Biology and Fertility of Soils

, Volume 34, Issue 1, pp 31–41

Kinetics of microbial phosphorus uptake in cultivated soils

  • Fritz Oehl
  • Astrid Oberson
  • Mirjam Probst
  • Andreas Fliessbach
  • Hans-Rudolf Roth
  • Emmanuel Frossard
Original Paper

DOI: 10.1007/s003740100362

Cite this article as:
Oehl, F., Oberson, A., Probst, M. et al. Biol Fertil Soils (2001) 34: 31. doi:10.1007/s003740100362

Abstract.

Knowledge about the role of microorganisms in P cycling at conditions of constant soil respiration rates and constant size of microbially bound P is lacking. To study the kinetics of microbial P uptake and cycling under such conditions, soils differing in biological activity were 33PO4 labelled by introducing a carrier-free tracer solution and incubated for 56 days. The 33PO4 incorporation into the fraction of microbial P releasable by chloroform treatment (Pchl) was assessed and the isotopic composition [=specific activity (SA); SA=<SUP>33</SUP>PO<SUB>4</SUB>/<SUP>31</SUP>PO<SUB>4</SUB>] of Pchl and soil solution P compared. Soils were taken from a 20-year-old field experiment including a non-fertilised control (NON), a minerally fertilised conventional (MIN) and two organic farming systems [bio-organic (ORG); bio-dynamic (DYN)]. Tracer P incorporation continuously increased during incubation in DYN, ORG and MIN soils. It decreased in the order DYN>ORG>MIN, with differences in 33PO4 uptake between the farming systems being higher than suggested by the differences in the amount of Pchl. In the P-deficient NON soil, the highest initial incorporation of tracer P was found, but no additional uptake could be detected thereafter. In all soils, the SA of Pchl converged to the SA of the soil solution with increasing time. Since Pchl remained almost constant during the experiment, the findings suggest an intensive uptake of P from the soil solution into Pchl and concomitant release of P back to the soil solution and, thus, a rapid cycling through Pchl. Intensive P cycling between Pchl and the soil solution was confirmed in an additional experiment where microbial activity was stimulated by glucose and N additions.

Microbial phosphorus uptake Microbial phosphorus turnover Organic farming Conventional farming Isotopic dilution techniques 

Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  • Fritz Oehl
    • 1
  • Astrid Oberson
    • 1
  • Mirjam Probst
    • 1
  • Andreas Fliessbach
    • 2
  • Hans-Rudolf Roth
    • 3
  • Emmanuel Frossard
    • 1
  1. 1.Institute of Plant Sciences, Swiss Federal Institute of Technology (ETH), P.O. 185, 8315 Lindau, Switzerland
  2. 2.Research Institute of Organic Agriculture (FiBL), Ackerstrasse, 5070 Frick, Switzerland
  3. 3.Seminar for Statistics, Swiss Federal Institute of Technology (ETH), Leonhardstrasse 27, 8092 Zürich, Switzerland

Personalised recommendations