Plant and Soil

, Volume 155, Issue 1, pp 91–94

Mobilization of different phosphate fractions in the rhizosphere


  • A. Jungk
    • Institute of Agricultural ChemistryGeorg August University
  • B. Seeling
    • Institute of Agricultural ChemistryGeorg August University
  • J. Gerke
    • Institute of Agricultural ChemistryGeorg August University

DOI: 10.1007/BF00024991

Cite this article as:
Jungk, A., Seeling, B. & Gerke, J. Plant Soil (1993) 155: 91. doi:10.1007/BF00024991


Availability of soil P fractions and mechanisms of acquisition by plants were studied. Plants mobilize soil P by desorption via depletion of P solution concentration around roots. In an oxisol, the process was enhanced by nitrate N nutrition of ryegrass, which increased soil pH, and by carboxylate release by white lupin. Ligand exchange and Fe/Al solubilization are assumed to be the mechanisms. Ammonium N nutrition of ryegrass decreased pH and allowed P mobilization in a luvisol but had no such effect in an oxisol, due to acid solubility of P in these soils. Organic P dissolved in soil solution contributed one third to the P uptake of field-grown barley on a luvisol. Laboratory experiments suggest that organic P is hydrolyzed by phosphatases at the root surface and replenished by micro-organisms.

Key words

barleyCa-Porganic PP depletionP fractionsP mobilizationrhizosphereryegrasssorbed Pwhite lupin

Copyright information

© Kluwer Academic Publishers 1993