A Review of Hysteresis in Soil Physics

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A Review of Hysteresis in Soil Physics

• Denis Flynn
• Philip O Kane
• Alexei Pokrovskii

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Discovery of Hysteresis in Soil Physics

• In 1930 W.B. Haines showed that there is a strong
  hysteretic effect between the Soil moisture
  content q and the capillary pressure y.
• On the Right is a typical hysteresis loop.
• Water drains along the curve ABC, and re-wets the
  soil along a different curve CDA.
• He also was the first to postulate an explanation
  of why this might happen.
• Below is a capillary tube with a large pore at
  the centre with a different radius to the pore
  throat.

Haines W.B. Studies in the Physical Properties of
Soil. V. The hysteresis effect in Capillary
Properties, and the Modes of Moisture
Distribution Associated Therewith. Journ. Agric.
Sci. xx  pp 97-116
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The Independent Domain Theory

• The Independent domain model (IDM) was developed
  by Neel, Everett et. al.
• Poulovassilis was the first to apply it to
  capillary hysteresis.
• Advantages allows prediction of ??-?
  relationship from a measured family of primary
  scanning curves.
• Integrating the density function f(ye,yf) over
  the whole area will give a total of 1.

Poulovassilis A.1962  ,Hysteresis of pore water,
an application of concept of independent
domains., Soil Sci., pp 405-412.  V93
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Application of the Independent Domain Model

• Need to find the density.
• The procedure is to find experimentally the
  primary wetting curves. (shown below is the
  result of an actual experiment by Poulovassilis)
• On the right diagram, the difference VB-VC is
  the volume of water removed from the soil. Then
  the difference between consecutive primary
  wetting curves is the water that is redistributed
  during re-wetting.

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Mualems Model

• Mualem further simplified the independent domain
  theory.
• Modelling assumption
• Introduced new notation
• Can represent any scanning curve with this
  notation
• Where
• Advantages Predicts ??-? relationship from the
  two outer drying and wetting curves.

• Mualem Y. A Modified Approach to Capillary
  Hysteresis Based on a Similarity Hypothesis.
  Water Resources Research 1973 pp 1324-31

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Further models

• Dependent domain theory.
• Parlanges scaling procedure
• Advantages Require now only one outer curve
  (preferably the main drying curve).
• Disadvantages Require parameters for each inner
  scanning curve.

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Comparison with the Modern Preisach Model

• Summer 2003, Hugh McNamara and I applied the
  Preisach model to data sets supplied by R.
  Haverkamp.
• Our density required only one parameter.
• The fitting results were much improved over that
  of previous models.

Application of the Preisach model in
soil-moisture hysteresis (Philip OKane, Hugh
McNamara, Denis Flynn, Alexei Pokrovskii)
Preprint is at http//www.bcri.ucc.ie/BCRI_15.pdf
(soon to be published in a two volume book The
Science of Hysteresis by I. Mayergoyz.