Population ecology and functioning of Enchytraeidae in some arable farming systems

W. Didden

    Research output: Thesisinternal PhD, WU

    Abstract

    <p>The population ecology of Enchytraeidae, and their functioning, were studied in some arable farming systems and in laboratory experiments. The systems studied consisted of a 'conventional' (high input of energy and matter) and several 'integrated' (reduced input of energy and matter) systems. Emphasis was given to population dynamics and the role of Enchytraeidae in nutrient cycling and soil structure evolution.<p>Mean yearly enchytraeid abundance and biomass in the systems studied ranged from 11000 ind/m <sup><font size="-2">2</font></SUP>to 43000 ind/m <sup><font size="-2">2</font></SUP>, and from 0.08 g C/m <sup><font size="-2">2</font></SUP>to 0.42 g C/m <sup><font size="-2">2</font></SUP>, respectively. It was calculated that 0.5-3.7% of the yearly organic carbon input was respired by the enchytraeid populations. Yearly nitrogen flux from the populations (through storage in enchytraeid tissue) ranged from 0.19 to 0.60 g/m <sup><font size="-2">2</font></SUP>.<p>There were no significant differences between the systems studied as regards population dynamical and production ecological parameters. However, vertical distribution of enchytraeid populations differed markedly between the conventional field and the integrated fields, probably related with differences in soil tillage and the resulting distribution of organic fertilizer and plant residues. These differences in vertical distribution may have consequences for the risk of nutrients leaching from the systems.<p>The impact of enchytraeid activity on soil structure evolution was studied in a field experiment with artificial soil cores, in combination with field observations. It was found that enchytraeid activity produced measurable effects on air permeability, pore size distribution, and distribution of aggregate sizes, probably through selective burrowing and transport of organic besides mineral material.<p>Life-history parameters of <em>Enchytraeus buchholzi,</em> the dominant species at the research site, were determined in a laboratory experiment, and predictions based on the laboratory trials were compared with data on population development under more natural conditions. There were significant discrepancies, indicating an influence of the physiological condition of the experimental animals on the length of the life-cycle in this species.
    Original languageEnglish
    QualificationDoctor of Philosophy
    Awarding Institution
    Supervisors/Advisors
    • Brussaard, Lijbert, Promotor
    • Pons, L.J., Promotor
    Award date8 May 1991
    Place of PublicationS.l.
    Publisher
    Publication statusPublished - 1991

    Keywords

    • Oligochaeta
    • soil fauna
    • field crops
    • arable farming
    • ecology
    • animal behaviour
    • habits

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