bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative study of organic dyes with time‐of‐flight static secondary ion mass spectrometry and related techniques
Authors: Adriaensen L. , Vangaever F. , Lenaerts J. , Gijbels R. 
Published: February 2005

AbstractA series of cationic, zwitterionic and anionic fluorinated carbocyanine dyes, spin‐coated on Si substrates, were measured with time‐of‐flight static secondary ion mass spectrometry (TOF‐S‐SIMS) under Ga+ primary ion bombardment. Detailed fragmentation patterns were developed for all dyes measured. In the positive mode, the resulting spectra showed very intense signals for the precursor ions of the cationic dyes, whereas the protonated signals of the anionic dyes were hardly detected. Differences of three orders of magnitude were repeatedly observed for the secondary ion signal intensities of cationic and anionic dyes, respectively. All measured dyes yielded mass spectra containing several characteristic fragment ions. Although the secondary ion yields were still higher for the cationic than the anionic dye fragments, the difference was reduced to a factor of ≤10. This result and the fact that M+, [M + H]+ or [M + 2H]+ are even‐electron species make it very likely that the recorded fragments were not formed directly out of the (protonated) parent ions M+, [M + H]+ or [M + 2H]+. In the negative mode, none of the recorded spectra contained molecular information. Only signals originating from some characteristic elements of the molecules (F, Cl), the anionic counter ion signal and some low‐mass organic ions were detected. A comparative study was made between TOF‐S‐SIMS, using Ga+ primary ions, and other mass spectrometric techniques, namely fast atom bombardment (FAB), electrospray ionization (ESI) and matrix‐assisted laser desorption/ionization (MALDI). The measurements showed that MALDI, ESI and FAB all give rise to spectra containing molecular ion signals. ESI and FAB produced M+ and [M + H]+ signals, originating from the cationic and zwitterionic dyes, in the positive mode and M− and [M − H]− signals of the anionic and zwitterionic dyes in the negative mode. With MALDI, molecular ion signals were measured in both modes for all the dyes. Structural fragment ions were detected for FAB, ESI and MALDI in both the positive and negative modes. Compared with the other techniques, TOF‐S‐SIMS induced a higher degree of fragmentation. Copyright © 2005 John Wiley & Sons, Ltd.
Plant‐growth‐promoting rhizobacteria isolated from a Calcisol in a semi‐arid region of Uzbekistan: biochemical characterization and effectiveness
Authors: Egamberdiyeva Dilfuza 
Published: February 2005

AbstractBacteria were isolated from the rhizosphere of cotton, wheat, alfalfa, and tomato grown in field locations within a semi‐arid region of Uzbekistan. Strains were identified as Pseudomonas denitrificans, P. rathonis, Bacillus laevolacticus, Bacillus amyloliquefaciens, and Arthrobacter simplex. The isolated strains produced different enzymes, phytohormone auxin and were antagonists against specific plant‐pathogenic fungi. Most of the strains are tolerant with respect to salt and temperature. All of the bacterial strains isolated in this study have been found to increase plant growth of wheat and maize in pot experiments.
Effects of nitrate‐, ammonium‐, and organic‐nitrogen‐based fertilizers on growth and yield of tomatoes
Authors: Heeb Anuschka , Lundegårdh Bengt , Ericsson Tom , Savage Geoffrey P. 
Published: February 2005

AbstractMineral and organic fertilizers contain different forms and amounts of nitrogen (N), which can affect yield and product quality. The aim of this study was to determine appropriate amounts of N applied as nitrate (NO$ _3^- $), ammonium (NH$ _4^+ $), and organic N (a mixture based on chicken manure) for optimal growth and quality of tomatoes. A pot experiment with sand as substrate was established in a greenhouse with six‐week‐old tomato plants (Lycopersicon esculentumMill. cv. “Armada”). Nitrogen was applied in nutrient solutions at different NO$ _3^- $: NH$ _4^+ $ratios combined with different chloride levels (NO$ _3^- $‐dominated, NO$ _3^- $= NH$ _4^+ $at low Cl–, NO$ _3^- $= NH$ _4^+ $at high Cl–, and NH$ _4^+ $‐dominated, respectively) or as organic N at four N‐application rates (250, 500, 750, 1000 mg N plant–1week–1). No significant differences in shoot biomass and yields of red tomatoes were observed between NO$ _3^- $‐ or NH$ _4^+ $‐fed plants. Nitrogen rates above 750 mg N plant–1week–1did not significantly increase marketable fruit yield, but enhanced shoot‐biomass production. The NH$ _4^+ $‐N‐dominated treatments (which also had high Cl–concentrations) showed increasing incidence of blossom‐end‐rot (BER)‐infected fruits. In the organic‐N treatments, shoot‐biomass production and yields were lower than in the inorganic‐N treatments, but fruit quality was good with few BER‐infected fruits. The results show that with a total N supply below 750 mg N plant–1week–1, NH$ _4^+ $can be used as equivalent N source to NO$ _3^- $, resulting in equivalent yields of marketable fruit under the conditions in this experiment.
Root morphology of Thlaspi goesingense Hálácsy grown on a serpentine soil
Authors: Himmelbauer Margarita L. , Puschenreiter Markus , Schnepf Andrea , Loiskandl Willibald , Wenzel Walter W. 
Published: February 2005

AbstractThe contribution of root morphology to enhanced uptake of heavy metals by hyperaccumulating plants is not well understood. The objective of this study was to describe root‐morphological characteristics of the natural nickel (Ni) hyperaccumulator Thlaspi goesingense Hálácsy. Plant samples were collected from a serpentine site near Redlschlag (East Austria), characterized by large soil Ni concentrations. Roots were evaluated for mass, length, surface area, diameter, and related ratios using an image‐analysis approach. Results showed that on the indigenous site, T. goesingense Hálácsy developed a fine‐branched root system, confined within a shallow soil depth. Coarse roots (>1 mm) accounted for about 60% of the total root mass (fresh and dry), while their contribution to the surface area and especially to the length of the system was small. Conversely, fine roots (<1 mm) represented 99% of the total root length and 88% of the surface area. The largest proportion of root length and area was found in the smallest diameter class of 0.0 to 0.5 mm. Shoot‐biomass production per unit root was high, in spite of the adverse soil conditions. Roots accounted for 8% of the total plant mass and about 4% of the total Ni accumulation. We conclude that the root system of natively grown T. goesingense Hálácsy exhibits a potential for enhanced Ni extraction from soil, since it mainly consists of very fine roots with extended absorptive area.
Anwendbarkeit geophysikalischer Prospektionsmethoden zur Bestimmung von Bodenverdichtungen und Substratheterogenitäten landwirtschaftlich genutzter Flächen
Authors: Petersen Hauke , Fleige Heiner , Rabbel Wolfgang , Horn Rainer 
Published: February 2005

AbstractDer Einsatz zunehmend schwerer Landtechnik bei der Bodenbearbeitung kann nachhaltig wirkende Bodenverdichtungen bzw. Bodenverformungen bis in den Unterbodenbereich (Tiefe > 30 cm) unterhalb des Bearbeitungshorizonts verursachen. Bei derartig verdichteten Böden sind Bodenfunktionen wie Wasser‐ und Luftleitfähigkeiten vermindert, so dass sich die Bedingungen für das Pflanzenwachstum verschlechtern und die Böden in ihrer natürlichen Regelungsfunktion beeinträchtigt werden können. Um Gegenmaßnahmen treffen zu können, ist also die Kenntnis des Verdichtungszustands im Boden notwendig.Da der Verdichtungszustand bisher nur punktuell durch aufwändige Messungen im Labor oder mit geringerer Genauigkeit im Feld bestimmt werden kann, stellt sich die Frage nach einem leistungsfähigen flächenhaften Kartierverfahren. Die prinzipielle Anwendbarkeit verschiedener geophysikalischer Prospektionsverfahren sollte auf diese bodenkundliche Fragestellung hin untersucht werden. Dazu wurden auf einem konventionell bewirtschafteten Jungmoränenstandort in Schleswig‐Holstein vergleichende bodenkundliche und geophysikalische Messungen durchgeführt. Folgende geophysikalische Verfahren kamen zum Einsatz: Georadar (GPR – Ground Penetrating Radar) im Frequenzbereich 500 MHz und 900 MHz, ergänzt durch induktive Leitfähigkeitsmessungen mit dem EM38 einerseits sowie hochauflösende Kompressions‐ und Scherwellenseismik andererseits. Substratheterogenitäten im Unterboden zeichneten sich in allen hier angewandten Verfahren ab, so dass Standorte mit höherer Verdichtungsempfindlichkeit (lehmige Böden) von Standorten mit geringerem Verdichtungspotenzial (sandige Böden) unterschieden werden konnten. Die Radardaten zeigten bei Feldkapazität starke Reflexionen in einer Tiefe von ca. 30 cm, die im Sommer bei trockenen Bedingungen nicht mehr zu beobachten waren. Diese zeitliche Variation der Radarsig‐nale lässt sich durch nur temporär vorhandene Stauwasserbereiche erklären, die auf eine Bodenverdichtung hindeuten können. Seismische Messungen mit Kompressions‐ und Scherwellen wurden entlang kurzer Profillinien (12 m) mit dichtem Sensorabstand (20 cm) durchgeführt. Die gute bis sehr gute Datenqualität dieser Messungen, die sonst für ingenieurgeophysikalische Zwecke eingesetzt werden, zeigt, dass dieses Verfahren auch für bodenkundliche Fragestellungen geeignet ist. Substratvariationen im Unterboden beeinflussten v. a. die Geschwindigkeiten von Kompressionswellen. Ob sich unterschiedlich verdichtete Bereiche detektieren lassen, ist noch offen, da in der Messfläche nur eine gleichmäßig starke Verdichtung des Unterbodens mit geringen Dichtekontrasten bei gleichem Bodentyp vorlag.
Rekonstruktion des Paläomilieus und der Geo‐Pedogenese kalkfreier Marschböden Niedersachsens
Authors: Duntze Oliver , Watermann Frank , Giani Luise 
Published: February 2005

AbstractDie Genese kalkfreier Marschböden ist nach wie vor strittig. Zur Klärung dieser Frage erfolgte deshalb beispielhaft an zwei Knickmarschen Ostfrieslands die Rekonstruktion ihres Paläomilieus mittels Ergebnissen der Röntgenfluoreszenzspektroskopie, Rasterelektronen‐ und Durchlichtmikroskopie. Profil 1 gliedert sich in sieben Fazies. Die Diatomeenflora deutet auf zeitlich variierende Paläomilieus limnischer, brackischer und mariner Ausprägung hin. Im Grenzbereich von mineralischem Material und Torf sowie im Torf selbst wurden Pyritkristalle gefunden. Die zudem häufig auftretenden engen Zr:Al‐ und Si:Al‐Verhältnisse sowie die engen Ca:Sr‐Verhältnisse weisen auf ruhige, brackische bis lagunäre Sedimentationsbedingungen mit Schilftorfbildung im Rückseitenwatt hin. Profil 2 gliedert sich in zwei Fazies, deren Übergang durch einen plötzlichen Wechsel der Diatomeenzusammensetzung, der geochemischen Eigenschaften und des Carbonatgehalts charakterisiert ist. Die Diatomeenflora und die Ca:Sr‐Verhältnisse der unteren Fazies kennzeichnen ein Priel‐Habitat mit marinem Kontakt und ungewöhnlich engen Si:Al‐ und Zr:Al‐Verhältnissen. Die Ergebnisse lassen vor allem für viele Fazies von Profil 1 auf Entkalkungsprozesse während der Geo‐Pedogenese schließen. Für heute kalkfreie Marschböden gibt es demnach zwei Stadien der Entkalkung, zum einen die frühe Geo‐Pedogenese, wie sie eher für die Knickmarschen Niedersachsens für wahrscheinlich gehalten wird, und zum anderen die spätere terrestrische Entwicklungsphase von der Kalk‐ zur Kleimarsch.
Zusammenhang zwischen hydraulischer und mechanischer Bodenstabilität in Abhängigkeit von der Belastungsdauer
Authors: Fazekas Orsolya , Horn Rainer 
Published: February 2005

AbstractIn Untersuchungen zur Bodenverdichtung wird meist nur die direkte Beziehung zwischen der mechanischen Belastung und der Porenänderung, nicht hingegen die Interaktion zwischen mechanischen und hydraulischen Prozessen als Funktion der Zeitdauer der Belastung bzw. der Häufigkeit der Belastung betrachtet. In der vorliegenden Arbeit wird daher die Beziehung zwischen der Vorbelastung als Maß der mechanischen Stabilität und der Wasserspannungsänderung während einer Belastung analysiert. Die Untersuchungen wurden an gestörtem Bodenmaterial (Ut3) bei einer Anfangslagerungsdichte von 1,4 g cm–3 mit einem Wassergehalt von 25 Gew.% jeweils an vier Parallelproben durchgeführt. Die Bodenproben wurden mit acht verschiedenen Auflasten zwischen 20 und 400 kPa und vier Auflastzeiten (10–240 min) belastet; die Wasserspannungs‐ und die Porenzifferänderungen wurden registriert. Mit steigender Belastungsdauer werden die Proben bei gleicher Auflast intensiver verdichtet. Dadurch sinkt der Wert der Vorbelastung. Gleichzeitig ändert sich während der Belastung die Wasserspannung, denn als Folge der Komprimierung werden die Porenquerschnitte enger und deshalb der Wassersättigungsgrad höher. Damit einher geht je nach verbleibender Bodenfestigkeit auch eine zunehmende Übertragung der mechanischen Auflast auf die flüssige Phase. Dies bedeutet, dass eine Änderung des Porenwasserdruckes von negativ (= Wasserspannung) bis hin zu einem positiven Wert (= Porenwasserüberdruck) reichen kann. Bereits unterhalb des nach Casagrande (1936) berechneten Vorbelastungswertes nimmt der Porenwasserdruck deutlich ab. Die erzielten Ergebnisse zeigen, dass Strukturstabilitätseffekte durch Berücksichtigung der Wasserspannungsänderungen während der Belastung quantifiziert werden müssen, um ein vollständiges Bild der Bodendeformation zu erhalten.
Erosion processes and erodibility of cultivated soils in North Rhine‐Westphalia under artificial rain. I. Site characteristics and results of laboratory experiments
Authors: Kehl Martin , Everding Christoph , Botschek Johannes , Skowronek Armin 
Published: February 2005

AbstractSoil erosion by water causes substantial on‐site degradation and off‐site damages in the densely populated state of North Rhine‐Westphalia (Germany). Measures of soil conservation should be adjusted to soil erodibilities and should be based on an understanding of the processes involved in water erosion including aggregate breakdown, rainsplash erosion, surface sealing, and soil loss. For a state‐wide assessment of erosion processes and erodibilities, we tested representative cultivated soils of North Rhine‐Westphalia in laboratory and field experiments with artificial rain. In the laboratory experiments described in this paper, rainsplash erosion, sealing susceptibility, and interrill erodibility of 25 topsoils filled in 0.5 m2 boxes were investigated.Results of different aggregate‐stability tests correlate with organic‐matter contents but not with parameters of rainsplash or soil loss. On most soil materials, rainsplash increases or maintains constant rates in the course of the simulation runs indicating that the soil surface did not attain a higher shear resistance. High sealing susceptibilities are found for soils of quite different textures ranging from loam sand to silt clay, whereas other silt clays, clay loams, and some clay silts maintain high infiltration rates. A trend of increasing sealing susceptibility and total soil loss with increasing clay content is observed for the loam sands to sand loams.Dynamics of soil loss is largely governed by runoff rates. Total soil loss is also determined by sediment concentration in surface runoff, which is low on most clayey soils, on loam sands poor in clay, and on a sand loam, and high in the case of highly erodible clay silts, loam sands, and sand loams. The most crust prone soils are not necessarily the most erodible.On most soils, soil‐loss rates do not stabilize until the end of the rainfall experiments. For comparing the interrill erodibilities of the soils, total soil loss is preferred instead of interrill erodibility factors (Ki, Kiq) published in the literature.
Digital soil mapping using artificial neural networks
Authors: Behrens Thorsten , Förster Helga , Scholten Thomas , Steinrücken Ulrich , Spies Ernst‐Dieter , Goldschmitt Michael 
Published: February 2005

AbstractIn the context of a growing demand of high‐resolution spatial soil information for environmental planning and modeling, fast and accurate prediction methods are needed to provide high‐quality digital soil maps. Thus, this study focuses on the development of a methodology based on artificial neural networks (ANN) that is able to spatially predict soil units. Within a test area in Rhineland‐Palatinate (Germany), covering an area of about 600 km2, a digital soil map was predicted. Based on feed‐forward ANN with the resilient backpropagation learning algorithm, the optimal network topology was determined with one hidden layer and 15 to 30 cells depending on the soil unit to be predicted. To describe the occurrence of a soil unit and to train the ANN, 69 different terrain attributes, 53 geologic‐petrographic units, and 3 types of land use were extracted from existing maps and databases. 80% of the predicted soil units (n = 33) showed training errors (mean square error) of the ANN below 0.1, 43% were even below 0.05. Validation returned a mean accuracy of over 92% for the trained network outputs. Altogether, the presented methodology based on ANN and an extended digital terrain‐analysis approach is time‐saving and cost effective and provides remarkable results.
Impact of organic manures with and without mineral fertilizers on soil chemical and biological properties under tropical conditions
Authors: Kaur Kulvinder , Kapoor Krishan K. , Gupta Anand P. 
Published: February 2005

AbstractSoils receiving organic manures with and without chemical fertilizers for the last 7 yr with pearlmillet–wheat cropping sequence were compared for soil chemical and biological properties. The application of farmyard manure, poultry manure, and sugarcane filter cake alone or in combination with chemical fertilizers improved the soil organic C, total N, P, and K status. The increase in soil microbial‐biomass C and N was observed in soils receiving organic manures only or with the combined application of organic manures and chemical fertilizers compared to soils receiving chemical fertilizers only. Basal and glucose‐induced respiration, potentially mineralizable N, and arginine ammonification were higher in soils amended with organic manures with or without chemical fertilizers, indicating that more active microflora is associated with organic and integrated system using organic manures and chemical fertilizers together which is important for nutrient cycling.
Root growth and N‐uptake activity of oilseed rape (Brassica napus L.) cultivars differing in nitrogen efficiency
Authors: Kamh Mahmoud , Wiesler Franz , Ulas Abdullah , Horst Walter J. 
Published: February 2005

AbstractNitrate‐N uptake from soil depends on root growth and uptake activity. However, under field conditions N‐uptake activity is difficult to estimate from soil‐N depletion due to different loss pathways. We modified the current mesh‐bag method to estimate nitrate‐N‐uptake activity and root growth of two oilseed‐rape cultivars differing in N‐uptake efficiency. N‐efficient cultivar (cv.) ‘Apex' and N‐inefficient cv. ‘Capitol' were grown in a field experiment on a silty clayey gleyic fluvisol near Göttingen, northern Germany, and fertilized with 0 (N0) and 227 (N227) kg N ha–1.In February 2002, PVC tubes with a diameter of 50 mm were installed between plant rows at 0–0.3 and 0–0.6 m soil depth with an angle of 45°. At the beginning of shooting, beginning of flowering, and at seed filling, the PVC tubes were substituted by PVC tubes (compartments) of the same diameter, but with an open window at the upper side either at a soil depth of 0–0.3 or 0.3–0.6 m allowing roots to grow into the tubes. Anion‐exchange resin at the bottom of the compartment allowed estimation of nitrate leaching. The compartments were then filled with root‐free soil which was amended with or without 90 mg N (kg soil)–1. The newly developed roots and nitrate‐N depletion were estimated in the compartments after the installing period (21 d at shooting stage and 16 d both at flowering and grain‐filling stages). Nitrate‐N depletion was estimated from the difference between NO$ _3^- $‐N contents of compartments containing roots and control compartments (windows closed with a membrane) containing no roots. The amount of nitrate leached from the compartments was quantified from the resin and has been taken into consideration in the calculation of the N depletion. The amount of N depleted from the compartments significantly correlated with root‐length density.Suboptimal N application to the crop reduced total biomass and seed‐yield formation substantially (24% and 38% for ‘Apex’ and ‘Capitol’, respectively). At the shooting stage, there were no differences in root production and N depletion from the compartments by the two cultivars between N0 and N227. But at flowering and seed‐filling stages, higher root production and accordingly higher N depletion was observed at N0 compared to N227. Towards later growth stages, the newly developed roots were characterized by a reduction of root diameter and a shift towards the deeper soil layer (0.3–0.6m). At low but not at high N supply, the N‐efficient cv. ‘Apex’ exhibited higher root growth and accordingly depleted nitrate‐N more effectively than the N‐inefficient cv. ‘Capitol’, especially during the reproductive growth phase. The calculated nitrate‐N‐uptake rate per unit root length was maximal at flowering (for the low N supply) but showed no difference between the two cultivars. This indicated that the higher N‐uptake efficiency of cv. ‘Apex’ was due to higher root growth rather than higher uptake per unit of root length.