Zum Alter des Plaggeneschs

Der Plaggenesch entstand durch jahrhundertelange Düngung mit Plaggendung, der hauptsächlich aus Plaggen, d. h. flach abgehackten Heide- oder Grasstücken, und Stalldung bestand. Dadurch wurde der Ap-Horizont über dem ursprünglichen Bodentyp immer mächtiger bis zu 80 cm und mehr, und damit entstand der anthropogene Bodentyp „Plaggenesch". Entstehung, Aufbau, Eigenschaften und Verbreitung des Plaggeneschs werden beschrieben. Es wird geschildert, wie man das Alter, den Beginn der Plaggendüngung feststellen kann. Hinweise geben Ortsnamen, die Geschichte der Ackerkultur sowie Scherben und andere Funde. Eine direkte Altersbestimmung erlaubt die 14C-Methode, indessen ist sie mit Fehlern behaftet, da die organische Masse der Plaggenesche nicht einheitlich ist, d. h. ein verschiedenes Alter haben kann. Es wird daher nur ein Mittelwert erzielt. Unter Beachtung aller Fehlerquellen wird auf Grund der bisher gewonnenen 14C-Werte das Alter der Plaggenesche, d. h. der Beginn der Plaggendüngung, mit etwa 800—1200 Jahren angenommen. Dieses Alter stimmt mit den vorher auf anderem Weg gewonnenen Altersdatierungen einigermaßen überein.researc

The C:N:P:S stoichiometry of soil organic matter

The formation and turnover of soil organic matter (SOM) includes the biogeochemical processing of the macronutrient elements nitrogen (N), phosphorus (P) and sulphur (S), which alters their stoichiometric relationships to carbon (C) and to each other. We sought patterns among soil organic C, N, P and S in data for c. 2000 globally distributed soil samples, covering all soil horizons. For non-peat soils, strong negative correlations (p < 0.001) were found between N:C, P:C and S:C ratios and % organic carbon (OC), showing that SOM of soils with low OC concentrations (high in mineral matter) is rich in N, P and S. The results can be described approximately with a simple mixing model in which nutrient-poor SOM (NPSOM) has N:C, P:C and S:C ratios of 0.039, 0.0011 and 0.0054, while nutrient-rich SOM (NRSOM) has corresponding ratios of 0.12, 0.016 and 0.016, so that P is especially enriched in NRSOM compared to NPSOM. The trends hold across a range of ecosystems, for topsoils, including O horizons, and subsoils, and across different soil classes. The major exception is that tropical soils tend to have low P:C ratios especially at low N:C. We suggest that NRSOM comprises compounds selected by their strong adsorption to mineral matter. The stoichiometric patterns established here offer a new quantitative framework for SOM classification and characterisation, and provide important constraints to dynamic soil and ecosystem models of carbon turnover and nutrient dynamics

Hamburg University Radiocarbon Dates II

This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Movement of ions and colloids in undisturbed soil and parent rock material columns

Undisturbed columns of different soils (Great Soil Groups) are subjected to percolation with repeated definite volumes of water, and the eluted rates of cations and anions are detennined. The transportation of $^{14}$C-labelled humic acid, $^{55} Fe^{+++}$ and $^{55}$Fe-labelled montmorillonite, applied to the surface of the profile column, is checked by liquid-scintillation techniques. The results show the characteristic solubility rates and sequences of the different tested ions as wellas the fractions in the individual soil types. This allows the balances of annual losses to be correlated with precipitation levels. After termination of the experiments (three to four years), the soil columns are transformed into thin-section layers which, by stripping emulsion autoradiography, reveal the localization of the labe!ledsubstances within the dispersal system of the soil skeleton and plasma. To study the sequential order and quantitative relation of ion liberation in different parent rock materials, 0,5-5-m grain size particles are continuously percolated with distilled water in columns at 60° C. The recycling system allows the dissolved and collected eluted material (ions and colloids) to be analysed at constant intervals of 1 to 2 months. Diagenetic concretions from d uripan, fragipan, pseudogley, laterite, podsol and caliche are continuously leached in Soxhlet extractors and the dissolved substances analysed

Gesteinsverwitterung im Lichte bodengenetischer lnitialprozessein Modellversuchen 1. Mitteilung: Die Säulenextraktoren und ihre Anwendung

For the extraction of stone-, soil-, organic matter- and other natural and chemical materials column extractors are developed and their use is described. The column extractor is offered in two types: one with underneath closed and one with underneath open column body. The latter is especially suitable for the extraction of undissturbed bore cores (soil cores a. o.). It allows to take intermediate samples at the bottom of the prof ile end during the research process. The column extractor with the open column body is composedof the following 5 parts: the cooling coil, the head cover with attached distributor of refluxed water, the column body, the bottom cover with loose but tightly fitting filter frit and the storage vessel for the elution liquid and the received extracts. The column body consists of a double walled glass tube with extraction space in the inner tube and heating or cooling jacket between the glass tubes. The working process is as follows: From the storage vessel, embedded in an electric heating mushroom, water vapour rises through a silicon tube into the cooling coil on top of the column extractor. After condensing the cooled extractant drops through the distributor on the extraction material which fills the column core in a cylinder of 1 m high and 10 cm diameter. It percolates through the test material, takes up the soluble constituents, and leaches together with these through the filter frit of the bottom cover out of the extractor into the storage vessel. From here the extractant vaporizes again maintaining a permanent recyling process. To speed up the processand enhance the yield of solute in the percolate, the column is heated by thermostatically controlled water flow between the two glass tubes. The extract can periodically be taken out of the storage vessel for further analysis, e.g. once a month. The control of theyield of the vaporizing extractant and the yield of the feed back of percolate is geared by a weighing device with electric contacts for cloosing and interrupting the heating circuit. As the column extractor is a closed system, it is useful for extraction work under application of radioactiv tracers

Studies on tagged clay migration due to water movement

$^{55}$ Fe-tagged clay minerals, produced by hydrothermal synthesis, serve to clarify the question whether clay migration or clay formation in situ is the predominating mechanism in the B$_{t}$ development of Parabraunerde (sol brun lessivé, grey brown podsolic, hapludalf, demopodsol). They further indicate the possibilities of clay transportation caused by water percolation. Suitable experimental approaches, such as thin-layer chromatography and autoradiography,translocation tests in columns filled with monotypical textural fractions or with undisturbed soil profiles, and synchronous hydrothermal treatment of $^{55}$Fe-containing material from different horizons of Parabraunerde, to reveal the specific readiness of the different profile zones for $^{55}$Fe-clay production, are described. The possibilities of clay percolation are discussed

University of Bonn Natural Radiocarbon Measurements VI

This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

University of Bonn Natural Radiocarbon Measurements IV

This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Untersuchungen lateritischer Böden 1 : Chemische und physikalische Untersuchungen

Lateritic profiles and plinthite samples from lndia, Ceylon, Congo, the Philippines, Portugal and Sierra Leone have been examined with chemical and physical methods. The results have more especially been interpreted in view of pedodynamic and pedogenetic processes

University of Bonn Natural Radiocarbon Measurements VII

This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202