bluuebunny/crossref_metadata_2025 huggingface dataset:
Dissolution and plant uptake of P from Ca phosphates with varying particle size in two soils I. Dissolution studies
Authors: Metwally A. I. , Omar M. , El‐Baz S.
Published: February 2007

Auflösung von Ca‐Phosphaten und P‐Aufnahme durch die Pflanze in zwei Böden bei unterschiedlicher Körnung dieser P‐Quellen. I. Auflösung der Ca‐Phosphate

In einem Alluvial‐ und einem Kalkboden wurde in Laborversuchen mit Hilfe von drei markierten Ca‐Phosphaten (MCP, DCPD u. HA) der Einfluß der Wasserlöslichkeit und der Oberfläche auf die Stabilität dieser Verbindungen untersucht.

Mit abnehmender Teilchengröße von DCPD nahm der 32P‐Anteil im Boden, der mit 0.5 M KH2PO4 rücktauschbar war, relativ zu, während er bei HA sehr niedrig und nur wenig durch den Teilchendurchmesser beeinflußt war; bei MCP dagegen wurde der rücktauschbare Anteil höher mit zunehmender Größe des Düngerkorns. Zunehmende Bodenfeuchte und Temperatur steigerten das rücktauschbare 32P in allen Fällen, während es mit der Inkubationsdauer zwar bei DCPD erhöht, bei MCP jedoch gesenkt wurde. Nach 8 Wochen Inkubationszeit war zwischen pulverisiertem (« 0,18 mm) DCPD und MCP kaum mehr ein Unterschied zu bemerken. Im Kalkboden (stL, 0,9% org. S., 30,6% CaCO3, pH 8,5) war der rücktauschbare 32P‐Anteil bei allen P‐Quellen niedriger als im Alluvialboden (T, 1,2%org. S., 2,5% CaCO3, pH 7,8), weil hier pH‐Wert und CaCO3‐Gehalt tiefer lagen.

Offensichtlich wurde der Anteil an rücktauschbarem 32P aus DCPD und HA vor allem durch deren Lösungsrate, der aus MCP dagegen durch dessen Immobilisierungsrate kontrolliert.
Cationic environment and hydrophysical properties of tropical soils
Authors: Rengasamy P. , Krishna Murti G. S. R. , Kathavate Y. V.
Published: February 2007

Kationen‐Milieu und hydrophysikalische Eigenschaften tropischer Böden

Der Einfluß eines wechselnden Kationen‐Milieus auf hydrophysikalische Eigenschaften (Wasserbindungen, hydraulische Leitfähigkeit, kapillarer Aufstieg und Infiltrationsverhalten) einiger tropischer Böden Indiens wurde untersucht. In den schwarzen Böden herrschte Smektit vor, in den lateritischen Kaolinit, während in den roten und alluvialen Böden Smektit und Kaolinit in gleichen Anteilen vorhanden waren. Folgende Kationen wurden untersucht: Na+, K+, Ca++, Mg++. Die Ergebnisse werden nachstehend zusammengefaßt: 1. Die genannten hydrophysikalischen Eigenschaften hängen hauptsächlich vom Bodentyp und insbesondere vom vorherrschenden Tonmineral ab. 2. Zweiwertige Ionen erhöhen die hydraulische Leitfähigkeit, den kapillaren Anstieg und die Infiltrationsrate; einwertige Ionen dagegen verursachen eine beträchtliche Reduktion. 3. Exponentielle Beziehungen zwischen austauschbarem Na (ESP) oder austauschbarem K (EPP) und der zugehörigen hydraulischen Leitfähigkeit wurde erhalten. Diese Beziehungen variieren mit den Böden und ihrer Tonmineralausstattung. Für Na und K wurde für alle Böden aufgrund der ESP‐ und EPP‐Werte ein kritischer Grenzwert gefunden, an dem die hydraulische Leitfähigkeit auf die Hälfte ihres ursprünglichen Wertes vermindert ist.
Outlines of a computer simulation model on residual and added nitrogen changes and transport in soils
Authors: Hagin J. , Amberger A. , Kruh G. , Segall E.
Published: February 2007

Grundzüge eines Computersimulationsmodelles über die Veränderungen und den Transport von Boden‐ u. Düngerstickstoff

Es wurde ein Computermodell entwickelt über die Veränderungen und den Transport von Stickstoff in Böden. Der theoretische Hintergrund und die notwendigen Annahmen für die Aufstellung eines solchen Programmes werden dargelegt. Die Umsetzungen von org. Stickstoff in Ammonium bzw. Nitrat sowie die Denitrifikation von Nitrat werden dargestellt als eine Reaktionsgleichung ersten Grades. Die Reaktionskonstanten und einige Parameter werden aufgezeigt und die Einflußgrößen der Umweltfaktoren auf die Reaktionsraten beschrieben. Das gebildete oder zugegebene Nitrat bewegt sich durch das Bodenprofil und kann verlorengehen durch Auswaschung, Aufnahme von Pflanzen bzw. immobilisiert oder denitrifiziert werden.
Einfluß exogener und endogener Faktoren auf den Calciumgehalt von Paprika‐ und Bohnenfrüchten
Authors: Mix G. P. , Marschner H.
Published: February 2007

Effect of external and internal factors on the calcium content of paprika and bean fruits

In water culture experiments with paprika and bean plants the effect of Ca supply, transpiration and growth rate on the Ca content of the fruits has been studied.

A 10‐fold increase in Ca supply only slightly increased the Ca content. The Ca content of the paprika fruits was increased considerably at high transpiration rates of either the whole shoot or the single fruit. High transpiration also increased the Mg content but had no effect on the K content. In bean high transpiration rates only increased the Ca content in the early stages of fruit development.

The ratio of Ca translocation versus water loss by transpiration sharply declined during fruit growth in both species. In paprika the highest ratio (μg Ca/ml) in the fruits corresponded with the ratio in the leaves. In bean fruits, however, this ratio distinctly exceeded that of fully developed leaves.

At high transpiration rates of the shoot 20% of the Ca (45Ca) injected into the fruit were translocated out of the fruit. At low transpiration rates of the shoot the corresponding value was below 1%.

Most of all the growth rate of the fruits affected the Ca content. With increasing growth rate the Ca transport into the fruits was hardly altered which in turn led to a sharp decrease of the Ca content per unit dry weight.

The results support the idea of the Ca transport into the fruit via the xylem. This Ca transport — i.e. also the Ca content of the fruit — is regulated and is also to be influenced by direct or indirect alterations of the water transport in the xylem.
Ein Verfahren zur Bestimmung der Lagerungsdichte skelettreicher oder geringmächtiger Bodenhorizonte
Authors: Becher H. H. , Wilke B.‐M.
Published: February 2007

A method for bulk density determination of gravel rich or thin soil horizons

A limitation of bulk density determinations using the core sample method is that soil horizons must be thick enough for coring and nearly free of rock material. The significance of the proposed method lies in the fact that it is applicable also to soil samples rich in rock fragments and/or thin horizons. The samples are impregnated in the laboratory using an epoxy resin. Bulk density (ρb) is determined after hardening according to the following equation:magnified imageρf = density of soil material Bulk densities determined by the new method were found to agree well with such resulting from the core sample method.
Characteristics of organic matter extracted from some solonetzic soils
Authors: Arshad M. A.
Published: February 2007

Charakterisierung von aus solonetzartigen Böden extrahierter organischer Substanz

In einer Serie von solonetzartigen und geographisch ähnlichen Böden wurde die Frage der Zusammenhänge zwischen spezifischen Veränderungen in ihrer Zusammensetzung und ablaufenden pedogenen Prozessen untersucht. Im allgemeinen hatten Calciumhumate den höchsten Anteil in allen Profilen, während Huminsäuren, die an Eisen‐ und Aluminiumoxide gebunden waren, den nächsthohen Anteil hatten. Freie Fulvosäuren hatten in den am stärksten verwitterten Horizonten einen höheren Anteil als in jedem anderen untersuchten Horizont. Die C/N‐Verhältnisse verschiedener Humin‐ und Fulvosäure‐Fraktionen waren im Ah‐ viel niedriger als im Bnt‐Horizont.

IR‐Untersuchungen von Humin‐ und Fulvosäure‐Fraktionen im Solonetz zeigten Ähnlichkeiten in ihren Strukturen. Jedoch zeigen sich Hinweise auf höheren Aromatisierungs‐ und Polymerisierungsgrad der Huminsäurefraktion.
Molekülkomplexe bei Huminstoffen durch e‐Donator‐ und e‐Acceptor‐Strukturen
Authors: Ziechmann W.
Published: February 2007

Molecule‐complexes on Humic‐substances by Structures with ϵ‐Donor‐ and ϵ‐Acceptor‐Qualities

For many considerations with reference to the biosynthesis of humic‐substances it is useful to formulate radicals prevailing for certain phases. Some interesting conclusions can be drawn from this conception based on a great number of experiments.

The formation of humic‐substances requires radicable materials, i.e. aromatic substances (initial reactants first order, e.g. lignins). The interpretation of X‐ray diffraction allows to estimate the distributation of aromatic and aliphatic share in humic‐substances.

The immense possibilities of chemical reactions therefore form extremely complex materials. But their uniformity makes impossible to separate them exactly.

Further, with the formation of particles possessing additional properties of mesomerism the stability of the radicals increases, whilst the humification rate decreases.
Transformations and Transport of NH4+‐N in a Flooded Soil
Authors: Bilal Ibrahim M.
Published: February 2007

Umbildung und Transport von NH4‐N in einem überfluteten Boden

Transport und Transformation von gedüngtem NH4+N wurden in einer überfluteten Bodensäule untersucht, um Aussagen über die Beeinflussung der Wasserqualität durch die Stickstoffdüngung bei Reisböden machen zu können.

Am ersten Tag nach der Düngerausbringung erreichte der NH4+‐ Gehalt im Überflutungswasser und in 1,2 cm Bodentiefe (oxidierter Bodenhorizont) Höchstwerte, die mit zunehmender Versuchsdauer bis auf < 1 ppm nach 10 bzw. 16 Tagen abnahmen. In größerer Bodentiefe konnten keine Veränderungen in der NH4+‐Konzentration der Bodenlösung festgestellt werden. Die Gehalte lagen immer unter 1 ppm.

Im Überflutungswasser und in der Bodenlösung des oxidierten Oberflächenhorizontes führten Nitrifikationsvorgänge zu Veränderungen der NH4+‐Gehalte. Höchstgehalte an NO2− und NO3− traten etwa 7 bzw. 10 Tage nach der NH4+‐Ausbringung auf. In größerer Bodentiefe konnten Veränderungen in der NO2− und NO3−‐Lösungskonzentration während der Versuchszeit nicht festgestellt werden.

Aus den Gehalten an gesamten anorganischem Stickstoff in der Lösungsphase folgt, daß erhöhte N‐Konzentrationen nur im Überflutungswasser und in einer Bodentiefe von 1,2cm auftreten. Die beobachtete Abnahme der N‐Gehalte im Verlauf einer 4‐wöchigen Untersuchungsperiode werden auf Denitrifikations‐, Immobilisierungs‐ und Fixierungsvorgänge zurückgeführt.
Einfluß der N‐Düngung auf den 14C‐Einbau in die Komponenten der äthanollöslichen Fraktion von Sommerweizen verschiedener Entwicklungsstadien
Authors: Höfner W. , Orlovius K.
Published: February 2007

Influence of N‐fertilization on the 14C‐labelling of the ethanol soluble fraction and its components in spring wheat at different stages of development

In spring wheat plants from pot experiments the effect of different N‐fertilization on the 14C‐labelling of the soluble fractions of amino acids, organic acids, and carbohydrates was studied.

The fraction of 14C‐labelled compounds, soluble in ethanol, was 50% at the start of the experiment, about 100% during flowering stage and 45% at the end of the experiment.

At the end of the 24h 14CO2‐assimilation period 90% of the activity in the plants were water soluble, carbohydrates containing 10 to 20 times higher 14C‐activity than amino or organic acids.

In plant labelled with 14CO2 during emergence of the ears, the solubility of 14C‐labelled assimilates decreased till the ripening stage to 15% of the total 14C‐activity, whereas the total activity itself decreased only to 50–80% during the same time.

The higher N‐supply results in an enhanced decrease of soluble carbohydrates and in an increase of the soluble amino acid fraction. This leads also to an increased protein synthesis and 14C‐assimilation into the protein of the kernels. The most important plant parts in respect to photosynthesis during the experiment period were upper leaves, upper stems and ears.

The 14C‐distribution throughout the plant is mainly determined by the time after 14CO2‐treatment and less by the N‐fertilization. This points to similar pathways of 14CO2‐assimilation in all trials.

It is concluded, that the positive effect of the high N‐fertilization on the yield is due to the quick transformation of soluble assimilates into insoluble compounds, e.g. proteins and protein precursors. Increase of yield by high N‐fertilization is also due to a prolonged period of photosynthesis and therefore delayed ripening of the photosynthetic active plant parts.
Symptome von Bormangel und Borüberschuß bei Hibiscus esculentus
Authors: Al‐Badrawy R. , Bussler W.
Published: February 2007

Boron deficiency and Boron toxicity in Hibiscus esculentus

The development of symptoms in Okra under conditions of B‐deficiency and B‐toxicity was observed. It was compared if the symptoms correspond with the B‐contents and the growth of the plants.

Symptoms of Boron deficiency in Okra are the same as in the other annual dicotyledons. The first visible microscopical symptom is a disturbance in the cambium region. Characteristic is an enlargement of the cambium. New divided cells do not differentiate. Visual symptoms are breaking of stems and petioles, thickening of these organs, cracking, dying of the tips and falling of buds. With a periodic supply of Boron correlations between Boron content and deficiency symptoms were not found.

In the B‐toxicity range small yellow chlorosis developed on the margins of the older leaves. These symptoms are not to be used for diagnosis. Boron contents higher than 72 μg B/g DM gave a better measure for B‐toxicity. Growth and development of symptoms were in agreement with the high Boron contents.
Wirkung hoher Phosphatdüngung auf die Wachstumsrate, den Zinkgehalt und das P/Zn‐Verhältnis in Weinreben (Vitis vinifera)
Authors: Schropp A. , Marschner H.
Published: February 2007

Effect of high phosphate fertilization on growth rate, zinc content and P/Zn ratio in grapevines (Vitis vinifera)

In a 2 years' pot experiment with a soil low in available Zn, high doses of phosphate fertilizer induced Zn deficiency in grapevines (var. „Riesling”︁ on 5 C root stock). This negative effect of phosphate fertilization could almost be prevented by simultaneous application of Zn to the soil.

The negative effect of high phosphate fertilization on the Zn status of the soil was well reflected in both the content of available Zn as well as in the diffusion rate of Zn (65Zn) in the soil.

In young leaves of grapevines, Zn deficiency can be expected at Zn contents lower than 20 μg/g DM and P/Zn ratios larger than 170. These values, however, cannot be generalized as external factors modify them considerably. This latter holds true for the P/Zn ratio in particular.

The most obvious Zn deficiency symptom was restricted elongation of the shoot due to shorter internodes. Typical for severe Zn deficiency were smaller leaves with intervenal chlorosis or even necrosis and the disappearance of the normally deeply lobed shape of the leaf blade. As a result of the growth inhibition of the shoot apex, growth of axillary buds had been enhanced and this led to a bushy shape of the Zn‐deficient plants.
Fluoreszenzspektroskopische Untersuchungen an Huminsäuren
Authors: Müller‐Wegener U.
Published: February 2007

Fluorescence Spectroscopic Studies on Humic Acids

The procedures of the fluorescence spectra of three humic acids have been investigated and compared. Differences were found in three points:

To get the maximum of fluorescence emission, different concentrations of the three humic acids were necessary.

The humic substances differed in pH‐dependence of the fluorescence.

With nearly equal wavelength of fluorescence emission, distinct deviations of the exciting wavelength were pointed out.

The results show a connection between the conditions of the fluorescence and the contents of phenolic hydroxyl groups of the selected humic acids.

The measurement of fluorescence is a relatively simple method for the characterization of humic acids.
Geometrische Interpolation von Saugspannungsverteilungen
Authors: Flühler H. , Richard F.
Published: February 2007

A procedure for interpolating the depth distribution of soil moisture tension

A programmable procedure is described to compute hydraulic gradients from soil moisture tensions non‐linearly distributed with depth.

This interpolation‐technique is based upon a geometrical procedure. Compared with other curve smoothing techniques it is flexible with respect to the given data constellation and requires a relatively small computational effort.

This method is compared with that of cubic splines.
The effect of sulphur on the yield and chemical composition of raya (indian mustard) (Brassica juncea Coss.) grown on a sulphur deficient soil
Authors: Singh Narendra , Singh Mahendra
Published: February 2007

Wirkung von Schwefel auf Ertrag und chemische Zusammensetzung von Raya (Brassica juncea Coss.) auf einem Boden mit Schwefelmangel

In einem Gefäßversuch mit Sandboden wurde der Einfluß von Schwefeldüngung (als K2SO4) auf Ertrag und Mineralstoffgehalt von Raya, Sorte R.L. 18, untersucht. Die Schwefeldüngung erfolgte in Höhe von 0; 15; 30; 60; 90 und 120 ppm. Schwefelgaben bis zu 90.
Einfluß von Bewässerung und Plazierung von markierten Stickstoff‐Düngern auf Ertrag und Stickstoffentzug bei Weizen unter semiariden Klimabedingungen im Iran
Authors: Dianati M.
Published: February 2007

Effect of Irrigation and Fertilizer Placement on the N‐Uptake by Wheat under Semiarid Conditions of Karadj/Iran

Field and greenhouse experiments were conducted under semiarid conditions of Karadj/Iran on a sandy to silty loam of alluvial soils (pH% 8,2) to study the effects of soil moisture regimes and N‐fertilizer placement on yield, N‐uptake and recovery of fertilizer N from 15NH4 15NO3, (15NH2)2CO and (15NH4)2SO4. There were two moisture regimes as main plots (W1 = Irrigation at 50% and W2 = Irrigation at 25% available water in 0–30 cm depth of soil), and two methods of fertilizer placement (broadcast and band application).

Irrigation at (W1) increased the grain and straw yield 11 and 19% but not total N‐uptake in the field experiment. (W1)‐irrigation combined with band application resulted in the highest yield and total N‐uptake. Utilization of applied N, however, was higher with (W2)‐irrigation in both fertilizer placements. This result was confirmed by the data of the greenhouse experiment. Band application was superior to broadcast application for fertilizer N‐uptake with both water managements. Ammonium sulfate showed the highest and urea the lowest difference between the two fertilizer placements.
Adsorption und Desorption von Methabenzthiazuron in verschiedenen Böden
Authors: Kerpen W. , Schleser G.
Published: February 2007

Adsorption and desorption of methabenzthiazuron in various soils

A method investigating adsorption and desorption of pesticides using radioactive tracers and a computer programme is described. The adsorption and desorption of the herbicidal substance methabenzthiazuron in 7 soil samples is investigated.

The adsorption of methabenzthiazuron decreases from the Ap‐ to the C‐horizons. A good correlation exists between the adsorbed amount of the herbicidal substance and the C‐ and N‐content of the soils.

The relatively highest desorption was found with nearly humusfree soils. The amount of adsorbed herbicide residues, not desorbable by water in 5 desorption cycles, is much higher in the humic soils than in the nearly humusfree soils.

From the relationship found between adsorption and corresponding herbicide concentrations proper adsorption values can be predicted for any herbicide concentration within the investigated concentration range by using one single adsorption measurement as a basis of calculation.
Nitrogen mineralization in sandy salt marsh soils of the Netherlands
Authors: Rozema J. , Nelissen H. J. M. , van Der Kroft M. , Ernst W. H. O.
Published: February 2007

Stickstoffmineralisation in sandigen, salzhaltigen Marschböden der Niederlande

Die jahreszeitlichen Veränderungen der Ammonifikation und Nitrifikation einer alkalischen Salzmarsch wurden untersucht. Ammoniumstickstoff war nicht vorhanden. Bedingt durch den geringen Gehalt an organischem Material bleiben die Nitratgehalte ebenfalls niedrig. Die jahreszeitlichen Schwankungen der aktuellen und der durch Inkubation erhaltenen Nitratmengen werden teilweise durch den Temperaturverlauf verursacht; doch dürften andere Faktoren ebenfalls eine Rolle spielen, wenn auch die nitrifizierenden Bakterien an mittlere Salzgehalte angepaßt sind. Insgesamt gesehen wird die Vegetationsentwicklung der sandigen Salzmarsch durch das geringe Stickstoffangebot nicht gefördert, und die Vegetationszonierung ist unabhängig vom Stickstoffhaushalt.
Vergleich verschiedener Extraktionsmethoden zur Bestimmung der Kaliumverfügbarkeit in Böden
Authors: Schachtschabel P. , Köster W.
Published: February 2007

Comparison of different methods for the determination of the potassium availability of soils

Extractable K was determined in 148 soil samples by using three different lactate solutions (AL, DL, CAL), 0.1 m HCl and 0.0125 m CaCl2 as extracting agents.

The extractable portion of the total exchangeable K (K(NH4)) was found to decrease with increasing content of the < 6,3 μm particle size fraction in the samples.

Correlation coefficients were calculated for characterizing the relationship between extracted amounts of K (K values) and the „K numbers”︁. The latter serve as a basis for fertilizer recommendations in the Netherlands, where they have been checked in a great number of field trials. The K number depicts the K supplying power of soils as determined by HCl soluble K, content of the < 16 μm size fraction, and pH.

The K (CaCl2) values were found to correlate more closely with the K numbers than the amounts of K extracted with lactate solutions. This is because the influence of particle size on K(CaCl2) is eliminated as shown by multiple regression analysis.

The strength of bonding of the easily exchangeable K is reflected much better by the K(CaCl2) values than by the lactate values. Improvement of K fertilizer recommendations by taking K(CaCl2) data as a basis can thus be expected.

The different methods of recommendation for K fertilization in the Fed. Republic of Germany and in the Netherlands are illustrated for the soils derived from loess.
Manganese availability as affected by calcium carbonate levels
Authors: Osman A. Z. , El‐Sherif A. F. , Bassiouny H.
Published: February 2007

Einfluß von Calciumcarbonat auf die Verfügbarkeit von Mangan

Die vorliegende Arbeit beschreibt Untersuchungen über den Einfluß von CaCO3 auf die Verfügbarkeit von gedüngtem (MnSO4 bzw. MnEDTA, markiert mit 54Mn) und nativem Boden‐Mn. Als Versuchspflanze diente Raygras.

Durch CaCO3‐Zusatz zum Boden nimmt die Verfügbarkeit von Mn ab, und zwar sowohl vom Dünger als auch von nativem Boden‐Mn. In jedem Fall war aber natives Boden‐Mn die Hauptquelle von Mn für die Pflanzen, über 90% des Mn in den Pflanzen stammten aus dem nativen Boden‐Mn. Von den beiden Mn‐Düngerformen war die Mn‐Aufnahme aus MnEDTA deutlich besser als aus MnSO4; die Anwendung von Mn‐Chelaten auf stark kalkhaltigen Böden kann daher von Nutzen sein.
Ermittlung von Kennwerten optimaler Magnesium‐Versorgung für Hafer, Sommerweizen und Mais
Authors: Wichmann W. , Finck A.
Published: February 2007

Determination of plant analysis criteria characterizing the magnesium nutrition of oats, spring wheat and maize

Cereal plants from pot trials were analyzed for criteria of optimal Mg nutrition. The critical Mg concentration in dry matter of aerial parts from oats and spring wheat at the beginning of the shooting stage was found to be 1.8 and 1.3 per mille Mg respectively. The critical Mg concentration with maize is about 2,2 per mille in dry matter of yount leaves at tasseling stage.

Because the Mg content of oats (based on dry matter) decreases significantly during the shooting stage, it seems advisable to have additional data (Mg content of green matter, Mg/N ratio, Mg/Ca ratio) which are less influenced by plant age.

The Mg/Ca ratio appears to be well suited for evaluating the nutritional status of cereals. Minimum critical Mg/Ca ratios (based on per mille contents) are 0,23 for spring wheat, 0.3 for oats and 0.4 for maize.
Die Wirkung der Schwermetalle Chrom, Nickel, Kupfer, Zink, Cadmium, Quecksilber und Blei auf die Aufnahme und Verlagerung von Kalium und Phosphat bei jungen Gerstenpflanzen
Authors: Oberländer Hans‐Erich , Roth Klaus
Published: February 2007

Effect of the heavy metals chromium, nickel, copper, zinc, cadmium, mercury and lead on uptake and translocation of K and P by young barley plants

The uptake of potassium and phosphate into the roots and shoots of 7 days old barley plants from double‐labelled (42K, 32P) nutrient solutions containing chromium, nickel, copper, zinc, cadmium, mercury or lead (10−6 ‐ 10−4 moles/1) was measured in a constant environment after 5 hours, in order to compare early stages of toxicity.

K and P uptake and translocation were inhibited by the 7 heavy metals to a different extent; K was more affected than P, and translocation of both nutrients into the shoots was more inhibited than uptake into the roots. Plants showed no visible injuries.

Mercury had by far the greatest effect, zinc was almost ineffective: K uptake e.g. was reduced to 21% of the control by 10−4 moles Hg/l, but only to 97% by the same amount of Zn, and P translocation was reduced to 8% by Hg, but was not affected by Zn. The least significant effect of Hg was detectable at a concentration of 4.10−7 moles Hg/l ( = 0,08 ppm) in the nutrient solution, the effect of Zn only above 10−4 moles Zn/l ( = 6,5 ppm).

Arranging the tested heavy metals according to their effects leads to the sequence

Hg > Pb > Cu > Cd > Cr > Ni > Zn which corresponds – apart from two deviations – to the electrochemical series of the elements.
Röntgenfluoreszenzspektrometrische Bestimmung von Spurenelementen in verdünnten wäßrigen Lösungen nach Anreicherung auf Cellulose‐Ionenaustauschern
Authors: Rabe R.
Published: February 2007

Determination of trace elements in dilute aqueous solutions by X‐ray fluorescence spectrometry after preconcentration on cellulose ion exchangers

Different methods dealing with the X‐ray fluorescence analysis of solutions are reviewed. Cellulose ion exchangers were found to be a medium for the preconcentration of traces of elements in aqueous solutions. The enrichment is carried out by filtering 11 water containing μg‐amounts of different ions through a column. After drying, the cellulose ion exchangers are pressed into pellets and analysed by X‐ray fluorescence.

For the collection step strong acid SE‐ (sulfoethyl‐) cellulose and strong basic DEAE‐(diethylaminoethyl‐) cellulose are used having an exchange capacity of 0,2 meq./gram and 0.85 meq./gram, respectively. The accuray of the method is about ± 10%. Detection limits (theoretical values) are in the range of 1–5 μg.

Variations of the method referring to preparation of pellets, sensitivity and column dimensions are discussed.
Abbau von Monolinuron in verschiedenen Böden
Authors: Süß A. , Eben C.
Published: February 2007

Degradation of monolinuron in different soil types

The degradation of 14C‐methyl, ‐ureido‐ and ‐phenyl‐labelled monolinuron was studied in laboratory experiments with different soil types. Mineralization of the ureido‐group was followed by two methods. It was found, that the mineralization rate depends on the soil. For the herbicide monolinuron there was a definite degradation characteristic. The release of 14CO2 from the methyl‐ and ureido‐group was faster than from the phenylring. In soil extracts monolinuron was found together with one or two radioactive substances not yet identified. Soil respiration was unchanged after the application of monolinuron. In a sterile soil no degradation occurred.
Überprüfung des Kontaminationsrisikos durch polycyclische aromatische Kohlenwasserstoffe im Erntegut von Möhren und Pilzen bei Anwendung von Müllkompost
Authors: Linne C. , Martens R.
Published: February 2007

Examination of the risk of contamination by polycyclic aromatic hydrocarbons in the harvested crops of carrots and fungi after the application of composted municipal waste

Investigations were conducted to determine if the often high, naturally‐occuring concentrations of polycyclic aromatic hydrocarbon (PAHs) present in municipal waste composts could cause hazardous contamination of plants when the composts are used as soil conditioners in agriculture and gardening. Carrots (Daucus carota) and mushrooms (Agaricus bisporus), used as representatives of higher and lower plants, respectively, were cultivated on compost‐free or compost‐amended substrates. To determine concentrations of PAHs in soils and plants a gas‐chromatographic method was employed which allowed benzo(a)pyrene and 12 other PAHs to be determined singly or as isomeric mixtures.

In the experiments with Agaricus it was found that fruiting bodies, even though grown in a substrate with very high concentrations of PAHs (i‐ e., 1000 ppb benzo(a)pyrene), contained no detectible quantities of these compounds. In contrast to this, experiments with carrots showed that there was a direct correlation between PAH concentrations in the substrate and PAH concentrations in both below‐ and above‐ground portions of the plants. The 25 to 40 fold increase of the PAH concentration in the substrate containing waste compost caused an increase of these compounds in the carrot roots by the same factor. The only 2 to 4 fold increment of the PAHs in the corresponding foliage was thought to be mainly due to a relatively great portion of air contamination by which the increase of the PAH quantities entering from below ground to the foliage was not so evident.

The concentrations of benzo(a)pyrene used in the present series of experiments with composted waste are 7 to 10 times higher than those found in soil to which compost has been added as in practical agricultural application. Relating the result of the described experiments to actual practice, it could be suggested that the normally very low concentrations of PAHs in below ground plant parts would increase with the use of composted municipal waste, but they would not become greater than the concentrations in above ground plant as caused by contamination from naturally occuring PAHs in the air.
The water balance of a sugar beet crop: A model and some experimental evidence
Authors: van der Ploeg R. R. , Beese F. , Strebel O. , Renger M.
Published: February 2007

For a loes soil with sugar beets (Beta vulgaris L.) a model was developed with which the difficult‐to‐measure components of the water balance equation can be determined. Basic component of the model is the unsaturated soil moisture flow equation. This equation is solved numerically by a finite difference method. As boundary condition at the soil surface, expressions for the potential and the actual transpiration and for the potential and the actual evaporation are used. Besides the hydraulic functions of the soil, standard meteorological measurements, together with leaf area index and root distribution data of the crop, enter the model. For a period of 316 days, calculated and measured soil suction values in 10 different soil depths, are compared as well as transpiration and seepage vaules. The comparison shows that the model provides acceptable results. The model calculations indicate that of the 519 mm of precipitation received during the 316‐day period, 503 mm were used for evapotranspiration and 119 mm left the soil profile as internal seepage.
Status of phophatases in the root‐soil interface of leguminous and non‐leguminous crops
Authors: Tarafdar J. C. , Chhonkar P. K.
Published: February 2007

Phosphatasen — Aktivitäten in der Rhizosphäre verschiedener Leguminosen und Nicht‐Leguminosen

Die Aktivitäten an saurer, neutraler und alkalischer Phosphatase in der Rhizosphäre 16 verschiedener Kulturpflanzen (Leguminosen und Nicht‐Leguminosen) wurden ermittelt. Mit Ausnahme von der Karotte (Daucus carota) waren die Aktivitäten der drei Phosphatasen in der Rhizosphäre stärker als in den umgebenden Böden. Im Schnitt war die Phosphatase‐Aktivität in der Rhizosphäre von Leguminosen höher als bei den Nicht‐Leguminosen. Unter den 3 Phosphatasen wurde die neutrale Phosphatase am stärksten gefördert.
A computer simulation of phosphate and nitrogen transport by water runoff
Authors: Kruh G. , Segall E. , Amberger A. , Hagin J.
Published: February 2007

Computersimulationsmodell des Phosphat‐ und Stickstofftransportes durch Wassererosion

Anhand der Ausarbeitungen von Meyer und Wischmeier (1969) und Ishihara (1967) wurde mit einigen Abänderungen ein Computermodell entwickelt, das den Prozeß der Bodenerosion durch Regen und Wasserabfluß beschreibt. Das Modell berechnet die Pflanzennährstoffmengen, die während des Erosionsprozesses von der Oberfläche weggeschwemmt werden. In der ersten Phase berechnet das Modell die Wasserabflußrate auf der Bodenoberfläche und in der obersten Bodenschicht und danach den Anteil der verschiedenen Erosionsmechanismen am Verlust von Phosphor, Stickstoff und Bodenmaterial.

Eine Anzahl von Computerdurchläufen mit verschiedenen Parametern zeigt die Empfindlichkeit des Modells für Änderungen der Bodeneigenschaften und Regenverteilung.
Einfluß der Schwefelversorgung auf das lösliche Blattprotein sowie die Ausbildung und die spezifische Aktivität einiger Enzyme junger Sonnenblumen
Authors: Pauler B.
Published: February 2007

Influence of the amount of sulfur supplied on the soluble leaf protein, the synthesis and the specific activity of some enzymes of young sunflower plants

The influence of a sulfur supplement on the pattern of leaf proteins, soluble in 0.1 M phosphate buffer, pH 7.5, was studied in experiments with young sunflower plants. The leaves were harvested after growing periods of 14 and 21 days, respectively.

In addition, the electrophoretic distribution of isoenzymes of some enzyme systems and their specific activities have been analyzed.

1. Plant fresh weight was not affected by the level of sulfur supply, although symptoms of S‐deficiency were observed in the low S‐treatment.

2. In contrast to this finding, a clear effect of S‐deficiency on the electrophoretic patterns of the leaf proteins was detected. This was specially the case in plants. grown for three weeks at a low sulfur level. Increased contents of low molecular protein fractions were found, whereas the relative amounts of high molecular proteins were reduced.

3. In plants, which were kept S‐deficient, the number of isoenzyme components was lower in comparison to plants, which were adequately supplied with sulfur. The isoenzymes of malate dehydrogenase and acid phosphatase, however, were synthesized to about the same degree in both S‐treatments.

4. The specific activities of most of the enzymes studied in these investigations were lower in the plants, grown at S‐deficiency in comparison with the control. These findings were particularly evident after a growth period of 3 weeks. The specific activities of glutaminate dehydrogenase, succinate dehydrogenase and a‐ketoglutarate dehydrogenase were not significantly influenced by the level of S‐supply. The specific activities of acid phosphatase and malate dehydrogenase were relatively high even in those plants, which were treated with low amounts of sulfur.
Porengrößenverteilung und Bodenfruchtbarkeit. Ein Beitrag zur physikalischen Kennzeichnung der Böden auf Bodenkarten
Authors: Wichtmann H.
Published: February 2007

Pore size distribution and soil fertility A contribution concerning the physical classifikation of soils at soil maps

Testing the physical classification of soils at soil maps pore size distribution of 17 well drained soils was measured. The results obtained for the 0–100 cm soil depth were correlated to land values as given in the „Reichsbodenschätzung”︁. Statistical evaluation of the data gave the following results: 1) Negative correlation (r = −0,11) between pore space pF 1,8–2, 9 and soil fertility. 2) Moderate correlation (r = 0,54) between pore space pF 1,8–4, 2. 3) Very close correlation (r = 0,95) between pore space pF 2,5–4, 2 and pF 2,9–4,2, respectively, and soil fertility. 4) Fair correlation (r = 0,76) between pore space pF > 4,2 and soil fertility.

Therefore soil fertility is strongly dependent on physical factors related to pore size distribution and concerning water and N‐economy of soils. In our humid climate the factor N‐economy obviously has a stronger bearing on soil fertility than the factor soil water.

The results make it possible to classify the soils in relation to N‐economy and water supply using the same index of pore size distribution. With the pore space pF 2,5–4,2, fertility and filter properties of soils are comprehended in the best manner. The terminus „Kapillare Sorptionskapazität”︁ is proposed to define both the factors.

Finally some consequences are mentioned concerning plant nutrition and N‐fertilizing in regard to the physical factors of soil fertility.
Bestimmung der Harnstoffabbaurate in Land‐ und Unterwasserböden nach verschiedenen Methoden
Authors: Pfanneberg Traudl , Fischer W. R. , Niederbudde E.‐A.
Published: February 2007

Determination of urease activity by two different methods in some soils and underwater soils

Two methods differing in microbial activity during incubation with urea were used for the determination of urease activity. The results obtained showed a better relationship with natural conditions such as pH, organic substance‐, or clay content, if the microbial activity was not inhibited during incubation. This effect was found to be particularly pronounced in underwater soils, where addition of a bacteriostatic substance (toluene) resulted in practically uniform values that reflected neither bacterial nor nutrient status.
Influence of some chelates of aluminium on the sorption of phosphate by hydrous Al‐oxides
Authors: Peinemann N. , Helmy A. K. , Buschiazzo D. E.
Published: February 2007

Sorption of phosphate by hydrous oxides of aluminium was studied as a function of pH, presence of chelates of aluminium and of the specific surface areas of the oxides.

Aluminon was most effective in reducing P sorption followed by oxalic acid and EDTA. Acetylacetone, 8‐hydroxyquinoline, salicylic acid and fluoride affected little P sorption. The sorption was found to be higher the higher the value of the specific surface area of the oxide, but the shape of the sorption curve was the same for all the oxides studied, exhibiting a maximum at about pH 5. This maximum was found to coincide with the point of zero charge as determined in the presence of acetate ions. The sorption data are explained in terms of a ligand exchange mechanism in which phosphate chemisorbs on surface aluminium atoms displacing uncharged surface hydroxyls.
A graphical scheme for the demonstration of fabric levels in soil thin sections
Authors: Babel Ulrich
Published: February 2007

Ein Zeichenschema zur Darstellung der Gefügeniveaus in Bodendünnschliffen

Es wird ein Zeichenschema zur einfachen Darstellung der Nachbarschaftsbeziehungen der Gefügeeinheiten in Bodendünnschliffen vorgeschlagen. Es handelt sich um ein stark abstrahiertes Bild, in dem die Art der Zusammenlagerung der Grundbausteine zu immer höheren Niveaus dargestellt ist.

Das Zeichenschema wird als Ergebnismitteilung verstanden. An einem Beispiel wird gezeigt, wie gezeichnet wird und wie es diskutiert werden kann. Die Arbeit mit dem Zeichenschema wirft Probleme der Klassifizierung der Gefügeeinheiten auf.
Kaliumernährung des Tabaks auf einem K‐fixierenden nordwestiranischen Boden
Authors: Karbachsch M.
Published: February 2007

Potassium nutrition of tobacco on a potassium fixing alluvial soil

A field experiment was conducted to study the effects of K‐fertilization on potassium uptake by tobacco and the K‐dynamics in an alluvial soil rich in clay and carbonate content. It was observed that the amount of exchangeable potassium and the concentration of K in the soil solution increased on fertilization. There were only small changes in exchangeable potassium and significant reduction in the concentration of K in the soil solution during the growth period.

Uptake of potassium by plants increased during first month due to its high concentration in soil solution. Decrease in the concentration of potassium after one month caused a rapid reduction in the uptake of potassium by plants (Figure 1).

K Fertilization decreases the K‐Ca and K‐Mg potentials especially during the first month (Table 2) which increase again during the experimental period (because of the slow release of K from the solid phase and its rapid uptake by plants). Where as the concentration of potassium in the soil solution is closely related with K‐Ca and K‐Mg potentials on the one hand and with K‐uptake by plants on the other, no relationship was observed between exchangeable potassium content and K‐uptake (Figure 2).

The potassium exchange curves of soils from K0 and K5 treatments show that the extent of K‐adsorption is greater in K0 soil. A major part of K adsorbed during the shaking experiment can be easily removed by CaCl2 solution in K5soil, where as in K0 soil a part of adsorbed potassium exists in nonexchangeable form. Illite is the dominant clay mineral in this soil which show wedge type structures (expansible at edges).
Gewebekulturen unter Bormangel
Authors: Krosing M.
Published: February 2007

Tissue culture under conditions of boron deficiency

Cambium tissue from sunflowers and carrots were cultured in nutrient solution according to Murashige and Skoog with graduated supplies of boron. A light‐coloured and well growing callus was formed only in the presence of boron. Explants on a boron‐deficient medium agglutinated at the edges, had only small areas of cell division and revealed appositions on the walls of some cells. Deficient tissues also became noticeably darker.

Callus grown on normal medium and then transferred to boron‐deficient medium slowed down in growth rate – at the latest after 4 weeks – and also turned dark. In contrast to normal calli, the deficient cultures could not be easily separated in water into individual cells or small cell groups. Moreover, the cells were smaller on the average and often revealed grainy contents and (in the case of carrots) accumulation of plasma at the ends of the cells. A large number of deficient cells were plasmolyzed.

An accumulation of undifferentiated cells in the cambium region is particularly striking in dicotyledons under conditions of boron deficiency. If this symptom should be the result of cell division activity, then isolated cambium should react to boron deficiency with intensive cell division. Contrary to expectation, isolated cambium of sunflowers and carrots in tissue culture did not reveal a promotion of cell division under conditions of boron deficiency.

These results indicate that the symptom of “increased cambium growth” in intact dicotyledons is due to a secondary effect of boron deficiency.
Makro‐ und Mikrosymptome des Zinkmangels bei höheren Pflanzen
Authors: Rahimi A. , Bussler W.
Published: February 2007

Macro‐ and Microsymptoms of Zinc Deficiency in Higher Plants

The development of zinc deficiency symptoms was studied in eight different plant species grown under controlled experimental conditions in soilless sulture. The following results were obtained.

One symptom of zinc deficiency was found to be the development of a violet to red colouring matter which first appeared in the form of small dots or as spots of discolouration which later covered the entire leaf. This discolouration was found primarily in young but already completely developed leaves. Here, the symptoms started to devlop in single cells.

Further symptoms of zinc deficiency were observed to be a retarded growth, short internodes, small leaves and a very poor formation of roots.
Der Einfluß von Bormangel und von mechanischer Zerstörung des Spitzenmeristems auf die Zellteilung bei Sonnenblumen
Authors: Krosing M.
Published: February 2007

Influence of boron deficiency and destruction of the apical meristem on the cell division in sunflowers

With a severe, nearly absolute boron deficiency metabolism and formation of tissues are so disturbed that the primary symptom of boron deficiency can not be recognized with certainty.

Investigations here had to clarify if cutting the tops or destruction of the apical meristem with a red‐hot needle will induce symptoms similar to those of boron deficiency or how symoms develop under mild boron deficiency.

With the red‐hot needle technique, it was possible to obtain cambial enlargement in plants with a normal boron nutrition.

Cutting off the tops also, induced an enlargement of the hypocotyl. In this case the enlargement was however due to an enlargement of the cortex by formation of an aerenchymlike tissue.

A boron supply near the deficiency level caused development of deficiency symptoms in growing plants (chlorosis, inhibited enlargement of the stem, small deaf' blades, small‐celled xylem, malformed and discoloured cell walls and appositions on the young cell walls). As long as the shoot apex displayed growth, enlargement of the cabium did not appear as a rule. This symptom seems to be a secondary symptom of boron deficiency caused by damage to the shoot apex and, thus disturbed auxin metabolism.
Labile and anion extractable phosphate in calcareous soils and their suitability for characterizing the phosphate availability
Authors: Abd El Aal R. S. , Römer W.
Published: February 2007

„Labiles”︁ und anionenaustauschbares Phosphat in Kalkböden und ihre Eignung zur Charakterisierung der Phosphatverfügbarkeit

In der vorliegenden Arbeit wurde an 10kalkhaltigen Böden aus der Arabischen Republik Ägypten geprüft, ob das „labile Phosphat”︁ (Mi) bei diesen Substraten ein besseres Maß für die pflanzenaufnehmbare P‐Menge darstellt als das durch Anionenaustauscher (Dowex 1 × 10) extrahierbare Phosphat. Als Maß dienten die linearen Korrelationskoeffizienten zwischen der P‐Aufnahme von Luzerne (Gefäßversuche, 6 Schnitte) und den Ergebnissen der Bodenanalysen. Folgende Resultate sind erzielt worden:

Die Bestimmung von Mi nach der Gleichung von Barbier et al. (1954) Mi =

in der R = zum Boden zugesetzte Radioaktivität, r = Radioaktivität in der Lösung, m = Phosphatmenge in der Lösung und Mr = zum Boden zugesetzte Phosphatmenge bedeuten, lieferte unabhängig von Mr reproduzierbare Werte für Mi.

Der lineare Korrelationskoeffizient r zwischen den Mi‐Werten und der P‐Aufnahme durch die Luzerne erreichte bei 1, 6, 24, 48 und 72 h Behandlungszeit jeweils Werte > + 0,8 und lag damit in der gleichen Größenordnung wie bei der Ionenaustauschermethode.

Wurden die Werte der kalkreichen Böden (> 5%CaCO3) allein verrechnet, ergaben sich für beide Methoden gleichermaßen viel schlechtere Korrelationen. Die Anionenaustauscher‐methode spiegelte für diese Böden die P‐Verfügbarkeit nicht besser wider als die Ermittlung der Mi‐Werte. Wegen der geringen Löslichkeit der Bodenphosphate dieser Böden dürfte das „Aufschließungsvermögen”︁ der Wurzel (sekretorische Tätigkeit?) wichtig für die P‐Aufnahme der Pflanze sein. Sowohl die Anionenaustauschermethode als auch die Mi‐Bestimmung können offensichtlich die Vorgänge an der Grenzfläche Boden/Wurzeloberfläche nicht simulieren.
Die Stammbastanalyse als Methode zur Beurteilung des Ernährungszustands von Coniferen
Authors: Hohenadl R. , Alcubilla M. , Rehfuess K. E.
Published: February 2007

Stem phloem analysis as diagnostic tool to evaluate the nutritional status of conifers

During late fall 1975 needles and stem phloem were sampled from 4–10 trees each on 44 experimental plots, belonging to five trials with fertilizer and sewage sludge application in Scots pine and Norway spruce stands in southern Germany. Treating the nutrient contents of both tissues by means of variance, regression and discriminant analysis gave evidence, that stem phloem analysis can be used effectively to evaluate the supply of those stands with N,P and Ca. Phloem analysis has several advantages as compared with traditional foliar analysis: Technical sampling difficulties in older stands as well as the hazard of dilution effects are smaller and the seasonal variation of nutrient contents seems to be less pronounced. Preliminary phloem threshold levels for N and P deficiency with pine may lie around 0,46 and 0,07%, respectively. There is some indication, that spruce suffers from N deficiency if the nitrogen content of its phloem is below 0,42%.