Podzolization Process Research Articles

Mapping pedomemory of spodic morphology using a species distribution model

Red spruce (Picea rubens) ecosystems in the high elevations of the central Appalachians of the eastern United States are the focus of ongoing restoration efforts due to the valuable ecosystem services these forests provide. Recent research has shown that spodic materials still present in the soil represent the pedomemory of the historic extent of red spruce forests in the region. A dataset containing 221 points with varying spodic intensities and 29 environmental variables collected from the Monongahela National Forest in West Virginia, USA, was used to evaluate the utility of a species distribution model, Maximum Entropy (MaxEnt), for predicting the presence of spodic properties. MaxEnt was selected for evaluation because, as a presence-only model, it inherently omits absence locations and thereby reduces the risk of including false absences (i.e., herein, locations that have undergone some level of depodzolization) unlike other models previously used to predict pedomemory. Model outputs that employed three different spodic intensity class inputs—very weak to strong expression, weak to strong expression, and strong expression—resulted in similar spodic probability predictions, though there was less area mapped as transitional probabilities in the strong expression model than the two models that included weaker spodic intensity input data. Permutation importance indicated that no single or small subset of environmental variables controlled the three model outputs, perhaps because the environmental covariates may have been too coarse or not strongly enough associated with podzolization processes to be very important. When the output from the MaxEnt model using the full range of spodic intensities (very weak to strong) was compared to an output produced using a presence-absence model (random forests), there was approximately 62% agreement (where both models predicted presence or both predicted absence) for the cells in the top 40% of the predicted probabilities.

Tracing Pb Pollution Penetration in Temperate Podzols

AbstractWe combine high‐resolution soil sampling with lead (Pb) analyses (concentrations and stable isotopes) in two temperate podzols, together with previous data obtained with selective Al and Fe dissolution techniques. We aim to assess how atmospheric Pb is incorporated into the soils during pedogenesis. Partial least squares modelling for Pb concentrations shows that the podzolization process has the largest effect on Pb concentration (80·3% of the variance). The proportion of inorganic secondary compounds, the input of fresh organic matter from the soil surface and the relative abundance of Fe versus Al are responsible for a small part of the Pb concentration variance. Lead isotopic composition (206Pb/207Pb ratios) depends on soil organic matter content either fresh/poorly humified (57·3% of the variance) or humified (24·7% of the variance). The Pb linked to inorganic compounds and the overall podzolization process play a minor role in isotopic signature (5·3 and 3·7% of the variance respectively). Soil pH appears to be the controlling variable of the different transport and retention mechanisms. The relatively low isotopic ratios observed in spodic horizons result from geogenic Pb released through the preferential dissolution of the isotopically distinct most weatherable minerals of the parent material in the eluvial horizons, which undergoes downward mobilization. An accurate knowledge of soil reactive components and formation mechanisms is essential to a correct diagnose of the scope of Pb pollution and a more effective design of remediation strategies. Copyright © 2017 John Wiley & Sons, Ltd.

The role of bilberry and Alpine lady-fern in soil formation within the Carpathian subalpine spruce forest stands

The effect of the understory vegetation in the spruce forests of the upper montane belt on soil properties was investigated. Three types of understory vegetation were included: dominant Alpine lady fern, dominant bilberry or a mix of the two species. All studied soils were derived from sandstone, had acidic soil reactions, were located under similar physiographic conditions and have been populated by coniferous forests with similar to today's understory species for more than thousand years. The effect of Alpine lady fern on soil organic matter accumulation and quality as well as the amount of total Fe and Al and the share of different forms of these elements (linked to humus, amorphous inorganic, silicate and non-silicate crystalline) in the total Fe and Al were compared to the effect of bilberry on the aforementioned soil features. This work aimed to assess if the understory vegetation effect was strong enough to influence pedogenic processes taking place in the soils. The main differences between the studied soil properties were related to organic matter transformation and Fe and Al mobility. They were caused by a different susceptibility of Alpine fern lady and bilberry plant residues to the decomposition. In the soils with bilberry dominance, there were greater amounts of less decomposed organic matter accumulated than in soils with Alpine lady fern dominance in which organic matter was characterised by a high humification degree, large CH/CF ratios and significantly lower C/N ratios. Bilberry in the understory caused the increased Fe and Al mobility. Therefore in soils under bilberry podsolization processes and spodic horizon formation occurred that was indicated by the values of Fe and Al mobility indices. In soils under Alpine lady fern influence, these indices values were lower and the podzolisation processes were not intensive enough to form spodic horizons. In these soils, regardless of the condition favouring podsolization (low pH, spruce forest), the mobility of Fe and Al was slowed. The presence of Alpine lady fern as a dominant understory species resulted in a decrease in solubility of metallo-organic complexes, probably because of the quicker oxidisation of litter then in soils under bilberry. The sites with a mix of Alpine lady fern and bilberry turned out to be in a transitional phase, which with time would probably change to bilberry or fern understory. The ecological role of the studied soils resulting from accumulation of inorganic amorphous Fe, which takes part in anion sorption, thus limiting leaching, was also emphasized.

Cemented Horizons and Hardpans in the Coastal Tablelands of Northeastern Brazil

Horizons with varying degrees of cementation are a common feature of the soils from the coastal tablelands of Northeastern Brazil. In most cases, these horizons are represented by the following subsurface horizons: fragipan, duripan, ortstein, and placic. The aims of this study were to analyze differences regarding the development and the degree of expression of cementation in soils from the coastal tablelands of Northeastern Brazil: Planossolo Háplico (p-SX), Espodossolo Humilúvico (p-EK), Espodossolo Ferrihumilúvico (p-ESK), and Argissolo Acinzentado (p-PAC) pedons. The pedons studied displayed features related to drainage impediments. The cemented horizons from p-SX and p-EK had the same designation (Btgm), displaying a duric character that coincided with gleization features and are under podzolized horizons. In the p-ESK, the podzolization process is of such magnitude that it leads to the cementation of its own spodic horizons, which were both of the ortstein type (Bhsx and Bsm). In the p-PAC cementation is observed in two placic horizons and in the Btx/Bt horizon, as well as in the upper parts of the Bt/Btx horizon. Analysis of the micrographies from the cemented horizons showed predominance of a low porosity matrix. Such porosity is relatively greater in the horizons of “x” subscript than in the horizons with duric character. The Fe segregation lines were notable in the cemented horizons from p-EK and p-PAC, which corroborates the presence of placic horizons in such pedons. The preponderance of kaolinite in the clay fraction was widely verified in all the cemented horizons analyzed. Water immersion tests were the criteria adopted to define the duric character of the Btgm horizons from p-SX and p-EK, and in the Bsm horizon from the p-ESK. These tests were also used to confirm field morphology. In most cases, the maximum values of Fe, Al, and Si, determined by different extractions, occurred in positions overlaying the cemented horizons, whether they were spodic or not. The extracts of the aqueous solution displayed a noticeable accumulation of Si in the cemented horizons, except in the p-PAC. The presence of argillans in all cemented horizons allows them to be defined as illuvial, with the exception of the placic horizons, regardless of the presence of podzolization processes. The cemented horizons were preponderantly apedal, with a matrix of little porosity. The Fe, Al, and Si contents extracted by acid ammonium oxalate were effective at highlighting the influence of compounds with a low degree of crystallinity in the morphology of cemented horizons.

PEDOGENESIS AND SOIL CLASSIFICATION OF AN EXPERIMENTAL FARM IN MOSSORÓ, STATE OF RIO GRANDE DO NORTE, BRAZIL

ABSTRACT The Rafael Fernandes experimental farm is located in the Alagoinha district, northwest of Mossoró, State of Rio Grande do Norte, Brazil, over two pedogenic formations of different edaphic characteristics, thus needing a more detailed description of its soil types, since this area hosts several experimental fields for researches on agriculture. The objective of this work was to characterize the morphological, physical, chemical and mineralogical features of the most representative soils of this farm, in order to understand its pedogenesis and define its classifications. The whole area was surveyed in order to assess its more representative pedogenic formations. Three soil profiles were classified and described, from which samples were collected in all horizons for physical, chemical and mineralogical analysis. The parent materials and the relief were the determining factors for pedogenic processes of desilication, podzolization and laterization, generating the three main soil types of the area, which were classified up to the 4th categorical level and described as: Typic Rhodustults (P1), Rhodic Haplustox (P2) and Typic Plinthustalfs (P3).

Changes in soil morphology of Podzols affected by alkaline fly ash blown out from the dumping site of an electric power plant

PurposeThe impacts of fly ash on the chemistry of forest floors were previously described in literature, while impacts on soil properties were less recognised. Soil investigations were focussed mainly on increases of pH and base saturations in surface horizons. The purpose of this study was to describe the influence of alkaline fly ash blown out from the dumping site of a lignite-fired power plant on pH changes of ectohumus horizons of Podzols and the morphology of deeper horizons.Materials and methodsWe investigated the soil profiles of Podzols derived from loose quartz sand and developed under pine forest surrounding the dumping site of the power plant Bełchatów, central Poland. In the vicinity of the fly ash dumping site, five Podzol profiles located at a distance of 50 m from the dumping site were investigated, as well as soil profiles located along the transect set at distances of 50, 300, 800 and 2000 m from the dumping site. Control profiles were located at a distance of 7.3 km from the dumping site. Soil morphology was described in the field and the following properties were determined: soil texture, hydrolytic acidity, exchangeable cations, total organic carbon and total nitrogen content.Results and discussionThe pH values of Podzol ectohumus horizons located close to the dumping site ranged from 6.01 to 7.34 compared to a range of 3.08–3.72 in the control. Ectohumus horizon located 300 m from the dumping site showed a pH range of 4.13–4.26, while at a distance of 800 m, the pH values did not differ from those of the control site. The upper part of the eluvial soil horizons located close to the dumping site had been transformed into transitional AE horizons in which humic substances translocated from ectohumus horizons were accumulated. Moreover, the organic carbon content of this horizon increased compared to the carbon content of the illuvial Bs horizon located below it. Under the influence of alkalisation of upper horizons, the illuvial Bhs horizons vanished and were transformed into Bs horizons.ConclusionsChanges in soils affected by fly ashes are connected with alkalinisation of ectohumus horizons. Podzolisation processes can be reduced or even completely stopped regarding the distance from the dumping site. Eluvial Podzol horizons located close to the dumping site may be transformed into AE horizons in which humic substances translocated from ectohumus horizons are accumulated. Due to transformation and translocation of organic components, Bhs horizons can be transformed into Bs horizons.

Structural composition of organic matter in particle-size fractions of soils along a climo-biosequence in the main range of Peninsular Malaysia

AbstractInformation on structural composition of organic matter (OM) in particle-size fractions of soils along a climo-biosequence is sparse. The objective of this study was to examine structural composition and morphological characteristics of OM in particle-size fractions of soils along a climo-biosequence in order to better understand the factors and processes affecting structural composition of soil organic matter. To explore changes in structural composition of OM in soils with different pedogenesis, the A-horizon was considered for further analyses including particle-size fractionation, solid-state13C nuclear magnetic resonance (NMR) spectroscopy and scanning electron microscopy (SEM). Due to the increase in the thickness of organic layer with increasing elevation, the A-horizon was situated at greater depth in soils of higher elevation. The relationship between relative abundances of carbon (C) structures and particle-size fractions was examined using principal component analysis (PCA). It was found that alkyl C (20.1-73.4%) and O-alkyl C (16.8-67.7%) dominated particle-size fractions. The proportion of alkyl C increased with increasing elevation, while O-alkyl C showed an opposite trend. Results of PCA confirmed this finding and showed the relative enrichment of alkyl C in soils of higher elevation. Increase in the proportion of alkyl C in 250-2000 μm fraction is linked to selective preservation of aliphatic compounds derived from root litter. SEM results showed an increase in root contribution to the 250-2000 μm fraction with increasing elevation. For the <53 μm fraction, pedogenic process of podzolization is responsible for the relative enrichment of alkyl C. This study demonstrates that changes in structural composition of OM in particle-size fractions of soils along the studied climo-biosequence are attributed to site-specific differences in pedogenesis as a function of climate and vegetation.

Paleosoils as an Indicator of Climate Change in the Late and Middle Pleistocene of the Center of the East European Plain

In sections of the loess-soil series of the Central part of the East European plain, the Mikulin interglacial paleosoils were formed according to texture-differentiated type with predominance of the processes of lessivage and possible podzolization in similar climatic conditions with modern climate. The Kamenka interglacial paleosoils contained the signs of the processes of argillization and lessivage and were formed in more humid conditions than the Mikulin interglacial paleosoils. The Inzhavino interglacial paleosoils were formed under forest vegetation, where the texture and differentiated paleosoils were formed by eluvial-illuvial type involving process of lessivage, as well as with significant involvement of the processes of surface-gleying or podzolization. It points to conditions, similar to conditions of formation of the Kamenka interglacial soils, but with more intense processes of hydromorphism. Interstadial paleosoils of the late and middle Pleistocene were formed under grass vegetation in semiarid conditions.

Carbon pool ratios as scientific support to field morphology in the differentiation of dark subsurface soil horizons

In soil surveys, it is usual to find profiles with an uncommon disposition of horizons. Dark horizons in depth might be either the consequence of erosion and redeposition of soil materials from upslope or an indication of the podzolization process, which forms a spodic horizon. Few laboratory analyses are known to characterize dark subsurface horizons which could allow for the differentiation of spodic from buried A horizons. Some researchers propose C-humic and C-fulvic acid fraction ratios and forms of carbon to analyze characteristics of these horizons. Therefore, this research aimed to characterize dark subsurface horizons found in soils under a Eucalyptus minimum tillage system in the state of Rio Grande do Sul, Brazil, and to relate soil organic carbon to landscape features in toposequences. The characterization was performed by using the following ratios: humic acid and fulvic acid fractions (Cha/Cfa); pyrophosphate extractable-C and organic carbon (Cp/OC); fulvic acid fraction and pyrophosphate extractable-C (Cfa/Cp), and fulvic acid fraction and organic carbon (Cfa/OC). Soil organic carbon was related to slope gradient and Geomorphons in a Geographic Information System (GIS). None of the horizons analyzed met the criteria required for spodic horizon classification, where Cha/Cfa < 0.50, Cfa/OC < 0.30, and the ratio Cp/OC ≥ 0.50 simultaneously with Cfa/Cp ≥ 0.50. A relationship was found between landscape features and soil organic carbon content. The methodology proved to be satisfactory for providing scientific support to field morphology classification of dark subsurface horizons, specifically in the case where they could be misinterpreted as spodic horizons.

Mapping of Hydropedologic Spatial Patterns in a Steep Headwater Catchment

A hydropedologic approach can be used to describe soil units affected by distinct hydrologic regimes. We used field observations of soil morphology and geospatial information technology to map the distribution of five hydropedologic soil units across a 42-ha forested headwater catchment. Soils were described and characterized at 172 locations within Watershed 3, the hydrologic reference catchment for the Hubbard Brook Experimental Forest, New Hampshire. Soil profiles were grouped by presence and thickness of genetic horizons. Topographic and bedrock metrics were used in a logistic regression model to estimate the probability of soil group occurrence. Each soil group occurred under specific settings that influence subsurface hydrologic conditions. The most important metrics for predicting soil groups were Euclidean distance from bedrock outcrop, topographic wetness index, bedrock-weighted upslope accumulated area, and topographic position index. Catchment-scale maps of hydropedologic units highlight regions dominated by lateral eluviation or lateral illuviation and show that only about half the catchment is dominated by podzolization processes occurring under vertical percolation at the pedon scale. A water table map shows the importance of near-stream zones, typically viewed as variable source areas, as well as more distal bedrock-controlled zones to runoff generation. Although the catchment is steep and underlain by soils developed in coarse-textured parent material, patterns of groundwater incursion into the solum indicate that well-drained soils are restricted to deeper soils away from shallow bedrock and the intermittent stream network. Hydropedologic units can be a valuable tool for informing watershed management, soil C accounting, and understanding biogeochemical processes and runoff generation.

Early stages of soil development on serpentinite: the proglacial area of the Verra Grande Glacier, Western Italian Alps

PurposeClimate change is driving strong variations in mountain habitats, such as glacier retreat, which is releasing large surfaces soon colonized by vegetation and attacked by weathering and pedogenesis. Many proglacial soil chronosequences have been studied in different parts of the world, but no study is available on early soil development and pedogenesis on serpentinite.Materials and methodsWe analysed the development of the main chemical (pH, organic matter, nutrients and exchangeable cations) and morphological properties in three soil chronosequences in the Verra Grande Glacier forefield (Italian side of the Monte Rosa Group, Western Alps), characterized by slightly different parent materials (pure serpentinite or serpentinite with small gneiss inclusions) and topography (steep lateral moraines or flat basal till).Results and discussionOrganic matter accumulation, acidification and base and metal leaching are the most important pedogenetic processes active during early stages of soil formation on serpentinite in the upper subalpine altitudinal belt. These processes are associated with minor changes in color and structure showing weak mineral weathering. Biocycling of nutrients is limited on pure serpentinite because of weak primary productivity of the plant community. Pedogenesis is quite slow throughout the forefield, and it is slowest on pure serpentinite. On flat surfaces, where slow erosion permits a fast colonization by Ericaceae, the podzolization process begins after few centuries since moraine deposition, while on steep slopes more time is required.ConclusionsPedogenesis on serpentinite is extremely slow. The fast colonization by grassland species increases the speed of pedogenetic trends where serpentinitic till is enriched by small quantities of P-rich gneiss. The encroachment of forest-shrub species increases the speed of pedogenetic trends thanks to a strong nutrient biocycling.

Structure and dynamics of oligomesic dry pine forests in land zones of the Lake Engure catchment area

Abstract Investigation of species composition, soil physical and chemical properties, as well as forest productivity of oligomesic dry pine forests (Vacciniosa and Myrtillosa forest types) was carried out in six dry land zones differing in age of the Lake Engure catchment area (sediment zones of the drained lakebed, Mia, Limnea, Litorina Sea, Baltic Ice Lake and glaciofluvial sediment zone in Northern Kursa Upland). Higher species diversity in the tree layer and a more typical podzolisation process was found in the older dry land zones (sediments of the Baltic Ice Lake, Northern Kursa Upland), while higher species diversity in the field layer (higher proportion of grasses and sword grasses), more intensive gleying process in soils, as well as considerably higher stand productivity was observed in the younger dry land zones (the drained lakebed, Mia, Limnea and Littorina Sea stages). Characteristic species of the Vaccinio-Piceetea class were dominant in the pine forests of older dry land zones, whereas species of the Pulsatillo-Pinetea class were typical in the sea coastal pine forests.

Pyrogenic carbon stocks and storage mechanisms in podzolic soils of fire-affected Quebec black spruce forests

Wildfire, a recurrent disturbance in the boreal, converts part of the forest floor into pyrogenic carbon (PyC). The latter is an important component of the global soil carbon pool, yet knowledge of its stocks and storage mechanisms in these boreal ecosystems is scarce. Podzolization processes, which are frequent under boreal vegetation, result in distinctive patterns of soil organic carbon (SOC) accumulation in the mineral subsoil; how this may affect PyC storage remains largely unknown. The objectives of this study were to estimate SOC and PyC stocks in podzolic soils from fire-affected black spruce forests, and to explore the storage mechanisms taking place in their mineral horizons. We also compared PyC stocks in mineral soils to forest floor stocks. Samples were collected from 23 soil profiles under black spruce forests located throughout the province of Quebec. To further explore the relationship between podzolization and PyC storage mechanisms, we measured SOC and PyC contents in size and density fractions of a subset of 11 podzolic B horizons. Total SOC stocks in the mineral horizons and forest floors were comparable. Pyrogenic carbon stocks in the mineral soils, estimated by a H2O2/dilute HNO3 digestion, averaged 0.2(±0.1)kgCm−2. This was significantly lower than forest floor stocks, which ranged from 0.2 to 1.2kgCm−2. Consequently, PyC constituted a smaller fraction of total SOC (2–15%) in mineral soils than in forest floors, where it was as high as 68% (±5) in some horizons. In the mineral soils, SOC and PyC concentrations were strongly correlated. While some PyC was found in unprotected particulate organic matter (POM), the rest was associated with organo-mineral and organo-metallic complexes in the micro-aggregate protected POM and fine fraction. Patterns of PyC accumulation in mineral soils were similar to SOC, and the greater PyC stocks were found in podzolic B horizons.

Vegetation influence on soil formation rate in a proglacial chronosequence (Lys Glacier, NW Italian Alps)

Climate change has huge impacts on alpine ecosystems. One of the most visible effects in the Alps is glacier retreat since the end of the Little Ice Age (LIA), which caused the exposure of previously glaciated surfaces. These surfaces are open-air laboratories, verifying theories regarding ecosystem and soil development.In order to increase our knowledge on the effects of time and vegetation primary succession on soil development in proglacial areas, we sampled soils and surveyed plant communities on stable points in the proglacial area of the Lys glacier, in the Italian north-western Alps (Valle d'Aosta Region). The sampling points were located on dated sites (based on literature and/or historical photographs).Glacial till is attacked by weathering processes immediately after deposition and stabilization, with a consequent loss of soluble compounds, decrease of pH and primary mineral weathering. The speed of these processes was largely increased after the establishment of a continuous vegetation cover, thanks to the organic matter accumulation caused by litter input and root decomposition below the soil surface.On sialic glacial tills, below timberline and under a quasi-climax larch–Rhododendron forest, fast and steady decrease in pH values, increase in organic matter content and horizon differentiation were observed. In particular, genetic eluvial horizons formed in approximately 60years, while diagnostic albic horizons were developed after ca. 90years, pointing to an early start of the podzolization processes. Cheluviations of Fe and, secondarily, Al were analytically verified. However, illuviations of Fe, Al and organic matter in incipient B horizons were not sufficient to obtain diagnostic spodic horizons on LIA materials.Under grazed grassland below timberline and alpine prairie above timberline, acidification and weathering were slightly slower, and no redistribution with the depths of Fe and Al oxi-hydroxides was observed. A cambic Bw horizon developed on the oldest LIA moraines.Therefore it seemed that this fast onset of the podzolization process in comparison to other proglacial chronosequences in the Alps was mainly driven by vegetation properties rather than by specific climatic conditions.

Low vertical transfer rates of carbon inferred from radiocarbon analysis in an Amazon Podzol

Abstract. Hydromorphic Podzol soils in the Amazon Basin generally support low-stature forests with some of the lowest amounts of aboveground net primary production (NPP) in the region. However, they can also exhibit large values of belowground NPP that can contribute significantly to the total annual inputs of organic matter into the soil. These hydromorphic Podzol soils also exhibit a horizon rich in organic matter at around 1–2 m depth, presumably as a result of eluviation of dissolved organic matter and sesquioxides of Fe and Al. Therefore, it is likely that these ecosystems store large quantities of carbon by (1) large amounts of C inputs to soils dominated by their high levels of fine-root production, (2) stabilization of organic matter in an illuviation horizon due to significant vertical transfers of C. To assess these ideas we studied soil carbon dynamics using radiocarbon in two adjacent Amazon forests growing on contrasting soils: a hydromorphic Podzol and a well-drained Alisol supporting a high-stature terra firme forest. Our measurements showed similar concentrations of C and radiocarbon in the litter layer and the first 5 cm of the mineral soil for both sites. This result is consistent with the idea that the hydromorphic Podzol soil has similar soil C storage and cycling rates compared to the well-drained Alisol that supports a more opulent vegetation. However, we found important differences in carbon dynamics and transfers along the vertical profile. At both soils, we found similar radiocarbon concentrations in the subsoil, but the carbon released after incubating soil samples presented radiocarbon concentrations of recent origin in the Alisol, but not in the Podzol. There were no indications of incorporation of C fixed after 1950 in the illuvial horizon of the Podzol. With the aid of a simulation model, we predicted that only a minor fraction (1.7%) of the labile carbon decomposed in the topsoil is transferred to the subsoil of the Podzol, while this proportional transfer is about 30% in the Alisol. Furthermore, our estimates were 8 times lower than previous estimations of vertical C transfers in Amazon Podzols, and question the validity of these previous estimations for all Podzols within the Amazon Basin. Our results also challenge our previous ideas about the genesis of these particular soils and suggest that either they are not true Podzols or the podzolization processes had already stopped.

The evidence of lateral podzolization in sandy soils of Northern Poland

Abstract Evidence of slope-scale element translocation (lateral podzolization) has been documented in sandy areas of Northern Poland. Accumulative soils enriched with organic matter, iron, aluminum, and manganese (Entic Podzols) have been found at the bottom of closed, small depressions in inland-dune fields and undulated surfaces of glaciofluvial terraces. Together with the surrounding weakly or moderately developed podzolic soils (Albic Arenosols, Haplic Podzols) Entic Podzols form regular toposequences, and seem to be geochemically linked. In the light of chemical, micromorphological and SEM-EDS analyses, the whole solum of the soils under study exhibit diagnostic features of the illuvial spodic horizon; however, they do not have an eluvial albic horizon. Landscape position and features of the studied soils suggest inter-pedon translocation of organic matter, iron and aluminum as the concept of Entic Podzol genesis. Furthermore, high values of Fe d /Fe t and Fe o /Fe d ratios in their solum can be interpreted as evidence of allochtonous character of iron accumulation. The results of this study show that the lateral podzolization process can be common even along slopes built from loose, permeable sandy deposits, where one would not expect any effective intra-layer solution flow. Organic matter and compounds illuviated to the Bhs horizon are the probable factors limiting percolation and modifying the direction of solutions movement. On slopes of more complex morphology, small closed depressions act as geochemical traps, where compounds leached from the upper slope soils can accumulate. Radiocarbon dating carried out on a buried Entic Podzol found in one of the profiles shows that the process has continued for more than 1200 years.

Study of podzolization process under different vegetation cover in the Jizerské hory Mts. region.

The development of Podzols is conditioned by many factors. One of them is vegetation cover. The aim of this study was to examine in detail special chemical properties, micromorphological features and water retention ability of Podzols under two different vegetation covers (spruce forest and grass). The study was performed in the Jizersk&amp;eacute; hory Mts., which were strongly influenced by atmospheric acidificant depositions in the past. The study was focused on the assessment of a 30-year grass amelioration impact on soils on the former forest land. It was shown that larger differences in the studied chemical properties (pH&lt;sub&gt;KCl&lt;/sub&gt;, pH&lt;sub&gt;H2O&lt;/sub&gt;, eCEC, content of Ca, Mg, Al&lt;sub&gt;KCl&lt;/sub&gt;, Al&lt;sub&gt;H2O&lt;/sub&gt;, Al(X)&lt;sup&gt;1+&lt;/sup&gt;, Al(Y)&lt;sup&gt;2+&lt;/sup&gt; and Al&lt;sup&gt;3+&lt;/sup&gt; species) were in the surface organic horizons and decreased with depth. Podzolization intensity was higher under the spruce forest than under the grass cover. Higher amounts of potentially dangerous Al forms were detected in the soils under the spruce forest than under the grass. Grass expansion on clear-cut areas (former forest) as a natural amelioration step results in the particular restoration of soil conditions. The micromorphological features studied on the soil thin sections using the optical microscope and soil water retention curves measured on the undisturbed 100 cm&lt;sup&gt;3&lt;/sup&gt; soil samples showed a significant influence of the organic matter presence on the soil structure and retention ability of H and Bhs horizons. Soil under the grass cover had denser structure (e.g. greater fraction of small capillary pores) and higher retention ability than soil under the spruce forest. Very similar retention curves were measured in the Ep and Bs horizons under both vegetation covers. Micromorphological features studied on the thin soil sections clearly documented a podzolization mechanism (e.g. organic material transport and its accumulation, weathering process and Fe&amp;nbsp;oxidation and mobilization).

Pleistocene–Holocene cover-beds on granite regolith as parent material for Podzols — An example from the Sudeten Mountains

Abstract Pleistocene periglacial cover-beds have been considered to be the proper parent material of soils in the medium mountains of the Central Europe and in other areas influenced by the periglacial conditions. The concept highlights an importance of solifluction and cryoturbation phenomena, and an addition of aeolian silt (loess) in the formation of cover-beds. Significant loess admixture may, however, hinder podzolization process. The objective of the present study was to recognize the stratification of slope materials in the upper zone (1000–1200 m ASL) of the Sudeten Mts. (SW Poland) and its relation to the morphology and properties of Podzols. Mineralogical and submicromorphological analyzes confirmed autochthonous origin of the parent materials and excluded loess admixture. Macro- and micro-observations proved periglacial formation of deeper beds, while the pollen analysis confirmed the Holocene age of an uppermost sand layer. Finally, four-partial mineral sequences were distinguished in soil profiles: (1) an underlying granite regolith (not always present within the standard soil pit), (2) a basal periglacial layer formed by solifluction, (3) a cryoturbated transitional zone instead of typical intermediate periglacial layer, (4) an uppermost sandy (or a sandy–silty) layer instead of the upper periglacial layer. Modification of periglacial cover-bed series by replacing of the silty “upper periglacial layer” with sandy Holocene cover allowed Podzol formation under favorable climate conditions. The same palynological and micromorphological observations confirmed polygenetic nature of Podzols. The present-day Bh horizon is in fact a humus layer of a late Pleistocene–early Holocene brown earth buried under a sandy cover. An albic horizon thickness and its lower boundary are therefore related to the lithological discontinuity in the cover-bed series.

Soil toposequence under man-planted vegetation in the Krkonoše Mts., Czech Republic

Mountainous areas represent regions with specific soil cover pattern that is naturally given by an altitudinal gradient. The objective of our study was to describe the soil cover development on the altitudinal gradient under changed environment given by man-planted vegetation and acidification. The studied area is characterized by spruce monoculture planting that replaced the original broadleaf natural vegetation and high load of anthropic acidification. The common hypothesis considering the sequence of Dystric Cambisol-Entic Podzol-Haplic Podzol with increasing altitude was not proved. The results of our study indicate that the influence of spruce vegetation causes the occurrence of Haplic Podzols at low altitudes where the natural soil formation does not induce their development. Results showed that the vegetation type can overrule other altitude-related soil-forming factors. The conversion of natural broadleaf and mixed forests to spruce monocultures leads to the expansion of podzolization process to lower altitudes.

The Podzol Hydrosequence of Itaguaré (São Paulo, Brazil). 2. Soil Organic Matter Chemistry by Pyrolysis‐Gas Chromatography/Mass Spectrometry

A Late Pleistocene to Holocene hydrosequence of podzols in the coastal plain of São Paulo (Brazil), of which the macromorphology was described previously, was investigated by pyrolysis‐gas chromatography/mass spectrometry (GC/MS). Differences in chemical composition of organic matter (OM) coincided very well with the morphological interpretation of these profiles with respect to drainage conditions, origin of OM, and decomposition. OM in B‐horizons of poorly‐drained profiles has a signature of dissolved organic matter (DOM), while that of well‐drained profiles indicates root‐derived material. Bands that, according to their morphology, were attributed to DOM have different signature within the profiles, reflecting DOM origin. The EB horizons of poorly‐drained profiles show a selective decay of B‐horizon material, resulting in a relative accumulation of aliphatics in poorly drained profiles. In the EB horizons of the well‐drained profiles, however, significant amounts of microbial products were accumulated and poly‐aromatic compounds were the most stable. This has not been described for temperate podzols. Factor analysis suggests that local differences in vegetation are responsible for about 50% of the total chemical variation in pyrolysates, whereas source, transport, and decomposition in the profile account for the other half. The results underline that OM composition of podzol horizons is strongly dependent on hydrological conditions, resulting in divergent soil organic matter (SOM) properties between soils from different landscape contexts. Nonetheless, there is a comprehensible relation between SOM fingerprints of horizons within one profile. Finally, changes in OM composition at horizon transitions provide insight into the podzolization process.