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  • Articles  (7)
  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (5)
  • Geosciences  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Foliar and fine root nitrate reductase activity in seedlings of four forest tree species in relation to nitrogen availability (1993)
    Springer
    Trees 7 (1993), S. 233-236 
    Details
    ISSN: 1432-2285
    Keywords: Nitrate reductase ; Nitrogen deposition ; Forests ; Nitrate ; Seedlings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seedlings of red maple, white pine, pitch pine and red pine were fertilized with nutrient solutions containing 4 levels of nitrate or ammonium additions. These levels corresponded to approximately 0.5, 1, 2 and 4 times normal availability of nitrogen in northeastern forests. Nitrate reductase (NR) activity was assayed in roots and leaves. Red maples treated with nitrate showed much higher leaf activities and higher ratios of leaf NR activity to root NR activity than any other species. Ammonium additions to red maple and white pine appeared to inhibit NR activity in leaves. With high nitrate additions, NR activity was induced in roots and leaves of pine species, but activity in roots remained much higher than in leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202079
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  • 2
    Electronic Resource
    Electronic Resource
    Seasonal patterns of ammonium and nitrate uptake in nine temperate forest ecosystems (1984)
    Springer
    Plant and soil 80 (1984), S. 321-335 
    Details
    ISSN: 1573-5036
    Keywords: Alfisol ; Ammonification ; Nitrification ; Nitrogen mineralization ; Temperate forests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seasonal patterns of net N mineralization and nitrification in the 0–10 cm mineral soil of 9 temperate forest sites were analyzed using approximately monthlyin situ soil incubations. Measured nitrification rates in incubated soils were found to be good estimates of nitrification in surrounding forest soils. Monthly net N mineralization rates and pools of ammonium-N in soil fluctuated during the growing season at all sites. Nitrate-N pools in soil were generally smaller than ammonium-N pools and monthly nitrification rates were less variable than net N mineralization rates. Nitrate supplied most of the N taken up annually by vegetation at 8 of the 9 sites. Furthermore, despite the large fluctuations in ammonium-N pools and monthly net N mineralization, nitrate was taken up at relatively uniform rates during the growing season at most sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02140039
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  • 3
    Electronic Resource
    Electronic Resource
    Fluxes of greenhouse gases between soils and the atmosphere in a temperate forest following a simulated hurricane blowdown (1993)
    Springer
    Biodegradation 21 (1993), S. 61-71 
    Details
    ISSN: 1572-9729
    Keywords: Atmospheric chemistry ; carbon dioxide ; disturbance ; hurricane ; methane ; nitrification ; nitrous oxide ; soils ; temperate forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Fluxes of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) between soils and the atmosphere were measured monthly for one year in a 77-year-old temperate hardwood forest following a simulated hurricane blowdown. Emissions of CO2 and uptake of CH4 for the control plot were 4.92 MT C ha−1 y−1 and 3.87 kg C ha−1 y−1, respectively, and were not significantly different from the blowdown plot. Annual N2O emissions in the control plot (0.23 kg N ha−1 y−1) were low and were reduced 78% by the blowdown. Net N mineralization was not affected by the blowdown. Net nitrification was greater in the blowdown than in the control, however, the absolute rate of net nitrification, as well as the proportion of mineralized N that was nitrified, remained low. Fluxes of CO2 and CH4 were correlated positively to soil temperature, and CH, uptake showed a negative relationship to soil moisture. Substantial resprouting and leafing out of downed or damaged trees, and increased growth of understory vegetation following the blowdown, were probably responsible for the relatively small differences in soil temperature, moisture, N availability, and net N mineralization and net nitrification between the control and blowdown plots, thus resulting in no change in CO2 or CH4 fluxes, and no increase in N2O emissions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000871
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  • 4
    Electronic Resource
    Electronic Resource
    Primary production and nitrogen allocation of field grown sugar maples in relation to nitrogen availability (1985)
    Springer
    Biogeochemistry 1 (1985), S. 135-154 
    Details
    ISSN: 1573-515X
    Keywords: Retranslocation ; in situ incubation ; canopy nitrogen ; nitrogen use efficiency ; stagnation ; canopy structure ; buried polyethylene bags
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Above ground net primary production (NPP), nitrogen (N) allocation, and retranslocation from senescing leaves were measured in 7 sugar-maple dominated sites having annual net N mineralization rates ranging from 26 to 94 kg · ha−1 · yr−1. The following responses were observed: (1) Green sun leaves on richer sites had higher N mass per unit leaf area than sun leaves on poorer sites; (2) Total canopy N varied much less than annual net mineralization, ranging from 81 to 111 kg · ha−1; (3) This was due to the existence of a large and relatively constant pool of N which was retranslocated from senescing leaves for use the following year (54 to 80 kg · ha−1); (4) The percentage of canopy N retranslocated by sugar maple was also relatively constant, but was slightly higher on the richer sites. Percent N in leaf litter did not change across the gradient; (5) Above ground NPP increased linearly in relation to N allocated above ground. Therefore, N use efficiency, expressed as above ground NPP divided by N allocated above ground was constant; (6) N use efficiency expressed as (NPP above ground/total N availability) was a curvilinear function of N availability; and (7) This pattern reflected a decreasing apparent allocation of N below ground with decreasing N availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185038
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  • 5
    Electronic Resource
    Electronic Resource
    Exchange of N2O and CH4 between the atmosphere and soils in spruce-fir forests in the northeastern United States (1992)
    Springer
    Biogeochemistry 18 (1992), S. 119-135 
    Details
    ISSN: 1573-515X
    Keywords: N2O ; CH4 ; red spruce ; balsam fir ; spruce-fir ; forests ; nitrogen ; deposition ; nitrification ; mineralization ; denitrification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract We measured the exchange of N2O and CH4 between the atmosphere and soils in 5 spruce-fir stands located along a transect from New York to Maine. Nitrous oxide emissions averaged over the 1990 growing season (May–September) ranged from 2.1 ug N2O-N/m2-hr in New York to 0.4 ug N2O-N/m2-hr in Maine. The westernmost sites, Whiteface Mtn., New York and Mt. Mansfield, Vermont, had the highest nitrogen-deposition, net nitrification and N2O emissions. Soils at all sites were net sinks for atmospheric CH4 Methane uptake averaged over the 1990 growing season ranged from 0.02 mg CH4-C/M2-hr in Maine to 0.05 mg CH4-C/m2-hr in Vermont. Regional differences in CH4 uptake could not be explained by differences in nitrogen-deposition, soil nitrogen dynamics, soil moisture or soil temperature. We estimate that soils in spruce-fir forests at our study sites released ca. 0.02 to 0.08 kg N2O-N/ha and consumed ca. 0.74 to 1.85 kg CH4 C/ha in the 1990 growing season.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00003273
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  • 6
    Electronic Resource
    Electronic Resource
    15N natural abundance in forest and pasture soils of the Brazilian Amazon Basin (1996)
    Springer
    Plant and soil 182 (1996), S. 249-258 
    Details
    ISSN: 1573-5036
    Keywords: nitrogen ; nitrogen fixation ; stable isotopes ; tropical forest ; tropical pasture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The natural abundance of 15N was examined in soil profiles from forests and pastures of the Brazilian Amazon Basin to compare tropical forests on a variety of soil types and to investigate changes in the sources of nitrogen to soils following deforestation for cattle ranching. Six sites in the state of Rondônia, two sites in Pará and one in Amazonas were studied. All sites except one were chronosequences and contained native forest and one or more pastures ranging from 2 to 27 years old. Forest soil δ15N values to a depth of 1 m ranged from 8‰ to 23‰ and were higher than values typically found in temperate forests. A general pattern of increasing δ15N values with depth near the soil surface was broadly similar to patterns in other forests but a decrease in δ15N values in many forest profiles between 20 and 40 cm suggests that illuviation of 15N-depleted nitrate may influence total soil δ15N values in deeper soil where total N concentrations are low. In four chronosequences in Rondônia, the δ15N values of surface soil from pastures were lower than in the original forest and δ15N values were increasingly depleted in older pastures. Inputs of atmospheric N by dinitrogen fixation could be an important N source in these pastures. Other pastures in Amazonas and Pará and Rondônia showed no consistent change from forest values. The extent of fractionation that leads to 15N enrichment in soils was broadly similar over a wide range of soil textures and indicated that similar processes control N fractionation and loss under tropical forest over a broad geographic region. Forest δ15N profiles were consistent with conceptual models that explain enrichment of soil δ15N values by selective loss of 14N during nitrification and denitrification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029056
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  • 7
    Electronic Resource
    Electronic Resource
    Carbon and nitrogen dynamics along the decay continuum: Plant litter to soil organic matter (1989)
    Springer
    Plant and soil 115 (1989), S. 189-198 
    Details
    ISSN: 1573-5036
    Keywords: carbon ; cellulose ; decomposition ; δ13C ; δ15N ; lignin ; nitrogen ; stable isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Decay processes in an ecosystem can be thought of as a continuum beginning with the input of plant litter and leading to the formation of soil organic matter. As an example of this continuum, we review a 77-month study of the decay of red pine (Pinus resinosa Ait.) needle litter. We tracked the changes in C chemistry and the N pool in red pine (Pinus resinosa Ait.) needle litter during the 77-month period using standard chemical techniques and stable isotope, analyses of C and N. Mass loss is best described by a two-phase model: an initial phase of constant mass loss and a phase of very slow loss dominated by degradation of ‘lignocellulose’ (acid soluble sugars plus acid insoluble C compounds). As the decaying litter enters the second phase, the ratio of lignin to lignin and cellulose (the lignocellulose index, LCI) approaches 0.7. Thereafter, the LCI increases only slightly throughout the decay continuum indicating that acid insoluble materials (‘lignin’) dominate decay in the latter part of the continuum. Nitrogen dynamics are also best described by a two-phase model: a phase of N net immobilization followed by a phase of N net mineralization. Small changes in C and N isotopic composition were observed during litter decay. Larger changes were observed with depth in the soil profile. An understanding of factors that control ‘lignin’ degradation is key to predicting the patterns of mass loss and N dynamics late in decay. The hypothesis that labile C is needed for ‘lignin’ degradation must be evaluated and the sources of this C must be identified. Also, the hypothesis that the availability of inorganic N slows ‘lignin’ decay must be evaluated in soil systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02202587
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