Description:
<jats:title>Summary</jats:title><jats:p>
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<jats:list-item><jats:p> Increased plant growth in sterilized soil is usually ascribed to the elimination of (often unidentified) soil‐borne pathogens. Plant–soil bioassays are reported here for three dune soils and two plant species (<jats:italic>Ammophila arenaria</jats:italic> and <jats:italic>Carex arenaria</jats:italic>).</jats:p></jats:list-item>
<jats:list-item><jats:p> Dynamics of plant growth, availability and uptake of nutrients were compared in sterilized (25 kGy gamma‐irradiation) vs control soils.</jats:p></jats:list-item>
<jats:list-item><jats:p> Plant growth, availability and acquisition of nutrients, for example P, even when provided in apparent excess, were significantly enhanced in gamma‐irradiated calcareous dune sands. With <jats:italic>A. arenaria</jats:italic>, the positive sterilization effect occurred independently of initial plant dry mass. The addition of extracts of planted soils to <jats:italic>A. arenaria</jats:italic> growing in unsterilized sand caused an increase in root growth that could not be related to either nutrients or pathogens.</jats:p></jats:list-item>
<jats:list-item><jats:p> Increased availability and acquisition of nutrients in sterilized soil may contribute to nonsterile : sterile ratios of plant growth that are < 1. Any ecological speculation involving the role of soil‐borne biological factors should be based on fully validated plant–soil bioassays, which account for nutritional or other nonpathogen‐related side‐effects induced by soil sterilization.</jats:p></jats:list-item>
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