ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (19,697)
  • Periodicals Archive Online (PAO)  (15,683)
  • Blackwell Science Ltd  (4,014)
  • Ethnic Sciences  (10,008)
  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (9,689)
Collection
  • Articles  (19,697)
Source
Publisher
Years
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Three-dimensional crack monitoring by electrical resistivity measurement (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: Soil cracks formed by natural processes play a key role in water and gas transfer. Patterns of soil cracks are, however, difficult to characterize. Our aim here is to assess the effectiveness of three-dimensional electrical resistivity surveys in detecting soil crack networks. A three-dimensional electrical survey was carried out by a square array quadripole with Cu–CuSO4 electrodes (electrode spacing of 3 cm). The measurements were made with two orientations (0° and 90°) on a block (26 cm × 30 cm × 40 cm) of soil while it dried for 18 days under controlled conditions. Two indexes, calculated from the apparent resistivity values, were evaluated to detect the degree of soil heterogeneity: (i) an anisotropy index based on the ratio between the apparent resistivity at 0° and that at 90°; and (ii) the angle-array orientation corresponding to the preferential anisotropic orientation (maximum resistivity). The anisotropy index provided information on the presence of cracks and the orientation for crack width 〉 1 mm in the first pseudo-depth (i.e. depth of investigation), while the angle-array orientation provided information on crack extension for the whole pseudo-depth. Information about the presence, position, orientation and extension of cracks can be obtained from an analysis of apparent resistivity obtained by a three-dimensional electrical survey. Such direct analysis will help the resistivity inversion to detect the crack network.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.2004.00632.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Total lipid extracts from characteristic soil horizons in a podzol profile (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: The podzolization process is studied through lipids in nine characteristic podzol horizons. Organic matter accumulates particularly with aluminium in the Bh horizon, while the hard, cemented Bs horizon below this is formed mainly by iron oxides. The low soil pH seems to have no great influence on the preservation of lipids as reflected by the absolute amounts present and the presence of bacterial lipid markers throughout the profile. Independent of soil pH, lipids accumulate in organically enriched horizons. Albeit, high molecular weight organic compounds accumulate to a relatively greater extent than lipids in these horizons. A lipid signal related to the aerial parts, i.e. leaves and flowers, of Calluna is observed only in the O horizon. This ‘n-alkane, steroid and triterpenoids’ signal is quickly lost in the underlying Ah horizon due to (bacterial) oxidation. The other total lipid extracts obtained are dominated by root-derived compounds. In subsoil horizons rich in organic matter, i.e. the Ahb and Bh horizons, root-derived friedooleanan and steroid compounds dominate the total lipid signal. Degraded horizons, poor in organic matter, i.e. the E2, Bhs, Bs and B/C horizons, are dominated by C22 and C24ω-hydroxy acids, long-chain (〉 C20) n-alkanoic acids with a strong even-over-odd predominance and C22 and C24n-alkanols. Steroid and root-derived triterpenoids with a friedooleanan structure have been removed from these horizons through degradation. Based on total organic carbon content and lipid composition, the formation of an E1 horizon has started, but is not yet complete. In the Ahb horizon, a contribution from buried vegetation to the total lipid signal is still present, although degradation and an input from roots have significantly altered the original signal. Overall, lipid data indicate that degradation (microbial oxidation) is an important process that should be taken into account, in addition to leaching, when describing podzolization processes in soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.2004.00633.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Calibrating soil respiration measures with a dynamic flux apparatus using artificial soil media of varying porosity (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: Measurement of soil respiration to quantify ecosystem carbon cycling requires absolute, not relative, estimates of soil CO2 efflux. We describe a novel, automated efflux apparatus that can be used to test the accuracy of chamber-based soil respiration measurements by generating known CO2 fluxes. Artificial soil is supported above an air-filled footspace wherein the CO2 concentration is manipulated by mass flow controllers. The footspace is not pressurized so that the diffusion gradient between it and the air at the soil surface drives CO2 efflux. Chamber designs or measurement techniques can be affected by soil air volume, hence properties of the soil medium are critical. We characterized and utilized three artificial soils with diffusion coefficients ranging from 2.7 × 10−7 to 11.9 × 10−7 m2 s−1 and porosities of 0.26 to 0.46. Soil CO2 efflux rates were measured using a commercial dynamic closed-chamber system (Li-Cor 6400 photosynthesis system equipped with a 6400-09 soil CO2 flux chamber). On the least porous soil, small underestimates (〈 5%) of CO2 effluxes were observed, which increased as soil diffusivity and soil porosity increased, leading to underestimates as high as 25%. Differential measurement bias across media types illustrates the need for testing systems on several types of soil media.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.2004.00642.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Aggregation and carbon storage in silty soil using physical fractionation techniques (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: Soil texture and degree of aggregation affect the stabilization of organic matter. We studied their influences in silty soils using samples from two field experiments with contrasting long-term use (cropped versus bare fallow). The cropped soil had a larger organic C content than the bare fallow, and allowed us to compare a soil with pools of organic C differing in turnover time with a soil dominated by the passive organic C pool. Increasingly dispersive treatments applied to the soils yielded aggregates of various sizes, stabilities, and organic matter contents. We found an intimate interaction between soil structure and organic matter by demonstrating that aggregation is hierarchical and that active pools of organic matter are responsible for this hierarchy. Microaggregates were found to consist of a constant ratio of clay to silt particle-size fractions. We propose that such a property be used to estimate true microaggregation and aggregate stability by estimating the amount of soil material dispersed by a given treatment. Organic matter associated with clay is confirmed as an important sink of long-term stabilized C, and it appears to have been increasingly preserved when in increasingly larger aggregates. However, most of the soil mass and associated organic C is in smaller aggregates. We hypothesize that the physical protection within macroaggregates does not directly control long-term stabilization of organic C in the soil, but rather contributes indirectly through the time and local conditions it offers for organic matter to gain chemical or physico-chemical protection by interacting with the soil environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1351-0754.2004.0608.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Improved automated extraction and separation procedure for soil lipid analyses (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: Analysis of soil lipids may contribute to an improved understanding of atmosphere to soil carbon fluxes, soil organic matter source differentiation and pollutant accumulation. Soil lipids, mostly originating from plants and microorganisms, have traditionally been analysed by non-automated extraction and separation methods, which produce several lipid fractions, operationally defined by polarity. Here we present a combination of fast, automated and reproducible techniques, adopted from organic geochemical studies, for preparative separation of individual soil lipid fractions with increasing polarity. These techniques involve commercially available instruments, including accelerated solvent extraction and a two-step automated medium-pressure liquid chromatography procedure. The method yields eight lipid fractions consisting of five fractions fully amenable to gas chromatography/mass spectrometry (GC/MS) (aliphatic hydrocarbons, aromatic hydrocarbons, ketones, alcohols, carboxylic acids), and three fractions of highly polar or high molecular weight compounds (bases, very long-chain wax esters (C40+), high polarity compounds) that were not measurable with GC/MS under standard conditions. We tested the method on five agricultural soils. Results show that (i) mass recoveries for the individual fractions are reproducible, (ii) within individual fractions compound distribution patterns are reproducible, as demonstrated for alkanes and carboxylic acids, and (iii) individual fractions represent distinct and clean compound classes, free of interfering substances detectable by GC/MS. Thus, automated separation can be a fast, effective and reproducible procedure for fractionation of complex mixtures of soil lipids into clean compound classes, directly suitable for a variety of molecular (e.g. GC/MS) and isotopic characterizations (e.g. gas chromatography coupled with isotope ratio monitoring mass spectrometry or accelerator mass spectrometry).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1351-0754.2004.00601.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Clear-cutting of a Norway spruce stand: implications for controls on the dynamics of dissolved organic matter in the forest floor (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: Clear-cutting of forest provides a unique opportunity to study the response of dynamic controls on dissolved organic matter. We examined differences in concentrations, fluxes and properties of dissolved organic matter from a control and a clear-cut stand to reveal controlling factors on its dynamics. We measured dissolved organic C and N concentrations and fluxes in the Oi, Oe and Oa horizons of a Norway spruce stand and an adjacent clear-cutting over 3 years. Aromaticity and complexity of organic molecules were determined by UV and fluorescence spectroscopy, and we measured δ13C ratios over 1 year.Annual fluxes of dissolved organic C and N remained unchanged in the thin Oi horizon (∼ 260 kg C ha−1, ∼ 8.5 kg N ha−1), despite the large reduction in fresh organic matter inputs after clear-cutting. We conclude that production of dissolved organic matter is not limited by lack of resource. Gross fluxes of dissolved organic C and N increased by about 60% in the Oe and 40% in the Oa horizon upon clear-cutting. Increasing organic C and N concentrations and increasing water fluxes resulted in 380 kg C ha−1 year−1 and 10.5 kg N ha−1 year−1 entering the mineral soil of the clear-cut plots. We found numerous indications that the greater microbial activity induced by an increased temperature of 1.5°C in the forest floor is the major factor controlling the enhanced production of dissolved organic matter. Increasing aromaticity and complexity of organic molecules and depletion of 13C pointed to an accelerated processing of more strongly decomposed parts of the forest floor resulting in increased release of lignin-derived molecules after clear-cutting. The largest net fluxes of dissolved organic C and N were in the Oi horizon, yet dissolved organic matter sampled in the Oa horizon did not originate mainly from the Oi horizon. Largest gross fluxes in the Oa horizon (control 282 kg C ha−1) and increased aromaticity and complexity of the molecules with increasing depth suggested that dissolved organic matter was derived mainly from decomposition, transformation and leaching of more decomposed material of the forest floor. Our results imply that clear-cutting releases additional dissolved organic matter which is sequestered in the mineral soil where it has greater resistance to microbial decay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1351-0754.2004.00609.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Simulation of water flow and solute transport in free-drainage lysimeters and field soils with heterogeneous structures (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: Lysimeters are valuable for studying the fate and transport of chemicals in soil. Large-scale field lysimeters are used to assess pesticide behaviour and radionuclide transport, and are assumed to represent natural field conditions better than laboratory columns. Field lysimeters are usually characterized by a free-draining lower boundary. As a result, the hydraulic gradient is disrupted, and leachate cannot be collected until the bottom of the lysimeter becomes saturated. We compared heterogeneously structured, free-drainage lysimeters and field soils with respect to water flow and solute transport. Numerical simulations were carried out in a two-dimensional heterogeneous sandy soil under unsaturated water flow conditions with the CHAIN_2D code. Three different soil structures (isotropic, horizontal, and vertical) were generated, and Miller–Miller similitude was used to scale the hydraulic properties of the soil. The results showed that ponding occurs at the bottom of the lysimeter for the three soil structures and that it occurred faster and was more pronounced with the vertical structure (preferential flow effect). Breakthrough curves of a conservative solute (bromide) showed that solutes are moving faster in the field than in the lysimeters. Fewer differences between lysimeters and field soils were found with the horizontal soil structure than with the isotropic and vertical structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2389.2004.00592.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Effect of degree of fluid saturation on transport coefficients in disturbed soils (2004)
    Oxford, UK : 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: To improve the predictive capability of transport models in soils we need experimental data that improve their understanding of properties at the scale of pores, including the effect of degree of fluid saturation. All transport occurs in the same soil pore space, so that one may intuitively expect a link between the different transport coefficients and key geometrical characteristics of the pores such as tortuosity and connectivity, and pore-size distribution. To understand the combined effects of pore geometry and pore-size distribution better, we measured the effect of degree of water saturation on hydraulic conductivity and bulk soil electrical conductivity, and of degree of air saturation on air conductivity and gaseous diffusion for a fine sand and a sandy loam soil. To all measured data were fitted a general transport model that includes both pore geometry and pore-size distribution parameters. The results show that both pore geometry and pore-size distribution determine the functional relations between degree of saturation, hydraulic conductivity and air conductivity. The control of pore size on convective transport is more for soils with a wider pore-size distribution. However, the relative contribution of pore-size distribution is much larger for the unsaturated hydraulic conductivity than for gaseous phase transport. For the other transport coefficients, their saturation dependency could be described solely by the pore-geometry term. The contribution of the latter to transport was much larger for transport in the air phase than in the water phase, supporting the view that connectivity dominates gaseous transport. Although the relation between effective fluid saturation and all four relative transport coefficients for the sand could be described by a single functional relation, the presence of a universal relationship between fluid saturation and transport for all soils is doubtful.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2389.2002.00493.x-i1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The relationship between particle-size distribution by laser granulometry and image analysis by transmission electron microscopy in a soil clay fraction (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: The aim of this study was to validate the use of laser granulometry in studies concerning fractions 〈 2 µm in soils. The study was carried out on the clay fraction of a loamy soil from northeast Thailand. Granulometry by light scattering requires the determination of the refractive indexes of the solid phases. Once these values have been established, laser granulometry can provide a detailed description of the particle-size distribution within the clay fractions. Laser granulometry showed a multimodal distribution in the clay fraction of this soil.The analysis of images obtained by transmission electron microscopy provided numerical distributions of soil particles, from which representations by surface area and by volume obtained by laser granulometry and by transmission electron microscopy could be compared. The representation of particle-size distribution by surface area, assuming that particles are similar to circles, is adequate and, in this range of particle size, minimizes the effect of larger diameters. The representation of the particle-size distribution assuming that particles are similar to platy discs is better than the current representation that assumes particles are similar to spheres. We used transmission electron microscopy to validate laser granulometry in the fractions 〈 2 µm.Elemental microanalysis was used to identify the mineralogy of the clay particles: illite, illite-smectite and kaolinite at a magnification of 31 000, corresponding to the clay fraction 〈 0.8 µm of the particle-size distribution. Quartz and illite were identified at a magnification of 3300, corresponding to the fraction between 0.8 and 2 µm. The mineral constituents of the soil are correlated with the modes of the particle-size distribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.2004.00597.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Changes in surface reactivity and organic matter composition of clay subfractions with duration of fertilizer deprivation (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: Preservation of organic matter in soils depends on the chemical structure of organic compounds and on the surface properties of the mineral matrix. We tested the effect of mineral surface reactivity on organic matter decomposition by (i) investigating changes of organic matter composition in clay subfractions of an illitic Haplic Chernozem along a time series of fertilizer deprivation and (ii) simultaneously characterizing the reactivity of mineral surfaces. The soil was subjected to fertilizer deprivation for 18, 44 and 98 years, respectively. Mineral surface properties were characterized by selective dissolution of pedogenic oxides. The number of hydroxyls released after exposure to sodium fluoride was taken as an index for mineral surface reactivity. Organic soil constituents were determined by 13C cross-polarization magic-angle spinning nuclear magnetic resonance (13C CPMAS NMR).Clay subfractions had different mineral surface properties. The coarse fractions have more reactive surfaces and contain more organic carbon than the fine clay fractions. Mineral surface properties are constant over time and are not affected by fertilizer deprivation. Surface reactivity is a function of iron oxide density and controls carbon concentrations in the clay subfractions. Within the time frame of our investigation, alkyl C and aromatic C responded to the duration of fertilizer deprivation, but were indifferent to mineral surface reactivity. O–alkyl C seems to be protected by interactions with pedogenic oxides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.2004.00610.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...