bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Verwitterung mafischer Chlorite
Authors: Schwertmann U. 
Published: February 2007

The Weathering of Mafic Chlorites in Soils (A Review)Recent results from the literature and some own data on chlorite weathering as derived from soil profile studies and laboratory work on artificial weathering are summarized. Among the two possible pathways of chlorite weathering ‐ vermiculitization after removing the hydroxide layer and complete dissolution ‐ vermiculitization appears to occur in rather “closed” systems not too acid and poor in organic compounds (e.g. saprolites). Complete dissolution, on the other hand, prevails in strong acid parts of the solum rich in organic matter, e.g. in podzol A horizons. Due to the presence of micaceous minerals in most profiles which also serve as a source for expandable mixed layer species the exact pathway of the chlorite during weathering cannot be followed up easily.
Bildung sekundärer Al‐(Fe‐)Chlorite
Authors: Blum W. 
Published: February 2007

Genesis of Secondary Al‐(Fe‐)ChloritesComparing the results of soil investigations with those obtained from laboratory syntheses it was concluded that secondary Al‐Fe‐chlorites in soils of moderate cool‐warm‐humid climates mainly develop through protonisation of Al and Fe in the mineral structure of expanded dioctahedral vermiculites with subsequent hydrolysis in the interlayer space. In this process characteristics of the mineral itself (e.g. layer charge) as well as carbonic acid and soil organic acids (as proton suppliers) are the most important factors.From this, the further conclusion was drawn that in the pH‐range 6, 5–6 secondary chlorites begin to develop increasingly until pH5 (development conditions) and in the pH‐range 5–4,5“conservation conditions” exist. ‐ At pH<4,5 secondary chlorites are unstable (dissolution conditions) through protonisation of Al‐Fe‐hydroxy polymers (reverse of hydrolysis) with subsequent solubilization and leaching especially through complexation by soil organic acids. ‐ As remaining minerals in this weathering sequence smectites occur, resulting from the decrease of layer charge in vermiculites through the chloritization process, thus indicating that chloritization may be an important process for the genesis of smectites under acid weathering conditions.
Verteilung von Stickstoff auf Sproß und Wurzel bei jungen Bohnenpflanzen nach der Aufnahme von NO und NH
Authors: Martin P. 
Published: February 2007

Translocation of nitrogen to the shoot of young bean plants after uptake of NO and NH by the rootPhaseolus vulgaris plants (var. nana, cv. Saxa) at the primary leaf stage (without nodules) were fed during 6 hours with 15NO and 15NH, respectively. 24 hours after the absorption period more 15N from the absorbed NO was translocated from the root to the shoot. The presence of NH in the nutrient solution enhanced the translocation of 15NON, probably by an inhibition of nitrate reductase. NH4‐+15N is mainly retained in the root by a high incorporation into the root protein. It can be concluded that nitrogen from newly absorbed NO is not retained and used for protein synthesis in the root according to the root's potential to synthesize protein. Nitrate reduction in the root is considered to be the limiting factor. This is supported by the fact that withdrawal of NO in the nutrient solution prior to the 15N‐experiment increased NOtranslocation to the shoot as a consequence of a lowered level of nitrate reductase. In an experiment with 14NOsupply to the roots and 15NOapplication to the primary leaves (infiltration method) a considerable amount of 15N was translocated from the leaves to the roots. This indicates that an insufficient NOreduction in the root can be substituted by a retranslocation of reduced N‐compounds from leaves to the roots. The proportion of NO reduced in the root influences also the pattern of primary distribution of nitrogen in the shoot of plants at the 4 leaf stage. At a concentration of 0,2 meq/l NO in the nutrient solution as compared to 20 meq/l NO during 10 hours a relative higher amount of 15N was transported from the root to the younger, growing leaves i.e. via the phloem to metabolic sinks.
Nitrogen distribution studies by emission spectrometry in free amino acids and amides of developing panicle of rice
Authors: Muhammad Shah , Kumazawa Kikuo 
Published: February 2007

Studien zur Stickstoffverteilung durch Emissions‐Spektrometric in freien Aminosäuren und Amiden junger ReisrispenDie Verteilung von Ammonium‐ und Nitrat‐Stickstoff auf die freien Aminosäuren und Amide junger, sich entwickelnder Reisrispen (Oryza sativa L.) wurde nach Aufnahme durch die Wurzeln ermittelt. Dabei erfolgten die Auftrennungen der Aminosäuren und Amide durch Dünnschicht‐Chromatographie und die 15N‐Bestimmungen mit Hilfe der Emissions‐Spektrometrie. In den Reisrispen fanden sich große Reserven an Asparagin, Glutamin und Glutaminsäure. Die 15N‐Anteile in freien Aminosäuren und Amiden waren bei Zufuhr von 15N‐Ammoniumionen höher als bei entsprechender Ernährung mit Nitrat. Glutaminsäure enthielt einen wesentlich höheren Anteil an 15N‐ und an Gesamt‐Stickstoff als jede andere Aminosäure, was als Hinweis auf die zentrale Bedeutung der Glutaminsäure für die Synthese der übrigen Aminosäuren aufgefaßt wurde. Allgemein waren für Aminosäuren, die primär oder sekundär im Krebs‐Zyklus entstehen, hohe Einbauraten festzustellen, und Aminosäuren mit niedrigem metabolischen turn‐over zeigten geringeren Einbau; dies gilt sowohl für das Angebot von 15NH als auch für 15NO.
Calciumgehalte in Früchten von Paprika, Bohne, Quitte und Hagebutte im Verlauf des Fruchtwachstums
Authors: Mix G. P. , Marschner H. 
Published: February 2007

Calcium content in fruits of paprika, bean, quince and hip during fruit growthThe Ca content and the Ca translocation into the fruits during their growth was determined in paprika and bean under controlled conditions (nutrient solution, growth room) and in quince and hip (Rosa rugosa Thumb.) under field conditions.Compared to leaves the Ca content in the fruits is very low in all 4 species and declines further during their growth. The K content, however, is similar in the leaves and in the fruits of all 4 species and remains nearly constant during fruit growth. The low Ca content of the fruits cannot directly be related to the cation exchange capacity (CEC) as there are no differences in the CEC between leaves and fruits.The generally low Ca content of the fruits and its decline during fruit growth is causally related in all 4 plant species to the low rate of Ca translocation compared to the rate of dry matter translocation into the fruits.There are, however, distinct differences between the 4 plant species in the course of the ratio Ca/dry matter translocation into the fruits: In paprika the Ca translocation into the fruits strongly declines during fruit growth and in bean the Ca translocation practically ceases with the onset of seed growth. In quince under field conditions the Ca translocation into the fruits rapidly declines at later stages and finally a translocation of Ca out of the fruit takes place (decrease in the amount of Ca/fruit). Only in hip the Ca translocation into the fruits remains constant during fruit growth. There is, however, a distinctly different distribution of Ca to the various parts within the hip fruits.The decline in Ca translocation during fruit growth can be explained in paprika and bean with a shift in water influx from the xylem (rich in Ca) to the phloem at the stage of high rates of dry matter influx into the fruit. In quince and hip, however, additional mechanisms (alternating water flux in the xylem, CEC) seem to be involved in the regulation of the Ca content of these fruits.
Differenzierung oxalatlöslicher Eisenoxide
Authors: Fischer W. R. 
Published: February 2007

Differentiation of oxalate soluble iron oxidesAccording to their mode of formation the oxalate soluble Fe(III)‐oxides show different rates of dissolution especially within the first 30 min of oxalate extraction.Precipitates formed by bacterial or oxidative decomposition of ferric citrate have a very high dissolution rate with more than 90 percent being dissolved within 30 min.Ferrihydrites prepared by alkaline hydrolysis of Fe(III) salts, after slow drying, dissolve to about 60 to 80 percent within this period, whereas similar products quenched with liquid N2 dissolve more rapidly. A plot of (Fe30/Feo) vs. (Feo/Fed) allows to draw a boundary line between the field of podzol values and the field of the other pedogenic iron oxides, as from brown earths and black earths (chernozems).
Einfluß der Frucht auf Photosynthese und Atmung
Authors: Lenz F. 
Published: February 2007

Fruit Effect on Photosynthesis and RespirationSeveral investigations about fruit effects on photosynthesis and respiration, mainly of Citrus madurensis (Lour.) and Solanum melongena (L) plants are reviewed.Fruiting plants had higher photosynthetic rates (mg CO2 · dm−2 · h−1) than non fruiting ones, particularly during stages of most intensive fruit growth. The photosynthetic rates could be stimulated by increasing fruit temperatures.No differences in dark respiration rates of fruiting and non fruiting plants were observed. However photorespiration was considerably higher in non fruiting plants as compared to fruiting ones. Leaves of non fruiting plants accumulated more sugars and starch in the leaves during the light periods than fruiting ones.The gaseous diffusive resistance of leaves was higher in non fruiting as compared to fruiting ones.The higher photosynthetic efficiency of fruiting plants is probably controlled by several mechanisms, some of which were discussed in the paper.
Molecular weight as influencing factor on the adsorption of dextrans on sodium and calcium montmorillonite
Authors: Guidi G. , Petruzzelli G. , Giachetti M. 
Published: February 2007

Der Einfluß des Molekulargewichtes auf die Adsorption von Dextranen an Natrium‐ und CalciummontmorillonitenSechs Glukosepolymere, deren Molekulargewicht von 10.300 bis 1.960.000 anstieg, wurden von Natrium‐ und Calciummontmorilloniten aus wäßrigen Lösungen adsorbiert. Bei 27°C folgten die Adsorptionsisothermen der Langmuir‐Gleichung. Die Langmuir‐Konstanten, a' (Adsorptionsmaximum) und, b' (Bindungsenergie) wurden berechnet. Ebenso wurden aus den Werten für die Langmuir‐Konstante, a' die maximal von Dextranen bedeckte Oberfläche berechnet.
Chemische Veränderungen am Lignin bei dessen Isolierung
Authors: Ziechmann W. , Weichelt Th. 
Published: February 2007

Chemical alterations on lignin during its isolationDifferent methods to isolate lignin from straw (Triticum aestivum) and wood (Picea axcelsa) were investigated.Yields, methoxyl contents as well as absorption spectra in the ultraviolet, visible and infrared region and in addition color reactions by phloroglucin/HCl indicated quite a lot of chemical alterations of the constitution of various lignins.The methods by Björkman (1956) and Pepper et al. (1959) reached the aims of isolation best. But Björkman‐Lignin had some impurities from carbohydrates, while the radical content may be unnatural high and the molecular‐weight too low. Although the method by Pepper et al. caused many irreversible alterations on lignin when the extraction time was too long (> 1h) and no N2‐atmosphere was used, this method is quite convient to isolate lignin if these mistakes are avoided.
Clay minerals as heterogeneous catalysts in preparation of model humic substances
Authors: Wang Thomas S. C. , Li Song Wu 
Published: February 2007

Huminstoffbildung unter katalytischer Einwirkung der Tonminerale im ModellversuchIn Gegenwart von Tonmineralien und Quarz verläuft die oxydative Polymerisation von Protocatechusäure zu Huminstoffen. Fulvosäuren treten hauptsächlich in der Lösungsphase auf, während Huminsäuren mit dem Bodensatz niedergeschlagen werden. Die Polymerisation wird von Abbau‐ und Mineralisierungsprozessen der verschiedenen organischen Zwischenprodukte begleitet, die über oxydative Ringsprengungen verlaufen. In ihrer katalytischen Wirkung ließen sich die Minerale in die Reihe Illit > Montmorillonit > Kaolinit > Quarz einordnen. Der Mechanismus der Katalyse wird diskutiert.
N2‐Fixation by roots and rhizosphere of sand dune plants
Authors: Ahmad M. H. , Neckelmann J. 
Published: February 2007

AbstractNitrogenase activity (by acetylene reduction assay) has been found on the roots and in the rhizosphere‐soil of various plant species collected from dune soils (Table 1.) located on the west coast of Denmark. Out of twelve plant species, five plant species (Deschampsia flexuosa, Ammophila arenaria, Calluna vulgaris, Empetrum nigrum and Corynephorus canescens) revealed a positive nitrogenase activity. Among these five, three were temperate grasses. Except Ammophila arenaria, all four plant species were collected from old sand dune and showed nitrogenase activity on roots as well as in their rhizosphere soil, Ammophila arenaria was collected from fresh sand dune and exhibited nitrogenase activity only on roots (Table 2).
Symptome von Mangan‐Überschuß bei Bohnen (Phaseolus vulgaris)
Authors: Horst W. J. , Marschner H. 
Published: February 2007

Symptoms of manganese toxicity in beans (Phaseolus vulgaris L)In water culture experiments with bush bean plants (Phaseolus vulgaris L. var. „Red Kidney”︁) the macro‐ and micro‐symptoms of manganese toxicity had been studied.Typical symptoms of Mn toxicity are small distinct blackish‐brown spots, first at the older leaves and at more severe toxicity also at the petals and stems. Using the autoradiographic technique on 54Mn‐distribution and comparing this with corresponding light microscopic studies it could be demonstrated that the blackish‐brown spots in the leaves resemble Mn‐precipitations.These precipitations are Mn‐compounds of higher oxidated form and are primarily localized in the walls of cells in vicinity of the vessels. The extend to which these precipitations occur is not only a function of the Mn‐content of the leaves but also of their age. At comparable Mn‐content the extend of the precipitation increases with the leaf age.As secondary symptom of Mn‐toxicity under certain conditions (presence of silicon e.g.) induced Fe deficiency (chlorosis of the youngest leaves) and Ca deficiency („crinkle leaf”︁) may occur.It is assumed that the process of Mn precipitation within the leaves is enzymatically regulated. The severe reduction in the growth of leaf blades at Mn toxicity is presumably related to an interference with the growth hormon balance.
Untersuchungen zum Bodenlufthaushalt in einem Bodenbearbeitungsversuch. 2. Gasdiffusionskoeffizienten als Strukturmaße für Böden
Authors: Richter J. , Großgebauer A. 
Published: February 2007

Investigation of the soil gas regime in a tillage experiment: 2. Apparent diffusion coefficients as a measure of soil structureIn a soil tillage experiment with nursery stock on three different soils the apparent diffusion coefficients for CO2 were measured using soil cores of different depths at different times. Not‐tilled, herbicide treated plots were compared with rototilled plots.The relationship between the relative apparent diffusion coefficient and the air content may be described by an exponential regression function Ds/Da = 0.0085 · e6.8EL, if all measurements are taken into the calculation. By dividing into different soil textures different regressions are obtained for the three studied soils: a sand, a silt and a clay loam. In many cases it is possible to show by the changing Ds(EL) regression changes of the soil structure with depth or as a result of tillage. In all these cases the soil of the not tilled plots turns out to be better structurized than that of the tilled ones, demonstrated by higher Ds‐values at equal EL.The interpretation of the differences is being tried with the aid of soil pore tortuousity and continuity. Finally the measured Ds(EL) relationships are applied to characterize the soil gas regime for two seasons, using CO2 concentration profiles of the soil air on a day in summer and fall, respectively. It is shown, that CO2 production reaches farther down in summer than in fall.
Anorganisch‐katalytische Umsetzungen von Cyanamid und dessen Metaboliten in Quarzsand I. Mechanismus des Cyanamidabbaues unter dem Einfluß von Eisenoxiden und Feuchtigkeit
Authors: Amberger A. , Vilsmeier K. 
Published: February 2007

Inorganic catalytical transformation of cyanamide and its metabolites in quartz sand I. Mechanism of cyanamide breakdown as influenced by iron oxides and moistureA study was made of the inorganically catalysed breakdown of cyanamide by iron oxides in quartz sand, and the formation of metabolites in relation to the type of iron oxide and the moisture level in the system. The possibility that cyanamide breakdown was biological and enzymic was largely eliminated.In the absence of iron oxides the added cyanamide was practically unchanged over the 100 days of the experiment.With the addition of iron oxides such as amorphous Fe(III)‐hydroxide, ochre or rust, the cyanamide rapidly took up water after a few hours and urea was formed. Water uptake was dependent on the type of iron oxide added. When the moisture level in the reaction medium was low (5% of the total water capacity) the process was accelerated.Different amounts of dicyanamide and guanylurea were produced depending on the iron oxides applied. When the water content was high, reactions leading to the production of these compounds were slowed down.The inorganically catalysed breakdown of cyanamide depends on reaction conditions. It can result either in the uptake of water to produce urea directly or in the production of dicyanamide which gives rise to guanylurea by the further addition of water.
Q/I relations and electroultrafiltration of soils as measures of potassium availability to plants
Authors: Grimme H. , Nair P. K. R. 
Published: February 2007

AbstractThe equilibrium activity ratio (ARo) of soil potassium and the K extracted by electroultrafiltration (EUF) within a desorption time of 10 min (EUF10) were compared as measures of K availability indicated by K uptake and dry matter yield of barley plants grown in four soils receiving different rates of K fertilization in a glasshouse experiment. As could be expected, both methods indicated that K intensity in soils increased with higher amounts of K dressings and decreased with progressive crop growth. With EUF10, 56–77% of the variation in plant response in dry matter yield and K uptake could be explained, where as with ARo, it was only 36–65%. There was good linear correlation between ARo, and EUF10 for a particular soil; but there was differential variation in the two parameters for the different soils. When compared on the basis of plant response, EUF10 was found to better describe K availability to plants and differentiate better between soils of different K selectivity.
Influence of water content and soil properties on unsaturated hydraulic conductivity of some red and black soils
Authors: Bhatnagar D. , Nagarajarao Y. , Gupta R. P. 
Published: February 2007

AbstractThe unsaturated hydraulic conductivity was determined in the laboratory for some red and black soils, following water movement into a horizontal column of homogenous soil of uniform packing. A highly significant positive relationship was found between moisture content and hydraulic conductivity values in all the soils studied. Correlation coefficients calculated for the relationships between soil constituents/properties and the change in hydraulic conductivity per unit change in moisture content (regression coefficient between hydraulic conductivity and moisture content) have shown positive relationship to sand and negative relationships to silt, silt + clay, clay, carbonates, aggregates > 0.25 mm and saturated hydraulic conductivity. It is concluded that the unsaturated hydraulic conductivity decreases rapidly with decrease in moisture content and this decrease depends on the soil constituents/properties and differences between soil types are clear.
Wechselwirkungen von Mikroorganismen und Tonmineralen‐eine Übersicht
Authors: Filip Z. 
Published: February 2007

AbstractDie Tonminerale gehören zu den wichtigsten bodeneigenen ökologischen Faktoren, welche die Zusammensetzung und die Stoffwechselaktivität der Bodenmikroflora beeinflussen. Ihr Einfluß auf die Bakterien, Aktinomyceten und mikroskopischen Pilze ist sehr komplex und kann auf trophogenen Beziehungen, Ionenaustauschkapazität, Sorptionsfähigkeit, osmotischen und anderen physiko‐chemischen Wirkungen beruhen. In dieser Übersichtsarbeit werden die unterschiedlichen Wirkungen der Tonminerale auf die Bodenmikroorganismen einerseits und andererseits auch der Einfluß der Mikroorganismen auf die Tonminerale zusammenfassend diskutiert.
Effect of biuret on the transformation of urea in two egyptian soils
Authors: Hadi A. H. Abdel , Hamissa M. R. , Khadr M. S. 
Published: February 2007

AbstractIn model experiments (60 % water holding capacity and 30°C) with a loamy clay (pH 8.3) and a calcareous sand (pH 7.9) the effect of biuret upon the breakdown of urea was studied. Ammonification and nitrification occured very quickly, in case of the calcareous sand at the beginning more NH4 was evolved.Biuret in concentration from 0.4 to 8 % maximum did not influence urea hydrolysis, however it resulted in higher NO2‐figures at the beginning of the experiments demonstrating an initial marked inhibition of the process NO2 → NO3 especially in the calcareous sand. The total nitrification seemed to be a little retarded but did not differ very much finally.
Efficiency of Urea, Nitrification Inhibitor treated Urea and Slow Release Nitrogen Fertilizers for Sugarcane
Authors: Parashar K. S. , Prasad Rajendra , Sharma R. P. , Sharma S. N. , Singh Surendra 
Published: February 2007

AbstractA field experiment conducted for two crop seasons (1976‐77 and 1977‐78) showed that the treatment of urea with nitrification inhibitor Nitrapyrin (also refered as ‘N‐Serve’) or neem (Azadirachta indica A. Juss) cake increased its efficiency by preventing N losses and produced significantly more cane. In one of the years sulphur coated urea (Gold N) at lower rate (75 kg N/ha) gave higher sucrose content in juice and significantly more commercial cane sugar (CCS) than uncoated urea. Considering both the cane yield and CCS production mixing or coating of urea with neem cake holds considerable promise and needs wider testing along with and in comparison to nitrification inhibitors and sulphur coated urea and other slow release fertilizers for increasing the efficiency of nitrogen applied to sugarcane.
Ferrous and ferric iron ratio in normal and chlorotic bean plants (Vicia faba L.)
Authors: Balba A. Monem , Osman A. Z. , Ghatas N. K. 
Published: February 2007

AbstractThe objective of this study was to determine the ratio and amount of Fe II and Fe III iron in different parts of 20 and 40 day old bean plants grown in pots under normal and HCO‐treatment. The Fe II and Fe III iron determination was carried out by a modification of a method described by Vogel (1969).The Fe II and Fe III concentrations in the plant varied according to its age, the plant part, the order of leaves and HCO‐treatment. At the second sampling date, the lower total iron content in the lower leaf particularly under the HCO‐treatment suggests that the supply of iron from the roots was restricted. The iron content of the different leaves was almost evenly divided into Fe II and Fe III at the first date. At the second date, most of the iron in the bud leaf was present as Fe II. Under HCO‐treatment the Fe II content of the bud leaf and the flower was similar as in the corresponding parts of the normal green plants whereas the Fe III content was considerably lowered in these plant parts as result of the HCO‐treatment.The results indicate a substantial retranslocation of iron from older to younger leaves and a higher Fe II/Fe III ratio in flowers and bud leaves particularly under HCO‐induced chlorosis.