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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biodegradation 14 (1991), S. 167-191 
    ISSN: 1572-9729
    Keywords: leaf longevity ; nitrogen ; nutrient use efficiency ; phosphorus ; requirement ; retranslocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Aboveground nitrogen (N) and phosphorus (P) requirement, retranslocation and use efficiency were determined for 28-year-old red oak (Quercus rubra L.), European larch (Larix decidua Miller), white pine (Pinus strobes L.), red pine (Pinus resinosa Ait.) and Norway spruce (Picea abies (L) Karst.) plantations on a similar soil in southwestern Wisconsin. Annual aboveground N and P requirements (kg/ha/yr) totaled 126 and 13 for red oak, 86 and 9 for European larch, 80 and 9 for white pine, 38 and 6 for red pine, and 81 and 13 for Norway spruce, respectively. Nitrogen and P retranslocation from current foliage ranged from 81 and 72%, respectively, for European larch, whereas red pine retranslocated the smallest amount of N (13%) and Norway spruce retranslocated the smallest amount of P (18%). In three evergreen species, uptake accounted for 72 to 74% of annual N requirement whereas for two deciduous species retranslocation accounted for 76 to 77% of the annual N requirement. Nitrogen and P use (ANPP/uptake) was more efficient in deciduous species than evergreen species. The results from this common garden experiment demonstrate that differences in N and P cycling among species may result from intrinsic characteristics (e.g. leaf longevity) rather than environmental conditions.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Ecosystems 3 (2000), S. 321-331 
    ISSN: 1435-0629
    Keywords: Key words: nitrogen input; forest biogeochemistry; long-term studies.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nitrogen (N) cycle of forest ecosystems is understood relatively well, and few scientists expect that major revisions will be necessary; most current work on N cycling focuses on improving the precision estimates of pools and fluxes, or measuring the magnitudes of well-known pools in response to management or disturbances. However, in the past few decades more than a dozen articles in refereed journals have claimed very high rates of N input, far beyond the rates expected for known sources of N. In this review, we summarize the literature on N accretion rates in forests that lack substantial contributions from symbiotic N-fixing plants. We critique each study for the strength of the experimental design behind the estimate of N accretion and consider whether unexpectedly large inputs of N really occur in forests. Only 6 of 24 estimates of N accretion had strong experimental designs, and only 2 of these 6 yielded estimates of 〉5 kgN ha-1 y-1. The high accretion estimates with a strong experimental design come from repeated sampling at the Walker Branch watersheds in Tennessee, where N accretion rates ranged from 50 to 80 kg N ha-1 y-1 over 15 years after harvesting. At the same location, an unharvested stand showed no significant change. We conclude that there is no widespread evidence of high rates of occult N input in forests. Too few studies have carefully tested for balanced N budgets in forests (inputs minus outputs plus change in storage), and we recommend that at least a few of these studies be undertaken on soils that permit high precision sampling.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 84 (1995), S. 129-145 
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Soil solutions were collected monthly by tension and zero-tension lysimeters in a low-elevation red spruce stand in east-central Maine from May 1987 through December 1992. Soil solutions collected by Oa tension lysimeters had higher concentrations of most constituents than the Oa zero-tension lysimeters. In Oa horizon soil solutions growing season concentrations for SO4, Ca, and Mg averaged 57, 43, and 30 μmol L−1 in tension lysimeters, and 43, 28, and 19 μmol L−1 in zero-tension lysimeters, respectively. Because tension lysimeters remove water held by the soil at tensions up to 10 kPa, solutions are assumed to have more time to react with the soil compared to freely draining solutions collected by zero-tension lysimeters. Solutions collected in the Bs horizon by both types of collectors were similar which was attributed to the frequency of time periods when the water table was above the Bs lysimeters. Concentrations of SO4 and NO3 at this site were lower than concentrations reported for most other eastern U.S. spruce-fir sites, but base cation concentrations fell in the same range. Aluminum concentrations in this study were also lower than reported for other sites in the eastern U.S. and Ca/Al ratios did not suggest inhibition of Ca uptake by roots. Concentrations of SO4, Ca, K, and Cl decreased significantly in both the Oa and Bs horizons over the 56-month sampling period, which could reflect decreasing deposition rates for sulfur and base cations, climatic influences, or natural variation. A longer record of measured fluxes will be needed to adequately define temporal trends in solution chemistry and their causes.
    Type of Medium: Electronic Resource
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