bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors controlling Al‐activity in soil solutions in an acid forest soil of the German Solling area
Authors: Matzner Egbert 
Published: February 2007

AbstractThe forests of the German Solling area are heavily impacted by acidic deposition. Analysis of soil solutions derived from suction lysimeters in the field reveal strong vertical gradients of Al‐activity in the soil solution and increasing activity with soil depth. Temporal pattern of Al‐ activity in soil solutions under field conditions cannot easily be predicted by equilibrium models using Al(OH)3 dissolution. Percolating disturbed soil samples under laboratory conditions with artificial acid soil solutions undersaturated to Al(OH)3 solids resulted in high rates of Al release in the 30–40 cm layer and revealed Al(OH)3 as a possible Al‐activity controlling solid. The laboratory findings are not in coincidence with field observations. This discrepancy with respect to the regulation of Al activity in the 30–40 cm layer is attributed to the effect of soil structure and the interaction of macropores and micropores under field conditions. Al activity of the soil solution in the 0–10 cm layer seems to be regulated by exchange reactions with organic substances.
Properties and composition of soil organic matter in forest and arable soils of Schleswig‐Holstein: 1. Comparison of morphology and results of wet chemistry, CPMAS‐13C‐NMR spectroscopy and pyrolysis‐field ionization mass spectrometry
Authors: Beyer Lothar , Schulten Hans‐Rolf , Fründ Rüdiger 
Published: February 2007

AbstractProperties and composition of 25 soil samples (0.8–51% Corg) were determined by morphology, wet chemistry, CPMAS‐13C‐NMR‐spectroscopy and pyrolysis‐field ionization mass spectrometry (Py‐FIMS). The recovery rate of organic carbon was 102% (±15%). The correlation between the litter compound/humic compound ratio and humification grade, estimated with morphological observations, was strong (r2 = 0.502***). A typical classification of horizons (L, O, H, Ah+M) with regard to organic compounds (wet chemistry and 13C‐NMR) was not always significant. The pyrolysis‐mass spectra confirmed and extended on the basis of molecular chemical structures the results of wet chemistry, especially with polysaccharides, nitrogen compounds, lignin, lipids and alkylaromatics (r2 = 0.818–0.937***). A correlation between the NMR‐aliphatics, the humic compounds isolated by wet chemistry, and the long‐chain aliphatic carbon units in the pyrolysis‐mass spectra was established.
Dissolution of Poorly Crystalline Iron Oxides in Soils by EDTA and Oxalate
Authors: Borggaard Ole K. 
Published: February 2007

AbstractPoorly crystalline iron oxides in soils are often estimated by 2 hours oxalate extraction at pH 3 and less often by 3–7 months EDTA extraction at pH 7.5–10.5. Calculated solubility products (Ksp) of iron oxides in equilibrium with EDTA and oxalate showed EDTA to dissolve only iron oxides with Ksp > 10−40‐10−41 at pH > 10, whereas at pH 3 oxalate (and EDTA) should theoretically dissolve all iron oxides. The different pHs could largely account for the great difference in extraction speed between the two methods.Although EDTA and oxalate seem to act by surface complexation, where the adsorbed ligand by attenuating lattice Fe‐O bonds causes iron detachment, the mechanisms are considered to be different. Possibly EDTA forms tetranuclear surface complexes, which are considered to inhibit dissolution of well crystallized but not poorly crystallized iron oxides due to differences in bond strengths. Oxalate forming binuclear and mononuclear surface complexes can probably also act as an electron bridge between iron(II) in solution and surface iron(III) leading to iron(II) catalyzed dissolution of iron oxides. This mechanism is obviously of particular importance in the dissolution of magnetite and maghemite.Despite the great theoretical differences the published methods with EDTA and oxalate dissolve comparable amounts of iron from many soils and the dissolved iron corresponds to poorly crystalline (highly reactive) iron oxides, mainly ferrihydrite.
Long‐term trapping efficiency of a vegetated filter strip under agricultural use
Authors: Schauder Horst , Auerswald Karl 
Published: February 2007

AbstractIn a hops‐producing area long‐term average trapping‐effectiveness of a grassed filterstrip under agricultural use was measured. Copper, applied as fungicide, was used to identify the colluvium in a meadow below a hop garden. 9,5 t material were trapped during 17 years per m width of the filterstrip. This annual accumulation of 540 kg/m width represents a trapping efficiency of 55% of the computed annual soil loss of the hop garden. The results agree with other publications which report the trapping efficiency for a longer period, whereas the reported results of short‐term experiments largely overestimate the efficiency.
Bildung schlechtkristalliner bis amorpher Verwitterungsprodukte in stark bis extrem versauerten Waldböden
Authors: Veerhoff Michael , Brummer Gerhard W. 
Published: February 2007

AbstractMit Hilfe röntgenographischer (RDA), röntgenfluoreszenzanalytischer (RFA), elektronenoptischer (REM, EDAX) und chemischer Analysen wurde versucht, die als Folge einer weitflächigen extremen Versauerung von Waldböden durch Silicatverwitterung gebildeten amorphen bis schlechtkristallinen Abbauprodukte mineralogisch und chemisch näher zu kennzeichnen. Die Untersuchungen erfolgten an fünf stark bis extrem versauerten Waldböden (verschiedene Parabraunerden, ein Parabraunerde‐Pseudogley und ein Parabraunerde‐Podsol) mit unterschiedlichem Ausgangsmaterial (Löß, Sandlöß und Geschiebesand/lehm) aus Nordrhein‐Westfalen und Schleswig‐Holstein. Wie die Ergebnisse zeigen, hat in den sehr stark bis extrem versauerten Oberböden sowie in den B‐Horizonten von Waldstandorten eine starke Zerstörung von Tonmineralen und anderen Silicaten und damit verbunden eine Anreicherung schlechtkristalliner bis amorpher Verbindungen stattgefunden. Die gebildeten Abbauprodukte liegen zumeist als flächenhaft auftretende kieselsäurereiche Aggregatüberzüge und Verkittungen oder in Form von kleinräumigen Ausfällungen auf Mineraloberflächen vor. Neben Si enthalten die Überzüge auch geringe Anteile an Al und Fe.
Wechselwirkungen zwischen Boden‐Huminstoffen und Metall‐Ionen III. Komplexbildung von Boden‐Huminsäuren und Boden‐Fulvosäuren mit Metall‐Ionen
Authors: Finger Wilfried , Klamberg Horst 
Published: February 2007

AbstractEs wurde die Komplexbildung zwischen isolierten und analytisch eingehend charakterisierten Boden‐Huminstoffen aus zwei Horizonten eines Podsols und einer Reihe ausgewählter Metall‐Ionen untersucht. Mit Hilfe der Ionenaustausch‐Methode wurden zunächst bei drei verschiedenen pH‐Werten Bedingungs‐Stabilitätskonstanten für die Komplexe von zwei Boden‐Huminsäuren mit den Metall‐Ionen Ca2+, Mn2+, Cu2+ und Zn2+ ermittelt. Danach wurden für die Komplexbildung von zwei Boden‐Fulvosäuren mit der um die Ionen Al3+ und Fe3+ erweiterten Auswahl an Metall‐Ionen bei konstantem pH‐Wert Bedingungs‐Stabilitätsfunktionen bestimmt. Durch Auswertung der gefundenen Stabilitätsfunktionen der Metall‐Fulvosäure‐Komplexe konnte zwischen der Metallbindung an Niederenergie‐ und Hochenergie‐Bindungsstellen vom Phthalsäure‐ bzw. Salicylsäure‐Typ unterschieden werden. Aus den Stabilitätsfunktionen wurden außerdem maximale Stabilitätskonstanten für die Komplexbildung an den unterschiedlichen Bindungsstellen sowie Hinweise auf die vorliegenden Komplex‐Stöchiometrien entnommen. Die erhaltenen Komplexbildungsparameter und ihre Bedeutung für die Beschreibung der Fixierung und des Transports von Metall‐Ionen im Boden werden abschließend diskutiert.
Iron deficiency stress responses amongst citrus rootstocks
Authors: Treeby Michael , Uren Nick 
Published: February 2007

AbstractSeedlings of citrus rootstocks differing in lime tolerance were grown in nutrient solution with and without Fe. Proton efflux, release of phenolic compounds and Fe reducing substances and root‐mediated reduction of FeIII in FeEDTA and freshly precipitated Fe(OH)3 in response to Fe deficiency were determined.Sweet orange, Carrizo citrange and trifoliate orange, the three least tolerant rootstocks used in the study, did not decrease nutrient solution pH in response to Fe deficiency. The more lime tolerant rootstocks, rough lemon, Cleopatra mandarin and sour orange, did decrease nutrient solution pH. But in CaSO4 solution only sour orange increased H+ efflux significantly under Fe deficiency.In response to Fe deficiency, the release of phenolic compounds was increased significantly in rough lemon and Cleopatra mandarin seedlings, while the release of reducing substances was increased significantly in rough lemon, sour orange and trifoliate orange.Rough lemon was the only rootstock to respond to Fe deficiency with an increase in root‐mediated reduction of chelated FeIII at pH 6.5. At pH 8.0, both Fe‐deficient rough lemon and Cleopatra mandarin roots reduced higher amounts of FeIII from freshly precipitated Fe(OH)3 than Fe‐sufficient seedlings.Iron reduction by detached roots of Fe‐deficient and Fe‐sufficient rough lemon did not follow Michaelis‐Menten kinetics at high substrate concentrations. Rates of Fe reduction at low substrate concentrations were inconsistent with the existence of an inducible ferric reductase in response to Fe deficiency.
Retention of Ni, Zn and Cd by Si‐associated goethite
Authors: Gerth Joachim , Brümmer Gerhard W. , Tiller Kevin G. 
Published: February 2007

AbstractSynthetic goethite used to study the effects of reaction time and temperature on the pH‐dependent sorption of Ni, Zn and Cd was associated with amorphous silica. Ni interacted with dissolved Si and formed a Ni/Si precipitate on the goethite surface. Individual metals added at a concentration of 0.5 μmol g−1 and sorbed during a reaction period of 504 hours (21 days) at 35°C were extracted by 0.7 M HNO3 for 14 days. At the end of this period 11,28 and 40 percent of Ni, Cd and Zn, respectively, were not extracted whereas 20 percent of the total Fe content of the goethite and 39 percent of the associated Si were dissolved. During the sorption process metals became immobilized in the goethite particles. This effect can be related to a diffusion of metal ions into micropores. A total mobilization of sorbed metals can only be achieved by a complete dissolution of the goethite. The strong fixation of Ni, Zn and Cd by goethite suggests that additions of this Fe oxide could be used to ameliorate highly contaminated sludges or soils.
Effect of pH on Zinc Adsorption and Solubility in Suspensions of Different Clays and Soils
Authors: Metwally A. I. , Mashhady A. S. , Falatah A. M. , Reda M. 
Published: February 2007

AbstractZinc solubility in clay and soil suspensions was controlled by chemisorption at pH 4.5 – 7.0. The solubility in clay mineral suspensions was in the order palygorskite < montmorillonite « kaolinite and reflected the high affinity of zinc to palygorskite and the high CEC of montmorillonite. The solubility in soil suspensions was in the order Haplustoll < Torrifluvents and reflected the effect of high CEC and organic matter content of the first. The slopes of the pH‐pZn curves, calculated zinc potential and sequential desorption data suggested that Zn++ − Zn(OH)2 aqueous controlled the solubility of zinc in soil and clay mineral suspensions at pH 7.5 – 9.0. The slopes of the pH–pZn curves of two soils were, however, modified by the possible peptization of organic matter and Zn(OH)2.
Long‐term nitrogen balance for pearl millet (Pennisetum glaucum L.) in an acid sandy soil of Niger
Authors: Hafner Hermann , Bley Joachim , Bationo André , Martin Peter , Marschner Horst 
Published: February 2007

AbstractOn acid sandy soils of Niger (West Africa) fertilizer N recovery by pearl millet (Pennisetum glaucum L.) is often more than 100 per cent in years with normal or above average rainfall. Biological nitrogen fixation (BNF) by N2‐fixing bacteria may contribute to the N supply in pearl millet cropping systems. For a long‐term field experiment comprising treatments with and without mineral fertilizer (F) and with and without crop residue application (CR) a N balance sheet was calculated over a period of six years (1983‐1988).After six years of successive millet cropping total N uptake (36‐77 kg N ha−1 yr−1) was distinctly higher than the amount of fertilizer N applied (30 kg N ha−1 yr−1). The atmospheric input of NH4‐N and NO3‐N in the rainwater was about 2 kg N ha−1 yr−1, 70 % in the form of NH4‐N. Gaseous NH3 losses from urea (broadcast, incorporated) were estimated from other experiments to amount to 36 % of the fertilizer N applied. Nitrogen losses by leaching (15 to > 25 kg N ha−1 yr−1) were dependent on the treatment and on the quantity and distribution of single rainfall events (>50 mm). Decline in total soil N content (0‐60 cm) ranged from 15 to 48 kg N ha−1 yr−1. The long‐term N balance (1983‐1988) indicated an annual net gain between 6 (+CR‐F) and 13 (+CR+F) kg N ha−1 yr−1. For the control (‐CR‐F) the long‐term N balance was negative (10 kg N ha−1 yr−1). In the treatment with crop residues only, the N balance was mainly determined by leaching losses, whereas in treatments with mineral fertilizer application the N balance depended primarily on N removal by the millet crop. The annual net gain in the N balance increased from 7 kg ha−1 with mineral fertilizer to 13 kg ha−1 in the combination mineral fertilizer plus crop residues.In both the rhizosphere and the bulk soil (0‐15 cm), between 9 and 45% of the total bacterial population were N2‐fixing (diazotrophic) bacteria. The increased N gain upon crop residue application was positively correlated with an increase in the number of diazotrophic and total bacteria. The data on bacterial numbers suggest that the gain of N in the longterm N balance is most likely due to an N input by biological nitrogen fixation. In addition, evidence exists from related studies that the proliferation of diazotrophs and total bacteria in the rhizosphere due to crop residue application stimulated root growth of pearl millet, and thus improved the phosphorus (P) acquisition in the P deficient soil.
Leaf nutrient analysis in Salix viminalis (L.) energy forest stands growing on agricultural land
Authors: Rytter Lars , Ericsson Tom 
Published: February 2007

AbstractThe seasonal pattern of morphological leaf characteristics, leaf nutrient and carbohydrate contents in two energy forest stands growing on fertile clay soil and consisting of Salix viminalis (L.) was investigated. One of the stands was irrigated and liquid fertilized (IL) daily from May to August while the other stand was untreated (C). The study was carried out on shoots growing for their second year on five‐year‐old roots.A pronounced seasonal variation in length, weight, and area of leaves of the same developmental stage was observed, while differences between the stands were small. The leaf content of carbohydrates and starch was low. Nitrogen was the only nutrient that was significantly higher in the IL stand compared with the C stand throughout the growing season. The small differences between stands were most probably an effect of the initially high soil fertility. Different bases for expressing plant nutrient status during the growing season, i.e. nutrient amount per leaf dry weight with and without carbohydrates, nutrient amounts per leaf or leaf area, nutrient proportions in leaves, and nutrient amounts in the total canopy, were compared and discussed. It was concluded that the common expression, nutrient weight per dry weight of leaves, without correction for non‐structural carbohydrates, was adequate to describe the nutrient situation in well‐growing basket willow plantations. The most appropriate time for leaf sampling was proposed to be the phase of most intensive growth.
Measurement of ammonia emissions after liquid manure application: I. Construction of a windtunnel system for measurements under field conditions
Authors: Braschkat J. , Mannheim T. , Horlacher D. , Marschner Horst 
Published: February 2007

AbstractA windtunnel system is presented applicable for measuring ammonia emissions under field conditions. With this system two objectives are achieved:

No alteration of the microclimatic conditions in the testing area
Reliable determination of the volumetric air flow and the ammonia concentration
The use of a transparent foil, the precise adjustment of the flow velocity to the windspeed outside, and the constant cross‐sectional area over the whole length of the tunnel are the most important constructional details of the system.
Mikrobielle Aktivitäten in landwirtschaftlich genutzten Böden Niedersachsens. I. Einfluß der ackerbaulichen Nutzung
Authors: Frank Thomas , Malkomes Hans‐Peter 
Published: February 2007

AbstractAuf drei Ackerböden an zwei niedersächsischen Standorten wurden vier Jahre lang verschiedene mikrobielle Aktivitäten untersucht. Häufig reagierte die Glucose‐induzierte Kurzzeitatmung und die Dehydrogenaseaktivität am empfindlichsten auf Umwelteinflüsse. Unter Getreide wurden meistens höhere Aktivitäten beobachtet als unter Zuckerrüben. Die einzelnen mikrobiellen Aktivitäten wurden unterschiedlich durch die Böden und die Vegetationsperiode beeinflußt. Pflanzenschutzmittel‐Spritzfolgen führten unter Zuckerrüben zeitweise zu einer Verringerung einiger mikrobieller Aktivitäten.
Kinetics of soil phosphate desorption as affected by citric acid
Authors: Gerke Jörg 
Published: February 2007

AbstractCitrate can accumulate in the rhizosphere of phosphate (P) deficient plants. Therefore, P desorption was investigated in relation to citrate concentrations applied in a single or sequential mode to a Luvisol and a Podzol. Cumulative P desorption increased up to 20 times that of the control, the absolute increase being higher in the Podzol. The rate of P release was closely related to the rate of Fe+Al release indicating that desorption originated mainly from Fe/Al associated P. The mode of citrate loading affected the P desorption in an ambiguous manner. P‐diffusion coefficients were calculated from the desorption data. The coefficients strongly increased with citrate loading, the increase being more pronounced in the Podzol.
Evaluation of Chemical Indices of Soil Pb Availability in Calcareous Soils
Authors: Al‐Afifi M. A. 
Published: February 2007

AbstractThe objective of this study was to compare six soil tests (1 M KNO3, 1 M NH4OAC, 0.005 M DTPA, 0.1 M EDTA, 1 M HNO3and 0.025 M Ca DTPA B4O7) as extractants for soil Pb and as predictors of plant available Pb for wheat (Triticum aestivumL.) in the greenhouse. The soils recieved 0, 200 and 400 mg Pb kg−1as Pb(NO3)2and are referred to as Pb0, Pb1and Pb2treatments respectively. Of the six soil extractants, 1 M HNO3was the most effective extractant for Pb from Pb0treatment whereas 0.1 M EDTA and 0.025 M Ca DTPA‐B4O7were the best and equally effective in their ability to extract Pb from Pb1and Pb2treatments. Regression analysis was used to develop two variable models for predicting Pb uptake by wheat as a function of extractable Pb and selected soil properties. The 0.025 M Ca DTPA‐B4O7extractant was the best in predicting uptake by wheat in Pb0(r = 0.791***significant at p = 0.001) and Pb1(r = 0.726***) and Pb2(r = 0.942***) treatments.
The effect of ultrasound on the stability of mesoaggregates (60–2,000 μm)
Authors: Tippkötter Rolf 
Published: February 2007

AbstractA standardized ultrasonic dispersion is presented with reference to soil structure. It is suggested that the parameters of aggregate stability can be expressed by the input of ultrasound energy which causes a soil‐dependent process of aggregate dispersion. Preliminary results for soils of different land use and parent materials show that, for the soils examined, the stability of mesoaggregates (60–2,000 μm) lowers in the sequence forest > grassland > wasteland >arable land and limestone > basalt > loess > glacial till. Close correlations were also found to the content of carbon and clay.
Die flächenhafte Variabilität bodenphysikalischer Parameter und des Corg‐Gehaltes in den Pflugsohlen je eines Ton‐, Sand‐ und Lößstandortes
Authors: Immler Ludwig G. , Zahn Michael T. 
Published: February 2007

AbstractAuf jeweils einem landwirtschaftlich genutzten Ton‐, Sand‐ und Lößstandort wurden mit Hilfe von Rasterbeprobungen in der Pflugsohle das Gesamtporenvolumen (PV), der Grob‐ und der Feinporenanteil (gPV (> 10 μm) bzw. fPV (< 0,2 μm)), die nutzbare Feldkapazität (nFK) und der Gehalt an organischem Kohlenstoff (Corg) flächenhaft bestimmt sowie statistisch und geostatistisch ausgewertet. Das Gesamtporenvolumen zeigte auf alien Standorten eine geringe Variabilität (Variationskoeffizient v = 5,9% bis 11,9%). Sein Mittelwert kann auf allen drei Untersuchungsflächen bereits bei einer Probendichte von 2/ha mit einem Standardfehler von Δa <10% geschätzt werden. Die Variabilität von fPV und gPV sowie der nFK und des Corg‐Gehaltes war bei der Ton‐ und der Sandfläche vergleichsweise hoch, so daß 10–20 Proben/ha für einen Standardfehler Δa <10% erforderlich sind.Eine Auswertung von Variogrammparametern zeigte, daß erst bei hohen Probendichten (> 100 Proben/ha) niedrige Nuggetwerte für genaue Kriging‐Interpolationen erreicht werden. Mit der geostatistischen Block‐Kriging‐Interpolation kann die flächenhafte Verteilung von Bodenparametern jedoch auch bei relativ geringen Probendichten (ca. 10/ha) deutlich realistischer dargestellt werden, als dies mit der klassischen inverse‐distance‐Interpolation möglich ist, wie ein Vergleich beider Verfahren zeigt.
Significance of microbial biomass for carbon and nitrogen mineralization in soil
Authors: Kaiser Ernst‐August 
Published: February 2007

AbstractC and N mineralization was quantified in an incubation experiment with two samples containing different amounts of microbial biomass. The samples from two layers (0–20, 20–30 cm) of an arable luvisol from loess were fertilized with nitrate, mixed with14C‐labelled straw and incubated for 52 days at different O2levels. Decreasing O2concentrations (21, 2, 1 and 0% O2) in soil conducted a decrease in C and N mineralization. More C and N were mineralized in samples with a higher initial microbial biomass. The differences in microbial biomass were still present at the end of the experiment, but more proliferation was detected in samples with the lower initial microbial biomass, leading to equal ratios between microbial biomass‐C and soil organic C in both soils.
The excretion of citric and malic acid by proteoid roots of Lupinus albus L.; effects on soil solution concentrations of phosphate, iron, and aluminum in the proteoid rhizosphere in samples of an oxisol and a luvisol
Authors: Gerke Jörg , Römer Wilhelm , Jungk Albrecht 
Published: February 2007

AbstractOrganic acid concentration in the proteoid rhizosphere of White Lupin in different soil samples (Oxisol‐Ap = Ox, Luvisol‐Ap and Luvisol‐C = LA and LC) was determined in order to study the influence of root‐released carboxylates on the mobilization of phosphate, aluminum, and iron in the rhizosphere. In the LC, organic acids were accumulated as Casalts extractable with water. In the proteoid rhizosphere of this soil sample 55 μmol citrate and 8 μmol malate per g soil were found. In the Ox, no water extractable organic acids were present. However, determination of citrate in the solid phase of this soil by Diffuse Reflectance Infrared Fourier Transform Spectroscopy gave concentrations of 88 and 68 μmol citrate per g soil without and with P application, respectively. Displaced soil solution from the proteoid root rhizosphere of the Ox and the LA increased in Fe and Al concentrations from <50 μmol/L (soil from reference pots without plants) to more than 600 μmol Fe+Al/L. The concentration of P was increased by a factor of 2 despite of P uptake by the proteoid roots. The mobilization of Al, Fe, and P is attributed to ligand exchange of phosphate against citrate and to the solubilization of Al and Fe as carboxylate complexes.