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  • 1
    Electronic Resource
    Electronic Resource
    Emissions of N2O from soils during cycles of freezing and thawing and the effects of soil water, texture and duration of freezing (2004)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    European journal of soil science 55 (2004), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Freezing and thawing influence many physical, chemical and biological processes in soils, including the production of trace gases. We studied the effects of freezing and thawing on three soils, one sandy, one silty and one loamy, on the emissions of N2O and CO2. We also studied the effect of varying the water content, expressed as the percentage of the water-filled pore space (WFPS). Emissions of N2O during thawing decreased in the order 64% 〉 55% 〉 42% WFPS, which suggests that the retardation of the denitrification was more pronounced than the acceleration of the nitrification with increasing oxygen concentration in the soil. However, emissions of N2O at 76% WFPS were less than at 55% WFPS, which might be caused by an increased ratio of N2/N2O in the very moist conditions. The emission of CO2 was related to the soil water, with the smallest emissions at 76% WFPS and largest at 42% WFPS. The emissions of CO2 during thawing exceeded the initial CO2 emissions before the soils were frozen, which suggests that the supply of nutrients was increased by freezing. Differences in soil texture had no marked effect on the N2O emissions during thawing. The duration of freezing, however, did affect the emissions from all three soils. Freezing the soil for less than 1 day had negligible effects, but freezing for longer caused concomitant increases in emissions. Evidently the duration of freezing and soil water content have important effects on the emission of N2O, whereas the effects of texture in the range we studied were small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.2004.00602.x
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  • 2
    Electronic Resource
    Electronic Resource
    Modelling cation transport and pH buffering during unsaturated flow through intact subsoils (2005)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    European journal of soil science 56 (2005), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Prediction of cation transport during unsaturated flow through soils is complex, and chemical models are necessary for the purpose. Our objectives were to determine whether the reactions considered in the model PHREEQC2 were appropriate to predict cation transport in soils when small amounts of CaCl2 or acid are added and to investigate the usefulness of different parameterization approaches. Undisturbed columns of three subsoils were irrigated for 2 years with 4 mm day−1 at 8°C. The experiments were (A) irrigation with 1 mm and 5 mm CaCl2 and (B) irrigation with 1 mm HCl. The model PHREEQC2 was used to calculate one-dimensional transport, inorganic complexation, dissolution or precipitation of Al(OH)3, AlOHSO4 and CaCO3 and multiple cation exchange. We compared three models: one with no adjustable parameters, a second with optimized solubilities within a reported range, pCO2 and cation exchange capacity (CEC), and a third which also included an optimization of the exchange coefficients. The first was of little use to predict cation transport in soils. The second was appropriate for one of the soils, but an optimization of the exchange coefficients was required for an accurate description and prediction of cation transport for the others. The CEC accessible for seepage water varied between 50% and 100% of the total CEC. Our results indicate that for a reliable assessment of cation transport in soils during unsaturated flow, calibration experiments are required. The parameter optimization program PEST in combination with PHREEQC2 gave a better understanding of cation transport in undisturbed soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.2005.00704.x
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  • 3
    Electronic Resource
    Electronic Resource
    The influence of soil type and cultivation system on the spatial distributions of the soil fauna and microorganisms and their interactions
    Amsterdam : Elsevier
    Geoderma 60 (1993), S. 109-118 
    Details
    ISSN: 0016-7061
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0016-7061(93)90021-C
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  • 4
    Electronic Resource
    Electronic Resource
    Microbial biomass, metabolic activity and nutritional status determined from fatty acid patterns and poly-hydroxybutyrate in agriculturally-managed soils
    Amsterdam : Elsevier
    Soil Biology and Biochemistry 26 (1994), S. 439-446 
    Details
    ISSN: 0038-0717
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0038-0717(94)90175-9
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  • 5
    Electronic Resource
    Electronic Resource
    Determination of phospholipid- and lipopolysaccharide-derived fatty acids as an estimate of microbial biomass and community structures in soils (1995)
    Springer
    Biology and fertility of soils 19 (1995), S. 115-123 
    Details
    ISSN: 1432-0789
    Keywords: Fatty acids ; Phospholipids ; Lipopolysaccharides ; Microbial biomass ; Gram-positive bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Several soils subject to different cultivation and management practices were examined by analysis of fatty acid profiles derived from phospholipids and lipopolysaccharides, using an improved sequential method which is capable of measuring ester-linked and non-ester-linked phospholipid fatty acids (EL-PLFA, NEL-PLFA, respectively) and the hydroxy fatty acids in lipopolysaccharides. A good correlation was obtained (r〉0.90) between the soil biomass and total EL-PLFA in the soils investigated, which ranged from forest soils to a variety of agricultural soils. Elucidation of the composition of the community structure was an additional task. Eukaryotes can be differentiated from bacteria by the presence of polyunsaturated and ω-hydroxy fatty acids, both of which were much more abundant in the OF layer of the forest soil than in the remaining samples. A relatively low proportion of monomethyl branched-chain saturated fatty acids was obtained in the forest OF horizon, these being indicators for Gram-positive bacteria and actinomycetes. Various subclasses of proteobacteria produce β and mid-chain hydroxy fatty acids, which occur primarily in agricultural soils. The ratios between monounsaturated fatty acids and saturated fatty acids seem to be very useful parameters of soil environmental conditions. In addition, on the basis of the differences in composition of the NEL-PLFA and hydroxy fatty acids of lipopolysaccharides, clear indications for the community structure of various soils were obtained. In the forest soils much more abundant anaerobic micro-organisms and relatively less abundant proteobacteria were present than in the other soils. In the cultivated soils, however, the proportion of Gram-negative bacteria was considerably higher. Furthermore, eukaryotes appeared to be pre-dominant in the soils once used for a manure deposit site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336146
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  • 6
    Electronic Resource
    Electronic Resource
    Pattern of microbial indicators in forest soils along an European transect (1995)
    Springer
    Biology and fertility of soils 19 (1995), S. 362-368 
    Details
    ISSN: 1432-0789
    Keywords: Microbial biomass ; Aluminium toxicity ; Acid stress ; Microcalorimetry ; Microbial activity ; Stress parameter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Microbial biomass C and activity were determined in six forest soils along a gradient in physical and chemical climate in Europe. Both parameters were measured microcalorimetrically. The upper 22 cm of the soils were sampled in undisturbed columns (24 cm deep). Measurements were made in homogenized samples of the different surface organic horizons (Ol, Of, Oh) and the mineral horizons (Ah, Aeh, Bv) down to 22 cm. On a mass basis values for both the biomass and the activity showed an exponential decrease with depth in all soils. Expressed on a volume basis these relationships varied with soil pH. in the strongly acidified soils most of the microbial biomass and activity was located in the forest floor. In less acidified soils both parameters were highest in the mineral soil. Further relationships between biomass and activity and between soil chemical properties showed significant positive correlations with exchangeable Ca2+, Mg2+, Ca/Al and negative correlations with Al3+. There were no significant correlations with exchangeable cations in less acidified soils. It was calculated that the microbial biomass is more affected by soil chemistry than activity. The caloric quotient (qW) is a good parameter for determining the ecophysiological state of microorganisms in acidified soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336108
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  • 7
    Electronic Resource
    Electronic Resource
    The spatial distribution of soil microbial biomass in a permanent row crop (1995)
    Springer
    Biology and fertility of soils 19 (1995), S. 322-326 
    Details
    ISSN: 1432-0789
    Keywords: Soil texture ; Spatial distribution ; Microbial biomass ; Metabolic quotient ; Hops
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of soil texture (silt loam or sandy loam) and cultivation practice (green manure) on the size and spatial distribution of the microbial biomass and its metabolic quotient were investigated in soils planted with a permanent row crop of hops (Humulus lupulus). The soil both between and in the plant rows was sampled at three different depths (0–10, 10–20, and 20–30 cm). The silt loam had a higher overall microbial biomass C concentration (260 μg g-1) than the sandy loam (185 μg g-1), whereas the sandy loam had a higher (3.1 μg CO2-C mg-1 microbial Ch-1) metabolic quotient than the silt loam (2.6 μg CO2-C mg-1 microbial C h-1), on average over depth (0–30 cm) and over all treatments. There was a sharp decrease in the microbial biomass with increasing depth for all plots. However, this was more pronounced in the silt loam than in the sandy loam. There was no distinct influence of sampling depth on the metabolic quotient. The microbial biomass was considerably higher in the rows than between the rows, especially in the silt loam plots. There was no significant difference between plots without green manure and plots with green manure for either the microbial biomass or the metabolic quotient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336102
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  • 8
    Electronic Resource
    Electronic Resource
    Nitrous oxide emissions from a fallow and wheat field as affected by increased soil temperatures (1998)
    Springer
    Biology and fertility of soils 27 (1998), S. 307-314 
    Details
    ISSN: 1432-0789
    Keywords: Key words Global warming ; Nitrous oxide ; Soil warming ; Agriculture ; Ecosystem manipulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  In order to determine the effects of increased soil temperature resulting from global warming on microbiological reactions, a 21-month field experiment was carried out in the Bavarian tertiary hills. The major objective was to focus on N2O releases as either a positive or negative feedback in response to global warming. The soils of a fallow field and a wheat field were heated 3  °C above ambient temperature and N2O fluxes were measured weekly from June 1994 to March 1996. During the experimental period, measured temperature differences between the control plots and the heated plots were 2.9±0.3  °C at a depth of 0.01 m and 1.0–1.8  °C at a depth of 1 m. Soil moisture decreased with the elevated soil temperatures of the heated plots. The mean differences in soil moisture between the treatments were 6.4% (fallow field) and 5.2%DW (wheat field dry weight, DW), respectively. Overall N2O releases during the experimental period from the fallow field were 4.8 kg N2O–N ha–1 in the control plot against 5.0 kg N2O–N ha–1 in the heated plot, and releases from the wheat field were 8.0 N2O–N ha–1 in the control plot and 7.6 N2O–N kg ha–1 in the heated plot. However, on a seasonal basis, cumulated N2O emissions differed between the plots. During the summer months (May–October), releases from the heated fallow plot were 3 times the rates from the control plot. In the winter months, N2O releases increased in both the fallow and wheat fields and were related to the number of freezing and thawing cycles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050438
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  • 9
    Electronic Resource
    Electronic Resource
    Potential contribution of Lumbricus terrestris L. to carbon dioxide, methane and nitrous oxide fluxes from a forest soil (2000)
    Springer
    Biology and fertility of soils 32 (2000), S. 142-148 
    Details
    ISSN: 1432-0789
    Keywords: Key words Lumbricus terrestris ; Carbon dioxide emission ; Nitrous oxide emission ; Methane flux ; Forest soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Potential effects of earthworms (Lumbricus terrestris L.) inoculated into soil on fluxes of CO2, CH4 and N2O were investigated for an untreated and a limed soil under beech in open topsoil columns under field conditions for 120 days. Gas fluxes from L. terrestris, beech litter and mineral soil from soil columns were measured separately in jars at 17  °C. The inoculation with L. terrestris and the application of lime had no effect on cumulative CO2 emissions from soil. During the first 3–4 weeks earthworms significantly (P〈0.05) increased CO2 emissions by 16% to 28%. In contrast, significantly lower (P〈0.05) CO2 emission rates were measured after 11 weeks. The data suggest that earthworm activity was high during the first weeks due to the creation of burrows and incorporation of beech litter into the mineral soil. Low cumulative CH4 oxidation rates were found in all soil columns as a result of CH4 production and oxidation processes. L. terrestris with fresh feces and the beech litter produced CH4 during the laboratory incubation, whereas the mineral soil oxidised atmospheric CH4. Inoculation with L. terrestris led to a significant reduction (P〈0.02) in the CH4 oxidation rate of soil, i.e. 53% reduction. Liming had no effect on cumulative CH4 oxidation rates of soil columns and on CH4 fluxes during the laboratory incubation. L. terrestris significantly increased (P〈0.001) cumulative N2O emissions of unlimed soil columns by 57%. The separate incubation of L. terrestris with fresh feces resulted in rather high N2O emissions, but the rate strongly decreased from 54 to 2 μg N kg–1 (dry weight) h–1 during the 100 h of incubation. Liming had a marked effect on N2O formation and significantly (P〈0.001) reduced cumulative N2O emissions by 34%. Although the interaction of liming and L. terrestris was not significant, N2O emissions of limed soil columns with L. terrestris were 8% lower than those of the control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740000228
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  • 10
    Electronic Resource
    Electronic Resource
    Distribution of inorganic nitrogen in agricultural soils at different dates and scales (1998)
    Springer
    Nutrient cycling in agroecosystems 50 (1998), S. 291-297 
    Details
    ISSN: 1573-0867
    Keywords: inorganic nitrogen ; agricultural soils ; frequency distribution ; spatial distribution ; site specificagricultural management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To avoid the leaching of nitrate from agricultural soils to groundwater, appropriate N-fertilization strategies aim at the depletion of the pool of soil inorganic nitrogen (Nmin = NO3-N + NH4-N) during crop growth. Such strategies need a good knowledge of the spatial distribution of inorganic nitrogen pools at the field sites and its change over time. Therefore inorganic nitrogen in arable soils of a farm was determined after harvest in 1990, 1991 and 1992 and in the spring of 1991 and 1992 with a high areal resolution. One bulk sample of four corings was taken per 50x50-m grid cell (n=152-178) from 0-90cm soil depth. At all arable sites, winter wheat was grown in the first, and spring barley in the second year of this study. Results show a wide range of nitrogen contents at the farm level, at the field level and at the level of subdivisions of fields. Almost no spatial dependence of Nmin contents could be found from calculated semivariograms. Because of this small-scale variation the subdivision of fields into fixed plots of homogenous N-fertilizer demand is difficult and can be seen as only a first step towards site specific farming.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009712916767
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