1 / 13

Soil water fundamentals

Soil hydrophobicity refers to the tendency of soil to repel water, characterized by the contact angle where liquid-vapor interfaces meet solid surfaces. Contact angles can vary from 0° on clean minerals to 180° on completely water-repellent surfaces, influencing water movement, especially after events like wildfires. This phenomenon can lead to enhanced overland flow and preferential flow patterns, accelerating contaminant transfer in soils. Understanding hydrophobicity is crucial for managing soil health and water resources, particularly in regions facing salinity crises.

kat
Télécharger la présentation

Soil water fundamentals

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Soil water fundamentals

  2. Contact angle • the angle at which a liquid-vapor interface meets a solid surface

  3. Contact angle • Ranges from • minimum of 0 for water on clean smooth minerals • maximum of 180 for a completely water repellent surface • surfaces with contact angles > 90 are called hydrophobic • Depends on • surface tension of the liquid • relative affinity of the surface for the liquid

  4. http://ralph.swan.ac.uk/hydrophobicity/soil_hydrophobicity.htmhttp://ralph.swan.ac.uk/hydrophobicity/soil_hydrophobicity.htm

  5. Sand grains with and without organic coatings http://www.agcsa.com.au/static/atm_articles/html/4_6b.html

  6. Soil hydrophobicity can enhance overland flow particularly after wildfire as seen here in a burnt Eucalypt forest in Australia (photo: courtesy of Rob Ferguson) http://ralph.swan.ac.uk/hydrophobicity/soil_hydrophobicity.htm

  7. Soil hydrophobicity can enhance preferential flow (as indicated by a tracer in this sandy soil), leading to accelerated contaminant transfer  (photo: courtesy of L.W.Dekker) http://ralph.swan.ac.uk/hydrophobicity/soil_hydrophobicity.htm

  8. “Localized dry spot” Hydrophobic zone created by excessive thatch and fairy ring mycelium. PHOTO BY ROB GOLEMBIEWSKI, OREGON STATE UNIVERSITY. http://www.turfmagazine.com/print-7012.aspx Turf discoloration resulting from patches of hydrophobic soil on a golf course in Wisconsin http://bullseyegreensblog.blogspot.com/2011/07/pump-house-down.html

  9. Does soil water repellency play a role in woody plant encroachment? Robinson, D.A., I. Lebron, R.J. Ryel, and S.B. Jones. 2010. Soil water repellency: A method of soil moisture sequestration in pinyon-juniper woodland. Soil Sci. Soc. Am. J. 74:624-634.

  10. Capillarity • the action which elevates or depresses the surface of a liquid where it is in contact with a solid (e.g. a capillary tube)

  11. Fluid pressures in a capillary

  12. Salinity crisis in the Murray-Darling Basin, Australia “When groundwater levels are close to the soil surface, capillary action carries salt upward to the plant root zone causing land to become saline. Streams and rivers become saline through salt being washed from the soil surface or where groundwater levels with high salt loads, begin to permanently intersect with the base of the stream or river.” Reduction in water resourcesReduction in agricultural landDamage to urban infrastructureConstraints and losses to industryReduction in biodiversityDegradation of aesthetics of the landscape

More Related