Bodengesellschaften von geomorphen Einheiten unter Berücksichtigung des Gefügestils im Stormarner Jungmoränengebiet (Brandenburger Stadium) in Nordwestdeutschland

Soil associations of different geomorpholocical units of a younger‐moraine area in Schleswig‐Holstein (NW Germany) considering matter fluxes As result of a detailed mapping work, the soil association of different geomorpholocical units of a younger‐moraine area (“Stormarner Jungmoränengebiet”) in Schleswig‐Holstein (NW Germany) is analyzed taking into account soil development in vertical and horizontal direction. The consequences for classification of soil types and soil associations are discussed. We distinguished between different patterns of matter fluxes (unilateral coupling, mutual coupling, no coupling of soils). By morphometric analysis of the relief, five geomorpholocical units were distinguished: till‐plains with dead‐ice kettles (I), tongue‐like basin with moraine slopes (II), terminal‐push moraine (III), moraine slopes with gutter valley (IV), und terminal‐push moraine valley with steep slopes (V). In the examination area with its intense agricultural land use, the regular sequence of erosion and accumulation of soils is a typical consequence of unilateral water‐flow direction. Thus, the truncated Stagnic Luvisols/Anthrosols association is dominating. We suggest to classify the truncated Luvisol with a Bt horizon exposed directly to the surface at the level of soil subtypes in the German soil‐classification system. Additionally soils in depressions such as Calcic Gleysols, Histosols and “subhydric soils”, which are influenced by solute and solid‐matter input, are frequently encountered. Within the till‐plains, a compensation of the relief by (historical) soil erosion took place, recognizable by the high percentage of Anthrosols (20 %). Therefore, no recent lateral transport of solid material can be found. The steep moraine slopes partly already show Regosols, thus indicating a high erosion potential (erosion rate for geomorphical unit IV: 13 t ha^–1 y^–1). In the depressions intersected with small streams, the afflux caused by mills led to an additional peat development.     

Preparing a soil carbon inventory of Saxony‐Anhalt,Central Germany using GIS and the state soil data base SABO_P

To obtain information on regional soil carbon (C) stocks, we prepared a soil C inventory for the central German State Saxony‐Anhalt. We used the State Soil Database SABO_P ( S achsen‐ A nhalt Bo den_ P rofildatenbank), which contains data from 3,600 soil profiles with 16,300 individual soil horizons and combined it with a geographic information system (GIS ArcView). Soil C stocks down to a depth of 100 cm were compiled for the three major soil regions of Saxony‐Anhalt (soil region 2: river valleys and floodplains; soil region 4: pre‐Weichselian moraines, and soil region 6: loess‐covered areas), which represent 83 % of the total state territory. The three major soil regions in Saxony‐Anhalt comprise on average 12.7 (soil region 2), 8.9 (soil region 4), and 12.8 kg C m^–2 (soil region 6). Total C content of the area investigated was 191 tg. The typical soils of the region, Haplic Chernozems, contain on average 13.9 kg C m^–2. With few exceptions, soil C did not vary significantly within identical taxonomic groups among different soil subregions. However, Chernozems of soil subregion 3 (Wanzlebener Löß‐Plateau; 19.8 kg C m^–2) contain significantly more C than the Chernozems of soil subregions 9 (Pollebener, Gerbstedter and Lettewitzer Löß‐Plateau; 12.1 kg C m^–2) and 15 (Barnstädter Löß‐Plateau 12.2 kg C m^–2). The spatial distribution of C stocks in Saxony‐Anhalt was represented in a map which suggests the existence of a strong link between the geomorphologic position of a given soil and its capacity to store organic C. Within the same taxonomic unit, finer textured soils stored more carbon than coarse‐textured ones.     

Plaggic Anthrosol: Soil of the Year 2013 in Germany: An overview on its formation,distribution, classification,soil function and threats

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 (70–130 cm) 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.     

The influence of long-term cultivation on soil properties and patterns in an undulating terrain in Poland

Soil utilization has, for many years, strongly influenced the properties of soils in the undulating terrain of the Lublin Upland. Population increase and suitability of the soils (particularly Luvisols, Cambisols and Chernozems derived from loess and loess-like formations) for arable agriculture were the main reasons for deforestation. This led to erosion, which caused changes in soil morphology and the development of a mosaic soil cover. Accelerated erosion was strongest on slopes exceeding 18%. It resulted in selective loss of clay. The main changes in silty soils developed from loess and loess-like deposits occurred in the first few decades after cultivation started. They included a decrease in organic matter content from an average of 2.3% organic C in the forest soils to about 1% in the arable soils. No further changes in humus content were observed, but the proportion of fulvic acids increased at the expense of humic acids. The pH_KCl rate decreased at the slope foot from about 5.8 to 5.0. Morphological changes in rendzinas were much lower than in the soils derived from loess. We do not expect big changes in these soils in the next 100 years if their use remains the same.     

Black carbon in the zonal steppe soils of Russia

Black Mollisols are typically rich in charred organic matter, however, little is known about the zonal distribution of black C (BC) in steppe soils. In this study, we used benzene polycarboxylic acids (BPCA) as specific markers for BC in particle‐size fractions of depth profiles in several zonal soils (Greyzem, Phaeozem, Chernozem, Kastanozem) of the Russian steppe. In addition, liquid‐state ¹³C‐NMR spectra were obtained on the alkaline‐soluble soil organic matter (SOM). The results showed that both the content and depth distribution of BC varies in the different soil types; the concentration of BC in the bulk top soils being closely related to the aromaticity of the SOM (r² = 0.98 for the native topsoils, 0.83 for top‐ and subsurface soils). Especially the Chernozems were rich in aromatic SOM, which partly contained more than 17% BC of total C, most of which being allocated in the mineral fractions. Long‐term arable cropping did not reduce the BC contents of the surface soil, though it did promote the enrichment of BC in the silt fractions. The same shift was detected as soil depth increased. We conclude that BC is not fully inert in these soils, but apparently can be preserved in the silt as decomposition of SOM increased, i.e., it accumulates exactly in that fraction, which has been formerly assigned to contain old, aromatic C.     

Accumulation soils like “Ockererde”—forgotten soil units in soil‐classification systems

Accumulation soils like those known as “Ockererde” are not yet represented in the German and in international soil‐classification systems, even though they represent important members of catenas found in humid low‐mountain areas influenced by the translocation of interpedon matter. Currently, this soil is referred to as “(Hang‐)Oxigley”, though this does not take into account its water and matter dynamics. Six representative catenas in the Black Forest (SW Germany) will be used to describe the occurrence, extent, and properties of the accumulation‐affected “Ockererde” derived from a variety of parent materials at specific altitudes. On the basis of their morphological, chemical, and physical properties as well as matter dynamics, it is possible to distinguish “Ockererde” clearly from soil units with similar characteristics (“Lockerbraunerde”, Andosols). Finally, suggestions will be given for the classification of “Ockererde”.     

Soil mapping for land‐use planning in a karst area of N Thailand with due consideration of local knowledge

For the development of sustainable land‐management systems in the highlands of N Thailand, detailed knowledge about soil distribution and soil properties is a prerequisite. Yet to date, there are hardly any detailed soil maps available on a watershed scale. In this study, soil maps on watershed level were evaluated with regard to their suitability for agricultural land‐use planning. In addition to common scientific methods (as underlying the WRB classification), participatory methods were used to exploit local knowledge about soils and to document it in a “Local Soil Map”. Where the WRB classification identified eight soil units, the farmers distinguished only five on the basis of soil color and “hardness”. The “Local Soil Map” shows little resemblance with the detailed, patchy pattern of the WRB‐based soil map. On the contrary, the “Local Soil Map” is fairly similar to the petrographic map suggesting that soil color is directly related to parent material. The farmers' perception about soil fertility and soil suitability for cropping could be confirmed by analytical data. We conclude that integrating local soil knowledge, petrographic information, and knowledge of local cropping practices allows for a rapid compilation of information for land‐evaluation purposes at watershed level. It is the most efficient way to build a base for regional land‐use planning.     

A classification scheme for earthworm populations (Lumbricidae) in cultivated agricultural soils in Brandenburg,Germany

Earthworm activity is observed at long‐term monitoring sites as an indicator of soil function to assess changes resulting from environmental and management conditions. In order to assess changes, characteristic values of earthworm populations under different site conditions have to be known. Therefore, a classification scheme for site‐specific earthworm populations was developed for soil in agricultural use, taking interactions between earthworm populations and soil properties into account. Characteristics of sites grouped by means of a cluster analysis after principal‐component analysis served as a basis for the derivation of the classification scheme. Soil variables found to characterize site differences with respect to earthworm populations were the texture of the topsoil, the texture of the subsoil, and the soil organic‐matter (SOM) content. The textural classes of the topsoil were divided into five groups comprising sandy soils (Ss), silty sand soils (Su), slightly loamy sand soils (Sl2), medium to strongly loamy sand soils (Sl3/Sl4), and loam and clay soils. Soil organic matter was divided into grades of equal size in a range from <1%, 1%–2% up to >6%. The variables “earthworm abundance” and “earthworm species” were selected to represent earthworm populations and were divided into six groups ranging from very low to extremely high. Defined groups of earthworm populations showed a clear structure in relation to soil textural groups and the content of SOM. From this distribution, a classification scheme was derived as basis for prognostic values of site‐specific earthworm populations, thus enabling the interpretation of changes over time. For some soil textural groups, selected variables appeared to enable the derivations of expected earthworm densities and species composition outside the range of the given database, but for some soil textural groups, broader databases will be needed to specify these derivations.     

Bodengefüge gegen Verdichtungen schützen – Lösungsansätze für den Schutz landwirtschaftlich genutzter Böden

Protecting soil structure against compaction—proposed solutions to safeguard agricultural soils To safeguard the ecological soil functions and the functions linked to human activities, measures against harmful changes to the soil are required, in line with the precautionary principle. The German Federal Soil Protection Act sets obligations for precaution in agricultural land use and, if harmful changes to the soil are foreseeable, measures for averting a danger. The results of a research project of the Federal Environmental Agency show that it is possible to describe an impairment of the soil structure, using methods of soil analysis. But this as a sole information would not qualify for the identification of harmful changes to the soil in the context of the Soil Protection Act, which requires an assessment of the severity of disruption of soil functions and the respective subject of protection. This would make additional soil investigations on site mandatory. Approaches in agricultural engineering and soil physics have introduced procedures to preserve the soil structure, in accordance with the precautionary principle. But these procedures have different goals and different ranges of application and hence offer partial solutions to safeguard against soil compaction. The assessment model of “trafficability by measuring the rut depth” provides information about the compaction status of the soil under applied conditions for farming gear, without providing detailed information about affected soil layers. The soil‐physical model of classifying soils into “risk classes for harmful soil compaction” focuses on the relationship between topsoil compaction and crop yields. The soil‐physical models “precompression stress” and “loading ratio” provide information for the assessment of subsoil compaction and a prognosis of a possible impairment of the soil structure at the water content of field capacity. It is necessary to validate the individual models with additional regional data about soil structure before a final assessment of the prognoses is made.     

Clay soils on limestone in South Limburg,The Netherlands, 1. Setting and general characteristics

Detailed soil mapping in the Ransdalerveld area pointed to the occurrence of clay soils of different ages, characteristics and genesis. Three representative soil profiles were therefore selected and studied in detail.In this first of three articles, some observations and conclusions on the distribution, age and characteristics of these soils are presented. The “old” soils, developed on the plateaus in predominantly limestone-weathering residues, are classified as Lithic Hapludalfs, whereas the “young” soils on the valley slopes are classified as Rendollic Eutrochrepts if they lack a loess cover and as Typic Hapludalfs if they have a loess cover. Weathering and soil formation are discussed in the second and third parts.     

Soil organic carbon and its sorptive preservation in central Germany

Soils are increasingly viewed as a potential sink for atmospheric carbon. However, their use to meet CO₂ emission reductions is problematic for there are knowledge gaps regarding the mechanisms involved in the sequestration of organic carbon (OC). There is evidence which suggests that OC concentrations are controlled by the mineralogy and related specific surface area (SSA) of a given soil. The goal of this study was to examine the importance of sorptive mechanisms on OC stabilization. The objectives were (i) to determine the SSA, clay mineralogy and dithionite‐ and oxalate‐extractable Fe and Al concentrations of several soils, and (ii) to analyse how these variables are related to OC concentrations. Five soils were sampled and analysed: two Umbrisols, a Stagnic Acrisol, an Anthrosol/Vertisol/Gleysol‐Chernozem and a Gleysol (FAO terminology), all located in Hesse, Germany. Oxalate‐extractable Fe and Al were found to be the best predictors of OC concentrations in the soils examined. Specific surface area correlated significantly with the OC content of the B and C horizons of one Umbrisol and the entire profile of the Anthrosol/Vertisol/Gleysol‐Chernozem. The relationship between SSA and OC concentrations is likely to be restricted to certain soils and might be a product of the sorptive capacity of Fe and Al oxides. We can assume that the available mineral surface area on oxides is a limiting factor in terms of a soil's capacity to sequester organic carbon. As such, attention should be paid to soil mineralogy and how this might limit the use of soils as a sink for atmospheric CO₂.     

Zur Genese von Schwarzerden auf der Sontheimer Hochterrasse in der Donauniederung bei Ulm

Pedogenesis of chernozems in the upper river terrace of the Danubian river near Ulm (South West Germany) The “chernozem-like” soils in the upper river terrace of the Danubian river near Ulm (FRG) were examinated. Field analyses as well as soil physical and chemical, clay mineralogical and pollen analyses were carried out. The parent material of the soils was identified as loess, on the basis of its texture, clay mineral composition, structure, carbonate content, the presence of loess molluscs, and the location on an upper river terrace with loess findings in the surrounding. Characteristic pedogenetic processes, such as deliming, silicate weathering, formation of oxides and hydroxides, neoformation of clay minerals and clay translocation prove a non-groundwater-influenced development of the soils within at least the last 8000 years. Therefore an accumulation of organic matter under anaerobic conditions during the peat formation in the lower river terrace nearby was not possible. According to this finding, it can be deducted that the humus accumulation may be due to influences of continental climate and forest steppe during the preboreal period, whereby the humus horizons were formed at deeper horizons through bioturbation. After the groundwater level was raised in boreal age, the steppe stage of the soils had ended and the fluctuating levels of groundwater, rich in carbonates, stabilized humic substances. Thus strong degradation of the soils to date was prevented. Therefore the soils under study could be classified as gleyic Chernozems or luvic Phaeozems.     

Classification of anthrosols with vitric/andic properties derived from lignite ash

To test the applicability of the Soil Reference Base of Soil Resources (ISSS/ISRIC/FAO, 1998. World Reference Base for Soil Resources, World Soil Resources Report 84, FAO, Rome) for soils derived from anthropogenic substrates, soils developed on lignite ashes in Germany which have some similarities with andosols were compared with natural volcanic soils from different countries. Soil parameters used for comparison were bulk density, clay content, Al_o+0.5 Fe_o, and P-retention, as they serve as diagnostic criteria to define either vitric or andic horizons. For Al_o+0.5 Fe_o, and P-retention, there was no statistically significant difference between both soil groups, the bulk densities of the lignite ash-derived soils were even significantly lower than those of the natural volcanic soils. Moreover, pH, total organic carbon, cation exchange capacity as well as the contents of carbonates and gypsum were collated and differences emerged between both soil groups concerning the contents of carbonates, gypsum and total organic carbon. In case of the lignite ash-derived soils, these parameters as well as the contents of oxalate soluble oxides were strongly influenced by the composition of the anthropogenic parent material. Up to now, such soil materials are not included as soil-forming materials in the World Reference Base for Soil Resources. We therefore suggested the introduction of a new diagnostic soil material, the so-called technogenic soil material into the anthropogeomorphic soil materials and to introduce “technogenic anthrosols” as a new reference subunit. In our proposition, technogenic materials are defined as anthropogeomorphic materials which are formed by technical processes including a distinct degree of transformation and/or new formation of soil-forming materials. Soil materials are categorised as “technogenic” when they consist of more than 70% (by volume) of soil material derived from technical processes like, e.g. combustion products of fossil energy sources, sewage sludges, blast furnace slags, etc.To include as much information as possible into the name of a soil, we developed a concept of reference soil series for the WRB combining pedogenetic and lithogenic information. Within this concept, these soils should be considered to be a subunit of anthrosols (vitri- or andi-technogenic anthrosols) and the specific properties of the soil-forming material (coaly, calcaric, gypsiric) should be given as additional information as Reference Soil Series as well as texture and kind of parent material.     

Andosols and soils with andic properties in the German soil taxonomy

The presence of soils with andic properties on German territory has been suspected for decades and there are numerous reports of sites where they may potentially occur. Andic properties, however, are not adequately represented by the German soil‐classification system. The German taxonomic category “Lockerbraunerde” has not been revised or reconciled with international taxonomic categories since the year 1957, when it was initially proposed. With this review, we show that there are true Andosols of both the silandic (allophane‐containing) and the aluandic (Al‐Humus‐dominated) type in Germany and that their properties differ substantially from other soils which merely exhibit low bulk density. By (1) comparing soil carbon storage between some German Andosols, Chernozems, and nonandic Cambisols with particularly low bulk density and (2) elucidation of the differential pedogenetic pathways leading to Andosol formation, we further demonstrate that Andosols are important objects of study in research issues of contemporary interest. We propose that appropriate measures be taken to lay the foundations for the protection and conservation of these soils, because they are valuable as archives of natural history and provide opportunities to study unique soil processes.     

Analysis and simulation of soil organic‐carbon stocks in grassland ecosystems in SW Germany

Grassland extensification is followed by a change of soil organic‐matter (SOM) contents. In order to give a better assessment of these developments on grassland sites in SW Germany, the CENTURY Soil Organic Matter Model was used on five long‐term experimental sites under three different management practices (“Mowing”, “Mulching” (mowing without removal of the phytomass), and “Natural succession”). On these sites, soil‐organic‐carbon (SOC) monitoring was continuously done for soil depths of 0–4 and 4–8 cm from 1975 to 2002. The contents of organic carbon (OC) were at steady state or showed a slight decrease for the mulched and succession plots. Carbon contents of the mowed plots were decreasing. Measured C contents were transferred into stocks and compared with the simulated OC stocks. Linear regressions between observed and simulated C stocks were calculated separately for mulched and succession plots. The regressions for OC yielded significant relationships (R² = 0.8) for both kinds of plots. However, the model did not reproduce the short‐term dynamics of C stocks. Whereas SOC stocks on mulched and succession plots are expected to stay stable for the next decades according to the simulation, they are expected to decrease for a couple of years before stabilization on mowed plots.     

Roughness of biopores and cracks in Bt‐horizons assessed by confocal laser scanning microscopy

In structured soils, water and reactive solutes can preferentially move through larger inter‐aggregate pores, cracks, and biopores. The surface roughness of such macropores is crucial for describing microbial habitats and the exchange of water and solutes between macropores and the soil matrix together with other properties. The objective of this study was to compare the roughness of intact structural surfaces from the Bt‐horizons of five Luvisols developed on loess and glacial till and to test the applicability of confocal laser scanning microscopy. Samples of 5 to 10 cm edge length with intact structural surfaces including cracks with and without clay‐organic coatings, earthworm burrow walls, and root channels were prepared manually. The surface roughness of these structures was determined with a confocal laser scanning microscope of the type Keyence VK‐X100K. The root‐mean‐squared roughness (R_q) the curvature (R_cu) and the ratio between surface area and base area (R_A) were calculated from selected surface regions of interest of 0.342 mm² with an elevation resolution of 0.02 µm. The roughness was smaller for coated as compared to uncoated cracks and earthworm burrows of the Bt‐horizons. This reduction of roughness by the illuviation of clayey material was similar for the structural surfaces of the coarser textured till‐Bt and the finer‐textured loess‐Bt. This similarity suggested a dominant effect of pedogenesis and a minor effect of the parent material on the roughness levels of structural surfaces in the Bt‐horizons. An expected “smoothing” effect of burrow wall surfaces by earthworm activity was not reflected in the roughness values compared to those of uncoated cracks at the chosen spatial scale. However, for root channel walls from one loess‐Bt, the roughness was reduced as compared to that of other structures. These results suggest that the surface roughness of the structural surface types should separately be considered when describing preferential flow and macropore‐matrix exchange or analysing root growth, microbial habitats, and colloidal transport in structured soils. The confocal laser scanning microscopy technique was found useful for characterizing the roughness of intact structural surfaces.     

Erodibilität repräsentativer Böden der Hallertau

Erodibility of representative soils of the Hallertau (South Bavaria) Differences between the USA and the Federal Republic of Germany in geology, soil types, and climate necessitate to verify the erodibility of the soils estimated according to Wischmeier and Smith (1978), when using the Universal Soil Loss Equation under local conditions. The erodibility of 5 representative soils of the region Hallertau within the so-called “Unterbayerisches Hügelland” was checked by measuring soil losses using a laboratory rainfall simulator. The estimated and measured erodibilities for two Aquic Hapludalfs from loess and one Ruptic-Alfic Eutrochrept from Tertiary sand compared very well as shown by coefficients of regression of 1. The estimated erodibilities for a Typic Eutrochrept and an Aquic Chromudert, both from Tertiary materials, however, underestimated the soil losses by a factor of 1.5. For all regressions the coefficients of correlation were 0.90. Due to the small number of soils checked, it is only possible to suggest causes for the observed deviations, particularly since the aggregate stability could not be the only property, as demonstrated by measurements.     

Effect of artificial soil compaction in landfill capping systems on anisotropy of air‐permeability

Soil air permeability is an important parameter which governs the aeration in soils that significantly promotes the root growth of field and grassland species and leads, in turn, to higher levels of evapotranspiration. The German Landfill Directive (2009) requires a rigid or a minimal shrinking capping system that ensures a high evapotranspiration rate to decrease the infiltration rate through the underlying waste body and therefore the leachate generation. This research is focussed on the questions if compacted glacial till can ensure the required rigidity and if and how air permeability is affected by soil compaction. The objective was to compare air‐filled porosity and the direction‐dependency of air permeability of a capping soil when assuming rigid and non‐rigid conditions considering a shrinkage factor. Intact soil cores were sampled in vertical and horizontal direction in 0.05, 0.2, 0.5, and 0.8 m depths at two profiles of a mineral landfill capping system at the Rastorf landfill in Northern Germany. Desiccation experiments were carried out on differently‐compacted soils and soil shrinkage was measured with a 3D laser triangulation device, while the air permeability was estimated with an air flow meter. The results indicate that the “engineered” soil structure which was predominately platy due to a layered installation, led to a more anisotropic behaviour and therefore to higher air permeability in horizontal than in vertical direction. The compacted installation of the capping system seems to be effective and observes the statutory required more‐or‐less rigid system, otherwise, soil shrinkage would lead to vertical cracks and a more pronounced isotropic behaviour.     

Spatial variation of tracer distribution in a structured clay field soil

Within the sensitive soils of the River Oder Basin (E Brandenburg, Germany), chloride‐tracer transport was studied with respect to soil‐surface conditions of the well structured clayey topsoil (disturbed vs. undisturbed) and irrigation mode (flooding vs. sprinkling). The spatial variation of chloride and dye distribution was sampled in a regular grid within different soil depths. Different methods were used for the analysis of spatial heterogeneity: a heterogeneity index HI derived from fitting parameters of the cumulative distribution function, semivariogram analyses to identify the spatial representativity of observations and to classify the spatial variation, and Spearman's rank correlations to examine the spatial similarity of tracer distribution across different soil depths. Soil aggregation was obvious throughout the soil profile, and macropores and fractures were preferred flow paths for the tracer. Flood irrigation resulted in more “uniform” distribution than sprinkling did. However, preferential flow was identified for all treatments, where, once established below the surface layer, flow paths led to heterogeneity indices manifesting nonuniform flow and reduced lateral mixing between macropores and soil matrix. Within the flooded plot, spatial structure of chloride concentration was moderate unlike the strongly structured variation within the sprinkled plots. For purposes to generalize and to assess regional risk of the water and solute transport within the topsoil of the River Oder Basin, spatial autocorrelation ranges of about 15 cm should be considered and included into concepts of soil protection and land‐use management, soil‐sampling strategies, or modeling approaches.     

Podzol: Soil of the Year 2007. A review on its genesis,occurrence, and functions

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.