogical techniques evidenced how the profile was lithologically and pedologically discontinuous. While the lower part of the profile was related to the underneath limestone, the upper part showed evidence of allochthonous aeolian addition. From a pedogenetic point of view, the existence of two different kinds of processes was revealed. The deepest horizons exhibited fully expressed nitic properties and a strong kaolinitization, whereas the upper horizons were less weathered, showing only rubefaction and slight lessivage, while the formation and hydroxy-interlayering of vermiculite was the dominant process in the clay minerals. The study revealed that Terra Rossa can differ not only in age and parent material, but also in evolutive process, so that quite different, and even contrasting, products of the pedogenesis can be present.     

A quaternary soil sequence in the Kennet Valley,central southern England

The field characteristics, texture, mineralogy and micromorphology of the soils of four chronologically separate river terraces of the River Kennet are described. The soils on the three uppermost terraces have illuvial (palaeoargillic) horizons, which have been intensely disturbed by periglacial activity. These horizons are overlain by similarly disrupted eluvial horizons mixed with aeolian silts derived from outside the Kennet catchment. The illuvial horizons most probably result from interglacial pedogenesis under climatic conditions warmer and wetter than at present, whilst the aeolian material was probably added to the soils during the last glacial period (Devensian). The lowest and youngest terrace is characterised by an undisturbed (normal argillic) soil developed in loams derived predominantly from the aeolian silts. Consequently, it is postulated that the soils of the lowest terrace owe their characteristics to a phase of postglacial pedogenesis.The results illustrate that several phases of pedogenesis can be recognised, which provide important information on the Quaternary development of the area. This is especially significant where floral, faunal, or archaeological evidence of environmental changes is unavailable.     

Nature of an overlapped paleosol and its significance in pedogenesis and paleogeography in North Huai region, China

An overlapped paleosol (albic Paleudalf) in North Huai region was studied by means of sand and clay mineralogy, elemental geochemistry, particle size distribution, observation of quartz sand surface structure under SEM, micromorphology, pollen analysis as well as soil dating. These albic soils are very extensive on uplands in this region and the profiles have developed on two individual formations rather than being differentiated by the homogenous eluvium of gneiss. It was also indicated that the soil evolution in this region proceeded from dessication and kaolinization during the middle Pleistocene to accumulation of bases and predominance of fragmental minerals in the early Holocene. The pedogenesis was further related to climate-landscape events in this region during the Quaternary. This study advocated that awareness of soil-landscape evolution was necessary in advance of pedogenesis research and a single soil-forming process could not account perfectly for soil formation with delicate evolution history.     

Paleosols in the moraine-mantle loam sequence of northeastern Europe: The memory of pedogenesis rates and evolution of the environment during OIS3

Morpho-analytical features of the paleocatena (a complexly organized heterochronous sequence), which contains 2 pedostratigraphical units: formed on the Holocene mantle loams Umbric Albeluvisol and the underlain Middle Valday (Wűrmian) paleopedocomplex developed on Moscowian (Riss II) moraine deposits, are described. The buried pedocomplex consisted of: 1) the paleohumus and paleogley (2Atgb–2Gtb–3Atgb) and 2) paleohumus (3Atgb–3AtGb) horizons. Thus, these pedostratigraphic units reflect two studies of pedogenesis marked by two paleohumus horizons. The horizons of the paleopedocomplex are separate parts of the profile classified as the Umbric Gley soil formed during OIS3. The ¹⁴C age of the three paleosol horizons varied between 24,350–30,900 yr BP. The studied paleopedocomplex is the only one known containing the Middle-Valday paleosol formed on moraine deposits, which is a clear sign of the northernmost occurrence of the Bryansk fossil soil in Europe. A detailed hierarchical morphological study of the paleopedocomplex, including meso- and submicromorphological and magnetic susceptibility analyses, allowed us to identify the Late Quaternary pedogenic processes under severe extra-continental climate, including gleyzation, aggregation, cracking and humus formation. Good preservation of these individual pedogenic processes is shown to be a soil memory under the overlapping press of Holocene pedogenesis. It was shown that the clay coating in the Middle Valday of the pedocomplex is a part of the Holocene soil formation. Based on the palynological data, it is possible to subdivide the development of paleovegetation of the area into four stages during which the paleosol horizons had being formed. At the beginning and the final stage of the Middle Valday, the forest–tundra landscapes with inclusions of tundra–steppe associations predominated. During the optimum of Bryansk Interstade, the periglacial pine-birch formations were widespread.     

Genesis and age of mineralogical profiles of Moldavian chernozems

In chernozems developed in the autonomous positions in Moldova, the mineralogy of their silicate component has some features indicative of stronger transformations than those that could be expected for the chernozems formed by the Holocene pedogenesis. The mineralogical profiles testify to the eluvial nature of the main subtypes of chernozems. It is suggested that the revealed changes are not due to the Holocene pedogenesis. According to the probable age of the mineralogical profiles calculated from the volumes of aluminosilicates removed, these profiles originated in the early and middle Late Pleistocene, i.e., about 50 000–120 000 years ago. The effect of forest pedogenesis in the past epochs on the mineralogy of the northern subtypes of chernozems also cannot be excluded. The presented data characterize the chernozems under study as polygenetic soil formations.     

PaleoVertisols of the northwest Caucasus: (Micro)morphological,physical, chemical,and isotopic constraints on early to late Pleistocene climate

Physical and chemical properties, macro‐ and micromorphology, clay mineralogy, and stable‐isotope compositions of paleosols within a pedostratigraphic column (PSC) of early to late Pleistocene age, interstratified paleosols, and loess (NW Caucasus, S Russia) were examined to better understand the evolution of the pedogenic environment over this time period, separating the effects of postpedogenic diagenesis. The column includes eight paleosols and six intercalated loessic horizons. Most of paleosols represent Vertisols or vertic intergrades. Vertic features increase in the middle of the PSC, where the paleosols are more clayey in texture and reddish in color. The morphology of carbonate nodules and soft masses, morphology‐ and depth(age)‐related changes in stable C and O isotope compositions, soil color, redoximorphic features, clay mineralogy, and illuviated clay indicate periods of wetter pedoenvironment in the past and suggest the Pleistocene paleosols are polygenetic and were formed with several wet/dry stages under a climate generally similar to the modern environment in the N Caucasus (mean annual temperature approx. 9°C–12°C). Interpretation of the time sequence of climate/environmental change requires careful separation of pedogenic mineral phases from phases altered by later diagenesis. The early Pleistocene period of paleosol formation appeared to be wetter or more humid, resulting in more significant development of vertic features. The terrestrial ecosystem remained dominated by C3 vegetation throughout the formation of the PSC, with four small periods of change towards a greater proportion of C4 plants or increased moisture stress.     

Stratigraphy of near-valley head quaternary deposits and evidence of climate-driven slope-channel processes in southern Brazilian highlands

During the past 40 years colluvial and alluvial deposits have been used in Brazil as good indicators of regional landscape sensitivity to Quaternary environmental changes. In spite of the low resolution of most of the continental sedimentary record, geomorphology and sedimentology may favor palaeoenvironmental interpretation when supported by independent proxy data. This paper presents results obtained from pedostratigraphic sequences, in near-valley head sites of southern Brazilian highlands, based on geomorphologic, sedimentologic, micromorphologic, isotopic and palynologic data. Results point to environmental changes, with ages that coincide with Marine Isotopic Stages (MIS) 5b; 3; 2 and 1. During the late Pleistocene, although under temperatures and precipitation lower than today, the local record points to relatively wet local environments, where shallow soil-water saturated zones contributed to erosion and sedimentation during periods of climatic change, as during the transition between MIS 2 and MIS 1. Late Pleistocene events with ages that coincide with the Northern Hemisphere Younger Dryas are also depicted. During the mid Holocene, slope-wash deposits suggest a climate drier than today, probably under the influence of seasonally contrasted precipitation regimes. The predominance of overland flow-related sedimentary deposits suggests an excess of precipitation over evaporation that influenced local palaeohydrology. This environmental condition seems to be recurrent and explains how slope morphology had influenced pedogenesis and sedimentation in the study area. Due to relative sensitiveness, resilience and short source-to-sink sedimentary pathways, near-valley head sites deserve further attention in Quaternary studies in the humid tropics.     

Periglacial cover-beds on the Swiss Plateau: indicators of soil, climate and landscape evolution during the Late Quaternary

Soils and the stratification of their parent materials were studied on the central Swiss Plateau. This area is characterized by glacial deposits varying from Late Glacial to pre-Würmian in age. Soils of all studied sites are developed within colluvial layers, the so-called cover-beds. In relation to the underlying deposits, we find a regular spatial distribution of cover-bed types. A surficial layer (Upper Layer) with relatively constant thickness (around 50 cm independent of relief position) covers Pleistocene sediments of any age. Therefore, it was formed mainly by cryoturbation/solifluction after the final glacier retreat from the Swiss Plateau (Younger Dryas or Oldest Dryas age). Layers that originate mainly from aeolian processes (Intermediate Layers) are restricted to areas outside the recessional moraines of the Berne-Stade (BS). Hence, they were formed merely up to the late Pleniglacial. They frequently consist of two distinct layers. Outside the glaciation of the Last Glacial Maximum (LGM), cover-beds in places overlie pre-LGM palaeosol relics (probably of Eemian age or even older). These are preserved even on higher relief positions, indicating that periglacial erosion during the Pleniglacial was only marginal. The palaeosol relics also occur on till of the so-called Older Wangen-Stade, which is commonly believed to represent the LGM, whereas we consider it to be older at least partly. Eventually, the distribution of soil types and their ecological characteristics are influenced considerably by cover-beds. As these beds reflect distinct phases of the Pleistocene, colluvial sediments provide a major tool for linking modern landscape characteristics to the Late Quaternary climate evolution.     

Paleosols in the moraine-mantle loam sequence of northeastern Europe: The memory of pedogenesis rates and evolution of the environment during OIS3

Morpho-analytical features of the paleocatena (a complexly organized heterochronous sequence), which contains 2 pedostratigraphical units: formed on the Holocene mantle loams Umbric Albeluvisol and the underlain Middle Valday (Wűrmian) paleopedocomplex developed on Moscowian (Riss II) moraine deposits, are described. The buried pedocomplex consisted of: 1) the paleohumus and paleogley (2Atgb–2Gtb–3Atgb) and 2) paleohumus (3Atgb–3AtGb) horizons. Thus, these pedostratigraphic units reflect two studies of pedogenesis marked by two paleohumus horizons. The horizons of the paleopedocomplex are separate parts of the profile classified as the Umbric Gley soil formed during OIS3. The ¹⁴C age of the three paleosol horizons varied between 24,350–30,900 yr BP. The studied paleopedocomplex is the only one known containing the Middle-Valday paleosol formed on moraine deposits, which is a clear sign of the northernmost occurrence of the Bryansk fossil soil in Europe. A detailed hierarchical morphological study of the paleopedocomplex, including meso- and submicromorphological and magnetic susceptibility analyses, allowed us to identify the Late Quaternary pedogenic processes under severe extra-continental climate, including gleyzation, aggregation, cracking and humus formation. Good preservation of these individual pedogenic processes is shown to be a soil memory under the overlapping press of Holocene pedogenesis. It was shown that the clay coating in the Middle Valday of the pedocomplex is a part of the Holocene soil formation. Based on the palynological data, it is possible to subdivide the development of paleovegetation of the area into four stages during which the paleosol horizons had being formed. At the beginning and the final stage of the Middle Valday, the forest–tundra landscapes with inclusions of tundra–steppe associations predominated. During the optimum of Bryansk Interstade, the periglacial pine-birch formations were widespread.     

Chrono-toposequences of soils on the river terraces in Transylvania (Romania)

A sequence of surface soil profiles and buried soils described on the 4th, 3rd, 2nd and 1st terraces of different rivers in Transylvania is presented as part of an attempt to perform a paleopedologic interpretation of the dominant soil types of this area. Excepting the first terrace, the described soils were formed from Pleistocene slopewash deposits of Würm, or possibly of Riss age, which overlay alluvial terrace deposits. On the basis of fossil animal remains, periglacial cryostructures, prehistoric artifacts (Coţofeni culture of the transition period from the Neolithic to the Bronze Age) and Scythian graves an approximate age of different soil horizons, as well as the polycyclic nature of soils was established. There is no essential difference between a Würmian buried soil horizon and the argic Bt horizon of the surface soils; moreover, in some cases, the buried paleosols become the Bt horizon itself of the surface soils, through the thinning of the overlying deposits. Even if the possibility of formation of the argic Bt horizons during the postglacial until the end of Neolithic, cannot be excluded, from the presented situations it seems that these horizons in the Transylvanian Basin are Würmian relics, formed in the periglacial interstadials. In most of the cases Bt horizon has nothing in common genetically with the topsoil.     

Natural radioactivity of some red Mediterranean soils

Seventeen samples of B-horizon of Pleistocene Terra Rossa soils from carbonate rock were collected in different Countries of the Mediterranean regions (Spain, Italy and Southern Turkey).     

The impact of environmental factors on early stage Andosol development south of Vatnajökull,Iceland

Icelandic soils develop in a dynamic environment affected by both natural processes and anthropogenic impacts. We present an extensive investigation of soil mineralogy and pedogenesis in a disturbed (i.e., by solifluction) pedon under such conditions. The study focuses on two distinct tephra layers, a rhyolitic tephra from the Öræfajökull eruption in 1362 CE (Ö1362) and a basaltic Veiðivötn tephra from 1477 CE (V1477). Both tephra layers form an important parent material in the study area south of Vatnajökull, Iceland. The Andosol developed from tephra and aeolian material, rich in volcanic glass. The pH (H₂O) values were between 5.5 and 6.6 and clay mineralogy displayed a predominance of allophanic material in both soil and tephra. The pedon can be seen in its early stage of chemical weathering and soil development. Despite the overall predominance of non- and poorly-crystalline short-range order secondary materials and Fe (hydr)oxides in the clay-size fraction, we found indication of smectite. High exchangeable Ca²⁺ and Mg²⁺ concentrations reflect enhanced aeolian input of volcanic material, while elevated exchangeable-Na⁺ concentrations are most likely caused by the oceanic composition of precipitation. The impact of erosion and aeolian processes on pedogenesis seemed to be higher between the deposition of Ö1362 and V1477, than in the soils above. Both, soil and tephra layers appeared disturbed by erosion–deposition processes over time. Characterised by a significantly coarser particle size composition, low soil organic carbon (SOC) content, and a more diverse mineralogy, a distinct fluvial sediment layer at 10–30 cm depth appeared sharply contrasting to the other soil layers in the profile. This possibly reflects the diverse composition of glaciofluvial material from a landslide originating from a Kvíárjökull moraine in the north. Changed weathering patterns and properties in the soils above the Ö1362 tephra indicated soil degradation following the deposition of the rhyolitic tephra.     

A micromorphological index of soil development for the Quaternary geology research

Profile development indices of Harden [Harden, J.W., 1982. A quantitative index of soil development from field: examples from a chronosequence in Central California. Geoderma 285, 1–98] and Ferrari and Magaldi [Ferrari, G., Magaldi, D., 1983. Significato ed applicazioni della paleopedologia nella stratigrafia del Quaternario. Boll. Mus. Civ. St. Nat. Verona 10, 315–340] have shown their utility for comparative dating of some paleosols during geomorphological and geological surveys. In Italy and other countries, pedostratigraphic methods have been commonly applied to soil profiles formed in continental formations. Unfortunately, buried and relict paleosols are very scarce or badly preserved in some areas of Italy due to past and recent tectonic activity and to strong human impact dating back to prehistoric times.In order to use relict paleosols for correct chronostratigraphic interpretation of relict paleosols and in order to correlate them with old landscape forms for the reconstruction of Quaternary sequences, a new micromorphological index (MISODI) for assessing soil development and degree of weathering was devised. The index was tested in the extensional tectonic basin of L'Aquila-Scoppito (Abruzzi, Central Italy) where some chronostratigraphic information is available.Results demonstrate that there is a good relationship between presumed relative age of paleosols and degree of weathering and pedogenesis in B and B/C horizons as assessed by this index. The index has the potential to be adapted for application to other paleosol types in other countries.     

Colluvisols under cultivation in Schleswig-Holstein. 2. Carbon distribution and soil organic matter composition

Soils under intensive cultivation have altered due to water erosion. This study was conducted to determine whether soil organic matter (SOM) composition of the colluvial source (Ap horizons) differs from the colluvial sink (M horizons). The SOM of a sandy Catena with erodic Cambisols and colluvic soils (Colluvisols) in Schleswig-Holstein, Northwest Germany, was investigated. A wet chemical analysis was combined with CPMAS ¹³C-NMR spectroscopy. In one case a significant correlation between the SOM composition of the Ap horizon of the erodic Cambisol and the M horizon of the Colluvisol was high (r² = 0.904^-), whereas the correlation for the other set was much weaker (r² = 0.640*). Two possible paths of pedogenesis are discussed. About 70% of the SOM of the colluvial source is decomposed during translocation or after deposition. A selective preservation or new formation of humins in the M material is probable. These humins contain, obviously, large amounts of polysaccharides, which were not detected by the wet chemical analysis. Further investigations of colluvic and erodic soils are necessary in order to specify the SOM quality and its possible modification due to soil translocation and accumulation.     

Occurrence and transformations of iron and manganese in a colluvial terra rossa toposequence of northern Italy

A soil toposequence in NE Italy was studied, which consists of a terra rossa on Cretaceous limestone on the upper slope grading downwards into a colluvial fan with terra rossa material and finally into alluvial river sediments. It is postulated that the red colluviated terra rossa material has come under a moister hydroregime which provided reducing conditions. Because hematite of the terra rossa dissolved preferentially over goethite, as shown by quantitative Fe oxide mineralogy, soil color changed from 2.5YR to 7.5YR. The soils contained two types of concretions, red ones with a low Fe_o/Fe_d ratio and a high content of hematite and low content of Mn-oxides and black ones with a high Fe_o/Fe_d ratio, a small amount of hematite and abundant Mn oxides. The red concretions are therefore considered as inherited from an earlier period of pedogenesis whereas the black ones are neoformed in the present pedoenvironment. This is further supported by the lower Al-for-Fe substitution of goethite in the black concretions as compared to a higher Al substitution in the goethite inherited from the terra rossa.     

Soil evolution over the Quaternary period in a semiarid climate (Segre river terraces,northeast Spain)

A macro- and micromorphologic study was done on the soils from a stepped sequence of seven dated fluvial terraces in the lower Segre river valley (Lleida, northeast Spain) under a present-day semiarid Mediterranean climate. The soils have evolved from the Holocene through the early Pleistocene, providing an excellent morphostratigraphic framework for evaluating time-dependent factors influencing soil formation in a dry and calcareous environment. Throughout the chronosequence, some properties are regularly age-related specially carbonatation in subsurface horizons. The carbonates occur mainly as micrite, and although microsparite and sparite also appear in the oldest soils, they are replaced by fine-grained calcite by dissolution–reprecipitation processes (micritization process), which is active at present. Some pedological paleofeatures as the presence of sparite and recarbonated argillans in oldest terrace can be interpreted as the reflex of climatic changes during the Quaternary. In spite of this climate variability, the soils display progressive and systematic patterns of carbonate accumulation: on the lowest terraces, the soils do not yet have secondary carbonates but in the beginning Late Pleistocene calcic horizons, with carbonate pendents, are developed; these pendents increase its thickness with age although pendent growth rates decreases from Late Pleistocene to Middle Pleistocene. In the middle of the Late Pleistocene, calcic horizons evolved to petrocalcic horizons, which increase its thickness in the Middle and specially in Early Pleistocene. The presence of calcic and petrocalcic horizons is the primary basis for soil classification. This criterion is applicable not only to the soils of the lower Segre river basin, but also to many soils throughout the semiarid Mediterranean region.     

我国南方不同母质土壤pH剖面特征及酸化因素分析

【目的】母质是影响土壤理化性质的主要因素之一,研究不同母质土壤pH的剖面特征及主要影响因素,为防治土壤酸化提供依据。【方法】选取湖南祁阳白茅草植被下七种母质(第四纪红土、红砂岩、板页岩、花岗岩、石灰岩、紫色页岩、河流冲积物)发育的土壤,测定不同层次(0-20、20-40、40-60、60-80和80-100 cm)土壤pH,通过比较表层(0-20 cm)与底层(60-100 cm) pH的差异来表征表层土壤是否酸化及酸化程度;测定0-20 cm土层的酸碱缓冲容量、有机质含量、阳离子交换量、比表面积及颗粒组成,分析影响表层酸化的主要因素。【结果】石灰岩剖面土壤的pH (8.46~8.72)最高,呈强碱性,其次为河流冲积物(7.37~7.87)、紫色页岩土壤(7.41~8.00),呈碱性;花岗岩、第四纪红土、红砂岩、板页岩四种母质发育的红壤呈酸性或强酸性,以花岗岩红壤pH (5.31~5.70)较高,其次为第四纪红土(4.62~4.97)、红砂岩红壤(4.31~4.67),板页岩红壤pH (4.25~4.49)最低。比较表层(0-20 cm)与底层(60-100 cm)土壤的pH,发现七种母质剖面土壤的表层均出现了pH降低,说明表层已出现酸化现象,酸化程度大小依次为:紫色页岩土壤>河流冲积物土壤、花岗岩红壤>第四纪红土、红砂岩红壤>石灰岩土壤、板页岩红壤。对表层土壤的比表面积、颗粒组成(黏粒、粉粒、砂粒含量)和pH、酸碱缓冲容量、阳离子交换量、有机质含量共八种理化因素进行逐步线性回归分析,由于多种因素的相互影响,七种母质土壤并未发现影响表层酸化的主要因素,但在四种母质(第四纪红土、红砂岩、板页岩、花岗岩)发育的酸性红壤中阳离子交换量是影响表层酸化的主要因素。【结论】土壤阳离子交换量与表层红壤酸化差值呈显著负相关,是影响第四纪红土、红砂岩、板页岩和花岗岩四种酸性红壤表层酸化的主要因素之一。     

Soil evolution on the low terraces of Lake Nero

The soil evolution in the depression of Lake Nero was driven by climate changes in the Holocene and by the history of the relief’s development in this region. In the Alleröd period, dark-colored soils were formed; in the Late Dryas period, they were cryoturbated and covered by colluvial deposits from the adjacent slopes. These specific paleosols are found on relatively high ancient surfaces. In the Early and Middle Holocene (10000–3700 BP), dark-colored horizons of soils with high stability of the organic matter were formed. The properties of humus in these soils are close to the properties of humus in forest-steppe soils. In the past 3500–3700 years, under conditions of some cooling and humidization of the climate with the development of taiga pedogenesis, these soils have evolved into soddy-podzolic soils. Their dark-colored horizons have degraded, though their lower parts are partly preserved in many places as the second humus horizons, the most distinctive feature of the soil polygenesis in the studied region. The soils of the low terrace (100–103 m a.s.l.) are younger than the soils of the higher and more ancient surfaces. Their evolution followed the same stages, though the Alleröd paleosols have not been found on this surface. In the coastal zone, at the heights below 97 m a.s.l., the soil formation began later, about 7000 years ago. Afterwards, the soils of this surface were subjected to the influence of fluctuations in the lake’s level. During the regression phase (7000–3500 BP), which corresponded to the dark-colored pedogenesis, these soils and the habitation deposits of the Bronze Age were formed on the dried bottom of the lake below its modern lake level of 93.2 m a.s.l. In the Late Holocene, these soils in the coastal zone were subjected to waterlogging rather than to podzolization due to the rise in the lake’s level; they have evolved into the soddy gley soils.     

Recognition and characterisation of the aeolian component in soils in the Girilambone Region,north western New South Wales,Australia

Characterisation of aeolian material in the Girilambone Region of New South Wales (600 km NW of Sydney), using particle size analysis, mineralogy, geochemistry and micromorphological analysis, shows that it consists of spheroidal, highly abraded 70 μm quartz grains. Although relatively pure aeolian accessions are found on top of Tertiary leucitite flows, the aeolian material is generally admixed with residual and transported soil to a depth of 0.3 m throughout the region. This study has established a set of criteria for identifying the aeolian contribution to soils in the Girilambone region of north western New South Wales where it is difficult to distinguish. These include: a characteristic particle size of 70 μm of the quartz grains; highly abraded and spherical morphology; presence of thin clay coats on well-rounded grains; and gradational patterns in particle size distribution, mineralogy and geochemistry through the soil profile. These types of soils, with a high content of silt and fine sand, do not readily form aggregates, particularly where they have low organic content. To improve the sustainability of cropping and pastoral activities on these soils, their management should aim to maintain or increase structural stability, for example by addition of organic material. Mineral exploration procedures should avoid the diluting aeolian component by sampling the > 150 μm fraction from surficial soils or material from below 0.3 m.     

Modeling of the evolution of steppe chernozems and development of the method of pedogenetic chronology

Geoarchaeological methods were used to study chronosequences of surface soils in the steppe zone and to trace soil evolution during the Late Holocene in northwestern Crimea. It was found that the morphological and functional “maturity” of the humus horizons in steppe chernozems of the Late Holocene was reached in about 1600–1800 yrs. After this, their development decelerated irreversibly. The maximum concentration of trace elements accumulated in these horizons in the course of pedogenesis was reached in 1400 yrs. A new method of pedogenetic chronology based on the model chronofunction of the development of irreversible results of pedogenesis over time is suggested. Original pedochronological data and growth functions—the most suitable models for simulating pedogenesis over the past three thousand years—suggest that the development of morphological features of soil as an organomineral natural body follows growth patterns established for biological systems.