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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 16 (1993), S. 269-274 
    ISSN: 1432-0789
    Keywords: Straw compost ; N fractions ; Amino acids ; Amino sugars ; Viable counts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The composting process found in real compost heaps was simulated in the laboratory with three treatments, nil, and urea, and cyanamide additions. Total N was separated into hydrolysable, amino acid, and amino sugar N. These fractions were related to counts of viable bacteria and spore-forming bacteria. The content of amino acid N and amino sugar N increased in all three treatments. The ratios of amino acid to amino sugar C and glucosamine to galactosamine decreased in all three treatments during composting of wheat straw. The increased contents of the N components were all significantly correlated with the number of spore-forming bacteria but not with viable bacterial counts. The closest correlation was found between spores and galactosamine. Amounts equivalent to 74% (urea treatment) or 48% (cyanamide treatment) of the added N were lost, mainly in the period after the maximum temperature was passed. The increased amounts of amino acid and amino sugar N accounted for 89% (urea treatment) and 68% (cyanamide treatment) of the added N remaining in compost.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 11 (1991), S. 163-169 
    ISSN: 1432-0789
    Keywords: Litter decomposition ; Litter bag experiment ; Macrofaunal effects ; Organic matter turnover ; Nutrient dynamics ; Hexosamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The decomposition of beech (Fagus sylvatica L.) leaf litter was investigated in a calcareous beech forest using mesh cages containing two layers, fresh leaf litter (O layer), and partly decomposed leaf litter (F layer). C loss was monitored, together with the changes in the contents of total N, hexosamines, ash, Na, K, Mg, Ca, Fe, Mn, Al, Cl, Sulphate, and Phosphate. In 1-mm mesh cages, which excluded access to the macrofauna, the mean annual loss rates for C were 28% in the O leaf litter and 17% in the F leaf litter, totalling approximately 23% for the two layers. The mean loss rates from the 12-mm mesh cages were 54% in the O leaf litter and 58% in the F leaf litter. Degradation processes and feeding activities caused increased contents of ash, total N, and hexosamines in the O layer of both treatments. This increase was greater for the ash and smaller for N, glucosamine, and galactosamine in the 12-mm mesh cages. The sum of ions (Na+K+Mg+Ca+Fe+Mn+Al+Cl+SO4+PO4) and also the contents of most single ions were not markedly affected, despite the much higher ash content in the O leaf litter of the 12-mm mesh cages. The ash content increased mainly as a consequence of contamination by soil, which increased the contents of Fe and Al in the ash.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 12 (1992), S. 253-260 
    ISSN: 1432-0789
    Keywords: Mesofauna ; Microbial biomass ; Litterbag ; Beech forest ; Moder ; Lime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In December 1988, litterbags (mesh size 45 or 1000 μm) were exposed in the organic layer of a limed and unlimed moder soil under beech forest in the Solling area (Germany). At both sites, substrata from the L1, L2, F1, F2 and from the H Layer were sampled shortly before the beginning of the experiment, defaunated, filled separately into litterbags and replaced in the respective horizons in the field. Litterbags were retrieved on three sampling dates (May, September, and November 1989). The soil microbial biomass was estimated by means of the fumigation extraction method. The results show that the effects of excluding mesofauna from the 45-μm litterbags were different in different horizons, on different sampling dates and in different study sites. Calculation of the “average” effect from the three sampling dates revealed that mesofauna exclusion reduced the microbial biomass C at both sites. It was concluded from horizon- and season-specific differences between the two litterbag treatments that a depression in microbial biomass C in the organic layer of a moder soil by mesofaunal grazers is confined to situations where environmental conditions cause strong feeding pressure and when the microflora is exposed to environmental stress.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 38-42 
    ISSN: 1432-0789
    Keywords: Key words Microbial biomass ; Depth profile ; Fumigation-extraction method ; Soil organic matter ; Dormant population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We measured microbial biomass C and soil organic C in soils from one grassland and two arable sites at depths of between 0 and 90 cm. The microbial biomass C content decreased from a maximum of 1147 (0–10 cm layer) to 24 μg g–1 soil (70–90 cm layer) at the grassland site, from 178 (acidic site) and 264 μg g–1 soil (neutral site) at 10–20 cm to values of between 13 and 12 μg g–1 soil (70–90 cm layer) at the two arable sites. No significant depth gradient was observed within the plough layer (0–30 cm depth) for biomass C and soil organic C contents. In general, the microbial biomass C to soil organic C ratio decreased with depth from a maximum of between 1.4 and 2.6% to a minimum of between 0.5 and 0.7% at 70–90 cm in the three soils. Over a 24-week incubation period at 25°C, we examined the survival of microbial biomass in our three soils at depths of between 0 and 90 cm without external substrate. At the end of the incubation experiment, the contents of microbial biomass C at 0–30 cm were significantly lower than the initial values. At depths of between 30 and 90 cm, the microbial biomass C content showed no significant decline in any of the four soils and remained constant up to the end of the experiment. On average, 5.8% of soil organic C was mineralized at 0–30 cm in the three soils and 4.8% at 30–90 cm. Generally, the metabolic quotient qCO2 values increased with depth and were especially large at 70–90 cm in depth.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 15 (1993), S. 301-307 
    ISSN: 1432-0789
    Keywords: Mesofauna ; Amino sugar ; Soil micro-flora ; Beech forest ; Moder ; Lime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In December 1988, litter bags (mesh size: 45 and 1000 μm) were exposed in the organic layer of unlimed and limed moder soil under beech forest in the Solling area of Germany. Bags were retrieved on three sampling dates (May, September, and November 1989) and amounts (g m-2) of glucosamine and galactosamine were determined. Horizon-specific differences generally explained by far the largest part of the treatment variance. In the substrate sampled in December 1988 from the unlimed area glucosamine increased by a factor of 11.8 from the L 1 layer to the H layer and galactosamine by a factor of 15.9. With the exception of the F2 layer, the hexosamine amounts found in the limed substrate sampled in December 1988 were higher in all horizons than in the corresponding horizons sampled from the unlimed area. Exclusion of mesofauna from the 45-μm litter bags generally reduced the level of amino sugars at both sites. The difference between the two mesh sizes was most pronounced in the lowermost horizons (F2 and H) and quite small in the upper horizons. The exclusion of mesofauna significantly increased the glucosamine: galactosamine ratio in the two L layers of the unlimed soil on all sampling dates. Seasonal fluctuations suggested that the actual amino sugar content of the organic layer was essentially the function of two components, the first reflecting long-term accumulation of microbial metabo-lites, and the second reflecting short term fluctuations in the microbial colonization of various C sources together with spatial and temporal differences in the ability of the microflora to produce and to decompose hexosamines. The results of this study show that the mesofauna in the beech forest soils investigated significantly affected both the amino sugar components measured, and thus stimulated the accumulation of one of the most important N pools in forest soils.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 19 (1995), S. 141-147 
    ISSN: 1432-0789
    Keywords: Microbial biomass ; Biomass C:N ratio Acidification ; Beech forest ; Soil organic C ; Total N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soils from 38 German forest sites, dominated by beech trees (Fagus sylvatica L.) were sampled to a depth of about 10 cm after careful removal of overlying organic layers. Microbial biomass N and C were measured by fumigation-extraction. The pH of the soils varied between 3.5 and 8.3, covering a wide range of cation exchange capacity, organic C, total N, and soil C:N values. Maximum biomass C and biomass N contents were 2116 μg C m-2 and 347 μg N m-2, while minimum contents were 317 and 30 μg m-2, respectively. Microbial biomass N and C were closely correlated. Large variations in microbial biomass C:N ratios were observed (between 5.4 and 17.3, mean 7.7), indicating that no simple relationship exists between these two parameters. The frequency distribution of the parameters for C and N availability to the microflora divided the soils into two subgroups (with the exception of one soil): (1) microbial: organic C〉12 mg g-1, microbial:total N〉28 mg g-1 (n=23), a group with high C and N availability, and (2) microbial:organic C≤12 mg g-1, microbial:total N≦28 mg g-1 (n=14), a group with low C and N availability. With the exception of a periodically waterlogged soil, the pH of all soils belonging to subgroup 2 was below 5.0 and the soil C:N ratios were comparatively high. Within these two subgroups no significant correlation between the microbial C:N ratio and soil pH or any other parameter measured was found. The data suggest that above a certain threshold (pH 5.0) microbial C:N values vary within a very small range over a wide range of pH values. Below this threshold, in contrast, the range of microbial C:N values becomes very large.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0789
    Keywords: Key words Analytical variations ; Root interference ; Root pre-extraction ; Fumigation-extraction ; Microbial biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A control soil stored at 4°C was analyzed 38 times by fumigation-extraction during a period of 11 months to correct for variations caused by the analytical procedure. The difference in extractable C between fumigated and unfumigated samples oscillated around the average without a positive or negative trend. When data from contemporaneously extracted field samples were corrected with control soil data the variations were lowered. The deviations between corrected and uncorrected biomass C values had maxima of ±12%. Data obtained for seven dates using pre-extraction, wet-sieving, and centrifuging were compared with data obtained by the conventional procedure without any pretreatment. A negative difference from data obtained without pretreatment was found when the soil water content was decreased to 6%. The largest positive difference (+38%) was found in May during the period of highest root growth.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 22 (1996), S. 299-304 
    ISSN: 1432-0789
    Keywords: Microbial biomass ; Fungal biomass ; Ergosterol ; Fumigation extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ergosterol and microbial biomass C were measured in 26 arable, 16 grassland and 30 forest soils. The ergosterol content ranged from 0.75 to 12.94 μg g-1 soil. The geometric mean ergosterol content of grassland and forest soils was around 5.5 μg g-1, that of the arable soils 2.14 μg g-1. The ergosterol was significantly correlated with biomass C in the entire group of soils, but not in the subgroups of grassland and forest soils. The geometric mean of the ergosterol: microbial biomass C ratio was 6.0 mg g-1, increasing in the order grassland (5.1), arable land (5.4) and woodland (7.2). The ergosterol:microbial biomass C ratio had a strong negative relationship with the decreasing cation exchange capacity and soil pH, indicating that the fungal part of the total microbial biomass in soils increased when the buffer capacity decreased. The average ergosterol concentration calculated from literature data was 5.1 mg g-1 fungal dry weight. Assuming that fungi contain 46% C, the conversion factor from micrograms ergosterol to micrograms fungal biomass C is 90. For soil samples, neither saponification of the extract nor the more effective direct saponification during extraction seems to be really necessary.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 43-49 
    ISSN: 1432-0789
    Keywords: Key words Nitrogen fractions ; Amino acids ; Amino sugars ; Microbial respiration ; Household waste ; Domestic garbage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An incubation experiment was performed to determine how the mixing of soil with municipal organic refuse compost affects C mineralization, growth of the microbial biomass, and changes in organic components, especially in the fractions of amino acids and amino sugars. Compost and soil differed in almost every parameter measured, with the organic C content of the compost representing only 10.8% of the dry weight. The fractions of K2SO4-extractable organic C and of non-hydrolyzable C were larger in the compost (1.24 and 62.9% of organic C, respectively) than in the soil (0.56 and 41.6% of organic C). These two fractions increased in proportion to the addition of compost, in contrast to amino sugar and amino acid C which were identified overproportionately in the mixture treatments, especially in the 30% compost treatment. Overproportionate increases in the microbial biomass C content and CO2 evolution rate were also measured in this treatment. The adsorption of compost colloids on the surface of regular soil silicates increased both the availability for microbial enzymes and the detectability for chemical analysis.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 22 (1996), S. 299-304 
    ISSN: 1432-0789
    Keywords: Key words Microbial biomass ; Fungal biomass ; Ergosterol ; Fumigation extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ergosterol and microbial biomass C were measured in 26 arable, 16 grassland and 30 forest soils. The ergosterol content ranged from 0.75 to 12.94 μg g–1 soil. The geometric mean ergosterol content of grassland and forest soils was around 5.5 μg g–1, that of the arable soils 2.14 μg g–1. The ergosterol was significantly correlated with biomass C in the entire group of soils, but not in the subgroups of grassland and forest soils. The geometric mean of the ergosterol:microbial biomass C ratio was 6.0 mg g–1, increasing in the order grassland (5.1), arable land (5.4) and woodland (7.2). The ergosterol:microbial biomass C ratio had a strong negative relationship with the decreasing cation exchange capacity and soil pH, indicating that the fungal part of the total microbial biomass in soils increased when the buffer capacity decreased. The average ergosterol concentration calculated from literature data was 5.1 mg g–1 fungal dry weight. Assuming that fungi contain 46% C, the conversion factor from micrograms ergosterol to micrograms fungal biomass C is 90. For soil samples, neither saponification of the extract nor the more effective direct saponification during extraction seems to be really necessary.
    Type of Medium: Electronic Resource
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