Pedogenic Factors Research Articles

How do reactive aluminum and iron phases control soil organic carbon and phosphate adsorption capacity in agricultural topsoils across Japan?

ABSTRACT The growing number of studies suggests that the prediction of soil organic carbon (SOC) storage and persistence can be improved by accounting for variations in soil reactive metal phases. Nevertheless, the dataset on reactive metals is often limited at a national scale. In Japan, the phosphate adsorption coefficient (PAC) has been measured for agricultural soils nationwide. PAC is known to be strongly controlled by reactive metals, and hence, it can be used as a surrogate for reactive metal content. However, the relationships between SOC, reactive metals and PAC across a wide range of agricultural soils remain unclear. We thus examined these relationships using agricultural topsoils taken from 115 sites across Japan, covering two major soil great groups, Andosols and Lowland soils, as well as various land uses and soil temperature regimes (7.2–19.1°C). For the whole dataset, PAC was strongly correlated with oxalate-extractable metals (Alox + 0.5Feox: Metalox, r = 0.83) and moderately with pyrophosphate-extractable metals (Alp + 0.5Fep: Metalp, r = 0.68). These results suggest a stronger contribution of short-range-order (SRO) minerals to PAC as the former parameter reflects the content of both SRO minerals and organically complexed metals, while the latter reflects only that of organo-metal complexes. Moreover, Metalp was the best predictor of SOC contents in both Andosols (r = 0.79) and Lowland soils (r = 0.65). When only soils at near neutral soil pH range were considered, the exchangeable Ca content also co-varied with SOC in Lowland soils (n = 17). Of the two metallic elements, reactive Al phases better explained the variation of SOC and PAC in Andosols, whereas reactive Fe phases also showed similar explanatory power for PAC in Lowland soils. Our analyses also suggested that soil group (esp. erosion intensity) and land use likely impacted the SOC-Metalox relationship in Andosols, whereas environmental factors such as soil temperature and soil redox regime affected those relationships in Lowland soils. Overall, we showed that PAC is a useful surrogate for SRO minerals and organo-metal complexes and, with careful considerations of the environmental and pedogenic factors, it is potentially useful to estimate the amounts of SOC stabilized by reactive metal phases in agricultural soils across Japan.

Soil silicon availability and silicon uptake by winter wheat in Tokachi district, Hokkaido

ABSTRACT Silicon (Si) is the second most abundant element in soils and is a beneficial element for plant growth, particularly for gramineous plants such as rice, corn, and wheat. In Japan, soil Si availability and its relationship with Si in plants have been mainly focused on paddy soils and rice. Although Si has also been reported to benefit wheat production via enhanced phosphorous uptake and resistance to diseases, there is little study on Si availability in agricultural soils related to wheat production in Japan. The objectives of this study were to (1) assess the soil available Si and its relation to other soil properties in upland fields, (2) evaluate Si concentration and its distribution in winter wheat, (3) clarify the relationship between the soil available Si and the Si concentration in wheat, and (4) identify suitable methods to determine available Si for agricultural soils. Surface soil and wheat samples were collected from 40 growers’ field along four different river terraces including lowland, low terrace, middle terrace, and high terrace of the Tokachi district in 2020 and 2021. Soil available Si was evaluated by three methods using acetate buffer and phosphate buffer solution. The soil available Si contents in agricultural soils varied from field to field considerably, and were remarkably larger in the fields located on the middle and high terraces compared to the lowland and the low terrace, suggesting the effects of soil parent materials and pedogenic factors, particularly volcanic ashes and amorphous clay minerals. The mean Si uptake by winter wheat was 13.4 g m−2 and comparable to N and K uptake and greater than P. Winter wheat mainly stores Si in culms, leaves and husks, and the highest mean concentration of Si in above-ground part of winter wheat was 27.6 g kg−1 in husks. The high Si concentration in the husk may be related to enhancing plant physical protection to preharvest sprouting and fungal diseases. Among three methods, the acetate buffer solution method could be the most promising method to determine soil Si availability in agricultural soils of the studied area.

Low variation in microbial carbon sequestration between farmland and apple orchards in typical loess-covered regions

The cultivation of deep-rooted vegetation greatly alters the tradeoffs between water and carbon dynamics, yet their impact on microbial carbon sequestration (MCS) remains inadequately documented, particularly in thick vadose zones. This information is crucial for global climate mitigation and ecosystem service enhancement. As such, we collected triplicate samples for each land use type, exploring the abundance and structure of cbbL-harboring microbial communities within 10-m deep profiles under cultivated farmland and two apple orchards of varying ages (n = 72). Our findings indicated a shift from water-dominated (improved water retention at the expense of reduced carbon sequestration) to carbon-dominated benefits (enhanced carbon sequestration at the expense of decreased water retention) in deep soil layers (2–10 m) after the transformation from farmland to apple orchards. Despite the lack of significant differences among the three land use types, the gene abundances and microbial diversity indices reduced with soil depths because of variations in substrates, resources, and microenvironments. The cbbL-harboring microorganisms consisted of 5 phyla, 7 classes, 19 orders, 30 families, and 55 genera, with Proteobacteria as the predominant bacterial phylum. The relative contributions of different genera varied with soil depths, reflecting their distinct survival strategies. The microbial network was positively connected in various soil layers under farmland and apple orchards. Furthermore, the results of correlation, redundancy analysis, and structural equation modeling jointly indicated that plant roots and soil properties, including total nitrogen and organic carbon, governed MCS processes in deep unsaturated zones. Specifically, the low microbial variation between farmland and apple orchards can be attributed to the predominant effects of climatic and pedogenic factors on soil properties, the restricted contribution of plant roots to soil nutrient levels per unit depth, and the adverse effects of plant-induced ecohydrological consequences on root systems and microbial populations. This study offers new insights within thick vadose zones containing deep-rooted plants, thereby contributing to a better understanding of global terrestrial carbon cycle processes.

Pore shrinkage capacity of Shajiang black soils (Vertisols) on the North China Plain and its influencing factors

Different pore sizes present different pore shrinkage capacities in a nonrigid soil. However, the shrinkage capacities of different pore sizes and their influencing factors are not clear. We aimed to quantify the shrinkage capacities of different pore sizes (large pores, > 50 μm; medium pores, 0.2–50 μm; fine pores, < 0.2 μm) and determine how soil properties impact soil shrinkage capacity at the regional scale. Two sampling transects from west to east (360 km long, 35 samples) and from north to south (190 km long, 29 samples) were selected to investigate soil shrinkage capacity and physicochemical properties of at 0–20 cm depth in the Vertisol (locally known as Shajiang black soil) region of the North China Plain. The results showed that soil total shrinkage capacity, indicated by the coefficient of linear extensibility (COLE), had a mean value of 0.041–0.051 in the west-east and north-south transects. Large pores had higher pore shrinkage index (PSI) values (0.103–0.109) than medium (0.077–0.096) and fine (0.087–0.091) pores. The PSI of fine pores showed a fluctuating increasing trend from northwest to southeast, and the fine pore shrinkage capacity determined the COLE (r2 = 0.789, P < 0.001). The PSI of large pores had a significant relationship with soil bulk density (r = 0.281, P < 0.05) and organic carbon (r = -0.311, P < 0.05), whereas those of medium and fine pores were correlated with soil clay content (r = 0.381 and 0.687, respectively, P < 0.001). In addition, the PSI of fine pores was also correlated with montmorillonite content (r = 0.387, P < 0.01). It can be concluded that the PSI of large pores is related to anthropogenically influenced soil properties with low stability, whereas those of medium and fine pores are related to pedogenic properties. The high variability in anthropogenic and pedogenic factors explains the spatial pattern of Vertisol shrinkage capacity on the North China Plain.

Disentangling the pedogenic factors controlling active Al and Fe concentrations in soils of the Cameroon volcanic line

Active Al, Fe and Si (i.e., oxalate extractable fraction: Alo, Feo, Sio) strongly affect soil physical, chemical and biological properties. This study examined the pedogenic factors affecting Alo, Feo and Sio contents across a soil weathering sequence in the Cameroon volcanic line. We investigated the B horizon (∼50-cm depth) from 26 soils formed in basaltic materials at different elevations (110–2570 m) incorporating a wide range of temperature (14–27 °C) and precipitation (1520–3130 mm). The weathering sequence ranged from weakly weathered Andisols in the southwest region grading to strongly weathered Oxisols on the central highlands. We assumed pyrophosphate extractable Al/Fe (Alp/Fep) as organo-Al/Fe complexes, and Sio, (Alo − Alp) and (Feo − Fep) as short-range-order (SRO) minerals. Factor analysis of climatic (e.g., temperature and precipitation/leaching metrics) and soil geochemical properties (e.g., weathering indices) identified three independent factors representing temperature/dry season intensity, weathering degree and precipitation/leaching as the primary determinants of Alo, Feo and Sio concentrations. Organo-metal complexes (Alp and Fep) were negatively correlated with the temperature/dry season intensity factor, whereas the SRO mineral phases (Sio, Alo − Alp and Feo − Fep) were negatively correlated with weathering degree. The precipitation/leaching factor positively correlated with Alo, Feo and Sio. Our analysis infers that low temperature promotes the formation and preservation of organo-Al/Fe complexes, whereas weathering degree is more critical for SRO minerals. Further, increased weathering and a drier climate enhance the formation of crystalline clay minerals at the expense of SRO minerals. Allophanic materials (Sio) were evident (Sio: 9–43 g kg−1) only in weakly weathered soils. However, low allophanic contents were found in more highly weathered soils (Sio: 2–7 g kg−1) accompanied by high Alp and Fep, suggesting the importance of volcanic parent materials as a direct source of Al and Fe via weathering for the formation of organo-metal complexes. In sum, we clarified the discriminatory effects of climatic factors and degree of weathering in regulating the composition of the active Al, Fe and Si fractions along the Cameroon volcanic line.

Pedological Development of Soils in Eastern Agroclimatic Zone of Haryana through Field Morphology Rating System

A study was carried out to evaluate the pedological development of soils in Eastern agroclimatic zone of Haryana using field morphology rating system. For this, nine pedons were excavated to study the morphological properties in field and rating scale was used to compare adjacent horizons with each other to give a comparison of the relative distinctness of horizons or to compare horizons in the solum with the C-horizon to give a relative profile development in soils occurring in different physiographic positions i.e. Shiwalik hills, recent and old alluvial plains with different precipitations throughout the study area. Some chemical properties were also used to evaluate the pedogenic factors as a result of being affected by process and factors of soil formation due to the distinct effect of climate. The Relative Horizons Distinctness (RHD) ratings were made by a comparison of adjacent horizons. The soils of Shiwalik hills, recent and old alluvial plains have RHD ratings from 6 to 14, 3 to 11 &amp; 3 to 12, respectively. The RPD ratings were made by a comparison of the C horizon to the horizons above it in the profile. The soils of Shiwalik hills, recent and old alluvial plains have RPD ratings from 7 to 15, 3 to 14 &amp; 5 to 16. The RPD values of all the profiles were maximum in A horizon due to maximum pedological development influenced by weathering. So, studies of these soils indicated the pedological development in the order of Shiwalik hills &gt; old alluvial plains &gt; recent alluvial plains.

Influence of Plants on the Spatial Variability of Soil Penetration Resistance

Abstract Soil penetration resistance is an informative indicator to monitor soil compaction, which affects a range of ecological processes in floodplain ecosystems. The aim of the investigation was to reveal the influence of vegetation cover on the spatial variability of penetration resistance of floodplain soils. The study was carried out in the elm oak forest in the floodplain of the Dnipro River (Dniprovsko-Orilsky Nature Reserve, Ukraine). The study of the soil profile morphology was performed in accordance with the guidelines of the field description of soils FAO. The soil penetration resistance was measured in the field using the Eijkelkamp manual penetrometer to a depth of 100 cm at 5-cm intervals within the polygon consisted of 105 sampling points. Vegetation descriptions were made in a 3×3-meter surrounding from each sampling point. The soil penetration resistance was found to regularly increase with increasing depth. The changes in resistance values were insignificant until 25–30 cm depth. After that, there was a sharp increase in penetration resistance up to the depth of 70–75 cm, after which the indicators plateaued. In the three-dimensional aspect, the spatial variation of soil penetration resistance can be fractionated into broad-scale, medium-scale, and fine-scale components. Tree vegetation induces a broad-scale component of soil penetration resistance variations, which embraces the whole soil profile. The herbaceous vegetation induces a medium-scale component, which embraces the upper and middle parts of the soil profile. The fine-scale component is influenced by pedogenic factors.

Physical properties of technosols at brown coal mine wastes in Eastern Siberia

Recultivation of disturbed lands is very important task of science and practice at large territories of mining in Siberia as in other regions of Russia and other countries. Condition of physical properties of new-formed soils technozems (Technosols) is one of key questions for future state and usage of these lands. Changes of technozem's physical properties over time as part of land restoration and reclamation at Nazarovsky brown coal mine wastes (Eastern Siberia) were studied at one, three, ten and twenty years after the beginning of reclamation. Technozems here are artificially formed soil-like formations, which were made by the method of filling a material of fertile soil layer (fertile soil material or FSM) on the leveled surface of technogenic deposits. In the process of keeping of FSM and mechanical formation of technozems, there was a marked deterioration of the physical state of the FSM. In order to restore physical properties of FSM, perennial herbs were sown on recultivated areas. Studies of physical properties at different age sites have shown that at the meliorative stage they are gradually restored by climatic, biological and pedogenic factors. Exposure to perennial herbs contributes to soil structure formation and reduction of compounding density. In case of prolonged (10–20 years) meliorative action physical properties are restored to norm of soils which are widespread in this geographical zone. However, the sharp interface between FSM and technogenic material remains, which can have a negative impact on the water regime of recultivated soils. In order to accelerate formation of optimal physical conditions in technozems it is necessary to carry out deep, irrevocable loosening, which contributes to reduction of density of both bulk layer and underlying technogenic rock. Some physical properties (bulk density, porosity) were gradually improving over time reaching Haplic Chernozems levels at the reference site.

Factors impacting soil organic carbon pool in different types of Andosols in Toya, Hokkaido, Japan

ABSTRACT Organic matter (OM) application is a possible solution to carbon (C) sequestration. Among the soil pedogenic factors for volcanic ash, time of exposure to weathering affects formation of short-range ordered minerals and soil organic carbon (SOC) accumulation. This study aimed to evaluate the effect of long-term OM application with the vertical infiltration of OM on different ages of Andosols in Hokkaido, Japan. Twelve fields of Vitric Andosols and 22 fields of Silandic Andosols were selected. Vitric and Silandic Andosols are characterized by newly erupted volcanic ash with weak weathering, and formation of short-range ordered minerals by weathering, respectively. The C application rate via OM was determined using questionnaires given to farmers, and soil physicochemical properties in the 0–0.15 m and 0.15–0.30 m layers were analyzed. The average C application rate in Vitric and Silandic Andosols were 1.71 ± 1.18 and 1.31 ± 1.28 (Mg C ha−1 yr−1), respectively (mean ± sd). The sand content was significantly higher in Vitric Andosols (55.7% ± 4.0%) than in Silandic Andosol (51.2% ± 2.0%). Although there was no significant difference in micro-porosity, Silandic Andosols had significantly higher total porosity and lower bulk density than Vitric Andosols. These results indicate better soil structure development in Silandic Andosols. The SOC stock in the 0–0.30 m layer in Vitric Andosols [71.5 ± 15.3 (Mg C ha−1 0.30 m−1)] was significantly lower than in Silandic Andosols [86.4 ± 12.7 (Mg C ha−1 0.30 m−1)]. The SOC stock in Vitric and Silandic Andosols showed a different response to the OM application. An increased C application rate significantly increased the SOC stock in the 0–0.15 and 0–0.30 m layers in Vitric Andosols, but the relations were not significant in Silandic Andosols. In contrast, in Silandic Adosols, weak trends (p = 0.07) were observed in the 0.15–0.30 m layer. In Silandic Andosols, SOC stock in the 0–0.15 m layer showed a z significant positive correlation with soil micro-porosity, suggesting physical protection of OM inside the aggregate. These results suggest that there are different factors affecting SOC stock between Vitric and Silandic Andosols.

Aspects on the Forming, Evolution and Improvement of the Soil Cover within the Community Territory of Moroeni

Abstract The purpose of the paper is to thoroughly understand the soil cover in the Moroeni commune, Dâmboviţa County, in order to establish the best measures for its protection, improvement and judicious use. The paper was drafted on the basis of data gathered in three research stages: • the investigation and documentation stage, which took place at the end of the academic year 2016-2017; • the stage of the field, which took place in the summer of 2017, when we made direct observations (on the spot) in the studied area, we made sketches, photographs; • the processing and interpretation stage of the cartographic material, which took place during the academic year 2017-2018. In the paper are presented the pedogenic factors and processes that contributed to the formation of the soil cover in the studied territory, as well, there are described both morphologically and in terms of physicochemical analyzes the classes and types of soils that have been identified on the field. It also presents the main categories of use in the studied territory and the measures for the protection and improvement of soils in order to increase their fertility.

Forms of iron in parent rocks of soils developed from Lower Triassic (Buntsandstein) deposits in the NE part of the Holy Cross Mountains (Poland)

Abstract The aim of the study was to characterize pedogenic iron forms in the sediments of the Lower Triassic (Buntsandstein) in the north-eastern part of the Holy Cross Mountains. These are sediments of continental origin and unique features as the so-called ‘red beds’. Three main types of rocks were studied – sandstones, mudstones and claystones. Chemical forms of iron: Fet (XRF), FeHCl (6M HCl), Fed (dithionite-citrate-bicarbonate, DCB), Feo (ammonium oxalate), Fep (sodium pyrophosphate) were determined. The XRD method revealed the occurrence of goethite in sandstones and hematite in mudstones and claystones. Differential XRD (DXRD) analysis did not show the presence of amorphous iron minerals. The average Fet content in sandstones was 83 g·kg−1, in mudstones 47 g·kg−1, in claystones 55 g·kg−1, while there were lower concentrations of Fed (66 g·kg−1, 13 g·kg−1, 26 g·kg−1, respectively). Feo form content was in the range of 0.3–4 g·kg–1, while there were only traces of Fep. Only Fet and FeHCl occurred in good correlation. In the pedogenic interpretation of the studied rocks, mutual relations between chemical forms of iron were used and their reference to the identified iron minerals. Siltstones and claystones have high resistance to pedogenic factors, which is indicated by low release rates Fed:Fet and very low amorphization index Feo:Fed. The reason is the presence of well crystalline hematite in these rocks. In sandstones, resistance is conditioned by the occurrence of goethite in the matrix. Chemical destruction of iron-carbonate cement promotes the release and amorphization of iron in soils developed from sandstones. The presented results indicate that the specificity of Lower Triassic rocks is important for the proper classification and assessment of properties of soils with a characteristic red colour.

Biomechanical and biochemical effects recorded in the tree root zone \u2013 soil memory, historical contingency and soil evolution under trees

Background and aimsThe changing soils is a never-ending process moderated by numerous biotic and abiotic factors. Among these factors, trees may play a critical role in forested landscapes by having a large imprint on soil texture and chemical properties. During their evolution, soils can follow convergent or divergent development pathways, leading to a decrease or an increase in soil spatial complexity. We hypothesized that trees can be a strong local factor intensifying, blocking or modifying pedogenetic processes, leading to local changes in soil complexity (convergence, divergence, or polygenesis). These changes are hypothetically controlled by regionally predominating soil formation processes.MethodsTo test the main hypothesis, we described the pedomorphological features of soils under tree stumps of fir, beech and hemlock in three soil regions: Haplic Cambisols (Turbacz Reserve, Poland), Entic Podzols (Žofínský Prales Reserve, Czech Republic) and Albic Podzols (Upper Peninsula, Michigan, USA). Soil profiles under the stumps, as well as control profiles on sites currently not occupied by trees, were analyzed in the laboratory for 20 physical and chemical properties. In total, we analyzed 116 soil samples. The age of trees and time of tree death were determined using the radiometry (14C), dendrochronology and repeated tree censuses. To process the data, we used multivariate statistics, namely, redundancy analyses (RDAs) and principal component analyses (PCAs). The statistical significance of variables was tested using Kruskal-Wallis, Dunn, and permutation tests. To reach the main aims of the present study, we examined the dataset at three levels of data complexity: 1) soil regions, 2) microsite (i.e., tree stump versus control site), and 3) soil horizon.ResultsLiving tree roots and empty or infilled root channels were the most important pedogenic factors that affected the dimensions of soil horizons and the moisture in the root zone under tree stumps. Microsites explained almost 6% of the soil variability (p < 0.001, F = 13.99), demonstrating that trees significantly impacted soil chemical properties in the root zone in all regions. In the Albic Podzols soil region, we found evidence of “basket” podzolization. Our results suggest the rapid eluviation of organic matter-sesquioxide complexes under the stump, probably leading to local soil divergence in Albic Podzols. However, soil analyses under the stumps in the Haplic Cambisols soil region suggested local polygenetic changes in soils (e.g., hydromorphic processes). The thickness of the A and B horizons increased, and soil chemistry changed under trees in the Entic Podzol soil region compared to the control profiles.ConclusionsIn addition to regional environmental factors that manifest themselves in regional pedogenesis and that have a key role in modifying the influence of trees on the soil, the tree species can specifically modify pedogenic processes under standing trees. Trees may influence rate of pedogenesis (hemlock in Albic Podzol region) or even soil evolutionary pathways (beech in Haplic Cambisol region).

CHARACTERIZATION OF YELLOW LATOSOLS (OXISOLS) OF SERRA DO QUILOMBO, IN PIAUÍ STATE SAVANNA WOODLANDS - BRAZIL

ABSTRACT The savanna woodlands of Piauí state has great economic importance since it is an area for agricultural expansion, being the fourth most important of Brazil and the first from Brazilian Northeastern. The area accounts for 5.9% of the Brazilian savanna woodlands and 36.9% of the Northeastern savanna, covering 46% of the Piauí state area, in a total of 11.5 million hectares. The goal of this research was to study pedoenvironments of Serra do Quilombo region, which is in Piauí state savanna, as well as identifying existing soil classes, according to the Brazilian System of Soil Classification - SiBCS. Soil identification consisted in characterizing soil profiles along a transect, assessing in-field conditions and collecting soil samples, in areas of native vegetation. The samples were gathered from three distinct points, being two at the edges and one at the center of the plateau. Soil analyses were carried out with samples collected from each horizon through trench digging up to a 2-m depth. Morphological, physical, chemical and mineralogical characterizations were performed for each soil profile, along with an evaluation of the effect of pedogenic factors on their formation and development. All soils under study were formed with source materials of the same geological formation; however, each rock has a distinct contribution to the process, involving sandstones and shales. The characteristics observed in the soil from Serra do Quilombo have no difference from the pattern found in the Brazilian plateaus, and soil profiles were classified as dystrophic clayey Yellow Latosols (Oxisols), according to the SiBCS.

Spatial prediction of soil properties in two contrasting physiographic regions in Brazil

This study compared the performance of ordinary kriging (OK) and regression kriging (RK) to predict soil physical-chemical properties in topsoil (0-15 cm). Mean prediction of error and root mean square of prediction error were used to assess the prediction methods. Two watersheds with contrasting soil-landscape features were studied, for which the prediction methods were performed differently. A multiple linear stepwise regression model was performed with RK using digital terrain models (DTMs) and remote sensing images in order to choose the best auxiliary covariates. Different pedogenic factors and land uses control soil property distributions in each watershed, and soil properties often display contrasting scales of variability. Environmental covariables and predictive methods can be useful in one site study, but inappropriate in another one. A better linear correlation was found at Lavrinha Creek Watershed, suggesting a relationship between contemporaneous landforms and soil properties, and RK outperformed OK. In most cases, RK did not outperform OK at the Marcela Creek Watershed due to lack of linear correlation between covariates and soil properties. Since alternatives of simple OK have been sought, other prediction methods should also be tested, considering not only the linear relationships between covariate and soil properties, but also the systematic pattern of soil property distributions over that landscape.

Effects of toposequence and land use-land cover on the spatial distribution of soil properties

Topographic properties can influence pedogenic processes, soil profile depth and spatial variations of soil properties. The objectives of this study were to determine the spatial variation of soil properties at different slope positions and land use-land cover and also the relationships among soil properties, slope and land use-land cover. The study area was divided into five topographic positions by an elevation transect from 935 to 1370 m. These positions were shoulder, flat plateau-1, flat plateau-2, lower back slope, and toe slope which were sampled at 10 × 20 m grid size. A total of 500 soil samples were collected from 0 to 20 cm depth. Soil properties showed significant variation among slope positions and land use-land cover type when analysed with ANOVA and post hoc multiple comparison tests. Slope was responsible for large discrimination effects compared to land use-land cover. It was also the main factor contributing to the transportation and accumulation of fine soil particles when soil organic matter content and water stable aggregates amount were low. Moreover, different land use-land cover type affected soil organic matter content and water stable aggregate amount and caused significant variance in them. Overall, the spatial variability of soil physico-chemical properties was strongly affected by pedogenic factors, slope and land use.

Profilowe zróżnicowanie form żelaza i glinu w glebach pod świerczyn górnoreglową Plagiothecio-Piccetum tatricum w Gorcach jako wskaźnik aktualnych procesów glebotwórczych / Distribution of Iron and Aluminum Forms as an Indicator of Present-Day Soil-Forming Processes in Soil Profiles under Wooded Spruce Plagiothecio-Piccetum Tatricum in the Gorce Mts. (Southern Poland)

AbstractThe aim of the study was to determine soil-forming processes in soils formed from the Magura sandstones (Carpathian flysch) under wooded spruce Plagiothecio-Piccetum tatricum in the Gorce Mts., southern Poland. The research focused on distribution of non-silicate forms of iron and aluminum in soil profiles. The content of pyrophosphate, oxalate, and dithionite phases of iron and aluminum in the genetic horizons of four soil profiles was measured and selected pedogenic factors were calculated. Based on the obtained results podzolization and brunification are dominant soil-forming processes in the studied soils. The brunification effect was more common in the soils under the large share of Athyrium distentifolium, whereas podzolization predominates in the soils where Vaccinium myrtillus prevails in forest floor. Studied soils were classified as Dystric Endoskeletic Cambisol (Loamic, Humic), Dystric Cambisol (Siltic, Humic) and Skeletic Folic Albic Podzol (Arenic).

Vertical distribution of Cu, Ni and Zn in Brunic Arenosols and Gleyic Podzols of the supra-flood terrace of the Słupia River as affected by litho-pedogenic factors

Abstract The aim of the study was to assess the influence of lithological and pedogenic factors in the shaping of Cu, Ni and Zn distribution patterns in the profiles of Brunic Arenosols and Gleyic Podzols of the lower supra-flood terrace of the Słupia River, which is located outside the range of significant anthropogenic sources of pollution with these metals. The contents of the investigated metals were analysed in aqua regia extracts of samples collected from three profiles of Brunic Arenosols, formed from river sands, and three profiles of Gleyic Podzols, formed from river sands transformed by eolian processes. In general, river sands contained higher amounts of Ni and Zn (2.6 - 6.9 mg·kg-1 Ni; 10.3 - 16.2 mg·kg-1 Zn) compared to eolian sands (1.2 - 2.4 mg·kg-1 Ni; 3.3 - 17.3 mg·kg-1), while the content of copper tended to be higher in eolian sands (1.3 - 1.9 mg·kg-1) than river sands (0.1 - 1.5 mg·kg-1). The observed differences between the two types of sand are due to the loss of fine granulometric fractions and various minerals during eolian processes. Higher concentrations of the investigated metals in soil solum as compared to parent material are due to their uptake from deeper parts of the soil by roots and subsequent return to the soil surface as a component of litterfall. Therefore, the highest concentrations of Cu, Ni and Zn were observed in ectohumus. In the mineral component of the soil, the highest concentrations were observed in organic matter-rich A and B horizons, which indicate close interactions between heavy metals, humic substances and iron oxides. The vertical distribution of the investigated metals in the profiles of Gleyic Podzols indicates their leaching during podzolization. The observed contents of Cu, Ni and Zn, both in Brunic Arenosols and Gleyic Podzols, were lower than the geochemical background, which confirms that anthropogenic contamination of the studied area with these metals is marginal

How anthropogenic activities affect soil heavy metal concentration on a broad scale: a geochemistry survey in Yangtze River Delta, Eastern China

Heavy metal pollution in soil is a growing concern, and little is known about how it is distributed in the soils of different districts with different land uses on a broad scale. A total of 873 surface soil samples (0- to 20-cm depth) were collected in the Huishan and Xin districts of Wuxi City. The pollution levels and sources of heavy metals in the two districts were identified using multivariate statistics and spatial analysis methods, and the results are discussed in this paper. The concentration of heavy metals in soils, particularly Hg, was higher in Xin, where there are many industrial parks. The concentrations of As, Cu, Hg, Pb, and Zn were higher than the corresponding background values in the two districts, and the soil Hg in Xin exceeded the grade II threshold value of the Chinese Environmental Quality Standard for Soils. Natural resources (e.g., geogenic and pedogenic factors) were predominately responsible for the heavy metal concentration in Huishan soils, but anthropogenic activities (industrial production and discharge) were the primary factors for soil heavy metal pollution in Xin. The soil heavy metal concentration in forestlands was high in Huishan, and among these metals Hg and As reached a moderate level of pollution [enrichment factor (EF) >2]. No pollution or minimal pollution happened in response to other land uses. In Xin, the Hg in cultivated land, rural-residential land, and underwater sediments reached a moderate level of pollution (EF >2), and the other heavy metal levels were low (EF <2) in response to different land uses.

Spatial distribution and vertical migration of 137Cs in soils of Belgrade (Serbia) 25 years after the Chernobyl accident

In this study, the specific activity of (137)Cs was determined by gamma-ray spectrometry in 72 surface soil samples and 11 soil profiles collected from the territory of Belgrade 25 years after the Chernobyl accident. Based on the data obtained the external effective gamma dose rates due to (137)Cs were assessed and geographically mapped. The influence of pedogenic factors (pH, specific electrical conductivity, cation exchange capacity, organic matter content, soil particle size and carbonate content) on the spatial and vertical distribution of (137)Cs in soil was estimated through Pearson correlations. The specific activity of (137)Cs in surface soil samples ranged from 1.00 to 180 Bq kg(-1), with a mean value of 29.9 Bq kg(-1), while in soil profiles they ranged from 0.90 to 58.0 Bq kg(-1), with a mean value of 15.3 Bq kg(-1). The mean external effective gamma dose at 1 m above the ground due to (137)Cs in the soil was calculated to be 1.96 nSv h(-1). Geographic mapping of the external effective gamma dose rates originating from (137)Cs revealed much higher dose rates in southern parts of Belgrade city and around the confluence of the Sava and Danube. Negative Pearson correlation coefficients were found between pH, cation exchange capacity and (137)Cs specific activity in surface soil. There were positive correlations between organic matter and (137)Cs specific activity in surface soil; and between specific electrical conductivity, organic matter, silt content and (137)Cs specific activity in soil profiles.

Chromium, nickel and vanadium mobility in soils derived from fluvioglacial sands

The presented study was focused on soils developed from fluvioglacial sands from the Puszcza Borecka forest complex. The mobility of chromium, nickel and vanadium was evaluated with regard to litho- and pedogenic factors. The aim of the study was to determine with which soil constituents fractions of heavy metals are bound with particular attention drawn on the mobile fractions (F1+F2). Heavy metal fractions in the soils were determined using the sequential extraction method of Tessier et al. The purpose of sequential extraction methods to soil samples provides relevant information about possible toxicity when they are discharged into the soil environment. Chromium, nickel, and vanadium occurred predominantly in the fraction bound with iron and manganese oxides and in the residual fraction, thus showed low mobility. With regard to mobility, the elements studied can be arranged as follows: V<Cr<Ni. The content of the mobile fractions depended on the soil texture. The influence of the rusting process on the distribution of the bioavailable fractions was observed in the soil profiles.