Abstract
The effect of bacteria secreting an extracellular polysaccharide (EPS) on the physical properties of rhizosphere soil has been investigated as a function of soil water content by using an approach in which wheat seedlings were inoculated with a strain Pantoea agglomerans (NAS206) selected from the rhizosphere of wheat (Triticum durum L.) growing in a Moroccan vertisol. Colonization by strain NAS206 occurred both on the rhizoplane and the root-adhering soil as opposed to the bulk soil. The intense colonization of the wheat rhizosphere by these EPS-producing bacteria was associated with significant aggregation and stabilization of root-adhering soil, as shown by the combined increases of (i) aggregate mean weight diameter (MWD), (ii) aggregate macro-porosity (pore throat diameter between 10 and 80 μm), (iii) adhering soil:root mass ratio (RAS/RT), (iv) water-stable >200 μm aggregates and (v) 0.1–2 μm elementary clayey micro-aggregates. Biological exudation and capillary pressure interactions leading to root-adhering soil aggregation are also analysed and discussed.
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Amellal, N., Bartoli, F., Villemin, G. et al. Effects of inoculation of EPS-producing Pantoea agglomerans on wheat rhizosphere aggregation. Plant and Soil 211, 93–101 (1999). https://doi.org/10.1023/A:1004403009353
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DOI: https://doi.org/10.1023/A:1004403009353