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  • Artikel  (12)
  • N2-fixation  (10)
  • kinetics
  • Springer  (12)
  • American Meteorological Society
  • 1995-1999
  • 1985-1989  (12)
  • 1965-1969
  • 1955-1959
  • 1950-1954
  • 1987  (12)
  • Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft  (12)
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  • Artikel  (12)
Schlagwörter
Verlag/Herausgeber
  • Springer  (12)
  • American Meteorological Society
Erscheinungszeitraum
  • 1995-1999
  • 1985-1989  (12)
  • 1965-1969
  • 1955-1959
  • 1950-1954
Jahr
Thema
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 125-137 
    ISSN: 1436-6215
    Schlagwort(e): vitamin C ; functions ; kinetics ; pool ; saturation ; requirements ; RDA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Bedeutung von Vitamin C für den menschlichen Organismus wird aus den wichtigen Funktionen ersichtlich, an denen das Vitamin beteiligt ist, wie zum Beispiel Kollagen- und Karnitinsynthesen. In neuerer Zeit entdeckt wurde seine Rolle bei der Noradrenalinsynthese, der Inaktivierung von freien Radikalen sowie der Verhinderung der Nitrosaminbildung. Die Vielfalt dieser Vitamin-C-abhängigen Funktionen läßt erkennen, daß die Bedarfsfestsetzung für Vitamin C nicht nur die Verhütung der Mangelkrankheit Skorbut anvisieren, sondern auch berücksichtigen sollte, daß alle diese Funktionen jederzeit genügend Vitamin C zur Verfügung haben müßten, um optimal reagieren zu können. Das Konzept der Gewebesättigung kommt diesem Ziel am nächsten. Studien mit einem kinetischen Modell haben ergeben, daß eine Sättigung mit täglicher Einnahme von 100 mg Vitamin C bei Nichtrauchern und von 140 mg bei Rauchern eintritt, Mengen, die als optimale Werte gelten können. Bei verschiedenen Krankheiten dürfte der Bedarf höher sein; die genauen Mengen müssen jedoch erst noch ermittelt werden.
    Notizen: Summary The importance of vitamin C is reflected in its multifunctional roles which include participation in collagen and carnitine syntheses, promotion of iron absorption and the more recently discovered participation in noradrenaline synthesis, inactivation of free radical chain reactions, prevention of N-nitroso compound formation and more. Given the many extra-antiscorbutic functions of the vitamin, the Recommended Dietary Allowances (RDA) should not just prevent deficiency disease but should aim at providing sufficient amounts for all vitamin C-dependent functions to operate at full capacity. The concept of vitamin C tissue saturation is best able to meet this demand. The use of kinetic models has shown that the body pool is saturated with a daily intake of 100 mg vitamin C in non-smokers and 140 mg in smokers, amounts that may be regarded as optimal RDA values. Certain disease states may be accompanied by still higher vitamin C requirements but the exact amounts are not yet known.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 4 (1987), S. 103-108 
    ISSN: 1432-0789
    Schlagwort(e): Kallar grass ; 15N isotopic dilution ; N2-fixation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Leptochloa fusca (L.) Kunth (kallar grass) has previously been found to exhibit high rates of nitrogen fixation. A series of experiments to determine the level of biological nitrogen fixation using 15N isotopic dilution were carried out in nutrient solution and saline soil. In the nutrient solution, E. coli inoculated plants were taken as non-nitrogen-fixing control. It was observed that nearly 60%–80% of the plant N was derived from atmospheric fixation. Estimations based on the N difference method gave much lower values (18%–35%). In experiments with saline soil which was initially sterilized with chloroform fumigation, a mixed culture of N2-fixing rhizospheric isolates from kallar grass roots was inoculated and planted to kallar grass. Uninoculated treatments were regarded as controls. The soil was previously labelled with 15N by adding cellulose and (15NH4)2SO4. The results of these studies showed fixation values of 6%–32% when estimated by 15N dilution, whereas by the N difference method 54% of the plant N was estimated to be derived from fixation. This discrepancy is due to the increase in root proliferation due to inoculation, which results in greater uptake of soil N. The distribution of 15N in different fractions of the soil-N indicted isotopic dilution due to bacterial fixation of atmospheric N2.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1432-0789
    Schlagwort(e): N2-fixation ; Arachis hypogaea ; 15N isotope dilution ; Groundnut ; Rhizobium inoculation ; Plant available soil N
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Nitrogen fixation in seven groundnut genotypes was measured by 15N-isotope dilution using a non-nodulating cultivar of groundnut as the nonfixing reference plant. Nitrogen fixation varied between 100 kg N ha−1 in genotype J-11 and 153 kg N ha−1 in Robut 33-1. The amount of plant-available soil N was small, so that 86%–92% of plant nitrogen was derived from N2-fixation. Thus differences in N2-fixation between genotypes closely reflected differences in their total N accumulation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 5 (1987), S. 18-22 
    ISSN: 1432-0789
    Schlagwort(e): Field water deficits ; Acetylene reduction assay (ARA) ; N2-fixation ; Indian desert ; Legumes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The nitrogenase activity of irrigated and rainfed plants of mung bean, cluster bean and moth bean was studied throughout the growth period in order to estimate the reduction in the potential nitrogen fixation (C2H2 reduction) rate due to field water deficits. Nitrogenase activity followed a similar trend in all crops and was dependent on both plant ontogeny and soil moisture levels. The loss of activity due to water deficits varied from 13% to 100% at different growth stages and was related to the plant water potential. The specific activity was directly correlated with the plant water potential under both the treatments. The average loss of nitrogen fixation rate during the season did not differ markedly among crops. There was an accumulation of ureides in the nodules with increasing field moisture stress in mung bean and moth bean while no such effect was found in cluster bean. The significance of these results is discussed in the N-economy of these legumes grown in the drought-prone areas of the Indian desert.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-0789
    Schlagwort(e): Blue-green algae ; Cyanobacteria ; Rice field ; Inoculation ; Nostoc ; Anabaena ; Calothrix ; N2-fixation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Algal populations were quantified (as colony-forming units [CFU] per square centimetre) in 102 samples of rice soils from the Philippines, India, Malaysia and Portugal, and in 22 samples of soil-based inocula from four countries. Heterocystous blue-green algae (BGA) were present in all samples. Nostoc was the dominant genus in most samples, followed by Anabaena and Calothrix. In soils, heterocystous BGA occurred at densities ranging from 1.0 × 102 to 8.0 × 106 CFU/cm2 (median 6.4 × 104) and comprised, on average, 9% of the total CFU of algae. Their abundance was positively correlated with the pH and the available P content of the soils. In soil-based inocula, heterocystous BGA occurred at densities ranging from 4.6 × 104 to 2.8 × 107 CFU/g dw (dry weight), comprising only a moderate fraction (average 13%) of the total algae. In most soils, the density of indigenous N2-fixing BGA was usually higher than that attained by applying recommended rates of soil-based inoculum. Whereas research on the practical utilization of BGA has been mostly directed towards inoculation with foreign strains, our results suggest that attention should also be given to agricultural practices that enhance the growth of indigenous strains already adapted to local environmental conditions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 102 (1987), S. 41-47 
    ISSN: 1573-5036
    Schlagwort(e): Azolla pinnata ; dual cropping ; N2-fixation ; spacing ; rice yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment conducted at Central Rice Research Institute, Cuttack, during three successive seasons showed that with the 120-day-duration variety Ratna two dual crops ofAzolla pinnata R. Brown (Bangkok isolate) could be achieved 25 and 50 days after transplanting (DAT) by inoculating 2.0 t ha−1 of fresh Azolla 10 and 30 DAT respectively. One basal crop of Azolla could also be grown using the same inoculum 20 days before transplanting (DBT) in fallow rice fields. The three crops of Azolla grown—once before transplanting and twice after transplanting—gave an average total biomass of 38–63 and 43–64 t ha−1 fresh Azolla containing 64–90 and 76–94 kg N ha−1 respectively in the square and rectangular spacings. Two crops of Azolla grown only as a dual crop, on the other hand, gave 26–39 and 29–41 t ha−1 fresh Azolla which contained 44–61 and 43–59 kg N ha−1 respectively. Growth and yield of rice were significantly higher in Azolla basal plus Azolla dual twice incorporated treatments than in the Azolla dual twice incorporation, Azolla basal plus 30 kg N ha−1 urea and 60 kg N ha−1 urea treatments. Azolla basal plus 30 kg N ha−1 urea and 60 kg N ha−1 urea showed similar yields but Azolla dual twice incorporation was significantly lower than those. The different spacing with same plant populations did not affect growth and yield significantly, whereas Azolla growth during dual cropping was 8.3 and 64% more in the rectangular spacing than in the square spacing in Azolla basal plus Azolla dual twice incorporation and Azolla dual twice incorporation treatments.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 102 (1987), S. 149-160 
    ISSN: 1573-5036
    Schlagwort(e): cowpea ; intercropping ; maize ; 15N methods ; N economy ; N2-fixation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Yields of above ground biomass and total N were determined in summer-grown maize and cowpea as sole crops or intercrops, with or without supplementary N fertilizer (25 kg N ha−1, urea) at an irrigated site in Waroona, Western Australia over the period 1982–1985. Good agreement was obtained between estimates of N2 fixation of sole or intercrop cowpea (1984/85 season) based on the15N natural abundance and15N fertilizer dilution techniques, both in the field and in a glasshouse pot study. Field-grown cowpea was estimated to have received 53–69% of its N supply from N2-fixation, with N2-fixation onlyslightly affected by intercropping or N fertilizer application. Proportional reliance on N2-fixation of cowpea in glasshouse culture was lower (36–66%) than in the field study and more affected by applied N. Budgets for N were drawn up for the field intercrops, based on above-ground seed yields, return of crop residues, inputs of fixed N and fertilizer N. No account was taken of possible losses of N through volatilization, denitrification and leaching or gains of N in the soil from root biomass. N2-fixation was estimated tobe 59 kg N ha−1 in the plots receiving no fertilizer N, and 73 kg N ha−1 in plots receiving 25 kg N ha−1 as urea. Comparable fixation by sole cowpea was higher (87 and 82 kg N ha−1 respectively) but this advantage was outweighed by greater land use efficiency by the intercrop than sole crops.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 104 (1987), S. 23-29 
    ISSN: 1573-5036
    Schlagwort(e): A-value ; difference method ; N2-fixation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The increasing need for protein at low cost has created a need to evaluate the biological nitrogen fixing potential of legumes in Cyprus. In field studies which were conducted over the growing years of 1982–3 and 1983–4, legumes which are traditionally grown in the country were evaluated for dry matter and nitrogen yield and biological nitrogen fixation (BNF). The legumes studied were medic (Medicago truncatula Gearth), ochrus vetch (Lathyrus ochrus L.), bitter vetch (Vicia ervilia L.) and faba bean (Vicia faba L. var major) in the first year and in addition chickpea (Cicer arietinum L.), woollypod vetch (Vicia dasycarpa Ten.) and tickbean (Vicia faba L. var minor) in the second year. Using the A-value method with barley and oats as reference crops, nitrogen (N) fixed by the various legumes in the first year was 30–50% and from 55–67% of total N yield for the two reference crops, respectively. In the second year the estimates of N fixed ranged from 70 to 80% with similar results obtained for the two reference crops barley and ryegrass. However, in the second year chickpea, which had limited nodulation, fixed only 40% of its N yield. Estimates of nitrogen from the atmosphere (Ndfa) obtained by the difference method (DM) were 10 to 14% lower than those from the A-value method. These results were obtained after correcting for the amount of N derived from the applied fertilizer. The two methods were highly correlated (r=0.98) for estimates of amount of BNF. The rates of N2 fixation of uninoculated legumes which are nodulated by the indigenous populations of Rhizobium in Cyprus are comparable to those of legumes inoculated with selected strains of Rhizobium in other countries. An exception was the amount of N fixed by chickpea. The appearance of the first nodules at late stages of growth may be the reason for the low BNF of this crop.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 104 (1987), S. 13-21 
    ISSN: 1573-5036
    Schlagwort(e): ammonification ; kinetics ; nitrification ; osmotic potentials ; soluble salts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Studies were conducted to compare N mineralization rates in salt-amended nonsaline soils to naturally-occurring saline soils. NaCl, CaCl2, and Na2SO4 were added to nonsaline soils at rates that produced electrical conductivities of the saturation extracts (ECe) of 5, 10, 15, and 20 dS m−1. Saline soils with similar properties were leached to the same ECc levels. N mineralization in the Chino soil was inhibited by salt addition, particularly with sodium and calcium chlorides. In the Domino soil there was some inhibition of N mineralization with the chloride salts, but enhancement with Na2SO4 was observed. Nitrification in both soils was more sensitive to salt addition than ammonification. N mineralization occurred more slowly in both leached saline soils compared to the salt-amended soils. Leached saline soils often accumulated greater amounts of inorganic N compared to their native saline counterparts, particularly with the 5 dS m−1 Chino soil (native, 44 dS m−1) and with the 5, 10, 15 and 20 dS m−1 Domino soils (native, 32 dS m−1). Kinetic parameters were estimated by the linear least squares (LLS) and the nonlinear least squares (NLLS) methods. Generally, the LLS transformation estimated greater values of potentially mineralizable N (No) and lower rate constants (k). With the NLLS equation, No values for the leached saline soils were usually lower, and k values usually higher than in the salt-amended soils. The nonsaline controls generally had the highest No and lowest k estimates. Average LLS rate constants for the salt-amended and leached saline soils were 0.055 and 0.083 for the Chino, and 0.104 and 0.137 week−1, respectively, for the Domino soils. With the NLLS equation, average k values for the salt-amended and leached saline soils were 0.087 and 0.089 for the Chino, and 0.181 and 0.387 week−1, respectively, for the Domino soils. These results suggest that N mineralization rates obtained in salt-amended nonsaline soils may not be representative of those in naturally-occurring saline soils.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    ISSN: 1573-5036
    Schlagwort(e): arctic ; effectiveness ; N2-fixation ; Onobrychis ; Rhizobium ; symbiosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Sainfoin (Onobrychis viciifolia), a temperate perennial forage legume, can be nodulated by rhizobia isolated from 3 arctic legume species:Astragalus alpinus, oxytropis maydelliana andOxytropis arctobia. Arctic rhizobia, which are adapted to growth at low temperatures, may be useful in improving symbiotic nitrogen fixation during cold phases of the growing season, if they are effective on a temperate legume. In this study, we report on the symbiotic effectiveness of arctic rhizobia on sainfoin, as appraised by the total shoot dry matter yield obtained from 2 harvests. Under N-free conditions, 5 arctic strains at the first harvest and 8 at the second harvest were as effective as temperate standard strains. In the presence of 30 mgl−1 NO3-N, 7 arctic strains gave significantly higher yields than temperate strains at the second harvest. These results indicate that effective arctic rhizobia have a potential for use as inoculants on sainfoin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 97 (1987), S. 151-154 
    ISSN: 1573-5036
    Schlagwort(e): Aluminum ; Calcium ; N2-fixation ; pH ; Rhizobium trifolii ; Trifolium subterraneum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Effects of soil chemical properties on biological N2-fixation (BNF) byTrifolium subterraneum L. ‘Mt. Barker’ —Rhizobium trifolii strain 162×95 were studied on thirteen soils in a greenhouse experiment. Dry matter production of inoculated/+N plants indicated three groups of soils. Mean soil solution activities of Al3+ were 29.4, 9.8 and 0.1 μM for groups of soils with no BNF, limited BNF, and unlimited BNF, respectively. Using easily measurable soil chemical properties, the following equation related relative dry matter production to pH and soil Al saturation: Inoculated/+N×100=−140+46.83 (soil solution pH) −0.31 (Al concentration ×100/CEC) (r2=0.66).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 98 (1987), S. 257-264 
    ISSN: 1573-5036
    Schlagwort(e): Azolla pinnata ; Inoculation ; Intercropping ; N2-fixation ; Rice yield ; Rice N-uptake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Inoculation of water fernAzolla pinnata R. Brown (Bangkok isolate) at the rate of 500kg fresh weight ha−1 in rice fields at weekly intervals after planting in addition to 30 kg N ha−1 as urea showed a decrease in its growth and N2-fixation with delay in application. Use of Azolla up to 3 weeks after planting (WAP) during wet and 4 WAP during dry season produced significantly more grain yield than 30 kg N ha−1, whereas its application upto one WAP produced more grain yield than 60 kg N ha−1. Grain yield with Azolla applied at the time of planting was similar to that of 60 kg N treatment during the wet season. Higher grain yields in zero and one WAP Azolla treatments resulted due to increase in both number of panicles m−2 and number of grains/panicle while the subsequent Azolla inoculations increased grain yield mainly by producing more number of grains/panicle. Dry matter and total N yields at maturity of rice crop were more with Azolla application upto 3 WAP during wet and 2 WAP during dry season while the reduction in sterility (%) was observed upto one WAP over 30 kg N ha−1 during both seasons. Number of tillers m−2 and dry matter production at maximum tillering and flowering were more than 30 kg N ha−1 with the use of Azolla upto one WAP. Increased grain N yield was observed with the use of Azolla upto 4 WAP during two seasons whereas straw N yield increased upto one WAP during wet and 2 WAP during dry season.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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