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  • Nitrification  (2)
  • 15N-labelled material  (1)
  • Clay-fixed NH inf4 sup+  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Transformation of 15N-labelled leguminous plant material in three contrasting soils (1989)
    Springer
    Biology and fertility of soils 8 (1989), S. 54-60 
    Details
    ISSN: 1432-0789
    Keywords: Biomass N ; Humus fractions ; Hydrolyzable N ; Legume N ; Mineralizable N ; N-mineralization ; 15N-labelled material
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two soils from Pakistan (Hafizabad silt loam and Khurrarianwala silt loam) and one from Illinois, USA (Drummer silty clay loam) were incubated with 15N-labelled soybean tops for up to 20 weeks at 30°C. Mineralization of soybean 15N was slightly more rapid in the Pakistani soils, and after 20 weeks of incubation, 50%, 53%, and 56% of the applied 15N was accounted for as (NH4 ++NO3 −)-N in Drummer, Hafizabad, and Khurrarianwala soils, respectively. Potentially mineralizable N (determined by anaerobic incubation) varied between 1.5% and 10% of the applied 15N in the three soils at different stages of incubation; somewhat higher percentages were mineralizable in the Pakistani soils than in the Drummer soil. From 3.7% to 9% of the applied 15N was accounted for in the microbial biomass. From 10% to 32% of the applied N was recovered in the humic acid and fulvic acid fractions of the organic matter by sequential extraction with Na4P2O7 and NaOH; from 12% to 49% was recovered in the humin fraction. Of the three soils, Drummer soil contained more 15N as humic and fulvic acids. In all cases, the 15N was approximately equally distributed between the humic and fulvic acid fractions. A significant percentage of the humin 15N (52%–78%, equivalent to 8%–34% of the applied 15N) occurred in non-hydrolyzable (6 N HCl) forms. Of the hydrolyzable 15N, 42%–51% was accounted for as amino acid-N followed in order by NH3 (17%–30%), hydrolyzable unknown forms (20%–22%), and amino sugars (6%–2%). The recovery of applied 15N for the different incubation stages was 87±22%. Recovery was lowest with the Khurrarianwala soil, presumably because of NH3 volatilization losses caused by the high pH of this soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260516
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Nitrogen fertilizers promote denitrification (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 211-220 
    Details
    ISSN: 1432-0789
    Keywords: Key words Denitrification ; Fertilizer efficiency ; 15N ; Labelled dinitrogen ; Nitrification ; Nitrous oxide ; Urea ; Waterlogged soil ; Water-soluble organic carbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A laboratory study was conducted to compare the effects of different N fertilizers on emission of N2 and N2O during denitrification of NO3 – in waterlogged soil. Field-moist samples of Drummer silty clay loam soil (fine-silty, mixed, mesic Typic Haplaquoll) were incubated under aerobic conditions for 0, 2, 4, 7, 14, 21, or 42 days with or without addition of unlabelled (NH4)2SO4, urea, NH4H2PO4, (NH4)2HPO4, NH4NO3 (200 or 1000 mg N kg–1 soil), or liquid anhydrous NH3 (1000 mg N kg–1 soil). The incubated soil samples were then treated with 15N-labelled KNO3 (250 mg N kg–1 soil, 73.7 atom% 15N), and incubation was carried out under waterlogged conditions for 5 days, followed by collection of atmospheric samples for 15N analyses to determine labelled N2 and N2O. Compared to samples incubated without addition of unlabelled N, all of the fertilizers promoted denitrification of 15NO3 –. Emission of labelled N2 and N2O decreased in the order: Anhydrous NH3〉urea〈$〉\gg〈$〉 (NH4)2HPO4〉(NH4)2SO4≃NH4NO3≃NH4H2PO4. The highest emissions observed with anhydrous NH3 or urea coincided with the presence of NO2 –, and 15N analyses indicated that these emissions originated from NO2 – rather than NO3 –. Emissions of labelled N2 and N2O were significantly correlated with fertilizer effects on soil pH and water-soluble organic C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050233
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of ammonium and nitrate on mineralization of nitrogen from leguminous residues (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 49-52 
    Details
    ISSN: 1432-0789
    Keywords: Nitrification ; N immobilization ; N mineralization ; N interaction ; N-Serve ; Nitrapyrin ; Soil N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A laboratory incubation experiment was conducted to compare the effects of NH inf4 sup+ and NO inf3 sup- on mineralization of N from 15N-labelled vetch (Vicia villosa Rotn) in an Illinois Mollisol, and to determine the effect of a nitrification inhibitor (nitrapyrin) on mineralization of vetch N when used with NH inf4 sup+ . The addition of either NH inf4 sup+ or NO inf3 sup- (100 and 200 mg N kg-1 soil) significantly increased mineralization of vetch N during incubation for 40 days. The effect was greater with NH inf4 sup+ than with NO inf3 sup- , and a further increase occurred in the presence of nitrapyrin (10 mg kg-1 soil). The addition of NO inf3 sup- retarded the nitrification of NH inf4 sup+ -N derived from vetch.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307840
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  • 4
    Electronic Resource
    Electronic Resource
    Transformations of chemically fixed liquid anhydrous ammonia by soil microorganisms (1991)
    Springer
    Biology and fertility of soils 11 (1991), S. 145-150 
    Details
    ISSN: 1432-0789
    Keywords: Nitrogen-15 ; Ammonia fixation ; Organic matter-fixed NH3 ; Clay-fixed NH inf4 sup+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The application of liquid anhydrous NH3 to soil leads to chemical fixation of NH3 by organic matter and of NH inf4 sup+ by clay minerals. A laboratory study was conducted to ascertain the biological transformations of newly fixed liquid anhydrous 15NH3 in a Drummer silty clay loam by incubation of the 15N-labelled soil with glucose for 0, 7, 30, and 90 days and by sequential extraction of organic-matter-fixed 15NH3 with 0.15 M Na4P2O7, 0.15 M KOH, 0.1 M NaOH, and acidified dimethyl sulfoxide. About 16% of the 15NH3 injected was fixed, of which 52% was accounted for by clay fixation. The various humic fractions (fulvic acid, humic acid, and humin) were obtained, and the distribution patterns of the fixed 15NH3-N in these fractions were compared. The potential availability of the fixed 15NH3-N was also estimated. The percentage of the 15NH3 recovered as organic-matter-fixed 15NH3 decreased as the length of incubation increased (to 28% after 90 days); the decrease was attributed in part to an increase in the amount recovered as clay-fixed NH inf4 sup+ (from 52 to 64%). Changes in the distribution of the organic-matter-fixed 15NH3-N in the humic fractions included: (1) an increase in the relative amount of the fixed 15NH3 as humic acid in both the Na4P2O7 and KOH extracts, (2) an increase in the percentage of organic-matter-fixed 15NH3-N in the fulvic acid fractions as high-molecular-weight components (determined by dialysis) or as generic fulvic acid (determined by sorption-desorption from XAD-8 resin), and (3) an increase in the percentage of the organic-matter-fixed 15NH3 as humin. The potential availability of the organic-matter-fixed 15NH3-N decreased as the length of the incubation increased, from 22 to 4% over the 90-day incubation period, and was correlated significantly (0.05 level) with Na4P2O7-extractable N. These results suggest that organic-matter-fixed liquid anhydrous NH3 is initially more labile than the native soil N but becomes less labile with time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336380
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    Paper (German National Licenses)
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