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Poster De Conférence Année : 2014

Nitrate supply controls phosphorus availability and microbial properties in the rhizosphere of intercropped species

Résumé

Positive interactions between cereals and N2-fixing legumes have been recently evidenced for phosphorus (P) but the underlying rhizosphere mechanisms are still unknown. We assumed that rhizosphere acidification induced by the N2-fixing activity of the intercropped legume in interaction with changes in microbial activity is one of the mechanisms enhancing P availability in neutral soils. To further investigate those mechanisms we applied an artificial gradient of nitrate supply since nitrogen nutrition is supposed to drive changes of rhizosphere pH. Durum wheat and chickpea were grown in a mini-rhizobox device as intercrops and sole crops on a luvisol with neutral pH. We applied 3 levels of nitrate supply to obtain a broad range of rhizosphere pH. Phosphorus availability, pH, and abundance of selected microbial groups were investigated in the rhizosphere and bulk soil. Plant biomass, P and N concentration in shoots and roots were measured. Phosphorus availability was enhanced when durum wheat and chickpea were intercropped. A negative relation between P availability and values of pH in the rhizosphere was obtained for chickpea grown alone, explaining the observed substantial increase of available P when no nitrate was added. Values in intercrop were distributed in a zone where root-induced changes of pH did not influence P availability. Abundance and relative abundance of BPP (beta-propeller phytase gene), microbial biomass and CNP stoichiometry were modified in the rhizosphere of intercropped species. Those results suggested that nitrate supply controls the fate of phosphorus and microbial properties in the rhizosphere of intercropped durum wheat and chickpea.
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Dates et versions

hal-01268834 , version 1 (04-02-2016)

Identifiants

  • HAL Id : hal-01268834 , version 1
  • PRODINRA : 280471

Citer

Elodie Betencourt, Xiaoyan Tang, Sarah Placella, Agnès Robin, Jianbo Shen, et al.. Nitrate supply controls phosphorus availability and microbial properties in the rhizosphere of intercropped species. PSP5 2014 - Facing Phosphorus Scarcity, Aug 2014, Montpellier, France. 2014. ⟨hal-01268834⟩
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