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  • Pisum sativum  (3)
  • Cucumis sativus  (2)
  • Residue quality  (2)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 16 (1993), S. 66-70 
    ISSN: 1432-0789
    Schlagwort(e): VA mycorrhiza ; Glomus intraradices ; Hyphal N transport ; Cucumis sativus ; 15N recovery ; Root compartment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Transport of N by hyphae of a vesicular-arbuscular mycorrhizal fungus was studied under controlled experimental conditions. The N source was applied to the soil as 15NH inf4 sup+ or 15NO inf3 sup- . Cucumis sativus was grown for 25 days, either alone or in symbiosis with Glomus intraradices, in containers with a hyphal compartment separated from the root compartment by a fine nylon mesh. Mineral N was then applied to the hyphal compartment as 15NH inf4 sup+ or 15NO inf3 sup- at 5 cm distance from the root compartment. Soil samples were taken from the hyphal compartment at 1, 3 and 5 cm distance from the root compartment at 7 and 12 days after labelling, and the concentration of mineral N in the samples was measured from 2 M KCl extracts. Mycorrhizal colonization did not affect plant dry weight. The recovery of 15N in mycorrhizal plants was 38 or 40%, respectively, when 15NH inf4 sup+ or 15NO inf3 sup- was applied. The corresponding values for non-mycorrhizal plants were 7 and 16%. The higher 15N recovery observed in mycorrhizal plants than in non-mycorrhizal plants suggests that hyphal transport of N from the applied 15N sources towards the host plant had occurred. The concentration of mineral N in the soil of hyphal compartments was considerably less in mycorrhizal treatments than in controls, indicating that the hyphae were able to deplete the soil for mineral N.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 24 (1996), S. 39-44 
    ISSN: 1432-0789
    Schlagwort(e): Key words Immobilization ; Mineralization ; 15N-labelled crop residues ; Residue quality ; Soil microbial biomass
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The immobilization and mineralization of N following plant residue incorporation were studied in a sandy loam soil using 15N-labelled field pea (Pisum sativum L.) and spring barley (Hordeum vulgare L.) straw. Both crop residues caused a net immobilization of soil-derived inorganic N during the complete incubation period of 84 days. The maximum rate of N immobilization was found to 12 and 18 mg soil-derived N g–1 added C after incorporation of pea and barley residues, respectively. After 7 days of incubation, 21% of the pea and 17% of the barley residue N were assimilated by the soil microbial biomass. A comparison of the 15N enrichments of the soil organic N and the newly formed biomass N pools indicated that either residue N may have been assimilated directly by the microbial biomass without entering the soil inorganic N pool or the biomass had a higher preference for mineralized ammonium than for soil-derived nitrate already present in the soil. In the barley residue treatment, the microbial biomass N was apparently stabilized to a higher degree than the biomass N in the pea residue treatment, which declined during the incubation period. This was probably due to N-deficiency delaying the decomposition of the barley residue. The net mineralization of residue-derived N was 2% in the barley and 22% in the pea residue treatment after 84 days of incubation. The results demonstrated that even if crop residues have a relative low C/N ratio (15), transient immobilization of soil N in the microbial biomass may contribute to improved conservation of soil N sources.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 24 (1997), S. 39-44 
    ISSN: 1432-0789
    Schlagwort(e): Immobilization ; Mineralization ; 15N-labelled crop residues ; Residue quality ; Soil microbial biomass
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The immobilization and mineralization of N following plant residue incorporation were studied in a sandy loam soil using15N-labelled field pea (Pisum sativum L.) and spring barley (Hordeum vulgare L.) straw. Both crop residues caused a net immobilization of soil-derived inorganic N during the complete incubation period of 84 days. The maximum rate of N immobilization was found to 12 and 18 mg soil-derived N g−1 added C after incorporation of pea and barley residues, respectively. After 7 days of incubation, 21% of the pea and 17% of the barley residue N were assimilated by the soil microbial biomass. A comparison of the15N enrichments of the soil organic N and the newly formed biomass N pools indicated that either residue N may have been assimilated directly by the microbial biomass without entering the soil inorganic N pool or the biomass had a higher preference for mineralized ammonium than for soil-derived nitrate already present in the soil. In the barley residue treatment, the microbial biomass N was apparently stabilized to a higher degree than the biomass N in the pea residue treatment, which declined during the incubation period. This was probably due to N-deficiency delaying the decomposition of the barley residue. The net mineralization of residue-derived N was 2% in the barley and 22% in the pea residue treatment after 84 days of incubation. The results demonstrated that even if crop residues have a relative low C/N ratio (15), transient immobilization of soil N in the microbial biomass may contribute to improved conservation of soil N sources.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 92 (1986), S. 3-13 
    ISSN: 1573-5036
    Schlagwort(e): A-value ; Barley ; Field bean ; Isotope dilution ; Nitrogen fixation ; 15N ; Non-fixing reference crop ; Pea ; Pisum sativum ; Vicia faba
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The total amount of nitrogen derived from symbiotic nitrogen fixation in two pea and one field bean cultivar, supplied with 50 kg N ha−1 at sowing (‘starter’-N), was estimated to 165, 136, and 186 kg N ha−1, respectively (three-year means). However, estimates varied considerably between the three years. At the full bloom/flat pod growth stage from 30 to 59 per cent of total N2 fixation had taken place. The proportion of total N derived from N2 fixation at maturity was higher in seeds than in vegetative plant parts and amounted to 59.5, 51.3 and 66.3 per cent of total above-ground plant N in the two pea cultivars and field bean, respectively (three-year means). The recovery of fertilizer N was 62.2, 70.2, 52.1, and 69.5 per cent in the two pea cultivars, field bean and barley, respectively. Growth analysis indicated that barley did not meet the claims for an ideal reference crop in the15N fertilizer dilution technique for estimating N2 fixation in pea and field bean. ‘Starter’-N neither increased the seed yield nor the N content of the grain legumes.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1573-5036
    Schlagwort(e): 15N ; Cucumis sativus ; Glomus intraradices ; hyphal N transport ; plant N status ; VA mycorrhiza
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Cucumis sativus L. cv. Aminex (F1 hybrid) was grown alone or in symbiosis with Glomus intraradices Schenck and Smith in containers with two hyphal compartments (HCA and HCB) on either side of a root compartment (RC) separated by fine nylon mesh. Plants received a total of either 100, 200 or 400 mg N which were applied gradually to the RC during the experiment. 15N was supplied to HCA 42 d after plating, at 50 mg 15NH4 +-N kg−1 soil. Lateral movement of the applied 15N towards the roots was minimized by using a nitrification inhibitor and a hyphal buffer compartment. Non-mycorrhizal controls contained only traces of 15N after a 27 d labelling period irrespective of the amount of N supplied to the RC. In contrast, 49, 48 and 27% of the applied 15N was recovered in mycorrhizal plants supplied with 100, 200 and 400 mg N, respectively. The plant dry weight was increased by mycorrhizal colonization at all three levels of N supply, but this effect was strongest in plants of low N status. The results indicated that this increase was due partly to the improved inflow of N via the external hyphae. Root colonization by G. intraradices was unaffected by the amount of N supplied to the RC, while hyphal length increased in HCA compared to HCB. Although a considerable 15N content was detected in mycorrhizal roots adjacent to HCB, only insignificant amounts of 15N were found in the external hyphae in HCB. The external hyphae depleted the soil of inorganic N in both HCA and HCB, while the concentration of soil mineral N was still high in non-mycorrhizal containers at harvest. An exception was plants supplied with 400 mg N, where some inorganic N was present at 5 cm distance from the RC in HCA. The possibility of a regulation mechanism for hyphal transport of N is discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 101 (1987), S. 29-37 
    ISSN: 1573-5036
    Schlagwort(e): assimilate partitioning ; growth analysis ; leaf area ; nitrate ; nitrogen fixation ; 15N isotope dilution ; pea ; Pisum sativum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The seasonal patterns of growth and symbiotic N2 fixation under field conditions were studied by growth analysis and use of15N-labelled fertilizer in a determinate pea cultivar (Pisum sativum L.) grown for harvest at the dry seed stage. The patterns of fertilizer N-uptake were almost identical in pea and barley (the non-fixing reference crop), but more fertilizer-N was recovered in barley than in pea. The estimated rate of N2 fixation in pea gradually increased during the pre-flowering and flowering growth stages and reached a maximum of 10 kg N fixed per ha per day nine to ten weeks after seedling emergence. This was the time of early pod-development (flat pod growth stage) and also the time for maximum crop growth rate and maximum green leaf area index. A steep drop in N2 fixation rate occurred during the following week. This drop was simultaneous with lodging of the crop, pod-filling (round pod growth stage) and the initiation of mobilization of nitrogen from vegetative organs. The application of fertilizer-N inhibited the rate of N2 fixation only during that period of growth, when the main part of fertilizer-N was taken up and shortly after. Total accumulation of fixed nitrogen was estimated to be 244, 238 and 213 kg N ha−1 in pea supplied with nil, 25 or 50 kg NO 3 − −N ha−1, respectively. About one-fourth of total N2 fixation was carried out during preflowering, one fourth during the two weeks of flowering and the remainder during post-flowering. About 55% of the amount of N present in pods at maturity was estimated to be derived from mobilization of N from vegetative organs. “Starter” N (25 or 50 kg NO 3 − −N ha−1) did not significantly influence either dry matter and nitrogen accumulation or the development of leaf area. Neither root length and root biomass determined 8 weeks after seedling emergence nor the yield of seed dry matter and nitrogen at maturity were influenced by fertilizer application.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 97 (1987), S. 63-70 
    ISSN: 1573-5036
    Schlagwort(e): Competition ; Indirect inoculation ; Inoculum rate ; N2 fixation ; Pisum sativum ; Rhizobium leguminosarum ; Streptomycin resistant mutants ; Yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Selected streptomycin resistant strains ofRhizobium leguminosarum suspended in nutrient broth were added to the planting furrow immediately before the sowing of pea. The nodule occupancy by a strain isolated from Risø soil (Risø la) was increased from 74 to 90%, when the inoculum rate was increased from 3.7×106 to 3.7×108 cells per cm row. The experimental soil contained 103 to 104 cells ofR. leguminosarum per gram. An almost inefficient strain isolated from Risø soil (SV10) was less competitive with respect to nodulation on two pea cultivars than an efficient Risø strain (SV15) and an efficient non-Risø strain (R1045). The nodule occupancy by the introduced strains varied between pea cultivars. Irrespective of the generally high nodulation by the efficient strains introduced to the soil, the pea seed yield, compared to pea nodulated by the indigenous population, was not significantly increased. Neither were two commercial inoculants, applied in rates corresponding to 3 times the recommended rate, able to increase the yield. This suggests that the indigenous populations ofR. leguminosarum were sufficient in number and nitrogen fixing capacity to ensure an optimal pea crop. However, some inoculation treatments slightly increased the seed N concentration and total N accumulation, indicating that it may be possible to select or develop bacterial strains that may increase the yield.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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