 |
| Titel |
The effect of heterogeneity and surface roughness on soil hydrophobicity |
| VerfasserIn |
I. Hallin, R. Bryant, S. H. Doerr, P. Douglas |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250042858
|
|
|
|
|
|
| Zusammenfassung |
| Soil water repellency, or hydrophobicity, can develop under both natural and anthropogenic
conditions. Forest fires, vegetation decomposition, microbial activity and oil spills can all
promote hydrophobic behaviour in surrounding soils. Hydrophobicity can stabilize soil
organic matter pools and decrease evapotranspiration, but there are many negative
impacts of hydrophobicity as well: increased erosion of topsoil, an increasingly scarce
resource; increased runoff, which can lead to flooding; and decreased infiltration, which
directly affects plant health. The degree of hydrophobicity expressed by soil can
vary greatly within a small area, depending partly on the type and severity of the
disturbance as well as on temporal factors such as water content and microbial
activity.
To date, many laboratory investigations into soil hydrophobicity have focused on smooth
particle surfaces. As a result, our understanding of how hydrophobicity develops on rough
surfaces of macro, micro and nano-particulates is limited; we are unable to predict with
certainty how these soil particles will behave on contact with water. Surface chemistry is the
main consideration when predicting hydrophobic behaviour of smooth solids, but for particles
with rough surfaces, hydrophobicity is believed to develop as a combination of surface
chemistry and topography. Topography may reflect both the arrangement (aggregation) of soil
particles and the distribution of materials adsorbed on particulate surfaces. Patch-wise or
complete coverage of rough soil particles by hydrophobic material may result in
solid/water contact angles -¥150Ë , at which point the soil may be classified as
super-hydrophobic.
Here we present a critical review of the research to date on the effects of heterogeneity
and surface roughness on soil hydrophobicity in which we discuss recent advances, current
trends, and future research areas.
References:
Callies, M., Y. Chen, F. Marty, A. Pépin and D. Quéré. 2005. Microfabricated textured
surfaces for super-hydrophobicity investigations. Microelectronic Engineering.
78-79:100-105.
Doerr, S.H. C.J. Ritsema, L.W. Dekker, D.F. Scott and D. Carter. 2007. Water
repellence of soils: new insights and emerging research needs. Hydrological Processes.
21:2223-2228.
Doerr, S.H., R.A. Shakesby and R.P.D. Walsh. 2000. Soil water repellency: its causes,
characteristics and hydro-geomorphological significance. Earth-Science Reviews.
51:33-65.
McHale, G. N.J. Shirtcliffe, M.I. Newton, F.B. Pyatt and S.H. Doerr. 2007.
Self-organization of hydrophobic soil and granular surfaces. Applied Physics Letters. 90.
054110. |
|
|
|
|
|
|