My present research interests concern the chemical, physical and biological properties of soil with particular focus on soil hydrophobicity (or water repellency) and the factors which influence its measurement, expression, abatement, destruction and recurrence. This phenomenon influences the delayed onset of water infiltration into affected soils reducing storage capacity and promoting surface run-off and/or evaporation. Recently atomic force microscopy (AFM) has been used to examine the distribution of surface mechanical properties on soil mineral particle surfaces and this has been used to infer the distribution and strength of adhesion of adsorbed organic material on particle specimens drawn from both hydrophilic and hydrophobic soils. It is hoped to extend the range of investigations to examine the extent to which micro-organisms (and their by-products) within soils influence hydrophobicity.

The heating of surface soils as a result of wild fire, or the use of fire as a land management tool, has a variety of interesting effects on soil chemistry leading to a redistribution of hydrophobicity (and changes in its persistence) within the soil column and a potential wide variety of outcomes dependent on subsequent weather conditions.

 

Recent publications

• Doerr SH, Dekker LW, Ritsema CJ, Shakesby RA and Bryant R.
  ‘Water repellency of soils: The influence of ambient relative humidity’ Soil Science Society American Journal, 66, 2002, 401:405.
• Doerr SH, Douglas P, Evans R, Morley CP, Mullinger N, Bryant R, Shakesby RA. 2005a. Effects of heating and post-heating equilibration times on soil water repellency. Austral. J.  Soil Res. 43: 261:267. DOI: 10.1071/SR04092   0004-9573/05/030261     
• Bryant R, Doerr SH, Helbig M. 2005. The effect of oxygen deprivation on soil hydrophobicity during heating. Int. J. Wildland Fire 14: 457:474. 
     DOI: 10.1071/WF05035  1049-8001/05/040449 
• Bryant R, Doerr SH, Hunt G, Conan S.  2007. Effects of soil compaction on soil surface water repellency Soil Use and Management  DOI: 10.1111/j.1475-2743.2007.00088.x

Conference Contributions

European Geosciences Union, Vienna 2004

Doerr, S.H., Shakesby, R.A., Blake, W.H., Bryant, R., Vuurens, S.H., Stagnitti, F., Humphreys, G.S. & Wallbrink, P. (2004) Effects of different wildfire severities on soil wettability: evidence from field observations and controlled laboratory experiments on Australian eucalypt soils. Geophysical Research Abstracts, 6, #04713.

Bryant, R. Helbig M and Doerr SH (2004) Heating effects on soil wettability under oxygen-deprived conditions: Results from a controlled laboratory study. Geophysical Research Abstracts, Vol. 6, #04724, SRef-ID: 1607-7962/gra/EGU04-A-04724

---

Bryant R, Doerr SH and Morgenstern P (2006)
Laboratory simulations of the effect of various fire residence times on hydrophobicity within soil profiles. International Soil Conservation Organisation (ISCO 2006)
14 th International conference 14-19 May Marrakech, Morocco

---

Biohydrology 2006 Prague: 19/09/06 - 22/09/06

Shuying: Cheng S, Bryant R, Wright C, Doerr SH, "Investigation of natural organic coatings affecting soil particle wettability using Atomic Force Microscopy"

Julia: Bayer J, Cheng S, Bryant R, Doerr SH, "Laser Scanning Confocal Microscopy (LSCM) study of surface properties of biological coated sand particles"

---

Florida: 29/04/07 - 03/05/07, Bouyoucos Conference 2007 on the origin of water repellency in soils

Shuying: S. Cheng, J.V. Bayer, R. Bryant, S.H. Doerr, C. Wright, AFM study on physico-chemical features of soil organic matter on natural soil particles

Julia: Julia V. Bayer, R. Bryant, Shuying Cheng, Stefan H. Doerr, "Soil pH and soil particle fluorescence