Beitrag zur Kenntnis der Nährelementgehalte in Latschennadeln (Pinus montana)

Zusammenfassung Die nadelanalytische Untersuchung der Latschen yon 17 Standorten (16 davon in den N?rdlichen Kalkalpen in 1600 bis 1900 m H?he, ein Standort auf Hochmoor in 480 m H?he) ergibt N-Konzentrationen yon 0,77 bis 1,26% und P-Gehalte yon 0,06 bis 0,12%. Die Kaliumspiegelwerte schwanken zwischen 0,17 und 0,55%, diejenigen des Magnesiums zwischen 0,05 und 0,12% und die Ca-Konzentrationen zwischen 0,10 bis 0,44%. Es besteht eine hochsignifikante negative Korrelation zwischen den Kalium-und Calciumkonzentrationen. Die Eisengehalte liegen zwischen 19 und 127 ppm, die Mangankonzentrationen zwischen 17 und 227 ppm. Mangelsymptome, wie chlorotische Verf?rbungen der Nadelspitzen, wiesen nur Latschen auf, die weniger als 0,21% Kalium in den Nadeln enthielten. Sichtbarer Kaliummangel ?u?ert sich wahrscheinlich wie an Kiefer, Fichte, Tanne, L?rche, Strobe und Schwarzkiefer auch bei der Latsche in gelben Nadelspitzen. Mit zunehmender Verflachung des Wurzelraumes sinken die Stickstoff-, Phosphor- und Kaliumkonzentrationen in den Nadeln ab, die Calciumgehalte steigen an. Auch das Gewicht von 100 Nadelpaaren, ein ungef?hres Sch?tzma? für die Wuchsleistung, ist auf den flachgründigen Standorten niedriger als auf den tiefgründigen. Die auf dem Hochmoorstandort in 480 m Seeh?he wachsenden Latschen enthalten in ihren halbj?hrigen Nadeln weniger Stickstoff, Phosphor, Kalium und Magnesium, aber mehr Calcium, Mangan und Eisen als die auf gleichem Standort stockenden Waldkiefern. Die Kupfer- und Borkonzentrationen dieser Kiefernarten sind dort etwa gleich hoch.     

Microbial degradation and resynthesis of proteins during incubation of beech leaf litter in the presence of mineral phases

 Organic N constitutes more than 90% of total N in surface soil horizons. Amino acids, peptides and proteins represent the most abundant N species. There are indications that clay minerals influence the degradation of proteins, but little is known about the effect of oxides and hydroxides on protein decay. We therefore conducted an incubation experiment with mixtures of beech leaf litter and Fe oxide, Al hydroxide, Mn oxide or quartz sand. The protein amounts (quantified as α-NH₂–N) during the 498-day experiment were recorded. During the first 90–239 days, plant-derived proteins were decomposed, resulting in a decline of protein amounts to about 60% of the initial value. Later in the experiment, the protein amounts increased again to between 70% and 90% of the initial amount, because microbial resynthesis of proteins outweighed decomposition. The change from dominating decomposition to prevailing microbial resynthesis occurred when the microorganisms had to adapt to less favourable conditions and therefore built new, protein-rich biomass. Although the mineral phases did not influence protein decomposition initially, Fe oxide and Al hydroxide stabilized plant-derived proteins. Al hydroxide reduced protein resynthesis in the second phase of the experiment, probably due to a reduction of microbial activity. Mn oxide increased protein decomposition and lowered microbial resynthesis due to its oxidative properties. The mineral phases therefore resulted in a shift of the relative intensities of protein decomposition and microbial resynthesis. Received: 26 August 1998     

Chemical changes of beech litter during passage through the gut of the lumbricid earthworm Eisenia fetida (SAV.)

Casts of the lumbricid earthworm species E. fetida were investigated by means of chemical analyses and ¹³C NMR spectroscopy and compared to the beech litter used as food. The casts are characterized by slightly reduced C-to-N ratios, higher ash contents and lower polysaccharide and lignin concentrations in comparison with the litter material. These differences between casts and litter are very small, ranging from 1 to 7%, and are not supported by any statistical evidence. In addition, NMR and Py-FIMS data complete the picture of E. fetida casts as almost exclusively physically altered (i.e. comminuted) plant residues.     

Distribution pattern of total lipids and lipid fractions in forest humus

Mull, moder, and mor humus profiles were investigated for their total lipid contents and the behaviour of lipid-phosphorus and of five neutral lipid classes identified by HPTLC. The quantitative distribution of total and neutral lipids among the humus types is, besides by natural differences between the various parent litter materials, mainly controlled by soil physicochemical properties. In particular strongly acidic conditions, i.e. conditions corresponding to a reduced biological activity, inhibit significantly the decomposition of lipid compounds in (moder and) mor humus. A feature of the lipid depth functions is the input of microbial and root litter-derived lipid material in the fermentation layers and a considerable lipid accumulation in the A horizons, probably at least partly due to mechanical transport processes. Phospholipids show no distinct variation dependent on the humus type, as far as the organic layers are concerned. But obviously, lipid-P in the mineral, soil is closely correlated with, and therefore is a valuable measure for, the overall biological activity increasing from mor to moder and mull humus.