Schätzrahmen für die effektive Durchwurzelungstiefe mehrschichtiger Böden

Estimating the effective rooting depth of layered soils The values of the effective rooting depth given by the Soil Mapping Instruction are valid only for homogenous soils. In addition to these values a calculation is presented estimating the effective rooting depth of layered soils. This method is proposed as a reference method in databases of soil information systems.     

Die Bedeutung von hohen Aluminiumgehalten für die Humusanreicherung in sauren Waldböden

The role of aluminium on humus accumulation in acid forest soils The impact of soil-borne aluminum on humus accumulation was investigated in a forest soil of the chestnut zone (Castanea sativa) in southern Switzerland (Ticino). Soil samples of two soils formed on bedrocks which differ mainly in their aluminum content were extracted with HNO₃, NH₄Ac.-EDTA, NH₄Cl, KCl, and NH₄F-HCl and analyzed for the most abundant elements. On gneiss which contains up to about 10% of total aluminum the common soil type in this area is a Cryptopodzol. This soil is similar to the nonallophanic Udands. It is rich in wellhumified organic matter and shows dark-colored A_h-, A(E)- and B_h-horizons. The soil samples of these horizons are extremely rich in nonexchangeable aluminum which is, however, extractable with NH₄Ac.-EDTA. It is assumed that this Al is intimately bound to the organic matter. The soil samples of these horizons contain large amounts of HNO₃-extractable phosphorus. Up to 90% of this P appears in the organic fraction. The content of NH₄F-HCl-extractable P is only 0.7 to 3.4 mg/kg. It is concluded that due to excessive Al in the organic matter the humus mineralization is inhibited compared to the Haplumbrepts of the region.     

Regenwürmer als Bioindikatoren für Schwermetallbelastungen von Böden unter Freilandbedingungen

The use of earthworms in monitoring soil pollution by heavy metals Total heavy metal contents (HNO₃-soluble) and exchangeable fractions (Ca(NO₃)₂-soluble) of Pb, Zn and Cd were measured in soils, litter layers and earthworms (dry masses) from forest, arable and pasture sites in a transect of the main wind direction and varying distances (1.5, 5.4, 11.4, 15.6 km) to a lead smelter near Bad Ems, Germany. Additionally, cast materials of Lumbricus terrestris-individuals were collected from the surface of the pasture sites. In the observed area total soil contents of Pb and Cd exceeded the C-level and total contents of Zn the B-level of the “Netherland-list”. Heavy metal contents in soils and earthworms decreased with increasing distance to the smelter. Pb showed the best correlation. Correlation between total contents of Pb and Cd in soils and earthworms were significant (rs = 0.66; p < 0.05 and rs = 0.67; p < 0.01, respectively). The uptake of heavy metals by Lumbricus rubellus, L. terrestris and Aporrectodea caliginosa was metal specific rather than species specific with factors of accumulation being <1 (Pb), 2.7–7.6 (Zn) and 19.5–85.5 (Cd). The heavy metal contents of the observed cast materials signified the different transfer of elements from soil material via earthworm individuals to the faeces. In the cast materials the amounts of Pb were high and the amounts of Zn and Cd were low. This indicates a high accumulation rate for Zn and especially for Cd in the tissues of the observed earthworm individuals. The present data support the necessity of ecotoxicological threshold levels.     

Zur Bestimmung von Gips in Böden

On the determination of gypsum in soils The (020) X-ray reflection of gypsum at 7,56 Å is nearly specific and may be used for detection and quantitative measurement of the mineral in soil samples. By X-ray powder diffractometry gypsum can be detected as far down as 0,5% by weight. This limit may be extended down to 0,005% by concentration in the density fraction 2,1–2,5 g/cm³. For quantitative measurements references may be prepared from sample parts by dehydration of the original gypsum and adding known quantities of this mineral. So it is possible to compare samples of nearly identical grain size distribution, and mineral contents. This is important in the powder-diffractometrical quantitative measurement of a mineral with low hardness and good cleavage where mechanical stress during homogenisation lowers the intensities of X-ray reflections. Under comparable conditions for sample and reference, gypsum contents can be determined in the range of 0,5 to 20% by weight with an accuracy of ± 3% (relative).     

Zur Pedogenese und Klassifikation von Marschböden des Unterweserraumes. II. Die Bedeutung von Schwefelmetabolismus,Methanproduktion und Ca/Mg-Verhältnis für die Marschen-Klassifikation

Development and Classification of Marsh Soils from the Unterweser Region, West Germany. II. Importance of Sulfur Metabolism, Methane Production and Ca/Mg Ratio for Classifying Marsh Soils The importance of sulfur metabolism in each step of marsh soil development (Brümmer, 1968) is also confirmed for the marsh soils of the Unterweser region. Sulfur contents and sulfur fractions indicate that soil development has advanced further in brackish marshes than in marine and river marshes. The results give additional evidence that the various properties of marsh soils are only partly caused by sedimentation conditions. – The sedimentation areas (Müller, 1954) apply only to small regions. Thus, methane production predominates in the freshwater area, while sulfate reduction predominates in the marine area. Both processes occur at high rates in the brackish area. Classifying soils on the basis of the Ca/Mg ratio gives the same soil groups as Brümmers classification. Consequently, classifying the marsh soils of Niedersachsen on the basis of Ca/Mg ratio is a suitable method, if the idea that sedimentation conditions cause soil properties – especially the contents of exchangeable Ca and Mg – and the present designations of the soil groups are rejected.     

Die Bedeutung der nicht austauschbaren Kaliumfraktion des Bodens für die Ertragsbildung von Weidelgras

Effect of the non exchangeable soil K fraction on the yield production of rye-grass 1. In pot experiments with rye-grass the question has been studied whether the K released from the non exchangeable soil K fraction will suffice to produce high crop yields. The soil used was a K rich clay soil (2.5 %total K, 1.9 % HCI soluble K) having a content of exchangeable K+ of 500ppm at the beginning of the experiment (K, treatment). In a 2 d treatment (K,) the level of exchangeable K was raised to 1140 ppm by fertilizer K application. According to the principle of “permanent cropping” rye grass was cultivated in both treatments which produced 11 cuts during the experimental period of two years. 2. The amount of K absorbed from the non exchangeable soil K fraction was higher in the K, treatment than in the treatment which received fertilizer K. The rate of K uptake from the non exchangeable soil K fraction increased with the depletion of exchangeable soil K. 3. The rate of decrease in exchangeable soil K became low as soon as the content of 4. No clear relationship between crop yield and K application has been found for the first 7 cuts of rye-grass. The 8th cut yielded a highly significant yield increase in the treatment with K application. The differences in yield between both treatments increased with the following cuts. The level of exchangeable soil K at which at first the significant yield depression in the K, treatment occured was 280ppm. Below this level the release rate of non exchangeable soil K was not high enough to meet the K demand of the crop. 5. In an additional experimental series with a more dry soil (50% of the max. water capacity) lower yields were obtained in the K, treatment as compared with the treatment which received fertilizer K. K uptake, in particular from the non exchangeable soil K fraction, was impaired by the dry soil medium.     

Die Bedeutung des Strohgehaltes für die Erhaltung des Stickstoffs während der Kompostierung von Rindermist

The significance of straw content for the rentention of nitrogen during the composting of cattle manure A mixture of cattle manure (low in straw content) and straw were held at room temperature in perforated cubic containers for a 5 month's composting period. The influence of the availability of carbon on the formation of organically bound nitrogen was examined. For this purpose the added straw was reduced in size to varying degrees. The prepared mixtures all contained the same C/N-ratio. Nutrient losses in liquid form could be avoided by careful addition of water. During the first 6 weeks the content of organically bound nitrogen increased, in the sequence of increasing proportions of milled straw, from 6 to 23 %. This was attributed to the increased availability of carbon. At the end of the experiment the content of organically bound nitrogen, in all mixtures, decreased again to the initial level. This was attributed to an extensive mineralisation into nitrate in the mixtures with straw chaff. It is assumed that the low nitrate content of the variant containing only powdered straw is caused by temporary anaerobic conditions, which may be have induced a denitrification.     

Protonenpuffersubstanzen in Böden

Proton buffer compounds in soils A classification of solid soil buffer substances according to the type of proton accepting sites, viz. carbonate buffer, variable charge buffer, silicate buffer and hydroxide buffer is proposed. The buffer reactions are discussed in some detail and so are formation and transformation processes of buffer. An association of pH-ranges to various buffer compounds is hampered by an insufficient knowledge of the acid strength of the different functional groups.     

Bedeutung der Mikroorganismen für die Bildung von Aggregaten im Boden

Significance of microorganisms in aggregate formation In soils microorganisms are the biological link between the physicochemical processes of synthesis and degradation. Because of their metabolic activities and their mechanical binding capacities they are directly involved in the development of soil structure. This review attempts to summarize knowledge of experimental work concerning aggregate formation by microorganisms. Especially distribution, adhesion processes, significance of biopolymers in aggregate formation and destabilization will be covered. The current state of art and open research areas will be indicated.     

Anthropogener Asbest in Böden

Anthropogenic Asbestos in Soils Fibers of different asbestos types as well as other fibrous minerals, e.g. zeolites, have been found as natural contamination of soils or quarries in numerous countries and regions. Epidemiological studies have shown that inhabitants of these regions have high incidence of calcified pleural plaques and malignant pleural mesotheliomas. Anthropogenic contamination of soils by asbestos as well as asbestos contamination of the soil-near air layer were measured in this study. Soils were contaminated with chrysotile and amphibole asbestos during and after industrial asbestos processing. Asbestos fiber contaminations in the range of 10⁶ to 10¹¹ fibers/g soil and fiber concentrations as high as 5 × 10⁵ fiber/m³ air were measured. Soil contamination by anthropogenic asbestos can produce high or very high contamination of water and of ambient air by very fine fibers and entail carcinogenic risk for the general population, mainly for the inhabitants in the neighbourhood.     

Zur Bestimmung der Kationenaustauschkapazität von Böden mittels Barium

Regarding the Determination of Cation Exchange Capacity of Soils with Barium Very often the cation exchange capacity (CEC) of soils is determined using Ba⁺⁺ as exchange cation. In soils with high contents of organic matter, Ba⁺⁺ cannot be desorbed completely by Mg⁺⁺ or H⁺ but by Ca⁺⁺. Soils containing vermiculite adsorb Ba⁺⁺ in non exchangeable form. The fixed Barium can only be determined by total digestion. Therefore in soils containing vermiculite the exchange with Ba⁺⁺ leads to an underestimation of the CEC.     

Schutzwürdige Böden in Nordrhein-Westfalen — Bodenkundliche Kriterien für eine flächendeckende Karte zum Bodenschutz

Valuable soils in Northrhine-Westphalia — soil scientific criteria for generating a complete map for soil protection At the Geological Survey of Northrhine-Westphalia a map was developed: Soils to be protected in Northrhine-Westphalia at a scale of 1:50.000. It is based on the Soil map of Northrhine-Westphalia at a scale of 1:50.000. This map indicates areas where such land uses should get high priority which need, save and develop the identified main soil functions. There are three groups of land use with main soil functions:

• natural habitat with high potential of biotope evolution
• agricultural production on soils with (regionally) high fertility
• regional specifica, including soils as archives of natural and cultural history.

Land uses disregarding or lowering these soil functions have to be placed otherwhere or have to be compensated by areas with comparable functions. The criteria generating this map are given and discussed. The evaluation of information coming from the digital soil map runs soil protection under the aim of securing the kind and state of soil substrate and characteristics, giving the functionality of soils in favor of other media of the environment.     

Die Bedeutung der Festigkeitsverteilung in Einzelaggregaten für den Wasser- und Stofftransport im Boden

Relevance of strength distribution within aggregates to the movement of soil water and soil solution Different transport processes exist not only between the total soil and single aggregates, but also within individual aggregates. To clarify the structure of single aggregates without thin-sectioning, resistance to penetration was repeatedly measured on the same aggregate at a predefined soil water tension. The aggregates were sampled from the G_{o 2} horizon of a Typic Fluvaquent (Φ 15-25mm) and from the B_{g 2} horizon of an Aquic Chromudert (Φ 30-50mm) and equilibrated with water tensions ranging from roughly OhPa to 1000hPa. The strength distributions within individual aggregates were calculated using penetration resistance values of all measurements on one aggregate at a single water tension. These distributions, as exemplified by those at 300hPa and 1000hPa. show that the aggregates are surrounded by a thin, but very strong mineral skin which may be discontinuous, especially for aggregates from the Aquic Chromudert soil. In these aggregates, slickenside-like friction planes were found to penetrate through the skin. The deviation in the skin composition from that of the inner-aggregate described in literature, together with the finding of its strength, suggest that the exchange of water and solutes between the inter-aggregate and intra-aggregate pores is strongly impeded. The weaker parts within the skin, however, must be interpreted as preferred pathways, perhaps resulting in some fingering within aggregates at the prevailing matrix potential. The significance of different pathways within aggregates for the general transport of matter in soils is briefly discussed.     

Einfluß polychlorierter Biphenyle auf die mikrobielle Aktivität in Böden

Effects of polychlorinated biphenyls on soil microbial activity In laboratory experiments the microbial toxicity of the PCB congeners 5 (2, 3-Dichlorobiphenyl), 8 (2, 4′-Dichlorobiphenyl), 29 (2. 4, 5-Trichlorobiphenyl) and 77 (3, 3′, 4, 4′-Tetrachlorobiphenyl) which is supposed to be extremely toxic to wildlife was investigated using Parabrownearth-Ap and Podsol-Ahe horizon material. In addition the technical PCB mixtures Arochlor 1242 and 1260 were tested. Microbial toxicity was measured by means of long-term respiration (CO₂-evolution), short-term respiration (CO₂-evolution 12 h, after addition of glucose), and dehydrogenase activity (TTC reduction) tests. 1 mg/kg of the Dichlorobiphenyls 5 and 8 reduced the long-term and short-term respiration of the Podsol-Ahe during the whole experiment (35 and 28 days, respectively). The Trichlorobiphenyl 29 became effective after addition of 10 mg/kg. No effect except a short stimulation of long-term respiration was observed for PCB 77 (Tetrachloro-PCB). Due to its higher sorption capacity, all PCB congeners reduced the microbial activity of the Parabrownearth-Ap to a lower degree. In general the toxicity of PCBs decreased with increasing degree of chlorination in both soil horizons. The technical mixtures reduced the long-term respiration only after high additions of 50 mg/kg (Podsol-Ahe) and 100 mg/kg (Parabrownearth-Ap), respectively. Arochlor 1242 proved to be more toxic than Arochlor 1260.     

Schwermetallverteilung und Tongehalte in Böden

Heavy metal distribution and clay contents in soils . In soil profiles differing considerably in horizon pattern and parent material the contents of Mn, Zn, Cu and Co were correlated with those of clay (and CEC), of total Fe (and dithionite soluble Fe) and - after relation to clay - with C. The correlations with clay, CEC, Fe_t and Fe_d were in all cases positive and highly significant, though differing between the different metals and between the references. Deviations for all elements are due to lithogenic differences in soils from mesozoic sediments and for Mn also due to its lower pedogenic stability. The correlations with C were not significant, since O horizons were not yet investigated. The ‘mobility’ of the heavy metals ( = EDTA + NH₄O Ac-extractable in relation to total amount) in topsoils could be more correlated (negative) with the reserves than with other soil features. Relating the ‘immobile’ heavy metal contents to the other soil features considerably improved the correlations.