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  • Acid rain  (2)
  • Key words Soil organic matter  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 31 (2000), S. 1-19 
    ISSN: 1432-0789
    Schlagwort(e): Key words Soil organic matter ; Soil macrofauna ; Faeces ; Soil microflora ; Carbon mineralization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract  The control of soil organic matter (SOM) stability by soil invertebrates is evaluated in terms of their impact on the inherent recalcitrance, accessibility to microorganisms, and interaction with stabilizing substances of organic compounds. Present knowledge on internal (ingestion and associated transformations) and external (defecation, constructions) control mechanisms of soil invertebrates is also reviewed. Soil animals contribute to the stabilization and destabilization of SOM by simultaneously affecting chemical, physical, and microbial processes over several orders of magnitude. A very important aspect of this is that invertebrates at higher trophic levels create feedback mechanisms that modify the spatio-temporal framework in which the micro-food web affects SOM stability. Quantification of non-trophic and indirect effects is thus essential in order to understand the long-term effects of soil biota on SOM turnover. It is hypothesized that the activities of invertebrates which lead to an increase in SOM stability partly evolved as an adaptation to the need for increasing the suitability of their soil habitat. Several gaps in knowledge are identified: food selection and associated changes in C pools, differential effects on SOM turnover, specific associations with microorganisms, effects on dissolution and desorption reactions, humus-forming and humus-degrading processes in gut and faeces, and the modification of invertebrate effects by environmental variables. Future studies must not be confined merely to a mechanistic analysis of invertebrate control of SOM stability, but also pay considerable attention to the functional and evolutionary aspects of animal diversity in soil. This alone will allow an integration of biological expertise in order to develop new strategies of soil management which can be applied under a variety of environmental conditions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 11 (1991), S. 151-156 
    ISSN: 1432-0789
    Schlagwort(e): Acid rain ; Mesofauna ; Decomposition ; Beech forest ; Calcareous soil ; Litterbag ; 14C-labelled beech leaf litter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The effects of simulated acid rain on litter decomposition in a calcareous soil (pHH 2 O 5.8) were studied. Litterbags (45 μm and 1 mm mesh size) containing freshly fallen beech leaf litter were exposed to different concentrations of acid in a beech forest on limestone (Göttinger Wald. Germany) for 1 year. Loss of C, the ash content, and CO2−C production were measured at the end of the experiment. Further tests measured the ability of the litter-colonizing microflora to metabolize 14C-labelled beech leaf litter and hyphae. The simulated acid rain strongly reduced CO2−C and 14CO2−C production in the litter. This depression in production was very strong when the input of protons was 1.5 times greater than the normal acid deposition, but comparatively low when the input was 32 times greater. acid deposition may thus cause a very strong accumulation of primary and secondary C compounds in the litter layer of base-rich soils, even with a moderate increase in proton input. The presence of mesofauna significantly reduced the ability of the acid rain to inhibit C mineralization. The ash content to the 1-mm litterbags indicated that this was largely due to transport of base-rich mineral soil into the litter.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 11 (1991), S. 285-289 
    ISSN: 1432-0789
    Schlagwort(e): Acid rain ; Soil fauna ; Litter decomposition ; Litter fragmentation ; Bioturbation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The effect of simulated acid rain on the decomposition of C-14-labelled beech leaf litter (4 months old), and the modification of this effect by litter fragmentation by the millipede Glomeris marginata (Villers) and by the burrowing activity of two earthworm species [Lumbricus castaneus (Savigny) and Octolasion lacteum (Örley)], was studied in laboratory experiments over a period of 168 days. The acid rain caused a strong decrease in C mineralization of intact beech leaf litter situated on the surface of the carbonate-rich mineral soil (to 0.43 of control), whereas CO2 production by the systems was increased (up to 1.12 times the control level). In general, the activity of the decomposer macrofauna buffered the effects of the acidity. Litter fragmentation by G. marginata reduced the effect of acid precipitation on litter decomposition by almost 50%. The burrowing activity of L. castaneus and O. lacteum led to contact between the intact leaf litter and the mineral soil, which buffered the effect of the acid precipitation on litter decomposition by 82% and 65%, respectively. The epigeic earthworm species L. castaneus, by feeding on and removing the faecal pellets of G. marginata from the soil surface, almost totally buffered the effect of the acid rain on pellet decomposition. The activity of the endogeic earthworm species O. lacteum in feeding on Glomeris faecal pellets and mixing them with mineral soil also buffered the effect of the acid rain. However, this effect appeared to be restricted to the first 5 weeks. In total, by mixing fragmented litter with mineral soil, O. lacteum stabilized organic matter in the mineral soil horizon. This stabilization effect was assumed to be independent of the simulated acid precipitation. In addition, the activity of O. lacteum compensated for the increased CO2 production induced by the acid rain. An intact soil faunal community is therefore considered to be a key component in the buffering characteristic of beechwood mull soils.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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