Current Research

Physical interactions between roots, microbes and soil

Roots and the microbes they feed have considerable impact on the physical properties of soil.  I use approaches from soil physics, materials science and engineering to quantify mechanical and hydrological processes that underly the physical engineering of soil by biology.  Work also examines the damage to structure by agricultural production.  Specific research areas are listed below.

• EcoEngineering
  In collaboration with the Geotechnical Engineering Group at the University of Dundee and Dr Glyn Bengough at SCRI, we are looking at using plant roots as a 'green' engineering solution to the stabilisation of engineered slopes.
• Microscale hydrology
  Plant and microbial exudates influence the contact angle and surface tension of water in soils. This can cause very low levels of hydrophobicity to develop, which has implications to water uptake, preferential flow, overland flow and soil stability. A microscale infiltrometer allows for measurements to be made at a fraction of millimetre in size, allowing for rhizosphere hydrology to measured with intact samples.
• Physical resilience of soil
  This work is closely integrated with research into the biological resilience of soil. The ability of soil to recover particular functions (i.e. decomposition, water transport) after stresses is examined using rapid laboratory tests that accentuate stresses and recovery processes.

Research History

Education

• 1996 PhD, School of Chemical Engineering, The University of Birmingham, Edgbaston, Birmingham, UK.
• 1992 Hons BSc (Agr), University of Guelph, Guelph, Canada.

Post-Doctoral Employment

• 2005 Principal Research Scientist (Band 4) Scottish Crop Research Institute (SCRI), Invergowrie, Dundee, UK.
• 2001 - 2005 Senior Research Scientist (Band 5/SPD), SCRI.
• 1997 - 2001 Research Scientist (Band 6/PD), SCRI.
• 1995 - 1997 Postdoctoral Scientist (Band 6/PD), Soil Science Group, Silsoe Research Institute, Silsoe, Bedford, UK.

External Duties

• Chair of Soil Physics Commission, International Union of Soil Science.
• Council Member, British Society of Soil Science.
• Honorary Lecturer, University of Dundee.
• Associate Editor, European Journal of Soil Science.
• Associate Editor, Vadose Zone Journal.

Recent Publications

• Gregory, A.S., Watts, C.W., Griffiths, B.S., Hallett, P.D., Kuan, H.L., and Whitmore, A.P. 2009. The effect of long-term soil management on the physical and biological resilience of a range of arable and grassland soils in England. Geoderma, 153, 172-185.
• George, T.S., Brown, L.K., Newton, A.C., Hallett, P.D., Sun, B., Thomas, W.T.B. & White, P.J. 2009. Impact of soil tillage on the robustness of the genetic component of variation in phosphorus (P) use efficiency in barley (Hordeum vulgare L.). Plant and Soil (in press).
• Mickovski, S.B., Bransby, M.F., Bengough, A.G., Davies, M.C.R., and Hallett, P.D. 2009. The resistance of simple plant root systems to uplift loads. Canadian Geotechnical Journal (in press).
• Barré, P. and Hallett, P.D. 2009. Rheological stabilisation of wet soils by model root and fungal exudates depends on clay mineralogy. European Journal of Soil Science, 60, 525-538.
• Loades, K.W., Bengough, A.G., Bransby, M.F. and Hallett, P.D. 2009. Planting density influence on fibrous root reinforcement of soils. Ecological Engineering (doi:10.1016/j.ecoleng.2009.02.005).
• Koza, A., Hallett, P.D., Moon, C.D. and Spiers, A.J. 2009. Characterisation of a novel air–liquid interface biofilm of Pseudomonas fluorescens SBW25. Microbiology, 155, 1397-1406.
• Mickovski, S.B., Hallett, P.D., Bransby, M.F., Davies, M.C.R., Sonnenberg, R. and Bengough, A.G. 2009. Mechanical reinforcement of soil by willow roots: impacts of root properties and root failure mechanism. Soil Science Society of America Journal, 73, 1276-1285 .
• Šìr, M., Lichner, L., Tesa, M., Hallett, P.D., Martinková, M. 2009. Simulation of phytomass productivity based on the optimum temperature for plant growth in a cold climate. Biologia, 64/3, 615-619.
• McKenzie, B.M., Bengough, A.G., Hallett, P.D., Thomas, W.T.B., Forster, B. McNicol, J.W. 2009. Deep rooting and drought screening of cereal crops: A novel field-based method and its application. Field Crops Research, 112, 165-171.
• Hudacsek, P., Bransby, M.F., Hallett, P.D. and Bengough, A.G. 2009. Centrifuge modelling of climatic effects on the long-term performance of compacted clay embankments. Engineering Sustainability, 162, 91-100.
• Barré, P., McKenzie, B.M. and Hallett, P.D. 2009. Earthworms bring compacted and loose soil to a similar mechanical state. Soil Biology and Biochemistry, 41, 656-658.
• Debeljak, M., Kocev, D., Towers, W., Jones, M., Griffiths, B. S. and Hallett, P.D. 2009. Potential of multi-objective models for risk-based mapping of the resilience characteristics of soils: demonstration at a national level. Soil Use and Management, 25, 66-77.
• Gordon, D.C. and Hallett, P.D. 2009. Rise in CO₂ affects soil water transport through repellency. Biologia, 64/3, 532-535.
• Hallett, P.D., Feeney, D.S., Bengough, A.G., Rillig, M.C., Scrimgeour, C.M., Young, I.M. 2009. Disentangling the impact of AM fungi versus roots on soil structure and water transport. Plant and Soil, 314, 183-196.
• Ashman, M.R., Hallett, P.D., Brookes, P.C. and Allen, J. 2009. Evaluating soil stabilisation by biological processes using step-wise aggregate fractionation. Soil and Tillage Research, 102, 209-215.

Posters

(View all posters)

Attachment	Size
Defining the soil for controlled environments and in the field	897 KB
SCRI examples
Deployment of disease resistance in barley: theoretical expectations and interactions with cultivation methods	875.34 KB
Resilience of soil microbial communities: relationships between land use microbial functional group and applied stress	1.14 MB
Application of multi-objective regression models to map the resilience characteristics of soil	250.94 KB
Getting water to roots in berry production: the challenges of poor soil wettability and root proliferation	1.56 MB
Compost use for geotechnical stability	267.08 KB
Gelifluction of soil on the Antarctic Peninsula	3.68 MB
Distribution of soil carbon and microbial biomass under different tillage regimes	415.41 KB
Effect of Substrate Quantity on Resilience	179.98 KB