Vergleich des mikrobiellen Abbaus von Fichten- und Buchenstreu auf verschiedenen Bodentypen

Soil Components

“…Carboxylic (BROADBENT and BRADFORD [1952]) or phenolic hydroxyl groups (FLAIG, SCHEFFER, and KLAMROTH [1955], LEWIS and BROADBENT [1961], MEYER [1962], and others) are responsible for the acidity of the humic substances. It is not possible to distinguish with certainty between the carboxylic and phenolic hydroxyl groups, because the acidities of these groups overlap.…”

“…It is not possible to distinguish with certainty between the carboxylic and phenolic hydroxyl groups, because the acidities of these groups overlap. mention in a review paper that those methods that measure pK and are based on titration in aqueous and nonaqueous solvents do not truly differentiate between these two groups ( VAN DIJK [1959, MEYER [1962], POMMER and BREGER [1960a, b], ). mention in a review paper that those methods that measure pK and are based on titration in aqueous and nonaqueous solvents do not truly differentiate between these two groups ( VAN DIJK [1959, MEYER [1962], POMMER and BREGER [1960a, b], ).…”

“…The total hydroxyl content (phenolic and aliphatic) has been determined by acetylation, followed by titrimetric determination of the excess of acetic anhydride (MEYER [1962], , MARTIN and JAY [1962]). Values obtained by deacetylation of the acetylated products are much smaller (FORSYTH [1947b], MARTIN, DUBACH, MEHTA, and DEUEL [1963], MEYER [1962]).…”

“…Values for carbonyl groups, determined by means of hydroxylamine (FLAIG, SCHEFFER, and KLAMROTH [1955], MEYER [1962], , SCHNITZER and SKINNER [1965]), 2,4-dinitrophenylhydrazine (FLAIG, SCHEFFER, and KLAMROTH [1955], SCHNITZER and SKINNER [1965]), phenylhydrazine (SCHNITZER and SKINNER [1965]), and sodium boronhydride (NaBH4) (MARTIN, DUBACH, MEHTA, and DEUEL [1963]) range between 1 to 3 meq/g. With these reagents, interfering reactions occur in the presence of quinones, and therefore exact values are not obtained (FARMER and MORRISON [1960]).…”

The effect of acid rain, soil temperature and humidity on C-mineralization rates in organic soil layers under spruce

“…The rates of production and accumulation of humus depend on factors such as (i) dominant tree species (Krhler and Kunze, 1979), (ii) degree of thinning (Mitscherlich and Kiinstle, 1970), (iii) type and chemical composition of the mineral soil (Lang and Beese, 1985;Meyer, 1960), and (iv) pollution caused by man (Klein et al, 1984;Like and Klein, 1985;Simbrey, 1987). Thus the total amount of organic material can range from 10 to 30 tons per ha under beech, and from 100 to 300 tons per ha under spruce (Wilhelmi, 1987).…”