bei Google ScholarTitelangaben
Eilers, G. ; Brumme, Rainer ; Matzner, Egbert:
Above-ground N-uptake from wet deposition by Norway spruce (Picea abies Karst.).
In: Forest Ecology and Management.
Bd. 51
(1992)
Heft 1-3
.
- S. 239-249.
ISSN 0378-1127
DOI: https://doi.org/10.1016/0378-1127(92)90489-V
Abstract
Nitrogen-uptake from wet deposition, by above-ground plant parts of IO-year-old Norway sprucetrees, was studied as a function of the N-form, N-concentration in precipitation and intensity of irrigationby using ‘SN-labelled solutions. The irrigated solutions contained all major cations and anionsas present in normal forest rainwater but with varying NH4 and NO3 contents. After 5 months oftreatment, the trees were harvested and needles, stems, main stem and roots were analysed for “Ncontent. Nitrogen-uptake was calculated from the sum of “N in all plant compartments.Significant amounts of N were taken up by the above-ground parts of the plants in all treatments.NH4 uptake was higher than NO3 uptake if applied in the same concentration. Nitrogen-uptake increasedwith increasing N-concentrations and irrigation intensity. Extrapolating these results to maturestands (by extrapolating needle biomass and with the assumption that mature spruces are able totake up N from wet deposition during the winter months at the same rate as determined for the youngtrees in this experiment) suggests annual uptake rates of N in the range of 9 kg ha-’ under fieldconditions. Measuring atmospher+ N input by throughfall collection may substantially underestimateactual N inputs to forest ecosystems. Uptake of N by above-ground parts may cause nutritionaldisturbances indicated by changes of the N: Ca and N: Mg ratios in the needles and thus may contributeto the occurrence of Mg-deficiency symptoms of Norway spruce.