Plant and Soil

, Volume 332, Issue 1–2, pp 163–176

Dynamics of soil water content in the rhizosphere

  • Andrea Carminati
  • Ahmad B. Moradi
  • Doris Vetterlein
  • Peter Vontobel
  • Eberhard Lehmann
  • Ulrich Weller
  • Hans-Jörg Vogel
  • Sascha E. Oswald
Regular Article

Abstract

Water flow from soil to plants depends on the properties of the soil next to roots, the rhizosphere. Although several studies showed that the rhizosphere has different properties than the bulk soil, effects of the rhizosphere on root water uptake are commonly neglected. To investigate the rhizosphere’s properties we used neutron radiography to image water content distributions in soil samples planted with lupins during drying and subsequent rewetting. During drying, the water content in the rhizosphere was 0.05 larger than in the bulk soil. Immediately after rewetting, the picture reversed and the rhizosphere remained markedly dry. During the following days the water content of the rhizosphere increased and after 60 h it exceeded that of the bulk soil. The rhizosphere’s thickness was approximately 1.5 mm. Based on the observed dynamics, we derived the distinct, hysteretic and time-dependent water retention curve of the rhizosphere. Our hypothesis is that the rhizosphere’s water retention curve was determined by mucilage exuded by roots. The rhizosphere properties reduce water depletion around roots and weaken the drop of water potential towards roots, therefore favoring water uptake under dry conditions, as demonstrated by means of analytical calculation of water flow to a single root.

Keywords

Root water uptake Water retention curve Rhizosphere Neutron radiography Mucilage Hysteresis 

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Andrea Carminati
    • 1
  • Ahmad B. Moradi
    • 1
  • Doris Vetterlein
    • 1
  • Peter Vontobel
    • 2
  • Eberhard Lehmann
    • 2
  • Ulrich Weller
    • 1
  • Hans-Jörg Vogel
    • 1
  • Sascha E. Oswald
    • 1
  1. 1.Helmholtz Centre for Environmental Research—UFZLeipzigGermany
  2. 2.Paul Scherrer Institute—PSIVilligenSwitzerland

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