ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Seasonal, annual, and treatment-induced variation in available nitrogen pools and nitrogen-cycling processes in soils of two Douglas-fir stands (1988)
    Springer
    Biology and fertility of soils 6 (1988), S. 93-99 
    Details
    ISSN: 1432-0789
    Keywords: Ammonium ; Nitrate ; N-mineralization ; Nitrification ; Fertilization ; Irrigation ; Forest ecosystems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Forest-floor and 0–10 cm depth mineral soil horizons in two stands of Douglas fir were sampled for available NH4 +-N and NO3 −-N, N-mineralization potentials, and nitrification potentials for 2 years. The plots in each stand were sampled for 1 year, treated with either ammonium sulfate, carbohydrate (sawdust-sucrose), irrigation, carbohydrate plus irrigation, or no treatment (control), and then sampled for 1 year following treatment. In general, the direction of change following the treatments was the same for both the forest-floor and the mineral soils. Fertilization increased the NH4 +-N and NO3 −-N pools, nitrification potential, and N-mineralization potential, while treatment with carbohydrate decreased all of these characteristics. Irrigation generally increased NH4 +-N pools, nitrification potential, and N-mineralization potential, but decreased these characteristics in the soil at one site. Irrigation plus carbohydrate gave similar results to those of carbohydrate alone. Treatments altered pool sizes and/or potentials, but did not reduce within-year variance in any of these characteristics. Distinct seasonal patterns occurred in all measurements, suggesting that control of short-term variation in N-transformation processes is by factors which are dynamic in nature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Plant regeneration from long-term suspension cultures of white clover (1984)
    Springer
    Planta 162 (1984), S. 1-7 
    Details
    ISSN: 1432-2048
    Keywords: Ammonium ; Cell culture (plant regeneration) ; Meristemoid ; Trifolium (regeneration)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A genotype of Trifolium repens L. capable of sustaining high-frequency plant regeneration from long-term (24-month old) cell cultures has been selected. Numerous densely cytoplasmic meristemoids were formed in suspension cultures following the coordinate removal of 2,4-dichlorophenoxyacetic acid (2,4-D) and trichloropicolinic acid (picloram) from the medium and an increase in the NH 4 + concentration. Some meristemoids arose from single cells in culture. Increasing the NH 4 + concentration in the medium resulted in increased meristemoid formation and decreased the growth rate. Ammonium stimulated meristemoid formation when it was the sole source of nitrogen only if a lethal shift in the pH of the medium was prevented. Meristemoids plated on hormone-free agar medium developed directly into shoots which spontaneously formed roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397413
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Forest-floor nitrogen dynamics in a 60-year-old paper birch ecosystem in interior Alaska (1980)
    Springer
    Plant and soil 54 (1980), S. 359-381 
    Details
    ISSN: 1573-5036
    Keywords: Alaska ; Ammonium ; Birch ; Forest-floor ; Isotopedilution ; Kinetics ; Nitrate ; Nitrogen pool
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary An analysis was conducted of nitrogen dynamics in the forest floor of a paper birch forest in subarctic Alaska. Low addition levels of high enrichment isotope (〈1% of the total nitrogen pool with 95 to 99 atom percent excess15N) and isotope dilution analysis, were used to establish the kinetics of nitrogen flow. The pools examined were NH4, NO3+NO2, soluble organic-N and forest floor organic matter. This approach allows a more realistic assessment of rates of N movement at the levels of nitrogen concentration encountered in natural systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02181831
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The effect of high solute concentrations on nitrification rates in soil (1987)
    Springer
    Plant and soil 97 (1987), S. 37-45 
    Details
    ISSN: 1573-5036
    Keywords: Ammonium ; Chloride ; Inhibition ; Nitrification ; Osmotic pressure ; Sorbitol ; Sulphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A short term nitrification assay (〈18 h) was used to assess the effect of high concentrations of different solutes on the rate of nitrate production. High solute concentrations were found to inhibit nitrification and the degree of inhibition was related both to the osmotic pressure of the soil solution and the osmoticum used. Ammonium chloride, ammonium sulphate and sorbitol were used as sources of osmotic pressure. The results showed that, with ammonium salts, no inhibition was observed with pressures less than 2 atm. Above these values, the severity of the inhibition followed the order ammonium chloride〉ammonium sulphate〉sorbitol up to the maximum osmotic pressure studied (25 atm). With ammonium chloride, a pressure of 3.5 atm. was sufficient to cause a 90% inhibition of nitrification rate. The inhibition produced by mixtures of ammonium chloride and sorbitol, each mixture generating an osmotic pressure of 5 atm. in the assay, was also investigated. The results suggest that inhibition by Cl-ion is disproportionate to its contribution to the osmotic pressure of the soil solution. The recovery of the nitrification rate, following exposure to high osmotic pressure solutions, was also investigated. It was found that the recovery of the nitrification rate was only partial, with the extent of the recovery diminishing as the severity of the initial osmotic stress applied increased. These results suggest that both reversible and irreversible mechanisms are involved in the inhibition of nitrification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02149821
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Modelling growth responses of soil nitrifiers to additions of ammonium sulphate and ammonium chloride (1985)
    Springer
    Plant and soil 86 (1985), S. 425-439 
    Details
    ISSN: 1573-5036
    Keywords: Ammonium ; Chloride ; Growth ; Inhibition ; Monod model ; Nitrification ; Soil ; Sulphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Following the addition of 0–75 μmole N g−1 as ammonium chloride or ammonium sulphate to a sandy loam soil the nitrate formed was measured daily for a period of 15–17 days. The nitrate produced as a function of time was described using the Monod equation for microbial growth. An optimisation technique is described for obtaining, from the nitrification time course data, the maximum specific growth rate, the affinity constantant and an index limited by the concentration of ammonium in soil solution. Additions of more than 7.3 μmoles N g−1 soil as ammonium chloride were found to inhibit nitrification. The inhibition was interpreted as being caused by osmotic pressure or by chloride ion. A similar effect was not found with ammonium sulphate, because the salt concentration in the soil solution was restricted by the precipitation of calcium sulphate. The model developed was capable of accounting for nitrate production in the soil under non-steady state conditions of substrate concentrations and nitrifier biomass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02145463
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...