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  • denitrification  (5)
  • nitrogen loss  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Determination of dinitrogen emission and retention in floodwater and porewater of a lowland rice field fertilized with15N-urea (1989)
    Springer
    Nutrient cycling in agroecosystems 19 (1989), S. 127-136 
    Details
    ISSN: 1573-0867
    Keywords: Nitrogen loss ; denitrification ; volatilization ; surface fluxes ; ammonia loss ; 15N-methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper reports a study on the distribution of dinitrogen between the atmosphere, floodwater and porewater of the soil in a flooded rice field after addition of15N-labelled urea into the floodwater. Microplots (0.086 m2) were established in a rice field near Griffith, N.S.W., and labelled urea (80 kg N ha−1 containing 79.25 atoms %15N) was added to the floodwater when the rice was at the panicle initiation stage. Emission of nitrous oxide and dinitrogen was measured directly during the day and overnight, using a cover collection method and gas chromatographic and mass spectrometric analytical methods. Ammonia volatilization was calculated with a bulk aerodynamic method from measurements of wind speed and floodwater pH, temperature and ammoniacal nitrogen concentration. Seven days after urea application the15N2 content of the floodwater and soil porewater was determined and total fertilizer nitrogen loss was calculated from an isotopic balance. Throughout the experimental period gas fluxes were low; nitrous oxide, ammonia and dinitrogen flux densities were less than 5, 170 and 720 g N ha−1 d−1, respectively. The greatest dinitrogen flux density was observed two days after urea addition and this declined to ~ 100 g ha−1 d−1 after seven days. The data indicate that, of the urea nitrogen added, 0.02% was lost to the atmosphere as nitrous oxide, 0.9% was lost by ammonia volatilization, and 3.6% was lost as dinitrogen gas during the 7 days of measurement. At the end of this period 0.028% and 0.002% of the added nitrogen was retained as dinitrogen gas in the floodwater and soil porewater respectively. Recovery of the15N applied as nitrogen gases, plant uptake, and soil and floodwater constituents totaled about 94% of the nitrogen added.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01054454
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of a new nitrification inhibitor (wax coated calcium carbide) on transformations and recovery of fertilizer nitrogen by irrigated wheat (1992)
    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 1-11 
    Details
    ISSN: 1573-0867
    Keywords: Nitrogen loss ; denitrification ; acetylene ; irrigation ; urea ; nitrogen isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effectiveness of wax coated calcium carbide to provide a slow release of acetylene to inhibit nitrification and denitrification in soil was evaluated in a field experiment with irrigated wheat (cv. Condor) grown on a red brown earth in the Goulburn-Murray Irrigation Region. The effect of the inhibitor treatments on biomass and grain yield was determined in 25 m × 3 m plots, and the effect on recovery, in the plant-soil system, of urea-N applied at sowing was determined in 0.3 m × 0.3 m microplots using a15N balance technique. The inhibitor limited ammonium oxidation, prevented nitrogen loss by denitrification for 75 days, increased N accumulation by the wheat plants, increased grain N and resulted in a 46% greater recovery of applied nitrogen in the plant-soil system at harvest. However, the inhibitor treatment did not increase grain yield because of waterlogging at the end of tillering and during stem elongation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01054388
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of encapsulated calcium carbide and urea application methods on denitrification and N loss from flooded rice (1995)
    Springer
    Nutrient cycling in agroecosystems 45 (1995), S. 31-36 
    Details
    ISSN: 1573-0867
    Keywords: nitrification ; denitrification ; 15N balance ; nitrogen loss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Poor N fertilizer use efficiency by flooded rice is caused by gaseous losses of N. Improved fertilizer management and use of nitrification inhibitors may reduce N losses. A microplot study using15N-labelled urea was conducted to investigate the effects of fertilizer application method (urea broadcast, incorporated, deep-placed) and nitrification inhibitor [encapsulated calcium carbide (ECC)] treatments on emission of N2+N20 and total loss of applied N on a grey clay near Griffith, NSW, Australia. Both incorporation and deep placement of urea decreased N2+N2O emission compared to urea broadcast into the floodwater. Addition of ECC significantly (P 〈 0.05) reduced emission of N2+N20 from incorporated or deep-placed urea and resulted in increased exchangeable ammonium concentrations in the soil in both treatments. Fifty percent of the applied N was lost when urea was broadcast into the floodwater. Total N loss from the applied N was significantly (P 〈 0.05) reduced when urea was either incorporated or deep placed. In the presence of ECC the losses were reduced further and the lowest loss (34.2% of the applied N) was noted when urea was deep-placed with ECC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749879
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  • 4
    Electronic Resource
    Electronic Resource
    Nitrous oxide emissions from agricultural soils (1994)
    Springer
    Nutrient cycling in agroecosystems 37 (1994), S. 191-200 
    Details
    ISSN: 1573-0867
    Keywords: control options ; denitrification ; nitrification ; N2O
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper addresses three topics related to N2O emissions from agricultural soils. First, an assessment of the current knowledge of N2O emissions from agricultural soils and the role of agricultural systems in the global N2O are discussed. Secondly, a critique on the methodology presented in the OECD/OCDE (1991) program on national inventories of N2O is presented. Finally, technical options for controlling N2O emissions from agricultural fields are discussed. The amount of N2O derived from nitrogen applied to agricultural soils from atmospheric deposition, mineral N fertilizer, animal wastes or biologically fixed N, is not accurately known. It is estimated that the world-wide N2O emitteddirectly from agricultural fields as a result of the deposition of all the above nitrogen sources is 2–3 Tg N annually. This amounts to 20–30% of the total N2O emitted annually from the earth's surface. An unknown, but probably significant, amount of N2O is generated indirectly in on and off farm activities associated with food production and consumption. Management options to limitdirect N2O emissions from N-fertilized soils should emphasize improving N-use efficiency. Such management options include managing irrigation frequency, timing and quantity; applying N only to meet crop demand through multiple applications during the growing season or by using controlled release fertilizers; applying sufficient N only to meet crop needs; or using nitrification inhibitors. Most of these options have not been field tested. Agricultural management practices may not appreciably affect indirect N2O emissions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00748937
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  • 5
    Electronic Resource
    Electronic Resource
    Use of nitrification inhibitors to increase fertilizer nitrogen recovery and lint yield in irrigated cotton (1993)
    Springer
    Nutrient cycling in agroecosystems 34 (1993), S. 37-44 
    Details
    ISSN: 1573-0867
    Keywords: acetylene ; denitrification ; irrigation ; nitrogen isotopes ; nitrogen loss ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper describes field experiments designed to evaluate the effectiveness of several nitrification inhibitors to prevent loss of fertilizer nitrogen (N) applied to cotton. The usefulness of nitrapyrin, acetylene (provided by wax-coated calcium carbide), phenylacetylene and 2-ethynylpyridine to prevent denitrification was evaluated by determining the recovery of N applied as15N labelled urea to a heavy clay soil in 1 m × 0.5 m microplots in north western N.S.W., Australia. In a second experiment, the effect of wax-coated calcium carbide on lint yield of cotton supplied with five N levels was determined on 12.5 m × 8 m plots at the same site. The15N balance study showed that in the absence of nitrification inhibitors only 57% of the applied N was recovered in the plants and soil at crop maturity. The recovery was increased (p 〈 0.05) to 70% by addition of phenylacetylene, to 74% by nitrapyrin, to 78% by coated calcium carbide and to 92% by 2-ethynylpyridine. In the larger scale field experiment, addition of the wax-coated calcium carbide significantly slowed the rate of NH 4 + oxidation in the grey clay for approximately 8 weeks. Lint yield was increased (p 〈 0.05) by the addition of the inhibitor at all except the highest level of N addition. The inhibitor helped to conserve the indigenous N as well as the applied N. The research shows that the effectiveness of urea fertilizer for cotton grown on the heavy clay soils of N.S.W. can be markedly improved by using acetylenic compounds as nitrification inhibitors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749958
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    Paper (German National Licenses)
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