bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evapotranspiration and groundwater recharge – A case study for different climate, crop patterns, soil properties and groundwater depth conditions ‐
Authors: Renger M. , Strebel O. , Wessolek G. , Duynisveld W. H. M. 
Published: February 2007

AbstractActual evapotranspiration and net groundwater recharge (drainage minus capillary rise) as a function of climate, soil properties, land use and groundwater depth were determined for a 15‐year period in the region north of Hannover, West‐Germany. Calculations were done using a simulation model calibrated for cropland, grassland and coniferous forest. Results of a sensitivity study showed, that the influence of climatic factors on actual evapotranspiration and net groundwater recharge increases with the amount of plant available water during the vegetation period.Under similar climatic conditions, evapotranspiration and groundwater recharge mainly depend on the two basic soil‐physical relations between.– soil water content and suction and – soil hydraulic conductivity and suction.For same groundwater depths, evapotranspiration rises with increasing plant available water in the rootzone, whereas groundwater recharge decreases.
Heavy metal species, mobility and availability in soils
Authors: Bruemmer G. W. , Gerth J. , Herms U. 
Published: February 2007

AbstractThe ecological effects of heavy metals in soils are closely related to the content and speciation of the elements in the solid and liquid phases of soils. Methods for the determination of metal species in both phases are described and critically evaluated. In connection with the possible binding mechanisms of heavy metals in soils the concept of specific and non‐specific adsorption is discussed. Recent results indicate that the adsorption of heavy metals on soil particles is not only restricted to the formation of surface complexes but can also take place in the interior of minerals. Diffusion processes of heavy metals into soil minerals are described for goethite. In order to assess metal mobility and availability in soils, the concentration and speciation of metals in the soil solution or in comparable aeqeous equilibrium solutions of soil samples and the transfer of metals from solid pools to the liquid phase and vice versa have to be assessed. Methods for the determination of the amount of plant available heavy metals are described and the associated problems discussed.
Properties of and heavy metal complexation by aqueous humic extracts
Authors: Fischer W. R. 
Published: February 2007

AbstractAqueous extracts of terrestrial and underwater soils were prepared by Soxhlet extractions at temperatures between 100 and 37°C (under reduced pressure). From the law of mass action, stability constants were derived for the complexation of Cd, Cu, and Pb by these extracts. The activity of the heavy metals was determined polarographically, whereas the concentration of acid functional groups was used for ligand activity.Visible spectra, electrical conductivity, organic matter contents, and complexation constants depended on extraction temperature as well as on soil properties. In most cases, complex stability increased with increasing pH of the polarographic medium, but sometimes maximum stability was found around pH 7.
The Nmin‐method – an aid to integrating various objectives of nitrogen fertilization
Authors: Wehrmann J. , Scharpf H. C. 
Published: February 2007

AbstractThere is increasing interest in the rate and timing of N‐fertilization from both an economical and an ecological point of view. Fertilizer recommendations for a variety of aims can be made using the Nmin‐method, as shown by experiments on deep rootable loess loam soils.Yields of cereal crops and sugar were increased by 2–3 dt/ha by application of the Nmin‐method. The Nmin‐method led to a reduction in the rate of fertilizer application by 30 kg N/ha with sugar beet.Any stipulated NO3 level in leaf vegetables can be met, if N is fertilized according to Nmin‐method. The necessary data for many vegetable crops are given. In particular low nitrate content in spinach and lettuce at high yield was achieved without loss of yield by adjusting both their NO3 and Cl nutrition.Leaching of nitrate out of soils often follows the application of too much fertilizer, but fertilization errors can be avoided and leaching reduced if the Nmin‐method is used.Applications and limitations of the Nmin‐method are discussed.
Potentials of nitrification inhibitors in modern N‐fertilizer management
Authors: Amberger A. 
Published: February 2007

AbstractModern agricultural practices require a new concept of N‐fertilizer management in order to optimize N‐utilization and avoid N‐losses. Nitrification inhibitors or „N‐stabilizers”︁ fit very good into this conception.Dicyandiamide (DCD) is an efficient nitrification inhibitor and blocks the first step of nitrification for 1–3 months (depending on temperature). This effect is bacteriostatic (not bactericidal) and does not affect other (esp. C‐heterotrophic) soil microorganisms („biological activity”︁).DCD is a non‐toxic, water soluble compound and will be degraded to CO2, NH3 and H2O without any residues.There are various possibilities to use DCD: addition to liquid manure temporarily prevents oxidation of ammonium nitrogen e.g. of slurry or waste water from potato starch production.In combination with inorganic fertilizers like ammonium sulfate or urea (with 10% of total‐N) it enables the farmer to control NH4‐supply to crop plants in certain stages of growth and to gain certain operational advantages by less frequently split applications of N especially on sand and rendzina soils.Thus, the systematic use of nitrification inhibitors not only represents a progress in agricultural technique but also helps to substantially reduce risks concerning pollution of surface and ground waters that are sometimes inevitable consequences of agricultural production.
Verteilung der Wurzelsysteme von Zea mays L. und Lupinus luteus L. in Mischkultur im Hinblick auf die Konkurrenz um Phosphat und Kalium
Authors: Fußeder A. 
Published: February 2007

AbstractIn einer Mischkultur von Mais (Stadium der Rispenblüte) und Lupine (spätes Blühstadium) wurde die räumliche Verteilung der Wurzelsysteme mit der radioautographischen Methode im Hinblick auf die Wurzelkonkurrenz um Makronährstoffe unter Freilandbedingungen in einem sandigen Boden untersucht.Die größten Wurzeldichten wurden für beide Arten in den obersten 40 cm Boden gefunden, und zwar im Umkreis von 10 cm um die jeweilige Sproßachse. Während das Wurzelwachstum von Lupine nahezu auf dieses Bodenvolumen beschränkt blieb, breitete sich das Wurzelsystem von Mais in der Horizontalen aus. Zur Erfassung einer eventuellen interspezifischen Wurzelkonkurrenz um Makronährstoffe wie Phosphat und Kalium, wurde der Durchdringung der Wurzelsysteme beider Pflanzenarten besonderes Augenmerk geschenkt. Die gegenseitige Durchdringung der Wurzelsysteme benachbart wachsender Mais‐ und Lupinenpflanzen (Abstand ca. 50 cm) war aber nur geringfügig. Auf Grund des gefundenen in situ‐Wurzelabstandsmuster der 32P markierten Mais‐ und 35S markierten Lupinenwurzeln ist keine Wurzelkonkurrenz der beiden Pflanzenarten um die im Boden wenig mobilen Makronährstoffe P und K zu erwarten. Hingegen dürfte intraspezifische Konkurrenz, d.h. Aufnahmeminderung durch Überlappung der Einzugsbereiche für P und K innerhalb des Wurzelsystems der Einzelpflanzen sowohl von Mais als auch Lupine aufgetreten sein.
Specific response of sugar beet cultivars to different nitrogen forms
Authors: Krstić B. , Gebauer G. , Sarić M. 
Published: February 2007

AbstractSix cultivars of sugar beet characterized by different sugar contents were grown in water culture on Reid‐York nutrient solution for 30 days. Nitrogen was included in the medium in the form of either NH4NO3, NH4Cl or Ca(NO3)2 at the concentrations 105, 210 and 420 mg N/l.The results obtained reveal that both shoot dry weight and leaf area were dependent upon the type of cultivar and the form and concentration of nitrogen present in the nutrient solution. The least amount of shoot matter and the smallest leaf area were obtained in the presence of ammonium as the sole nitrogen source.The concentration of total nitrate and ammonium nitrogen measured in the shoot was found to be dependent on the cultivar type and on the concentration of nitrogen present in the nutrient solution.The highest oxalic acid concentrations were detected in plants grown on nitrate. No synthesis of oxalic acid was detected upon growth on ammonium as the sole nitrogen source.
Influence of rhizosphere bacteria on morphological characteristics of maize seedlings (Zea mays L.)
Authors: Schönwitz Roswitha , Ziegler H. 
Published: February 2007

AbstractThe effect of a rhizosphere microflora on some morphological and physiological plant characteristics was studied with maize seedlings grown for five days in a mineral nutrient solution. In the presence of the microorganisms the root dry weight is lower than that of axenically grown plants due to a smaller diameter of the primary root. In addition, the root content of some vitamins and sugars is affected.Pure cultures of rhizosphere bacteria were isolated and their influence on morphological characteristics of the maize plant was classified. Whereas one culture retards the overall plant development, the remaining nine cultures exert a significant influence only on specific morphological parameters. These results are discussed as an indication of the participation of phytohormones in interactions between roots and bacteria.
Quantitative and qualitative aspects of a developing rhizosphere microflora of hydroponically grown maize seedlings
Authors: Schönwitz Roswitha , Ziegler H. 
Published: February 2007

AbstractThe roots of 7‐day‐old hydroponically grown maize seedlings inoculated with a soil suspension 2 days after sowing are mostly inhabited by shorter rods and occasionally by actinomycete‐like filaments, as seen by scanning electron microscopy. The density of the bacterial cover increases from 39 × 103 bacteria/mm2 in the region where root hairs are just emerging to 63 × 103 in the root hair zone 10 mm below the emerging secondary roots, and 188 × 103 in the oldest part 10 mm below the grain. In this region the bacterial cover can locally form a coherent multilayer. The average area covered by 1 bacterium is 1.04μm2 as measured by means of an image analyser. The percentage of the root area covered by its microflora, presuming a monolayer, is therefore 4%, 7% and 20%, respectively, of the three root zones under investigation. With an average dry weight of 0.64pg/cell all the 1.2 × 109 rhizoplane bacteria/g root dry matter only account for less than 0.1% of the root weight.The microbial population adapted to the rhizosphere has very simple nutritional demands. Whereas 65% of the soil microflora isolated on yeast extract grows on the simple aforementioned medium, the value is 92% for the rhizosphere organisms. In spite of appreciable amounts of vitamins found in the inoculated nutrient solution, the growth of vitamin requiring species is not stimulated compared to the soil population. The same is true for amino acids.
Study of wet and dry atmospheric deposition at two altitudes in central Switzerland
Authors: Fuhrer J. 
Published: February 2007

AbstractThe analysis of various ions in atmospheric deposition at two altitudes (515 m and 950 m a.s.l.) in Switzerland during 1983/84 revealed that dry deposition depends more on altitude than wet deposition. During autumn and winter, when vertical air exchange is limited, dry deposition of substances from anthropogenic sources (e.g. SO4‐S) was higher at the lower site. In the course of the year, the pattern of wet deposition was independent of altitude and showed highest rates for S, N and Ca in summertime. A comparison between rates of wet, particulate and gaseous S and N deposition suggested that during the growing season wet deposition is the dominant flux. Total (wet + dry) deposition of S, N and Cl was lower than in other parts of Europe, but a substantial increase of NO3‐N deposition during the past 25 years must have occured.
The influence of 6‐BA‐Application on Yield, Phosphorus and Nitrogen Uptake and Endogenous Cytokinin Concentrations in Carrots (Daucus carota L.) Grown in Phosphorus‐ or Nitrogen‐Depleted Soil
Authors: Stiebeling Brigitte , Pauler Bruno , Neumann Karl‐Hermann 
Published: February 2007

AbstractThe decrease in yield productivity of carrots on nitrogen and phosphate depleted soil could be compensated by 6‐BA sprays. In nitrogen or phosphorus deficient plants the concentration of 2‐iP and 2‐iPA are lower than in the control and an increase could be observed following 6‐BA applications. Nitrogen or phosphorus uptake of deficient plants was virtually not affected by 6‐BA application. Consequently dry matter production per unit nutrient taken up by the plants (nutrient efficiency ratio) was increased as compared to the optimally with nitrogen and phosphate supplied control or the deficient plants.
Characterization of humic substances obtained from calcareous soils from Greece with various extractants. II. Physical characterization
Authors: Kallianou Chariklia S. , Ziechmann Wolfgang , Yassoglou N. J. 
Published: February 2007

AbstractHumic substances from the Ah horizons of five differently calcareous soils from Greece were successively extracted with organic solvents and/or 0.1 N NaOH and they were characterized by UV/VIS/IR spectroscopy and differential thermal analysis (DTA).Diethylether, acetone and dioxane extracts contained non‐humic substances such as aliphatic and aromatic ethers, esters, alcoholes and long aliphatic chains, while low molecular weight humic substances were found in the ethanol extracts. All the extracts were found to contain phenolic and ϵ‐acceptor compounds.Some differences in the physical characteristics of the humic substances were associated with the kinds of vegetation. The IR‐spectra showed no essential differences between HA's and FA's extracted directly with NaOH or after previous soil extraction with organic solvents. HA's extracted directly by NaOH from soil samples under grass had a higher degree of condensation and thermal stability and generally higher carbon contents than those from soils under pine, cultivation and sedges.
Dynamik verschiedener N‐Fraktionen bei Abbauversuchen mit Brennesselblättern (Urtica dioica L.)
Authors: Zucker Alfons , Zech Wolfgang 
Published: February 2007

AbstractAn vier verschiedenen Standorten (Auenwälder, Halbtrockenrasen, Feldrain) wurden Urtica‐dioica‐Blätter in Nylonnetzen unterschiedlicher Maschenweite (0,05, 1,5 und 5,0 mm) deponiert, um die Stickstoffdynamik während der Streuzersetzung unter differierenden Standortsbedingungen und unter dem Einfluß verschieden großer Destruenten zu studieren.Lediglich das Tempo, nicht jedoch die Richtung der N‐Dynamik ist standortsabhängig. Im Gegensatz dazu bedingt die unterschiedliche Maschenweite charakteristische Veränderungen. Der Abbau verläuft auf den Freiflächen langsamer als im Auenwald, wo auch der Aminozuckergehalt der Exponate höher ist. Der Anteil der Aminozucker am Gesamt‐N steigt im Lauf der Zersetzung von durchschnittlich 0,75 auf 2,8 in den 0,05 mm Netzen bzw. auf 4,8% in jenen größerer Maschenweiten. Die gleiche Tendenz zeigt der nicht hydrolysierbare Stickstoff, der von durchschnittlich 13% zu Beginn der Experimente auf 25% von Gesamt‐N ansteigt. Hydrolysierbarer unbekannter N nimmt am Versuchsende in den 0,05 mm Beuteln dagegen durchschnittlich 21, in den 1,5 mm Netzen 13 und in den 5,0 mm Beuteln nur 9% des Gesamt‐N ein. Amid‐N nimmt geringfügig, wasserlöslicher Stickstoff stark ab. Der Amino‐N unterliegt auffälligen Schwankungen während des Abbaus, am Versuchsende aber werden, wie zu Versuchsbeginn, etwa 48% des Gesamt‐N von aminosäurebürtigem Stickstoff eingenommen.
Denitrification losses from an Inceptisol field treated with mineral fertilizer or sewage sludge
Authors: Benckiser G. , Gaus G. , Syring K.‐M. , Haider K. , Sauerbeck D. 
Published: February 2007

AbstractIn order to evaluate the climatic and soil variables which control the denitrification processes in the field, measurements of N2O‐losses using the C2H2 inhibition technique were carried out in an Inceptisol cropped with spring wheat. The silty sand was amended with mineral fertilizer (120 kg N ha−1) or additionally with sewage sludge (620 kg total N ha−1). Soil temperature, moisture, nitrate and available carbon, the release of nitrous oxide (N2O) from the soil surface as well as the N2O concentrations along the soil profile were measured from March until November 1985The N2O surface fluxes from the inorganically fertilized field were well correlated with those from the sewage sludge amended plots (r = 0.76). Multivariate correlation analyses show that particularly soil moisture and nitrate content had a significant effect on the nitrate respiration. The correlation with the soil water content was more clearly expressed by the N2O surface fluxes than by the N2O concentrations of the soil air. The N2O surface fluxes during 1985 totalled about 3 kg N ha−1 in the minerally fertilized field. Sewage sludge amendments increased the N2O evolution by 5 times. Spatial variability was high and the N2O surface fluxes were not well correlated (r = 0.4) with the N2O concentrations in the soil atmosphere.These experiments provide the background data for a denitrification model and better knowledge about the variables which have to be considered for its validation.
Methoden zur relativen Quantifizierung der pilzlichen Biomasse im Boden
Authors: Zelles Laszlo , Hund Kerstin , Stepper Kai 
Published: February 2007

AbstractZur Erfassung des pilzlichen Anteils der Bodenmikroflora wurden der Chitin‐ und Ergosterolgehalt und die Entfärbung des Farbstoffes Poly‐B‐411 quantitativ bestimmt. Diese Verfahren ergaben einen linearen Zusammenhang von eingesetzter Bodenmenge und Gehalt der jeweiligen Substanz. Methodisch bedingt konnte das Ergosterol präziser erfaßt werden als das Chitin. Bei der Entfärbung von Poly‐B‐411‐Farbstoff lag die Aktivität in feuchtem, aerobem Boden über der in Bodensuspension. Die Extinktionsverhältnisse (593/483 nm) als Maß für den Abbau stabilisierten sich zwischen dem 5. und 7. Tag.
CPMAS 13C NMR and IR spectra of spruce and pine litter and of the Klason lignin fraction at different stages of decomposition
Authors: Zech Wolfgang , Johansson Maj‐Britt , Haumaier Ludwig , Malcolm Ronald L. 
Published: February 2007

AbstractFresh and decomposed spruce and pine litter and the Klason lignin fraction of spruce needles at different stages of decomposition were studied by CPMAS 13C NMR and IR spectroscopy as well as by chemical methods. It was shown that decomposition of needles is accompanied by an increase in aliphatic substances and carboxyl group content; the amount of polysaccharides is reduced. It is assumed that stable aliphatic compounds like cutin and lipids of microbial origin will accumulate during litter decomposition and humification. Aromaticity is low and does not alter drastically. The NMR spectra of the Klason lignin fraction show pronounced peaks at 30, 55, 115, 130, 150 and 175 ppm. Obviously, this fraction contains appreciable amounts of aliphatic and carboxyl carbon besides the typical aromatic units of lignin. During decomposition aromaticity decreases whereas the relative amounts of aliphatic substances and carboxyl groups increase. This is probably due to splitting of aromatic ring structures and side chains. The findings agree with the results from chemical analyses.
Comparison and classification of the effects of simple ions and molecules upon the transformation of ferrihydrite into more crystalline products
Authors: Cornell Rochelle M. 
Published: February 2007

AbstractThe effects of various simple ions and molecules on the extent and products of the conversion of ferrihydrite into more crystalline products are compared. These ions and molecules can be classified according to how strongly they retard the transformation of ferrihydrite, whether they favour the formation of haematite relative to goethite or whether they retard the formation of goethite more strongly than that of haematite and finally, whether foreign ions can replace a proportion of Fe in the goethite structure.Simple ions and molecules operate through two mechanisms. They adsorb on ferrihydrite and stabilize it and they also act by hindering the nucleation of goethite in solution. Adsorption on ferrihydrite retards the transformation to a far greater extent than does interference in solution.
Die Bedeutung von hohen Aluminiumgehalten für die Humusanreicherung in sauren Waldböden
Authors: Blaser Peter , Klemmedson James O. 
Published: February 2007

AbstractAm Beispiel von zwei repräsentativen Bodenprofilen in der Kastanienstufe des Kantons Tessin (Schweiz) wurde die Wirkung von hohem Aluminiumgehalt auf die Humusbildung untersucht. Der Kryptopodsol repräsentiert die sauren Waldböden, welche auf Al‐reichen Gneisen und Glimmerschiefern verbreitet sind. Das Vergleichsprofil, eine saure Braunerde, entspricht dagegen einem sauren Waldboden, der aus einem Kalksilikatgestein hervorgegangen ist. Dieses Gestein enthält ca. 20 mal weniger Aluminium als der Gneis.Die Extraction der Bodenproben mit HNO3, Ammoniumacetat‐EDTA, NH4Cl, KCl und NH4F‐HCl erlaubt eine Beurteilung der relativen Bindungsstärken und ‐formen wichtiger Elemente in den beiden Böden. Im Al‐reichen Kryptopodsol ist Aluminium vorwiegend an die organische Substanz gebunden. Dieser Boden ist sehr humusreich und bis in 70 cm Tiefe schwarz gefärbt. Es wird vermutet, daß die Humusmineralisation durch die Bindung von Aluminium an die organische Substanz gehemmt wird. Die hohen Anteile an organischem Phosphor bei gleichzeitig geringen Mengen von NH4F‐HCl‐Orthophosphat deuten in die selbe Richtung. Die Kryptopodsole besitzen morphologische, chemische und physikalische Eigenschaften, die jenen von nicht allophanhaltigen Andosolen ähnlich sind. Bei der sauren Braunerde fehlen diese Eigenschaften.
Exogenous application of vitamins as regulators for growth and development of plants — a review
Authors: Oertli J. J. 
Published: February 2007

AbstractA survey of the recent literature on plant responses to exogenous vitamin application yielded the following results:Vitamins have been applied by soaking seeds, dipping cuttings, by sprays or dusts and as drenches to soils.Substantial yield increases due to exogenous vitamin application have been reported by a number of researchers.Vitamins may cause morphogenetic responses in plants. Most pronounced is the stimulation of root formation and of flowering under non‐inductive conditions.Certain vitamins protect plants against ozone and sulfur dioxide, two important agents of air pollution.
Reclamation of a fine clayey montmorillonitic soil with high‐salt water under laboratory conditions
Authors: Misopolinos N. D. 
Published: February 2007

AbstractAn impermeable fine clayey montmorillonitic soil (Aquic Xerofluvent) was reclaimed using high‐salt water and the addition of a constant quantity of Ca at each step in successive dilutions. The soil attained the theoretically expected values of ESP and the depth of water which passed through the soil was close to the theoretical level. The leachate was studied throughout the process of reclamation and the following results obtained: At the end of the reclamation all ions were seen to be decreasing. The percolation rate of the soil and the „valence‐dilution”︁ effect of the reclaiming water permitted a satisfactory exchange of Na by Ca and Mg keeping the quantity of water close to the theoretically expected levels. The mean hydraulic conductivity (MHC) is strongly depended on the electrolyte concentration and the sodium/total concentration (Na/C) or Ca+Mg/total concentration (R) values of the leachate.