bluuebunny/crossref_metadata_2025 huggingface dataset:
Einfluß von NaCI‐Salinität auf die CO2‐Assimilation und auf den Einbau von 14C in verschiedene Inhaltsstoffe bei jungem Sommerweizen
Authors: Kang Shen , Judel G. K.
Published: February 2007

Der Einfluß steigender NaCI‐Salinität auf die CO2‐Assimilation und den Einbau von 14C in verschiedene Stoffgruppen von jungen Weizenpflanzen wurde untersucht. Zunehmende Salinität hemmte das Wachstum und besonders die bei Ende der Versuchsperiode gemessene Assimilation von 14CO2. Dementsprechend waren auch die absoluten Mengen an 14C, die in den einzelnen Stoffgruppen (Aminosäuren, organische Säuren, Kohlenhydrate, Proteine, Lipide, unlöslicher Rückstand) vorlagen, mit steigender Salinität beachtlich erniedrigt. Salzstreß beeinflußte auch die Verteilung des 14C: Bei geringer Salinität wurden niedrige Anteile in den niedermolekularen und hohe Anteile in den hochmolekularen Stoffgruppen gefunden. Bei hoher Salinität war diese Tendenz nur noch schwach ausgeprägt.

Steigende Salinität hatte praktisch keinen Einfluß auf die Nährstoffgehalte (N, P, K, Ca, Mg) in den oberirdischen Pflanzenteilen; die Na‐ und besonders die Cl‐Gehalte wurden jedoch stark erhöht. Es wird angenommen, daß die überhöhten Gehalte an Cl und Na in den oberirdischen Pflanzenteilen die Ertragsdepression verursachten.
Veränderung und Fixierung von Lignin durch Ca‐Bentonit
Authors: Tadjerpisheh N. , Ziechmann W.
Published: February 2007

Unter dem Einfluß von Ca‐Bentonit wird schwer zersetzbares Lignin chemisch verändert. Dieses ist dann ölig und schwer zu trocknen. Ein bestimmter Teil des Lignins wird vom Ca‐Bentonit fixiert, so daß, wie UV‐, IR‐Spektren, Kohlenstoff‐Analysen und Glühverluste erweisen, erstmalig reine Ton‐Lignin‐Komplexe unter den milden Bedingungen eines natürlichen Bodens hergestellt und nachgewiesen werden konnten. Die Bindung des veränderten Lignins erfolgt vermutlich an den Kanten des Tonminerals.
Determination of “normal” levels and upper limit values of trace elements in soils
Authors: De Temmerman L. O. , Hoenig M. , Scokart P. O.
Published: February 2007

To determine “normal” levels of trace elements in soils, soil samples taken all over Belgium were analysed. The selection of the sampling places was based on the geological substrata, from which the soils originate and on the texture class to which they belong. The elements As, B, Be, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Ti, V and Zn were determined using an extraction method with strong acids. The found concentrations were called “total acid extraction concentrations”, although this extraction does not extract all the elements which are incorporated into the minerals.

This has been done, however, by arc emission spectrography which was applied to determine the elements Ag, B, Co, Cr, Ga, Mo, Ni, Sn, Sr and V. The greatest difference between the “overall total” concentrations and the “total extractable concentrations” were found for chromium.

Based on the obtained results, an upper limit for normal levels of trace elements was fixed.

For Ag, Cd, Hg, Pb and Sb, this upper limit value is almost the same for all the investigated soils irrelevant of their texture. The same conclusion could not be made for the other elements. For these elements, the soil texture and also the geological parent material, on which the soil was formed, have an influence on the upper limit value.
Quartz Sand: Apparent dehydroxylation – rehydroxylation and water retention
Authors: Tschapek M. , Falasca S. , Wasowski C.
Published: February 2007

The lack improvement in the capillary rise and retention of water in quartz sand dehydroxylated by calcination after its hydroxylation and rehydroxylation by alkali, hot water and H2O2 treatments, can be accounted for by its instantenous hydroxylatiton and rehydroxylation or by the limited effect of the OH groups on those hydric properties. An alternative interpretation could be a lack analogy between silica and quartz.
Transformations and effects of urea derivatives in soil
Authors: Moawad H. , Enany M. H. , El‐Din S. M. S. Badr , Mahmoud S. A. Z. , Gamal Rawia F.
Published: February 2007

The application of urea phosphate, urea nitrate and thoiurea to a silty clay soil from Nile Delta (pH 7.4, 1,9% CaCO3) inhibited soil urease activity if compared to urea. The nitrification process of ammonia formed from urea hydrolysis was retarded. The use of these urea derivatives eliminated nitrite accumulation and greatly retarded nitrate formation with increased recovery of urea‐N throughout the experimental period. Gaseous losses of urea‐N as ammonia or by denitrification were reduced. These derivatives may be much more advantageous than urea if fertilizer effeciency is to be increased.
Phytotoxizität von Thallium (TI) in Hydrokultur Teil2: Einfluß von TI(III) auf das Wachstum und die Schwermetallgehalte von Erbsen‐ und Ackerbohnenpflanzen
Authors: Pieper Bettina , Austenfeld F.‐A.
Published: February 2007

In Hydrokultur wurde der Einfluß von TI(NO3)3 bzw. TI(III)EDTA (bei gleichzeitiger Komplexierung der essentiellen Schwermetalle) auf das Wachstum, sowie die Akkumulation von Thallium (TI) und essentiellen Schwermetallen in verschiedenen Organen von Erbsenpflanzen (Pisum sativum L. var. Aromata) und Ackerbohnenpflanzen (Vicia faba L. var. Hangdown) untersucht.

Es zeigte sich, daß die Trockensubstanzbildung von Erbsenpflanzen durch TI(III)EDTA stärker gehemmt wurde als durch Tl(NO3)3. Unabhängig von der Form des applizierten Tl(III) wiesen die Erbsenpflanzen die höchsten Tl‐Gehalte in den Stengeln auf. Der Einsatz von Tl(III)EDTA hatte zur Folge, daß gegenüber der Belastung mit Tl(NO3)3 bei gleichbleibenden Tl‐Gehalten der Wurzeln das Tl in größerem Umfang in die Stengel und Blätter translokiert wurde. Die Form des applizierten Tl(III) hatte zudem unterschiedliche Auswirkungen auf den Gehalt an essentiellen Schwermetallen. Beim Einsatz von Tl(NO3)3 wurde in allen Organen der Mn‐Gehalt und in der Wurzel der Zn‐Gehalt erniedrigt. Im Stengel kam es dagegen zu einem Anstieg des Zn‐Gehaltes. Für die Fe‐ und Cu‐Gehalte zeigte sich in keinem Organ eine Beziehung zum verabreichten Schadstoff. Die Komplexierung von Tl(III) bewirkte, daß nur die Mn‐Gehalte der Wurzel gesenkt wurden, während im Stengel der Gehalt an Fe und Mn, in den Blättern der Gehalt an allen essentiellen Schwermetallen erhöht war. Der Anstieg der Nährstoffgehalte kann ein Konzentrierungseffekt durch Wachstumshemmung sein.

Das Wachstum der Ackerbohnenpflanzen wurde nur durch Tl(NO3)3 gehemmt. Unabhängig von der Form des verabreichten Tl(III) fanden sich bei der Ackerbohne die höchsten Tl‐Gehalte in den Wurzeln, die niedrigsten in den Blättern. Bei Komplexierung von Tl(III) erhöhten sich die Tl‐Gehalte sowohl der Wurzeln als auch der Stengel, jedoch nicht die der Blätter. Während Tl(NO3)3 die Mn‐Gehalte aller Organe, sowie den Zn‐Gehalt der Wurzeln und Blätter absenkte, bewirkte Tl(III)EDTA ausschließlich eine Minderung des Mn‐Gehaltes der Wurzeln.
Eine Methode zur quantitativen Bestimmung von Pentachlorphenol in Umweltproben
Authors: Khairy A. , Müller‐Wegener U.
Published: February 2007

Es wird eine analytische Methode zur Bestimmung von Pentachlorphenol vorgestellt, mit der die Chemikalie aus Umweltmatrizes (Pflanzen‐, Tierwelt‐ und Bodenproben) gewonnen, gereinigt und gaschromatographisch quantitativ bestimmt werden kann. Die Nachweisgrenze dieser Methode liegt bei 5 ppb oder 10 pg absolut.
Natürliche Radiokohlenstoffmessungen als Beitrag zur Definition rezent‐ oder paläoklimatischer Leithorizonte in Tunesien
Authors: Scharpenseel H. W. , Schiffmann H.
Published: February 2007

Es werden die in Tunesien definierten Klimaleitlinien und Leithorizonte der kontinentalen sowie ozeanischen Quartärstratigraphie dargestellt. Radiokohlenstoffdaten von 116 Bodenproben aus Bodenprofil‐ oder weitergehenden Quartäraufschlüssen deuten auf mindestens einen Leithorizont, der einer meist vom “Historique” überdeckten Mollisol ‐ Paläobodenbildung des Rharbien, etwa 7‐8000 B. P. entspricht. Oft liegt ein Doppelhorizont vor mit einer jüngeren Komponente von 5000 B. P. Ein weiterer ochric fA‐Horizont von 10‐15000 B. P. des jüngeren Soltanien wurde mehrfach, aber nicht so regelmäßig angetroffen. Der C‐Gehalt noch älterer Paläoböden, bis auf einen Paleargid von 23000 B. P., ist so niedrig, daß der verbleibende organische Kohlenstoff durch die Prozedur der Karbonatzerstörung zur Beseitigung des lithogenen C nicht ausreicht für eine Benzolmeßprobe oder die Gefahr einer Verfälschung besteht. 0,1% organischer Kohlenstoff scheint die untere Schwelle zu sein für vernünftiges Arbeiten. Einige Profile zeigten ganz unten, direkt über der Erosionsebene des Wadi eine Altersinflektion. Sie deutet an, daß durch laterale Anlagerung jüngeren alluvialen Substrats eine irreführende Verjüngung erfolgen kann.

Die Ergebnisse zeigen, daß schichtweise Datierung des gesamten Profils ratsam ist. Interpretation einzelner Datierungsproben in semiariden Quartäraufschlüssen erscheint gewagt und wenig zuverlässig.

An einigen Horizonten/Schichten, wo Sedimentwechsel möglich erschienen, wurden als Entscheidungshilfen Allelementanalysen durchgeführt. Ein Histogramm aller bisher in Tunesien gewonnenen 14C‐Daten von Böden, Sedimenten oder Grundwasser zeigt Häufigkeitsmaxima, d. h. klimatische Phasen genügender Feuchte für Boden‐ und Grundwasserbildung um 5000, 7‐8000, 10‐11000 und 13‐15000 B. P.
Zinc and copper in some soils of Egypt as related to other soil properties
Authors: Awad F. , Fuda S. , Arafat S. M.
Published: February 2007

Total Zn in alluvial and calcareous soils (average 138 and 70 ppm respectively) was significantly related to their contents of CaCO3 (negatively), O.M. and clay (positively). Extracting Zn by Na2EDTA gave the highest values for both soil types. Total Cu contents varied widely from 26 to 111 ppm in alluvial and from 15 to 30 ppm in calcareous soils. They were negatively correlated with the CaCO3 contents. The pot experiments showed that EDTA(NH4)2CO3, Na2EDTA and DTPA are reasonable extractants for available Zn from both soil types. DTPA was efficient for all soils investigated, while Na2 EDTA and EDTA‐citrate were specific for extracting Cu from calcareous soils.
Effect of Phosphate and Zinc application on dry matter yield and uptake of nutrients in Cowpea (Vigna unguiculata (L.) Walp.)
Authors: Yadav D. S. , Antil R. S. , Kumar V. , Singh M.
Published: February 2007

To find out the effect of P and Zn levels on dry matter yield, concentration and uptake of P and Zn in cowpea, a pot experiment was conducted in greenhouse. Phosphorus and zinc were added at the rate of 0, 20, 40, 80 and 160 ppm P and 0, 2.5, 5, and 10 ppm Zn, respectively. Response of P and Zn on dry matter yields of shoots and roots at 40 days and grain yield at maturity was observed upto 80 ppm P and 5 ppm Zn, respectively, and further increase in their levels decreased the yields. The addition of 10 ppm Zn decreased and 2.5 ppm Zn increased P concentration in different plant parts. The application of P decreased Zn concentration in different plant parts mainly at maturity stage. The available P and Zn at each harvesting stage were not affected by application of Zn and P, respectively, suggesting that P‐Zn interaction occurred somewhere in the plants not in the soil.
Evaluation of availability and quantity‐intensity relationship of zinc in some tropical soils
Authors: Singh M. , Mittal S. B.
Published: February 2007

Zinc was extracted from seven soils collected from Haryana state (India), representing the tropical region of the country, to predict the availability of Zn to crops. Weakly adsorbed Zn extracted by 0.05 M CaCl2 was almost negligible. Similarly 1 M MgCl2, designated to extract the lattice Zn, extracted small quantities of Zn indicating that no Zn was substituted for any other cation in clay lattice. Maximum zinc was extracted by chelating agents like DTPA and EDTA and were correlated significantly among themselves. None of the methods tested was significantly correlated to plant Zn indicating that in addition to crop requirement, other soil factors play a major role in determining the Zn availability. Equilibrium Zn values in all except a sandy soil, were less than 1 μg Zn/ml indicating the possibility of moderate to severe Zn deficiency in these soils.
Beziehung zwischen dem durch K‐Düngung erzielbaren Mehrertrag und dem K‐Gehalt der Böden nach Feldversuchen in der Bundesrepublik Deutschland
Authors: Schachtschabel P.
Published: February 2007

Es wurden mehrere hundert K‐Felddüngungsversuche auf verschiedenen Standorten der Bundesrepublik ausgewertet. Die Versuche liefen meist mehrere Jahre auf dem gleichen Feld (Fruchtfolgeversuche), wobei auch die Ernterückstände (Stroh, Rübenblatt usw.) vom Feld abgefahren wurden.

Der K‐Gehalt wurde in der Ackerkrume nach der DL‐ und CAL‐Methode (zusammenfassend “lactat”) bestimmt und in mg K2O/100g Boden angegeben.

Zwischen dem K(lact)‐Gehalt des Bodens im Bereich über 5 mg K2O und dem durch mineralische K‐Düngung erzielbaren maximalen Mehrertrag von Weizen, Gerste, Zuckerrüben und Kartoffeln besteht keine Beziehung. Es kann daher daraus keine Notwendigkeit einer K‐Anreicherung im Boden abgeleitet werden.

Die relativ geringen Mehrerträge durch K‐Düngung sind nur in wenigen Fällen statistisch gesichert, so daß nicht gesicherte Einzelwerte im Gegensatz zu Mittelwerten keine Aussagekraft haben.

Ökonomische Mehrerträge durch K‐Düngung wurden im Mittel bei Zuckerrüben und Kartoffeln, seltener bei Gerste und nicht bei Weizen erzielt.

In allen mehrjährigen Versuchen war innerhalb einer Fruchtfolge höchstens eine K‐Düngung zur Erzielung des maximalen Mehrertrags notwendig, die der K‐Abfuhr durch die Ernteprodukte vom Feld entsprach (Netto‐Entzugsdüngung).

Aus 7‐27jährigen Feldversuchen auf tonreicheren Böden (Kap. 5) ist ersichtlich, daß der K‐Vorrat in der Ackerkrume bis auf 5‐10 mg K2O (lact)/100 g Boden abgebaut werden konnte, ohne daß sich erhöhte Mehrerträge durch mineralische K‐Düngung ergaben.

Einen überragenden Einfluß auf die Hohe der Mehrerträge hatte die Witterung, wie die teilweise hohen Mehrerträge bei starker Trockenheit im Sommer zeigen.

Der hohe Vorrat an leicht verfügbarem Kalium in der Ackerkrume wird auf die hohe K‐Düngung in den letzten Jahrzehnten zurückgeführt.

Aufgrund der Versuchsergebnisse ist bei einem Gehalt der Ackerkrume von 5‐10 mg K2O(lact) eine Netto‐Entzugsdüngung zur Erzielung ökonomisch optimaler Erträge ausreichend (Gehaltsklasse C); oberhalb 10 mg K2O kann die K‐Düngung unter dem Netto‐Entzug bleiben, unterhalb 5mg K2O sollte sie höher sein.

Infolge der hohen Schwankungen der K2O (lact)‐Werte (Kap. 5) ist eine Kontrolle der K‐Düngung durch die Lactatmethoden nur begrenzt möglich.

Nach einer K‐Bilanz für die Bundesrepublik lag die K‐Zufuhr über mineralische Handelsdünger (1981/82), bezogen auf die landwirtschaftlich genutzte Fläche, um 958970t K2O (= 79 kg K2O/ha) über der K‐Abfuhr (1982) aus den landwirtschaftlichen Betrieben.

Die hohen K‐Düngungsempfehlungen in der Bundesrepublik und die im praktischen Landbau angewandte hohe K‐Düngung stehen im Widerspruch zu den Ergebnissen der Feldversuche.
Response of acid sulphate soils to different liming treatments I. Solubility of sulphate and phosphate
Authors: Hartikainen Helinü
Published: February 2007

In a preliminary laboratory experiment, samples from three cultivated and three virgin acid sulphate soils (pH 3.9‐4.7) were treated with water or equivalent amounts of Ca(OH)2 or KOH and incubated at about field capacity for three months. Both base treatments (133 meq/kg) similary reduced soil acidity and, thus, the same influence on the pH‐dependent biological and chemical reactions was concluded. The liming‐induced mineralization of organic S seemed to account for increased extratability of sulphate, being in most soils of the same magnitude in both treatments.

Inversely, the solubility of P hardly was affected by the decomposition of organic matter but rather by the reactions of inorganic P. KOH markedly raised water‐soluble P, whereas Ca(OH)2 did not. The results of a rapid extraction test suggested that the poorer extractability of P in the soils amended with Ca(OH)2 could partly be ascribed to a higher Ca saturation and its impact on the electrochemical properties of charged surfaces. In addition, a higher base‐associated ionic strength created by Ca2+ was of great importance in reducing the P desorption in the Ca(OH)2‐ treated soils.
Comparison of different measuring and calculating methods to quantify the hydraulic conductivity of unsaturated soil
Authors: Schindler U. , Bohne K. , Sauerbrey R.
Published: February 2007

The double‐plate method and the evaporation method provide comparable results on the hydraulic conductivity of soil (K(hs)). Adaptation of the water retention curve according to the method of Vachaud and Vauclin proved to be very reliable. The course of the K(hs) function is well shown by all indirect identification methods included in the comparison. In some cases, the absolute deviations of the measured from the calculated values are, however, considerable and primarily determined by the initial value of the hydraulic conductivity. In quantifying the capillary water rise, best approximation to the measured values was reached in 11 of 13 cases with the van Genuchten method.
Einfluß einer mineralischen und symbiontischen Stickstoffernährung auf Protonenabgabe der Wurzeln, Phosphat‐Aufnahme und Wurzelentwicklung von Rotklee
Authors: Hauter R. , Steffens D.
Published: February 2007

Im Gefäßversuch wurde Rotklee in einer Variante mit mineralischem Stickstoff (NH4NO3 bzw. Ca(NO3)2) und in einer anderen mit symbiontisch produziertem Stickstoff auf einem schwach gepufferten lehmigen Sandboden angebaut. Rotklee senkte dabei den pH‐Wert des Bodens innerhalb von 6 Schnitten in der mineralischen N‐Variante von anfänglich 7,6 auf 6,0 und in der symbiontischen N‐Variante auf 5,2 ab. Bei gleichem oberirdischen Pflanzenertrag pro Gefäß hatte der N2‐fixierende Rotklee eine größere Wurzelfrischmasse, ‐länge, ‐oberfläche und ‐dichte pro Gefäß als der mit mineralischem Stickstoff gedüngte Rotklee. Aufgrund der stärkeren Bodenversauerung und der besseren Wurzelausbildung konnte der N2‐fixierende Rotklee die Rohphosphatkomponente eines teilaufgeschlossenen P‐Düngers (Novaphos) effizienter ausnutzen als der mit mineralischem Stickstoff versorgte Rotklee.

Die Protonenabgabe von symbiontisch gewachsenen Rotkleewurzeln konnte nur zu 68% mit dem mineralischen Kationenüberschuß (Differenz aus aufgenommenen Kationen minus aufgenommenen Anionen) in Rotklee‐Sproß‐ und Wurzelteilen erklärt werden. Es wird dabei angenommen, daß die über den Kationenüberschuß hinaus abgegebenen Protonen wahrscheinlich über eine Ausscheidung von Anionen der Wurzeln elektrostatisch ausbalanciert werden.
The influence of phosphorus nutrition on growth, chlorophyll formation and 14CO2 fixation of chlorophyllous carrot callus cultures
Authors: Bender L.
Published: February 2007

Freshly isolated carrot root sec. phloem explants were cultured in nutrient solution plus inositol, IAA and kinetin and a varied supply of inorganic phosphorus. 14CO2 fixation experiments with the greened cultures were carried out under steady state conditions at the age of 21 days in light and darkness for four minutes. The results show that photosynthetic CO2 fixation by the Calvin cycle is greatly reduced in phosphorus deficient cultures whereas CO2 fixation via PEPC is enhanced. Under phosphorus deficiency the export of primary photosynthetates from the chloroplasts seems to be suppressed while the radioactivity of the labelled insoluble fraction, which represents mainly chloroplastic starch after this short time of 14CO2 fixation, was increased. The results are discussed with respect to the influence of phosphorus nutrition on photosynthetic CO2 fixation and PEP carboxylation in carrot tissue cultures.
Influence of K nutrition and drought on water relations and growth of sunflower (Helianthus annuus L.)
Authors: Lindhauer M. G.
Published: February 2007

Sunflower plants (Helianthus annuus L. cv. Zwerg Sonnengold) were cultivated in pots containing 1 kg of soil fertilized with 0.6 g K (K1) and 5.0 g K/pot (K2). At the age of 5 and 11 weeks, respectively the plants were transferred to a growth chamber. 50% of the plants per K treatment received sufficient watering (controls), the remaining 50% were subjected to water stress until visible signs of severe wilting were observed. At that stage the plants were rewatered.

In both growth stages and even under water stress conditions the up to 5 times higher K concentrations in the tissue of K2 plants caused an increased dry matter production during the experimental periods and a larger total leaf area which was less reduced under water stress than the leaf area of K1 plants.

During continuous watering the water content per leaf area of K2 plants was on the average 1.5g H2O dm−2 (K1: 1.35g), the water content of older K2 plants being on the average 1.33g H2O dm−2 (K1: 1.25g). During water stress and subsequent recovery this relation observed between K2 and K1 remained constant. In young K1 plants, however, no intensified loss of succulence was found during severe drought compared with 11‐week‐old K1 plants where the water content decreased from 1.2g to 0.6g H2O per dm2 of leaf area.

At almost equally high soil water availability stomatal diffusive resistance especially of the older unstressed K2 plants was higher than in K‐deficient plants. Under water stress, the degree of stomatal opening of K2 plants at first decreased more rapidly, but at equally low soil water potentials diffusive resistance in the leaves of K2 plants remained lower than in K1 plants.

A relation of the leaf water characteristics, total water potential (41), osmotic potential (42), and turgor potential (Φp) to the corresponding soil water potential showed that under stress Φ1 and Φs in plants with sufficient K nutrition always remained on a higher level than in K1 plants. Consequently, they were able to maintain a higher turgor pressure even under conditions of restricted water availability.
Ermittlung der Gesamtsäuredeposition in nordrheinwestfälischen Fichten‐ und Buchenbeständen
Authors: Bartels U. , Block J.
Published: February 2007

An jeweils sieben Niederschlagsmeßstellen im Freiland, unter Buchen‐ und Fichtenbeständen in Nordrhein‐Westfalen wurden über ein Jahr u.a. die Depositionen von H+ + NH4+, Al3+, + Fe3+, Mn2+ sowie die Basekapazität bis pH 8,2 (BK8, 2,) ermittelt. Es wird gezeigt, daß die Berechnung der Gesamtsäuredeposition als Summe der Äquivalente von (H+ + NH4+ + Al3+ + Fe3+ + Mn2+) die tatsächliche Belastung unterschätzt. Als einfache Alternative bietet sich die Summe der H+‐Äquivalente von (BK8,2 + 0,9 NH4+ + Mn2+)an.
Response of Soybean to dual Inoculation with Rhizobium japonicum and Phosphate dissolving Bacteria
Authors: El‐Din S. M. S. Badr , Khalafallah M. A. , Moawad H.
Published: February 2007

A field experiment in silty clay soil was carried out to evaluate the effect of dual inoculation with Rhizobium japonicum and phosphate dissolving bacteria (PDB) on nitrogen and phosphorus uptakes as well as seed yield of soybean. Seed inoculation with PDB before planting did not induce marked enrichment of PDB counts in the rhizosphere. Inoculation with R. japonicum alone increased the dry weight, N‐uptake and seed yield significantly. Further significant increases in P‐uptake and seed yield were recorded by inoculation with rhizobia and fertilization with superphosphate. However, the inoculation with PDB in combination with R. japonicum in the presence of rock phosphate or superphosphate did not show significant increases in dry weight, N and P uptakes or seed yield as compared with the treatments inoculated with rhizobia alone.
Untersuchungen zur Schwermetalladsorption in einem sauren Waldboden
Authors: Asche N. , Beese F.
Published: February 2007

Um das Verhalten von eingetragenen Schwermetallen in einen sauren Waldboden zu untersuchen, wurden 5 cm lange, ungestörte Bodensäulen eines Pseudogley‐Pelosol‐Oberbodens 276 Tage lang mit schwermetallhaltigen Lösungen belastet. Die zugeführten Schwermetalle wurden bevorzugt im oberen, humusreichen Bereich des Bodens adsorbiert. Bei gleichzeitiger Belastung mit vier Schwermetallen wurden die Elemente Pb, Cu und Cd vollständig an der Bodenmatrix adsorbiert während ca. 20% des zugeführten Zn aus den Säulen ausgewaschen wurde. Änderungen des pH‐Wertes der Perkolationslösung von 4 auf 3, führten zu einer Mobilisierung vorher adsorbierter Metalle. Nur das Element Pb verblieb auch unter diesen veränderten Bedingungen vollständig im Boden.
Effect of plant roots on carbon metabolism of soil microbial biomass
Authors: Helal H. M. , Sauerbeck D.
Published: February 2007

The utilization of plant‐ and soil‐C by the microbial biomass in the rhizosphere of maize plants was investigated as a function of root proximity. The plants were cultivated in pots with divided root chambers and their shoots supplied with 14CO2 for 23 days. Subsequently the individual soil zones were analyzed for organic C, 14C, biomass C and biomass 14C.

Plant roots induced a 197% increase in microbial biomass and a 5.4% decrease in soil organic C compared with an 1.2% decrease in the unplanted control soil. The contributions of plant‐ and soil‐C to this increased microbial growth amounted to 68% and 32% respectively. Biomass‐14C corresponded to 1.6% of the total photosynthetically fixed 14C, to about 15% of the organic 14C‐input into the rhizosphere and to 58% of the plant carbon remaining in soil after the removal of roots. 20% of this biomass‐14C was found outside the immediate root zone.

These results demonstrate that growing roots are a significant C‐source for the microbial biomass and render an additional fraction of soil‐C available to microbial utilization. The efficiency of C‐utilization by the rhizosphere biomass is lower than values obtained with liquid cultures in laboratory experiments. The supply of plant‐C to the microbial biomass outside the immediate root vicinity indicates that the overall volume of the maize rhizosphere is greater than what has been supposed so far.
A concept of compaction
Authors: Hartge K. H.
Published: February 2007

Bulk density data of about 150 soil profiles from America, Europe and Asia were used to obtain the regression curve of void ratio ϵ as a function of vertical stress σz. For virgin soils straight lines were obtained if a linear scale was used for ϵ and a logarithmic scale for σz. The slope of these lines was steepest for forest zone soils, less steep in soils of high‐grass zones and flattest in short‐grass soils. This difference is attributed to varying amounts of loosening by bio‐ and cryoturbation. Thus the compaction state of virgin soils is that of normal compaction caused by pedogenic processes which are superimposed on previous strong overconsolidation due to desiccation. Against this background agricultural land use creates overconsolidation in the upper soil layers, which is particularly pronounced when the previous bioturbate action has been strong. Young soil deposits cannot develop normal compaction, because of the lack of previous drying of the whole profile.
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

Actual 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

The 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

Aqueous 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

There 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

Modern 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

In 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

Six 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

The 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

The 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

The 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

The 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

Humic 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

An 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

In 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 1985

The 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

Zur 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

Fresh 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

The 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.