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Until the beginning of the 20th century, bog burning culture was a common cultivation system for food production on otherwise non-arable bog peat soils. Burning and preliminary drainage of the peat impacted the soils nutrient supply, bog morphology and soils properties. To gain insights into the long-term effects of bog burning culture on the landscape and soils, a burned and unburned area within a rewetted bog complex were comparatively analysed. It was hypothesised that bog burning had a lasting effect on the soil chemistry, that the trenches created for drainage prior to burning are still detectable in the bog morphology, and that the altered soil chemistry exhibiting enhanced nutrient supply resulted in a change of vegetation patterns. To verify this, the soil chemistry was analysed regarding pH, carbon/nitrogen (C/N) ratio, and contents of plant available phosphate (PO43-) and potassium (K). The morphology was examined by means of aerial imagery and vegetation patterns were assessed in the field. It was shown that while PO43-- contents were similar, pH values and K contents of the burned area were elevated compared with the unburned area. Accordingly, they can be used as an indicator for bog burning culture, even a century after the end of the practice. As expected, C/N ratios were narrowed in the burned area, which however cannot exclusively be attributed to bog burning, since peat mineralisation in the previously drained bog soils caused narrowing C/N ratios as well. The trench structure for drainage was still visible in aerial images and vegetation patterns were similar in the burned and unburned areas. Overall, the aftermath of bog burning was still apparent in morphology and soil chemistry, however the effect was less severe than expected, as vegetation patterns and the overall restoration success were not impacted. This provides a reasonable expectation that bogs are resilient towards bog burning and the latter is no obstacle for successful restoration.

Hydrochar (HC), produced by hydrothermal carbonization, offers technical advantages over biochar (BC) produced by pyrolysis, and is suitable for soil amelioration, carbon sequestration, and enhanced plant growth. BC grain size has been shown to influence nutrient retention, microbial colonization and aggregate formation; however, similar research for HC is lacking. Pot trials were conducted to investigate the influence of HC grain size [coarse (6.3–2 mm), medium (2–0.63 mm) and fine (4–P, K and Nmin) and germination and biomass success using standard laboratory and statistical methods. Soil pH showed a compensatory shift toward the HC pH (7.2) in all soils over the course of the study. For example, the pH of the medium grained HC treatment for the Chernozem decreased from 7.9 to 7.2 and increased in the Podzol and Gleysol from 5.9 to 6.1 and 4.9 to 5.5, respectively. The nutrient-rich HC (2034 ± 38.3 mg kg−1 PO4–P and 2612.5 ± 268.7 mg kg−1 K content) provided only a short-term supply of nutrients, due to the relatively easily mineralized fraction of HC, which allowed for quick nutrient release. The pH and PO4–P effects were most pronounced in the fine grained HC treatments, with a ~ 87%, ~ 308% and ~ 2500% increase in PO4–P content in the Chernozem, Podzol and Gleysol, respectively, compared to the controls at the beginning of the study. The same trend was observed for the K and NH4+ content in the fine and medium grained HC treatments in all soils. No seed germination inhibition of Chinese cabbage was observed, with average germination rates > 50% in all soils. An effect on NO3− content was indeterminable, while there was little to no effect on biomass production, WHC, CEC and aggregate stability. In conclusion, the application of 5% fine grained HC significantly influenced the nutrient content over a short-term. However, the application rate was insufficient to substantially improve plant growth, nor to sustain a longer-term nutrients supply, regardless of grain size.

Historical land use and soil management left behind anthropic soils such as Amazonian Dark Earths (Terras Pretas de Indio - pretic Anthrosols), Anthropic shell mounds (Sambaquis - terric Anthrosols), and Plaggen soils (plaggic Anthrosols), enriched in soil organic matter and soil fertility. The objective of this study was to compare soil organic matter quantity and quality of these tropical and temperate anthropic soils among each other and against their adjacent non-anthropic soils. All anthropic soil horizons had enhanced total contents of C, N, P, K, Ca, Mg and Fe, reflecting a soil organic matter and nutrient enrichment compared to their reference soils, mostly expressed by the Sambaquis. In order to better understand the mechanisms of soil organic matter stability, besides black carbon analysis, topsoils and subsoils were incubated in the laboratory at 10 °C and 30 °C and the emitted CO2 was recorded for 44-days. The Plaggen soil released the highest amount of CO2 at 30 °C, being two to three times higher compared to Terra Preta de Indio and Sambaqui anthropic horizons. The highest mean residence times (MRT), between 38 and 63 years, were calculated for the subsoils of the anthropic soils incubated at 10 °C. In the artificial system of this study, the stability of anthropic soil horizons under study was not generally enhanced when compared with their reference soils. However, enhanced stability of total organic carbon (TOC) was indicated by a negative relationship between black carbon portion of TOC and the relative amount of CO2-C released from TOC of all anthropic soils. During the incubation period of 44 days, the cumulatively mineralized amount of soil organic carbon (SOC) in the top of anthropic soils at 30 °C was three to six times as high as that at 10 °C. Consequently high temperature under tropical conditions should have stimulated the decay of organic matter, which however was not reflected by high TOC contents found in Terra Preta and Sambaqui samples, corroborating their low degradability in the long term. Therefore, we propagate that a high stability of carbon stocks exists in anthropic soil horizons, which may become a promising opportunity for the establishment of a new generation of anthropic soils with improved soil fertility and soil organic matter using the principle of soil-biochar systems.

This chronosequential study focuses on the vegetation succession, Luvisol pedogenesis, and long-term carbon dynamics during post-agricultural restoration in the temperate broad-leaved forest of European Russia. The study comprises three chronosequences of 37 years (North), 120 years (Middle), and 42 years (South) to cover climatic differences within the study area. The sites of each catena were mostly comparable in terms of climate, soil texture, and land history, but the duration of agricultural abandonment differed between sites. Plant succession developed via a birch forest or a pear-ash woodland to a birch-oak forest with Aegopodium podagraria after 120 years, which indicates the plant association is near to a climax oak forest. Former homogenous plow horizons formed a new morphological stratification similar to natural Luvisols, due to the formation of a well rooted Ah horizon and an O horizon of mull; a change in soil structure from coarse blocky to granular; and decreasing bulk densities. However, plow features were identified even after 120 years of Luvisols restoration. During restoration, the former plow horizons showed minor changes of pH 5.4–5.6 (CaCl2). However, a slightly increased pH value within the newly developed Ah and O horizons induced a new pH stratification of the former plow horizon, approaching the natural soils. Compared to the former plow horizons below, soil organic carbon (SOC) and plant available nutrients (P, K) enrichment was observed within the newly developed Ah horizons. The SOC stocks of the 5 cm mineral topsoil increased from 0.8 to 1.7 kg m−2 (North), from 1.3 to 1.7 kg m−2 (Middle), and from 1.4 to 2.3 kg m−2 (South) during restoration. The surface organic layers showed SOC stocks of 0.1–0.2 kg m−2. However, the levels of the near-natural soils were not reached after 37 years (North) and 42 years (South) of restoration. The model predicted a recovery time of about 150 years to achieve a comparatively steady state. A negative effect of mowing was observed for the modelled SOC accumulation. Despite all these alterations, the study showed no full restoration for many parameters within the chronosequential timescale of 120 years.

Freshwater lenses below barrier islands are a precious resource for the local water supply and important for coastal ecosystems. The aim of this study was to investigate the hydrochemical evolution of a freshwater lens, using the barrier island Spiekeroog, Germany, as an example. For this purpose, groundwater samples were obtained during several campaigns, and hydrochemical data and 13C/12C isotope ratios of dissolved inorganic carbon were linked to apparent groundwater ages. Results show that apparent groundwater ages increase with depth and range between 4 and 51 years. All groundwater samples were close to equilibrium with respect to calcite and considerably enriched in calcium and bicarbonate, suggesting calcite dissolution in the unsaturated zone of the dune sediments. The estimated average rate of decalcification was ∼13 mm/a, resulting in a decalcification depth of ∼4.6 m for the oldest sediments of an approximate age of 350 years. Moreover, 13C/12C isotope ratios of dissolved inorganic carbon indicated secondary carbonate mineral reactions within the aquifer, such as recrystallization and closed-system calcite dissolution. Cation exchange was primarily observed in older groundwater, i.e. the deeper part of the aquifer, and the calculated time of complete freshening of the aquifer is ∼600 years. Regarding redox reactants, dissolved oxygen and nitrate concentrations decreased rapidly in young groundwater, while dissolved manganese and iron were virtually absent in samples collected below the zones of oxygen and nitrate reduction. Dissolved sulfide species indicate sulfate reduction in older groundwater, and methanogenesis was detected locally. The absence of solute manganese and iron may be explained by the formation of minerals, such as iron sulfides, siderite, and rhodochrosite, that serve as possible sinks for redox-sensitive solutes. In conclusion, this study showed that hydrochemical data can be linked to groundwater ages to describe the hydrochemical evolution of a freshwater lens in a homogeneous sandy aquifer as a function of residence time.

The island Spiekeroog (Germany) at the southern North Sea coast exhibits an island tail (Ostplate) of which large parts formed after 1860 by gradual eastward deposition of marine sediments. This study aimed to (i) provide a first overview of soils on the Ostplate, (ii) verify whether soil formation stages in different landscape elements (dune chain, dune slacks, saltmarsh, pioneer zone) are linked to the island’s gradual development and (iii) to assess the impact of tides and winds on soil formation. Standard physicochemical properties of dune -and dune slack topsoils and 19 pedons (i.a. pH, total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen (TN), and mean weight diameter (MWD) of water stable aggregates) were analyzed. Soils of the dune slacks, the saltmarsh and the pioneer zone classified as Gleysols which showed no trend towards differences along the Ostplate. The dune chain exhibited Protic Arenosols that were initially acidified in lee positions (min. pH = 5.1). Carbon (C) and nitrogen (N) isotopes (δ13C, δ15N) signatures of saltmarsh sediments were used as a proxy for the tidal influence on soil formation. In addition, sulfur (S) isotope (δ34S) signatures revealed insights on sulfur sources in the saltmarsh. The δ13C signatures of organic matter (OM) decreased and TOC/TN -and TOC/total sulfur (TS) ratios increased with increasing elevation and decreasing flooding frequency. At higher flooding frequency, δ15N resembled the dominant input of OM from the southern North Sea, at a lower interaction level, mixing of a wider range of sources was indicated. S isotopes indicated dissolved sulfate and reduced species as sulfur sources. It was concluded that an ongoing impact of wind-induced sand movement at the dunes, and flooding-induced sediment movement in the saltmarsh and the pioneer zone, repealed any potential disparities in soil formation stages, which might have existed along the Ostplate.

The Southern North Sea coast has served as an exemplification to analyse and discuss the genesis of soils from Holocene tidal deposits. The accumulation wedge of Holocene tidal deposits at the North Sea coast is artificially embanked for the most part. In the enclosed area (hinterland) a variety of different soils developed. Disparate models attempting to explain the genesis of these soils deduce genesis of hinterland soils from recent foreland conditions, disregarding that geogenic preconditions have fundamentally changed. By consolidating and reviewing established literature we show that differences in geogenic preconditions are the initiating key for a feasible model. Describing geogenic preconditions to infer pedogenic processes, we develop a model comprising four different development pathways. High settling velocities and regular flooding, as present in the foreland, cause high inputs of mineral sediments and carbonate, moderate sulfur dynamics and thus the development of calcareous soils. Synsedimentary decalcification prevails in irregularly flooded areas due to enduring low sedimentation rates, low carbonate inputs and moderate sulfur dynamics under alternating redox states, as mainly proposed for the unobstructed landscape. High contents of soil organic matter (SOM) facilitate intensive sulfur dynamics creating potential acid sulfate soils (PASS), which become extreme acid upon oxidation (actual acid sulfate soils (AASS)). A great gradient in depositional conditions, occurring at unobstructed plain coasts, enables the deposition of deflocculated fine-grained sediments which promotes the formation of very compact soils with low water conductivities. Although this proposed model is based mainly on conditions known from the German North Sea coast, it is shown that shaping geogenic and pedogenic processes are applicable to other humid coastal regions around the world.

The zonation of different Salicornia species within saltmarshes has been described controversially in prior publications. The aim of this study is to detect substantial relations between pedological conditions and the distribution of different Salicornia species (Salicornia stricta Dumort. 1868, Salicornia europaea L. 1753, and Salicornia procumbens Sm 1813). 37 sites were investigated regarding vegetation pattern, soil morphology and physicochemical and chemical soil properties. A multivariate approach indicate a clear differentiation of the sites dominated by different Salicornia species in respect to sand content, redox potential and water content. However, results of a detailed statistical assessment indicate that redox potential and salinity are the most relevant parameters. Salicornia stricta sites are characterized by a variety of grain sizes, reduced conditions in the rhizosphere, highest water contents (median: 71.5 Vol-%) and lowest Eh values (median: −19.0 mV), indicating the best adaptation to anaerobic soil conditions. Salicornia procumbens occurs on aerated soils (median Eh: 455.6 mV) with high sand contents independent to position relative to mean high tide level. Exhibiting the lowest (11.5‰) and highest soil salinities (41.7‰), even developing in salt pans (136‰), Salicornia europaea feature a great ecological amplitude regarding temporal variations of salinity. These findings underline the ecotypic and phenotypic plasticity of Salicornia species and offer a promising approach for further experimental settings focussing on phenotypic adaptions and ecological amplitudes of Salicornia taxa and ecotypes.

Environmental parameters controlling fluxes of greenhouse gases (GHG) differ spatially within landscapes. This study aimed to improve the understanding of landscape processes controlling GHG-fluxes of different landscape units of marshes (in terms of vegetation, land use and seawater inflow) at the Southern North Sea coast. For this emissions of methane (CH4) and nitrous oxide (N2O) were quantified and related to reported carbon sequestration rates. Ancillary environmental parameters were determined to identify controlling factors and thresholds enabling GHG emissions. For inland marshes (enclosed by embankments) the water level was the predominant factor controlling CH4 emissions ranging between 1.58 and 1544.70 kg CH4 ha−1 a−1. The duration of threshold (10 cm below surface) exceedance was found as a predictor for annual CH4 emissions. Emissions of outland marshes (influenced by tides) varying from −1.34 to 55.14 kg CH4 ha−1 a−1 were predominantly controlled by sulphate (\( \mathsf{S}{\mathsf{O}}_{\mathsf{4}}^{\mathsf{2}\hbox{-} } \)) concentrations, because soil CH4-contents were negligible when soil \( \mathsf{S}{\mathsf{O}}_{\mathsf{4}}^{\mathsf{2}\hbox{-} } \)-contents exceeded 0.5 mg g−1. The variability of the N2O-fluxes (−0.81 to 17.78 kg N2O ha−1 a−1) could not be explained by the collected environmental parameters. GHG balances indicated that inland extensive grasslands and particularly reed stands are net sources of CO2-equivalents (100 year time horizon), while outlands are natural sinks.

This study is concerned with the rate of soil formation in Arenosols of dunes on the barrier island Spiekeroog at the southern North Sea coast. It focuses on Fe dynamics in the soils in relation to slope aspect, as well as on the interaction between minerals and soil organic matter (SOM) in the course of soil formation. Ten quartz-rich (≈ 95 wt%) Arenosols on slopes with different aspects (north/south), low in primary carbonates (≈ 0.5 wt%) and total Fe (Fet, ≈ 0.15 wt%), were studied across a soil chronosequence with optically stimulated luminescence (OSL) ages between 43 ± 7 and 279 ± 26 years. During this period, pH (CaCl2) decreased from 7.1 in fresh sands to 3.1 in initially podzolized soils. SOM contents and the optical density of oxalate extracts (ODOE) increased with soil age. Differences in Fe stocks, vertical distribution of Fed, Feo and Fep and horizontation of equally old soils indicated an influence of microclimate on pedogenesis determined by slope aspect. Initial podzolization features occurred after 179 ± 17 years. Eluviation resulted in the formation of an E horizon free of amorphous and poorly crystalized Fe oxides (Feo-Fep), indicating that these oxides provided a source of Fe during podzolization. However, illuviation features were absent. Field findings, macroscopic examinations and carbon fractionations revealed, that SOM was exclusively present in free particulate form (free POM). This indicated, that prior to podzolization, mineral grains did not become enclosed by organic pigments during the formation of Ah horizons.

Organic-poor, permeable quartz sands are often present at land-sea transition zones in coastal regions. Yet, the biogeochemical cycles of carbon, sulfur, and iron are not well studied here. The aim of this work was, therefore, to improve our understanding regarding the chemical processes in these prominent coastal sediments. A 10 m core was collected at a dune base of the barrier island Spiekeroog, Germany, for this purpose. Additionally, groundwater was sampled from a multi-level well for one year to record seasonal hydrochemical variations. Methods included the analyses of geochemical (total carbon, total inorganic carbon, reactive iron, total sulfur, reduced inorganic sulfur) and hydrochemical parameters (field parameters, major ions, DOC, and molecular compositions of DOM), as well as stable sulfur isotopes (δ34S-sulfate, -sulfide, -total reduced inorganic sulfur). Moreover, optically stimulated luminescence (OSL) dating was applied. Results show that the core sediments are very young (

The objective of this study was to provide a general concept of post-agrogenic self-restoration of vegetation, soils, and carbon stocks in different climatic zones of European Russia based on comparative analysis of our previous studies (Kalinina et al., 2009, 2010, 2011, 2013, 2014). The focus was on post-agrogenic plant succession, pedogenesis, carbon stocks and different carbon pools of Podzols and Albeluvisols of the taiga, Chernozems of the semi-humid steppe, and Calcisols–Solonetzes of the semi-arid steppe of Russia. During self-restoration, vegetation and soils developed towards their natural conditions. Former homogenous plow horizons developed a vertical stratification in terms of the morphological and chemical properties typical of the undisturbed soils, promoting pedodiversity. With the exception of the post-agrogenic Chernozems, the plow boundary was present during the studied period of self-restoration (42–170 years). The trend towards natural soils was also observed in every chronosequence in terms of increasing soil organic carbon (SOC) dynamics, indicating a net carbon sink function during self-restoration. Accelerated SOC gains occurred when forests established in the taiga and steppe species appeared in the Chernozem and Calcisol sequences. SOC gains occurred in the taiga mostly within the organic surface layer whereas in the steppe areas within the mineral topsoil of 0–0.2 m. The investigation of different carbon pools showed a significant organic carbon (OC) enrichment of the density fractions 1.8 g cm− 3 (sand coarse/medium silt, fine silt, clay) following the increase of total SOC during self-restoration. In the taiga, SOC restoration time was almost identical with the duration of natural plant succession of about 150 years; in the steppe areas, SOC restoration took about 100 years and was longer than plant succession. Although self-restoration developed towards natural conditions, a full recovery was hardly ever reached, revealing that self-restoration is a long or infinitely long-term process.

The objective of this study was to investigate changes in soil total organic C (TOC), total nitrogen (TN), phosphorus (P) fractions, and microbial community structure during secondary succession after abandonment of vineyards on calcareous soils. Two chronosequences covering 200 years and differing in aspect and slope were established in Hungary, and the upper 10 cm of the mineral soils were studied. We found strong increases in TOC concentrations after land-use abandonment, especially at the south-exposed sites. The TOC/TN ratio increased by a factor of 1.3 in the south-west exposed chronosequence and by a factor of 1.6 in south exposed chronosequence. The concentration of labile P (NaHCO3-extractable P) diminished during the first 50 years after land-use abandonment, leading to low P availability at the later stages of the succession. The total organic P (TOP) concentration increased during the first 40 years after abandonment. At the later stages of succession, TOP concentrations decreased again, while the ratio of TOC/TOP increased continuously over 200 years. The ratio of arbuscular-mycorrhizal-fungi-to-bacteria (AMF/bacteria) increased strongly during the first decade after abandonment of the vineyards. Our study indicates that impacts of former cultivation on secondary ecosystems persisted for more than a century, and that especially P concentrations showed long lasting legacy effects.

This chronosequential study focusses on the vegetation succession, pedogenesis, carbon stocks and different carbon pools of post-agrogenic Calcisol–Solonetz complexes in the dry steppe zone of Russia. The sites were comparable in terms of climate, soil texture and land-use history, but differed in the duration of agricultural abandonment, covering 1, 7, 12, 17 and 42 years of self-restoration. During self-restoration without direct human impact, the vegetation developed towards a steppe with dominance of Artemisia lercheana / pauciflora and Stipa pennata . After 17 years, the abundance of Artemisia pauciflora indicated again the Solonetz locations within the Calcisol–Solonetz complex, which were not visible during arable land use. Pedogenesis resulted in the recovery of the natural soil structure—fine subangular polyhedral for Calcisol and crumble fine platy for Solonetz. The recovery of soil structure of Solonetz was in accordance with a decline of water-stable aggregates from 84% to 68%. The plow features were still well visible after 42 years of self-restoration in both soil groups. Partial integration of Btn materials into the plow layer induced a pH increase during cultivation of the Solonetzes, while slight pH decreases were observed during self-restoration afterwards. Other chemical properties of both soil groups remained unchanged. Post-agrogenic Solonetzes showed an exchange sodium percentage (ESP) below 5.0% and an electrical conductivity (ECe) below 50 mS m − 1 at the topsoil during the period of self-restoration. The development towards natural soils was observed in terms of soil organic carbon (SOC) dynamics. SOC stocks of the Calcisols increased slowly from 2.0 to 3.5 kg m − 2 in the upper 0–0.5 m, comprising 64% of the natural soil. SOC stocks of the Solonetzes grew from 1.7 to 3.1 kg m − 2 in the upper 0–0.5 m and almost reached the level of natural soil already after 12 years of self-restoration. The long-term modelling showed a recovery of SOC stocks almost after 100 years for the Calcisol and the Solonetz chronosequences. The nutrient dynamics traced SOC dynamics during the self-restoration. The investigation of different carbon pools showed a significant organic carbon (OC) enrichment of the density fractions − 3 (free particulate organic material (POM) and occluded POM) and the density fractions > 1.8 g cm − 3 (sand coarse/medium silt, fine silt, clay) following an increase of total SOC during self-restoration. In the Calcisol chronosequence, the dynamics of all fractions was close to the dynamics of total SOC with the exception of free POM showing a moderate accumulation rate in relation to total SOC. Post-agrogenic Solonetzes showed a more intensive accumulation of free POM and a slower OC sequestration in aggregates compared to total SOC. Both chronosequences showed comparable recovery rates for the passive SOC pool and total SOC. Despite all these alterations the study showed no full restoration for many parameters within the chronosequential time scale of 42 years.

Two chronosequences, one south (S-sequence) and one southwest (SW-sequence) with differing times since their abandonment (193, 142, 101, 63, 39 and 14 years), were studied on Tokaj Nagy-Hill. The sites were investigated in respect of vegetation characteristics, soil physico-chemical characteristics, total organic carbon stocks (TOC stocks), accumulation rates of total organic carbon (TOC accumulation rates), and soil profiles, which were classified according to the World Reference Base (WRB) 2007. The S-sequence was 25–35% sloped and strongly eroded, and the SW-sequence was 17–25% sloped and moderately eroded. Vegetation development at the S-sequence resulted in shrub-grassland mosaics, supplemented by protected herb species and forest development at the earliest abandonment. The SW-sequence was predominantly covered by forest vegetation, and trees were absent at the 63 and 14 year old abandonment sites. Soils of the S-sequence show shallow remnants of loess cover with redeposited soil materials containing 15–65% skeletal volcanic rock of weathering products coated by secondary calcium carbonates. The SW-sequence profiles are developed on deep loess or loess derivatives. The calcium-carbonate content was higher in profiles of the S-sequence (18.1 ± 10.4%) than in the SW-sequence (6.7 ± 2.7%); consequently, the pH of the topsoil was higher in the S-sequence, and correlated significantly negatively with the age of abandonment in both sequences (r = − 0.893; p = 0.01 in S, and r = − 0.739; p = 0.05 in SW). TOC stocks of the top 6 cm soil layers were higher in the S slope (1.82 ± 0.71 kg m − 2 ) than in the SW-sequence (0.95 ± 0.49 kg m − 2 ), and correlated significantly positively with the duration of abandonment. When calculated for the whole profile, TOC stocks were similar in both S- and SW-sequences (S: 8.21 ± 3.31 kg m − 2 ; SW: 8.24 ± 6.01 kg m − 2 ). The TOC accumulation rates of the top 6 cm soil layers exhibited 18.9 ± 10.0 g C m − 2 y − 1 in the S and 7.0 ± 4.2 g C m − 2 y − 1 in the SW-sequence. Sites with the same age of abandonment showed different vegetation and soil features in both chronosequences, indicating that time is not the most decisive factor in soil transformation processes after abandonment of viticulture on Tokaj Nagy-Hill. Additional directing factors were slope steepness and exposition.

This study aimed at clarifying whether a notable group of soils of the Jaeren region, SW Norway, with deep humus-rich top soils support a man-made genesis. Four sites were investigated. The soils are characterized by thick top soils of 45, 70, 80, and 90 cm, which are enriched in soil organic matter and often also in artifacts, like fragments of potter's clay, indicating an anthropogenic origin. Soil pH ranges from 5.4 to 6.2 (H2O) and 4.4 to 5.3 (CaCl2), respectively. Soil organic C (SOC) contents range from 6.4 to 51.6 g kg−1 and N contents vary between 0 and 2.9 g kg−1. Increased P contents of up to 2,924.3 mg kg−1 total P (Pt) and 1,166.4 mg kg−1 citric acid-soluble phosphorus (Pc) in the humus-rich top soils support the assumption of an anthropogenic influence. Although many characteristics indicate an anthropogenic genesis, one soil lacks the required depth of 50 cm of a plaggen horizon and cannot be classified as Plaggic Anthrosol (WRB) and Plagganthrept (US Soil Taxonomy). As the requirement is 40 cm in the German system, all soils can be classified as Plaggenesch. The formation of these soils is related to human activity aiming at increasing soil fertility and overcoming the need of bedding material, the basic aims of the plaggen management in Europe. Highest P contents ever found for this kind of soils and references from the literature indicate that the formation of the soils in Norway started at Viking time, hence, being older than most other Plaggic Anthrosols.

The purpose of this study was (1) to determine the vertical distribution of rare earth element (REE) concentrations, stocks, and geochemical fractions in two different marsh soil profiles and (2) to quantify the relations between REEs and soil properties. A sandy Fluvisol recently flooded by tidal water and a clayey Gleysol landward the dike impacted by fluctuating groundwater levels served as reference marsh soils. An aqua regia extraction was used to determine the concentrations of REEs; additionally, a sequential extraction procedure developed by the Commission of the European Communities Bureau of Reference was conducted to assess the geochemical fractions (exchangeable, reducible, oxidisable, residual fraction) of REEs. Both extractions were carried out according to genetic horizons. The stocks of REEs were calculated and the relations between physico-chemical soil properties and concentrations/mobility of REEs were quantified via correlation analysis. The aqua regia extractable REE concentrations and stocks of the Gleysol were about two times higher compared to the Fluvisol since the Gleysol was more clayey and REEs might adsorb onto clay minerals. We have detected small differences of REE concentrations and geochemical fractions between the horizons of the single profiles. Rare earth elements existed mainly in residual or reducible fraction, followed by oxidisable, and water soluble/exchangeable/carbonate bound fraction. The most striking difference between the two marsh soil profiles regarding the geochemical fractions was the higher residual fraction in the Fluvisol than in the Gleysol what seemed to be due to the lower aqua regia extractable concentration in the former. The aqua regia extractable concentration as well as reduction and oxidation processes of (amorphous) iron and manganese complexes seemed to have the most important impact on the geochemical fractions of REEs in the studied marsh soil profiles. In future, those findings should be verified in further marsh soils worldwide. In particular, future studies should elucidate the specific release kinetics of REEs and their determining factors.

The Plaggic Anthrosol (German: Plaggenesch) has been elected "Soil of the Year 2013" in Germany. This article reviews present knowledge on the formation, distribution, classification, soil functions, and threats of Plaggic Anthrosols. As the colors of Plaggic Anthrosols differ, we introduce a "Grey Plaggic Anthrosol" and a "Brown Plaggic Anthrosol". The term Plaggic Anthrosols is used in WRB, whereas those soils are classified as Agrosems according to the Russian, as Plagganthrepts according to the US Soil Taxonomy, and Plaggenesch according to the German taxonomy. The formation of Plaggic Anthrosols is the result of a former arable land use technique, the plaggen agriculture, starting ≈ 1000 y ago and lasting since the introduction of mineral fertilization. During processing plaggen agriculture, plaggen or sods of humic topsoil horizons were cut in the landscape, carried to the stables, enriched with dung, and subsequently spread out onto the fields as an organic-earthy manure. The manure decomposed and humified, whereas the mineral fraction remained and raised the land surface by 0.1 cm y -1 in average. Hence, the diagnostic horizon, a thick (70-130cm) humus-rich man-made epipedon, often containing artefacts, was formed over time. The main region of spatial distribution of Plaggic Anthrosols is NW Germany, The Netherlands and NE Belgium. Minor occurrences are reported from other parts of Europe. Compared to the associated soils, Plaggic Anthrosols hold considerable natural, archive and utilization functions, but are threatened by degradation when their use as arable soil is rendered.

Abandonment of croplands ongoing on 220 million ha worldwide contributes strongly to soil restoration by improvement of degraded properties and medium- and long-term carbon (C) sequestration in post-agricultural ecosystems. Two interrelated processes – decomposition and stabilization of soil organic carbon (SOC) – govern SOC dynamics and affect the C source or sink functions of former croplands. We investigated how the abandonment of arable soils affects (i) accumulation of SOC, its composition, stability, and turnover during the post-agricultural restoration of soils, and (ii) microbial activity parameters. A chronosequence study was carried in two bioclimatic zones of European Russia: deciduous forest (Luvic Phaeozems, PH-chronosequence) and dry steppe (Calcic Chernozems, CH-chronosequence). Each chronosequence included an arable soil, 3–4 soils abandoned at increasing time periods (up to 35 years), and natural soil: never cropped Phaeozem and completely restored Chernozem. We combined the results of nuclear magnetic resonance (NMR), thermal analysis including Differential Scanning Calorimetry and Derivative Thermogravimetry, long-term incubation for SOC mineralization, and microbiological activity (basal respiration and microbial C content). Degraded Phaeozems with low SOC amount had much higher relative increase in SOC content (134%) during the post-agricultural restoration compared to SOC-rich Chernozems (38%). SOC gains were recorded in all organic compound classes identified by NMR and thermal analysis, but the increase of recalcitrant SOC was more pronounced in the post-agricultural Chernozems than in the Phaeozems. The post-agricultural Chernozems were characterized by higher SOC aliphaticity and aromaticity than Phaeozems. Microbial activity and biodegradable SOC increased gradually during post-agricultural restoration. Being mostly a function of climate and vegetation, the soil type was the primary factor explaining the greatest portion (54–88%) of the total variance for most soil and microbial parameters. Concluding, despite SOC content increased in both Chernozems and Phaeozems during the post-agricultural restoration, the mechanisms of C sequestration and stabilization were dependent on climate, vegetation, and on the degradation intensity during the agricultural use. The accumulation of organic compounds was specific for virgin soils dominating in deciduous forest and steppes, and had direct consequences for microbial activities, C turnover and sequestration.

In order to bridge the gap of knowledge in respect of soil organic matter (SOM) dynamics of post-agricultural Luvisols during restoration, the study focused on alteration processes of functionally different SOM pools, 14C ages, and C turnover rates in a chronosequential approach. The study comprises three Luvisol chronosequences of 37 years (North), 120 years (Middle), and 42 years (South) across a climate gradient of the temperate broad-leaved forests of European Russia. Restoration led to SOM accumulation within both active (free particulate organic matter (POM) and occluded POM and passive (clay fraction) pools, and as a result, in gains of total organic carbon (C). Accumulation of new C was confirmed by increasing ∆14C signatures of occluded POM and clay fractions. After 22 years of restoration, ∆14C signatures progressed from negative to positive values for the occluded POM fraction, whereas they showed a similar development but remained negative for the clay faction. This highlights the fact that the incorporation of new C into the passive pool takes place, but that it occurs at a slower rate compared to that of the active pool. The 14C age of occluded POM fraction declined from 600 to 1200 years before present (BP) in arable sites to about 200 years BP after 22 years of restoration and thereafter. The 14C age of the clay fraction decreased from 1670 to 2660 years BP in arable soils to 750 years BP in 22 year abandoned site, 450–310 years BP in 32–66 year abandoned sites, and 200–370 years BP in near-natural forests. This decline of the 14C age reveals a change of the proportions between old and young C within the passive pool caused by management and the development of an ecosystem towards a steady state. Recovery of C was accompanied by initially increasing and then decreasing turnover rates of SOM, both again, much more pronounced in the active pool. These dynamics trace an initial ecosystem disturbance after abandonment, which slows down with time. Although C recovery and adjusted turnover rates of SOM progressed towards a new steady state of ecosystem; full restoration was not achieved within the chronosequential time scale of 120 years.

This chronosequential study focuses on the vegetation succession, pedogenesis, carbon stocks and functionally different carbon pools of post-agrogenic Albeluvisols under self-restoration in the Taiga zone of the European part of Russia. The sites investigated were comparable in terms of climate, soil texture and land-use history, but differed in duration of agricultural abandonment, covering 4, 12, 17 and 68 years of self-restoration. During self-restoration, the vegetation showed a development towards a mesophytic spruce forest. Pedogenesis resulted in recovery of morphological and chemical features with a vertical differentiation typical for the undisturbed Albeluvisols. During self-restoration, new organic surface layer (O) and new humic topsoil horizon (Ah) were developed. At the end of the chronosequence, the bottom of the well visible former ploughing horizon showed eluvial characteristics. Simultaneously, leaching caused a pH decrease of about 1.8 units, loss of the exchangeable cations, depletion of base saturation from 100% to 18%, and loss of nutrients. A vertical differentiation due to redistribution processes was found for soil organic carbon (SOC) and plant available phosphor and potassium. During self-restoration, the measured carbon stocks did not change substantially in the upper 0.5 m, but show a distinct redistribution within different soil layers, causing SOC accumulation from 0.64 to 0.78 kg m − 2 in the organic surface layers and from 0.75 to 2.64 kg m − 2 in 0–0.1 m, but SOC loss from 3.60 to 1.71 kg m − 2 in 0.1–0.5 m. The simulation results showed also minor alterations for the chronosequence time interval, followed by an increasing SOC sink functioning at long terms of up to 200 years. The investigation of functionally different SOC fractions showed a significant enrichment of free particulate organic matter (POM) and occluded POM, hot water extractable carbon (Chwe), and carbon in grain size fractions, significantly following the increase of total SOC during self-restoration. Nevertheless, self-restoration affected the distribution pattern of carbon to functionally different pools, predominantly stimulating SOC sequestration within free POM fraction. Despite all these alterations the study showed no full restoration for the vegetation and the soils within the chronosequential time scale of 68 years.

Marshes on the southern North Sea coast store large amounts of organic matter (OM). The objective of this study was to investigate the effect of inundation frequency on carbohydrates, organic carbon (OC), inorganic carbon (IC) and nitrogen (N) in a marine and a brackish marsh. To gain insights into the origin of OC in the marshes we used monosaccharides as biomarkers. We studied soils in a marine and a brackish marsh along a gradient of inundation frequency. It was found that TOC and N stocks in soils of a marine and a brackish marsh increased with decreasing inundation frequency. Concentrations of carbohydrates were significantly higher in the topsoils of the marine marsh than of the brackish marsh. In the upper mid-zone of the marine marsh, which is inundated by the sea approximately 20-times a year, carbohydrate stocks were up to 2.4-times higher than in the upper mid-zone of the brackish marsh with the same inundation frequency. Differences in carbohydrate concentrations can be attributed to differences in the abundance of fine and medium roots in these soils. In the daily-inundated soils of both marshes we observed high hexose-to-pentose ratios, indicating a microbial origin of the carbohydrates, while the hexose-to-pentose ratios were significantly lower in the middle and upper zone of the two marshes, indicating a high proportion of plant-derived carbohydrates. This study shows that monosaccharides are useful biomarkers to explore the origin of OM in coastal soils.

Land use change is known to strongly affect soil aggregation and aggregate stabilizing compounds. In this study we wanted to gain insight into the temporal and spatial dimension of this process. Therefore, we studied water-stable aggregates, total organic carbon (TOC), carbohydrates and glomalin-related soil protein (GRSP) in a 110-year chronosequence of Stagnosols, which have been converted from pasture to cropland at different times in history. To describe the temporal dimension, the measured concentrations were approximated by an exponential decay function. The spatial dimension was assessed by analyzing the distribution of TOC, carbohydrates, GRSP, and 14C among the different aggregate-size fractions over the course of 110 years of cropland use. It was found that the TOC concentration decreased monoexponentially (R2 = 0.92) from 195.2 t ha−1 to 45.13 t ha−1 in the first depth interval (0–20 cm) during the first 110 years after the conversion, and reached a new equilibrium 23 (±5) years after land use change. Carbohydrates and GRSP obtained a new equilibrium after 14 (±6) and 56 (±5) years in the same depth interval. The mean-weight diameter (MWD) of the water-stable aggregates reached a new equilibrium 33 (±2) years after the land use conversion. With respect to the spatial dimension we found that TOC, carbohydrates, and GRSP showed higher concentrations in the macroaggregates than in the microaggregates. The ratios of the distribution of TOC, carbohydrates and GRSP among macro- and microaggregates did not change significantly during the 110 years of arable use of the soils. The average age of the organic carbon in the different aggregate-size fractions analyzed by its 14C concentration showed of a wide range from 65 (±25) to 251 (±30) years, and did not change significantly during the cultivation of the sites. Thus, we conclude that water-stable aggregates and the concentrations of TOC, carbohydrates and GRSP reacted towards land use change at different speeds and reached a new equilibrium between 14 (±6) and 56 (±5) years after the conversion of land use. Secondly, we found, that the spatial distribution of aggregate stabilizing compounds was not significantly changed during the first 110 years of cultivation.

This chronosequential study focuses on the vegetation succession, pedogenesis, carbon stocks, and functionally different carbon pools of post-agrogenic chernozems under self-restoration in the forest steppe zone of the European part of Russia. The sites investigated were comparable in terms of climate, soil texture, and land-use history, but differed in their duration of agricultural abandonment, covering 8, 19, 37, and 59 years of self-restoration. During self-restoration, the vegetation showed development towards virgin steppe and the soils towards natural chernozem. Pedogenesis resulted in the formation of a fine granular structure and loss of ploughing features. Organic carbon (OC) content increased from 38.9 g kg− 1 to 54.5 g kg− 1 in the upper 10 cm of topsoil. Increasing C contents did not reach the OC level of the natural chernozem, showing 78.9 g kg− 1. Nitrogen contents and cation exchange capacity (CEC) values increased, showing significant positive correlations with soil organic carbon (SOC) content and resulting in chronosequential constant Corg/N ratios. The SOC accumulation rate for the 59 years of self-restoration was about 52 g m− 2 y− 1 for the mean of the upper 0.2 m and 103 g m− 2 y− 1 in the upper 0.5 m. Thus, carbon stocks increased to 91% of the natural chernozem. Functionally different SOC pools showed their quantitative alterations during self-restoration. The OC of the clay fraction (% of soil) increased in line with the recovery of total SOC at soil depths 0–0.5 m from 1.49% to 2.17% on average. The OC of the density fraction

The conversion of pasture to cropland leads to a decline of aggregation in topsoils and to a decrease of aggregate-binding agents such as carbohydrates and glomalin-related soil protein (GRSP). Till now, studies on soil aggregation focused either on carbohydrates or on GRSP as a binding agent in aggregates. In this study we analyse the development of the relationship between carbohydrates, GRSP, TOC and aggregate-stability following land-use change. Furthermore, we discuss the contents of carbohydrates, GRSP and TOC in each of the aggregate fractions. For these purposes, a chronosequence of sites, which were converted from pasture to cropland at different periods in history, was established. To get further insight into the impact of different types of land-use, also soils under forest, either afforested or permanent, were studied. The mean-weight diameter (MWD) of water-stable aggregates, the carbohydrate, and the GRSP content were determined in 49 soils. It was found that the MWD of the water-stable aggregates decreased monoexponentially ( R 2 = 0.66) by 66% during the first 46 years after conversion of the soils from pasture to cropland. During the same period, the carbohydrate content decreased very rapidly after the land use change by 64% and the GRSP content decreased more slowly by 57%. The MWD of the forest soils were in the same range as those of the permanent pasture soils although they exhibit significantly higher TOC contents, which indicate that other stabilization mechanisms are dominant in forest soils, less important in the chronosequence soils. TOC, carbohydrates and the GRSP contents were sigmoidally correlated with the MWD. Among the four water-stable aggregate fractions TOC and carbohydrates exhibited high contents in the macroaggregates and were less present in the microaggregates. GRSP, in contrast, was more equally distributed among the four water-stable aggregate fractions.

Soil organic carbon stocks decrease after conversion of soils from pasture to cropland. It has been assumed that this applies especially to mineral hydromorphic soils. In this paper we evaluate hot-water extractable carbon (Chwe) as a measure for detecting long-term changes in the SOM following land use change. Furthermore, we assess whether a treatment of the soils with NaOCl leads to the isolation of long-term stable C fractions. For these purposes, we established a chronosequence of sandy hydromorphic soils that have been converted from pasture to cropland at different periods of history. To gain further insight into the impacts of different types of land use on carbon sequestration, soils under forest, either afforested or permanent, were studied. Bulk density, total organic carbon (TOC), Chwe, and NaOCl-resistant C were quantified in the surface soils of 72 Gleyic Podzols and Haplic Gleysols. The bulk density increased from 0.9 (±0.2) g cm−3 to 1.4 (±0.1) g cm−3 during the first 25 years after the conversion of the soils from permanent pasture to cropland. In the permanent pasture sites, the TOC concentration amounted to 35.4 (±12.1) g kg−1. It decreased to 12.88 (±5.9) g kg−1 during the first 46 years of cultivation (R2 = 0.71). In the permanent forest soils the TOC concentrations were significantly higher than in the soils that have been afforested. Chwe concentrations of the chronosequence sites were linearly correlated to the TOC concentrations (R2 = 0.84), while permanent forest sites exhibited significantly higher Chwe/TOC ratios. This shows that the determination of the Chwe is a very promising measure for detecting changes in SOM dynamics following afforestation. In the permanent pasture sites, 14.3 (±5.38) g kg−1 NaOCl-resistant C was measured, while 46 years after conversion, only 2.8 (±1.2) g kg−1remained. No enrichment of NaOCl-resistant C was observed in the chronosequence, as NaOCl-resistant C decreased faster in the course of cultivation than the TOC. Therefore, we conclude that that the C fraction that resists the oxidation with NaOCl is not long-term stable in soils, and most probably, there is no such long-term stable C fraction in the soils under study.

The study focuses on the properties of soil organic matter (SOM) of Plaggic Anthrosols from Northwest Germany, Northwest Russia and North Russia. As the sites differ in type of plaggen material and manner and duration of plaggen management, the aim was to find out whether these differences influence SOM. The studied soils show different SOM qualities by the C/N ratios of TOC, by the C/N ratios in the particle size fractions and IR spectra, the latter indicating the occurrence of keto- and carboxyl groups only for the German soil and amides exclusively for the Russian ones. The HCl-resistant organic carbon (OC) and the H2O2-resistant OC was largest and the HF-soluble OC was lowest in the Northwest Russian soil. With decreasing amounts in the sequence Northwest Germany, North Russia and Northwest Russia, the highest OC content was found in the fine silt and clay fractions. With the exception of the HF-soluble OC the parameters stay constant with depths of the plaggic epipedons, indicating no alteration with...

The focus of this chronosequential study was on the vegetation succession, profile morphology, nutrient dynamics, and carbon stocks of post-agrogenic sandy soils under self-restoration of the southern Taiga zone in the European part of Russia. The sites investigated were comparable in climate, texture, and land-use history, but differed in the duration of agricultural abandonment, covering 3, 20, 55, 100, and 170 years of self-restoration. During self-restoration, the vegetation developed towards natural spruce forests and the soils towards natural Podzols. After 55 years of self-restoration, an initial albic horizon under a 2–3 cm thick raw humus layer had developed and after 100 years, all typical Podzol horizons (O–E–Bsh), though relicts of former land use (Ap features), were still present after 170 years. Increasing podzolisation was indicated by a pH decrease from 6.7 to 3.6 (CaCl 2 ), decrease of exchangeable Ca and Mg and decrease of base saturation from 54.0% to 4.3%, C/N ratios increasing from 15.6 to 31.2 and by the loss of pyrophosphate-soluble Fe in the top soil from 340 to 214 μg g − 1 and accumulation in the subsoil from 162 to 896 μg g − 1 in 170 years of self-restoration. During self-restoration, the contents of P and K in total and plant-available forms as well as total N decreased in the top mineral soil, causing a considerable nutrient depletion after 55 years and partly shifting the source of plant nutrients from the mineral part of the soil upwards to the forest floor. Despite this over-all release, the P contents stayed high (817 mg kg − 1 ) within the relictic ploughed horizons, which was also true for C. But mainly because of increasing SOC stores of the organic surface layer, carbon stocks increased from 4.5 kg C m − 2 to 6.3 kg C m − 2 during self-restoration, indicating a carbon sink. Because of the continued existence of C in parts of the former ploughed horizons, the carbon sink functioning is even larger in self-restorated Podzols than in natural ones.

The Podzol has been elected “Soil of the year 2007” in Germany. This article reviews the present knowledge on the development, functions, and threats of Podzols. The main theories on mobilization and transport of organic matter, Fe, Al, and Si are (1) metal-organic migration, (2) metal reduction, and (3) inorganic sol migration. Immobilization theories include precipitation or polymerization due to increasing pH/abundance of base cations with depth, mechanical filtering in soil pores, oxidation of metal-organic complexes, biodegradation of the organic part, decreasing C-to-metal ratios during translocation, adsorption to soil particles, and flocculation at the point of zero charge. Podzolization is discussed also on the catena scale, where vertical and lateral translocation processes (across pedon boundaries) need to be considered to understand Podzol patterns in landscapes. Chronosequence studies show that incipient podzolization usually becomes visible between 100 and 500 y and mature Podzols develop in 1,000–6,000 y. The occurrence of Podzols worldwide is concentrated mainly on the boreal zone and mountain regions within the humid temperate zone. Smaller Podzol areas are found in some perhumid tropical and subtropical regions. In Germany, Podzols occur in the Alps, in the glaciofluvial valleys and heathlands of N Germany, and in the mountain ranges. They fulfil several ecological functions, especially for groundwater recharge. Main threats for these mostly sandy soils are wind erosion and surface mining of sand. Two pedons which were chosen to represent the “Soil of the year 2007” are presented. Finally, some conclusions about podzolization processes are drawn, which may explain the diverse observations reported in the literature.

Pristine and impaired mangrove soils (from road construction, aquaculture, and sewage) in Baja California Sur, Mexico were investigated for methane dynamics, related soil properties, and their impact on initial establishment of black mangrove propagules. All soils (Salic Fluvisols and Histosols) had neutral to alkaline pH, were saline, and had variable organic carbon content, and redox potentials. Most pristine mangrove soils showed low methane concentration, low methane production rates, and no methane emission. Impaired mangrove soil (from aquaculture) and mangrove soil affected by sewage water showed high methane concentration, high methane production rates, and high methane emission, thus acting as a methane source. Elevated methane concentrations, similar to levels detected in the impaired mangrove soil, reduce the growth of seedlings under closed chamber conditions. Addition of sulfate to the soil reversed the trend. These results indicate that impaired mangrove soils in dry climatic regions produce and emit methane and that elevated methane concentration in the vicinity of propagules may affect establishment of mangrove seedlings in impaired mangrove soils.

To clarify whether a particular group of soils of Archangelsk region (European N Russia) with humus-rich topsoils exceeding the plowing zone supports an anthropogenic formation, four exemplary profiles were investigated. The investigation sites are characterized by distinct elevated surfaces, and the soils show thick toplayers of up to 60 cm with enrichment of soil organic matter and artifacts like brick, charcoal, and peat fragments, all indicating an anthropogenic origin. Increased phytolith amounts and high P contents of up to 800 mg kg–1 citric acid–soluble P and up to 1,400 mg kg–1 total P in the top horizons support an anthropogenic influence. These properties are very similar to the Plagganthrepts of NW Europe. The same is true regarding the main management aims: increasing soil fertility and overcoming the need of bedding materials. Having the required depths of the anthropogenic topsoil, the properties of the soils of the Archangelsk region allow a classification as Agrozems (Russian classification), Plaggenesche (German classification), and Plagganthrepts (US taxonomy). Since the high base saturation of the topsoil excludes a designation as plaggic horizon, the topsoil has to be considered as terric horizon, which leads to a classification as Terric Anthrosol according to WRB.

Die Genese kalkfreier Marschboden ist nach wie vor strittig. Zur Klarung dieser Frage erfolgte deshalb beispielhaft an zwei Knickmarschen Ostfrieslands die Rekonstruktion ihres Palaomilieus mittels Ergebnissen der Rontgenfluoreszenzspektroskopie, Rasterelektronen- und Durchlichtmikroskopie. Profil 1 gliedert sich in sieben Fazies. Die Diatomeenflora deutet auf zeitlich variierende Palaomilieus limnischer, brackischer und mariner Auspragung hin. Im Grenzbereich von mineralischem Material und Torf sowie im Torf selbst wurden Pyritkristalle gefunden. Die zudem haufig auftretenden engen Zr:Al- und Si:Al-Verhaltnisse sowie die engen Ca:Sr-Verhaltnisse weisen auf ruhige, brackische bis lagunare Sedimentationsbedingungen mit Schilftorfbildung im Ruckseitenwatt hin. Profil 2 gliedert sich in zwei Fazies, deren Ubergang durch einen plotzlichen Wechsel der Diatomeenzusammensetzung, der geochemischen Eigenschaften und des Carbonatgehalts charakterisiert ist. Die Diatomeenflora und die Ca:Sr-Verhaltnisse der unteren Fazies kennzeichnen ein Priel-Habitat mit marinem Kontakt und ungewohnlich engen Si:Al- und Zr:Al-Verhaltnissen. Die Ergebnisse lassen vor allem fur viele Fazies von Profil 1 auf Entkalkungsprozesse wahrend der Geo-Pedogenese schliesen. Fur heute kalkfreie Marschboden gibt es demnach zwei Stadien der Entkalkung, zum einen die fruhe Geo-Pedogenese, wie sie eher fur die Knickmarschen Niedersachsens fur wahrscheinlich gehalten wird, und zum anderen die spatere terrestrische Entwicklungsphase von der Kalk- zur Kleimarsch. Reconstruction of the paleo-environment and geopedogenesis of non-calcarous marshland soils (Eutric Gleysols) of Lower Saxony The genesis of non-calcarous marshland soils is still controversially. For clarification, the paleo-environments of two Eutric Gleysols were reconstructed by using X-ray fluorescence spectroscopy, light microscopy, and scanning electron microscopy. Profile 1 shows seven facies. The diatom composition reveals paleo-environments variable in time with lacustrine, brackish, and marine conditions. Pyrite was found at the transition of clastic material and peat and within the peat, indicating together with frequently found small Zr:Al and Si:Al ratios and small Ca:Sr ratios calm, brackish, and lagoonal sedimentation conditions with reed-peat formation. Profile 2 shows two facies; their transition is very sharp and characterized by a sudden change in diatom composition, geochemical quality, and carbonate contents. The diatom flora and Ca:Sr ratios of the lower facies reveal a tidal creek habitat with a connection to the sea and exceptional small Si:Al and Zr:Al ratios. The results, particularly for many facies of profile 1, suggest a decalcification during geopedogenesis. Two genetic phases of this decalcification are therefore likely for today non-calcarous marshland soils, either during early geopedogenesis or during later terrestrial development.

Ziel dieser Arbeit war die eingehende Untersuchung und exakte bodentypologische Benennung von Dunenboden der Ostfriesischen Inseln. Innerhalb der Dunensukzession zeichnen sich auf der Grundlage der Laboranalytik die Bodenentwicklungsprozesse Humusakkumulation und -verlagerung, Entkalkung, Versauerung, Umladung der Bodenkolloide und Abnahme der Basensattigung ab. Ungestutzt durch Labordaten war im Gelande eine leichte Verbraunung erkennbar. Bei exakter Anwendung der diagnostischen Horizonte entsprechend der deutschen Systematik fehlen die quantitativen und qualitativen Grundlagen zur Klassifikation dieser Boden als Regosole, Braunerden und Podsole. Nach der WRB-Systematik entsprechen sie exakt den Arenosolen.

To clarify the properties, genesis and classification of typical anthropedogenic soils of St. Petersburg area, exemplary five profiles were thoroughly investigated. The soils are characterised by humus-rich, well-structured and biologically active anthropedogenic epipedons, reaching depths of 52 and 55 cm. The texture, the mineral distribution and the XRD analysis confirmed the multiple geological composition of the profiles. The bulk densities of the anthropedogenic epipedons were 1.0–1.3 g cm−3 and down to 1.9 g cm−3 in the underlying horizons. The pH values were 4.9–6.8 (CaCl2). Small lime amounts were found in two cases. The Corg contents were 23.5–74.0 g kg−1 and the N contents 2.0–3.9 g kg−1 in the anthropedogenic horizons and 0.8–4.9 g kg−1 and 0.1–0.3 mg kg−1 in the underlying ones. Decreased humus contents in the root zone indicated degradation processes. The base saturation was mostly 100% and the CEC 9.3–17.1 cmolc kg−1 in the top and 3.0–9.3 cmolc kg−1 in the subsoils. The total P contents were 884–1835 mg kg−1 and the citric acid soluble P content 321–776 mg kg−1 in the anthropedogenic epipedons and 189–355 and 46–321 mg kg−1 in the underlying horizons. Thus, the anthropedogenic St. Petersburg soils showed distinct similarities to the Plagganthrepts of northwest Europe in respect of Corg enrichment, surface raise and P enrichment. The same is true regarding the main management aims: increase of soil fertilisation combined with an overcome of lacking bedding materials. Hence, the genesis and most properties of the anthropedogenic St. Petersburg soils support a classification as Agrosems (Russian taxonomy) Plaggeneschs (German taxonomy) Plagganthrepts (U.S. taxonomy) or terric Anthrosol (World Reference Base for Soil Resources [WRB] taxonomy). But the required thickness of the anthropedogenic epipedon is barely achieved. Thus, Plagganthrepts occur as small patches, which may even decrease, because of soil degradation.

The vertical distribution and bioavailability of 137Cs in Histosols and mineral soils with different physicochemical properties from the southeast of Bavaria (Germany) more than ten years after the Chernobyl accident were the focus of this study. The vertical distribution of 137Cs was low in the investigated soils. About 85–98 % of the total 137Cs was located in the upper 10 cm of the mineral soils. Slightly higher 137Cs percentages were observed in deeper soil layers of the peat soils. Although the organic matter is assumed to enhance 137Cs mobility in soils, 137Cs was also located in the upper 10 cm of the peat soils (73–85 %). The highest 137Cs-activities were found in the humus layers of forest soils, where 45–93 % of the total 137Cs soil inventories were observed. To determine the bioavailability of radiocesium, the soil-to-plant transfer of 137Cs and additionally added 134Cs was investigated under controlled conditions. The results revealed that the 134+137Cs soil-to-plant transfer factors as well as the percentages of NH4-exchangeable 134+137Cs were much higher for the peat soils and humus layers than for the mineral soils. Nevertheless, the migration of 137Cs from the humus layers to the underlying soils was low. Considering the high bioavailability and low migration of radiocesium in the humus layers, it is suggested that radiocesium is involved in a shortcut element cycle in the system humus layer-plant uptake-litter. Furthermore, the organic matter has to be taken into account for radiocesium immobilization. Vertikale Verteilung und Bioverfugbarkeit von 137Cs in organischen und mineralischen Boden Die vertikale Verteilung und Bioverfugbarkeit von 137Cs in ungestorten Moor- und Mineralboden mit unterschiedlichen physikochemischen Eigenschaften unter Wald und unter Grunland im Sudosten Bayerns uber zehn Jahre nach dem Reaktorunfall von Tschernobyl war Gegenstand dieser Untersuchung. Die vertikale Verteilung von 137Cs in den untersuchten Boden war gering. In den Mineralboden lagen 85–98 % des gesamten 137Cs in den obersten 10 cm vor. In den Moorboden konnte dagegen eine etwas grosere Tiefenverlagerung beobachtet werden. Obwohl der organischen Substanz weitgehend eine 137Cs-mobilisierende Wirkung zugesprochen wird, lag auch hier 137Cs hauptsachlich in den obersten 10 cm vor (73–85 %). Die hochsten 137Cs-Aktivitaten wurden in den Auflagehorizonten der Waldboden ermittelt, wo zwischen 45–93 % des gesamten 137Cs-Inventars der Boden vorlagen. Um die Bioverfugbarkeit von Radiocaesium zu ermitteln, wurde der Transfer von 137Cs und zusatzlich zugefuhrtem 134Cs vom Boden in die Pflanze unter kontrollierten Laborbedingungen untersucht. Die Ergebnisse zeigten, dass sowohl die 134+137Cs Transferfaktoren Boden–Pflanze als auch die prozentualen Anteile an NH4-austauschbarem 134+137Cs bei den Moorboden und Humusauflagen deutlich hoher waren als bei den Mineralboden. Trotz der hoheren Mobilitat und Bioverfugbarkeit von 137Cs in den Auflagehorizonten war die Migration in den darunter liegenden Boden gering. Aufgrund der hohen Bioverfugbarkeit und der geringen Migration von 137Cs in den Auflagen, gehen wir davon aus, dass 137Cs in einem kurzgeschlossenen Kreislauf im System Humusauflage – Pflanzen – Streu eingebunden ist. Daruber hinaus muss auch die Immobilisation von Radiocaesium durch die organische Substanz in Betracht gezogen werden.

Wahrend fur niedersachsische Rohmarschen im allgemeinen erhebliche Kalkvorrate charakteristisch sind, wurden auf Spiekeroog kalkfreie initiale Marschen gefunden. Ziel dieser Arbeit war es deshalb, die Marschboden Spiekeroogs vergleichend zu denen des Festlandes zu untersuchen und die Ursache des Fehlens von Carbonat zu klaren, die im Zusammenspiel von Schwefel-Dynamik und Sedimentationsverhalten vermutet wurde. Die Rohmarschen Spiekeroogs sind bezuglich ihres Bewuchses, vieler physikalischer Parameter und vor allem chemischer Eigenschaften (z. B. pH, Corg, Salinitat, Feo, d, aK, KAK) vergleichbar mit denen der niedersachsischen Festlandskuste. Im Unterschied erstrecken sich die Rohmarschprofile Spiekeroogs uber die gering machtigen Marschensedimente und den darunter liegenden Sand, sind schluffreicher und tonarmer sowie carbonatarmer (0, 3 – 34, 5 g kg–1). Eine Kartierung wies kalkfreie Flachen aus. Die vergleichsweise moderate Schwefel-Dynamik ist durch eine zeitlich und raumlich stabile SO4-S-Fraktion, im Mittel von 0, 3 – 0, 6 mg g–1 gekennzeichnet. Mit 1, 5 – 2, 9 mg g–1 ist auch die HNO3-HCl-S-Fraktion eher stabil, wahrend vor allem die HCl-S-Fraktion, bei grosen Unterschieden zwischen den Standorten, in Korrelation mit sich andernden Redoxpotenzialen einer zeitlichen Variabilitat (monatlich HCl-S-Abnahmen bzw. Anstiege ∅ 0, 2 mg g–1) unterlag. Die vertikale Cs-137-Verteilung zeigte Peaks in 3 – 4 und 7 – 8 cm Bodentiefe und damit eine eher geringe Sedimentationsrate von 0, 2 – 0, 5 cm a–1. Die Ergebnisse haben gezeigt, dass die Schwefel-Dynamik uber langere Zeitraume zu erheblichen Kalkverlusten fuhrt, die aufgrund der relativ geringen Sedimentationsrate und damit geringen Neuanlieferung von Carbonaten nicht ausgeglichen wird, so dass die Rohmarschen Spiekeroogs entkalkt in die terrestrische Bodenentwicklungsphase ubergehen werden. Neben dem rezent ublichen Weg der Pedogenese der Kleimarschen uber Roh- und Kalkmarschen gibt es den von Rohmarschen direkt zu Kleimarschen, der auch z. T. fur heute alte Kleimarschen (Brackmarschen) Niedersachsens fur moglich gehalten wird. Geo-pedogenesis of Salic Fluvisols on the North Sea island of Spiekeroog Although the mainland's Salic Fluvisols of the southern North Sea coast are rich in carbonate, those of the adjacent island Spiekeroog are not. Thus, the aim of this study was to investigate the Salic Fluvisols of Spiekeroog in comparison to those of the mainland and to find out the reasons for the lack of carbonate, which was supposed to be an interaction between sedimentation and sulfur dynamics. The vegetation, many physical and chemical properties (e.g. pH, Corg, salinity, Feod, exchangeable cations, CEC) of the Spiekeroog Fluvisols are similar to those of the mainland. However, the Spiekeroog soil profiles extended over the marsh sediments, and the sand sediments below and they contained more silt and less clay and carbonate (0.3 – 34.5 g kg–1) than the soils of the mainland. A survey proved carbonate-free areas. The relatively moderate S dynamics showed a spatial and temporal stabile SO4-S-fraction (0.3 – 0.6 mg g–1), a fairly stabile HNO3-HCl-S fraction (1.5 – 2.9 mg g–1), but a variable HCl-S fraction. The vertical Cs-137 distribution showed peaks at 3 – 4 and 7 – 8 cm soil depth, indicating sedimentation rates of 0.2 – 0.5 cm a–1. The results showed that moderate S dynamics lead to carbonate losses which are not compensated because of low sedimentation rates. Consequently, the Spiekeroog Salic Fluvisols will enter the terrestrial phase of soil development without carbonate. Thus, besides the usual pedogenesis of Eutric Fluvisols via Salic and Calcaric Fluvisols, the investigation proved a direct development from Salic to Eutric Fluvisols.

In einem Transekt vom Watt zum Deich wurde im sudostlichen Dollart (Niedersachsen) die Marschbodenentwicklung aus brackigen Sedimenten untersucht. Vom Watt zum Deich nahm die Ausbildung und Machtigkeit von oxidierten Horizont-Merkmalen zu, es erhohten sich die Bodendichten von 0,57 g cm—3 auf 1,12 g cm—3 und die Wassergehalte nahmen von 78,8 % auf 54,9 % ab. Die wattnachsten Boden waren koharent, der deichnachste Standort wies eine krumelige Struktur auf. Die Ton/Carbonat-Verhaltnisse zeigten eine leichte Erweiterung von 3,3 auf 4,8 vom Watt zum Deich, mit einer Erweiterung von 13,9 auf 15,6 gilt dies auch fur die C/N-Verhaltnisse. In gleicher Abfolge nahm die Salinitat der Oberboden von 7,8 ‰ auf 1,5 ‰ ab und die anfangliche Na-Dominanz der austauschbaren und in Losung befindlichen Kationen wurde durch eine Ca-Dominanz abgelost. Die ableitbaren initialen Bodenentwicklungsprozesse sind: Gefugebildung, Sackung, Beluftung, Entsalzung, Ab-, Umbau organischer Substanzen, Entkalkung, Umbelegung der Bodenkolloide. Vergleichbar mit marinen Bildungen werden diese Boden als kalkhaltige Marschen in die terrestrische Phase ubergehen und damit in ihrer spateren Merkmalsauspragung nicht von den brackigen Sedimentationsverhaltnissen bestimmt sein. Fur die initiale Phase aus brackigen Sedimenten von heute alten Kleimarschen wird im Gegensatz dazu fur wahrscheinlich gehalten, dass sie aufgrund von Reduktion und Oxidation des Schwefels und geringen Sedimentationsraten bereits im Initialstadium entkalkten und damit entkalkt in die terrestrische Phase ubergingen. Initial marsh soil development from brackish sediments The initial marsh soil development from brackish sediments was investigated in a transect from the tidal flat to the dike in the southeast Dollart (Lower Saxony, Germany). Oxidized morphological features increased from the tidal flat to the dike. Simultaneously the bulk density increased from 0.57 g cm—3 to 1.12 g cm—3 and the water content decreased from 78.8 % to 54.9 %. The soils closest to the tidal flat were massive, those closest to the dike had a crumble structure. The clay/carbonate ratio increased slightly from 3.3 to 4.8 in the same succession as well as the C/N ratio from 13.9 to 15.6. Likewise the salinity decreased from 7.8 ‰ to 1.5 ‰ and the dominance of Na was replaced by Ca within the pool of exchangeable and soluble cations. The data indicate initial processes of marsh soil development: structure forming, settlement, aeration, salt and lime loss, decomposition and changing ratios of adsorbed cations. Similar to marine developments the soils will enter the terrestrial phase as carbonate containing soils not characterized by the brackish sedimentation conditions. For the initial development of today old marshland soils (”Kleimarshes”) from brackish sediments, in contrast, it is likely, that they were already free of carbonate when entering the terrestrial phase. This is explained by long-term reduction and oxidation of sulfur and low sedimentation rates.

The methane dynamics of soils covering a landfill in Oldenburg, Lower Saxony, was investigated in 1996. The methane concentration was often < 20 nmol (dry g)−1 within the cover layer and up to 9950 nmol (dry g)−1 within the refuse body. The methane production rates correlated positively with the methane concentrations and were mostly < 10 nmol (dry g)−1 d−1 within the cover layer and up to 1090 nmol (dry g)_1 d_1 within the refuse body. The methane oxidation rates varied between 38.0–2310 nmol (dry g)−1 d−1. The methane emission rates showed values of up to 574 mol m−2 h−1, but in two cases no emission of methane was found. The data indicate that the methano-genesis of the deep refuse layers did not substantially affect the methane behaviour of the upper soil sections. It is likely that the emission of methane from landfills can be reduced by thick well aerated cover layers. The term “Reduktosol” for landfill soils is critically discussed. Methan-Dynamik von Mulldeponie-Boden und Aspekte ihrer Klassifikation 1996 wurde die Methan-Dynamik von Boden einer Mulldeponie in Oldenburg, Niedersachsen, untersucht. Die Methan-Konzentration war haufig < 20 nmol (g TS)−1 im Auftragsmaterial und bis zu 9950 nmol (g TS)−1 im Mullkorper. Die Methan-Produktions-Raten korrelierten positiv mit den Methan-Konzentrationen und betrugen meistens < 10 nmol (g TS)−1 d−1 im Auftragsmaterial und bis zu 1090 nmol (g TS)−1 d−1 im Mullkorper. Die Methan-Oxidations-Raten variierten von 38.0–2310 nmol (gTS)−1 d−1. Die Methan-Emissions-Raten erreichten bis zu 574 mol m−2 h−1; in zwei Fallen wurden keine Methan-Emissionen gefunden. Die Daten weisen darauf hin, das die Methanogenese im tieferen Mullkorper das Methanverhalten der oberen Bodenbereiche nicht wesentlich beeinflust, und das die Emission von Methan durch machtige gut durchluftete Abdeckschichten reduziert werden kann. Die Bezeichnung., Reduktosol” fur Boden von Mulldeponien wird kritisch diskutiert.

Die Entstehung und die Klassifikation von Marschboden sind nach wie vor umstritten. Um die Kenntnisse uber die Genese von Organomarschen zu verbessern, wurden 11 Bodenprofile untersucht. Die Boden wiesen fast immer Phragmitis im Unterboden auf. Der Beginn der Gr-Horizonte lag in geringer Bodentiefe (40–60 cm). Der Tongehalt betrug haufig um die 60% und der Corg-Gehalt bis zu 480 g kg−1. Der Gesamtschwefelgehalt betrug bis 29,6 g kg−1, der Gehalt aus-tauschbaren Sulfats bis 4608 mg kg−1 und der Sulfatgehalt der GBL bis 51,2 mg l−1. Mit pH(H2O)-Werten zwischen 2,0–7,4, Carbonat/S-Verhaltnissen 7,5 g kg−1 wiesen einige Profile die Merkmale von „Actual Acid Sulfate Soils” (AASS) auf. Die pH(per)-Werte betrugen 2,4 bis 7,1, entsprechend sind einige Boden als „Potential Acid Sulfate Soils” (PASS) einzuordnen. Brackische als auch marine Milieus mit intensiver Schwefeldynamik und Entkalkungsprozessen sind fur die geogene Phase von Organomarschen wahrscheinlich. Die pedogene Phase ist uber die Steuerung des Hydroregimes wesentlich anthropogen bestimmt. Wir schlagen fur humusreiche Marschen eine Unterteilung in „Organomarsch” und „Thiomarsch” auf der Bodentyp-Ebene vor. Formation and classification of humus-rich marshland soils of the Weser marshland, Germany The formation and classification of marshland soils are still controversial. To improve the knowledge on the formation of humus-rich marshland soils 11 soil profiles have been investigated. The soils mostly showed Phragmitis in the subsoil. The Gr-horizons began at low depths (40–60 cm). The clay content was often about 60% and the Corg content up to 480 g kg−1. The amount of total sulfur was up to 29.6 g kg−1, that of exchangeable sulfate up to 4608 mg kg−1 and that of sulfate in the saturation extract 51.2 mg l−1. With pH (H2O) values between 2.0 and 7.4, Carbonate/S ratios 7.5 g kg−1 some soils showed “Actual Acid Sulfate Soil” (AASS) properties. The pH(per) values varied between 2.4 and 7.1, thus some profiles showed “Potential Acid Sulfate Soils” (PASS) properties. Brakish as well as marine environments with an intensive sulfur dynamics and carbonate leaching are likely within the geogenetic phase of soil development. Via the control of the water regime the pedogenetic phase is mainly of anthropogenic influence. We propose to classify humus-rich marshland soils into “Organomarsch” and “Thiomarsch” on the soil type level of the German systematics.