Tel: +44(0) 1382 568555 (direct line)
- Non-invasive imaging of roots and root-soil interactions with x-ray CT.
- Improving resource use efficiency at the root-soil interface.
- Effects of dwarfing and semi-dwarfing genes on root growth of temperate cereals.
- Root growth in response to soil drying.
- Global environmental change and food security.
- My research is conducted at two scales. The rhizosphere is a very active region for physical and chemical changes in soils and my research, through PhD students and postdoctoral researchers, is concerned with the quantification of the processes leading to these changes. Non-invasive imaging has proved a novel tool for investigating root growth in soils and the movement of insects towards roots and is being developed to examine other processes with collaborators at Abertay University, Dundee. Most recently I have been exploring the effects of dwarfing and semi-dwarfing genes on root growth in wheat and barley with a student registered at the University of Reading.
The second scale of my research is global with interests in global environmental changes and food security. This research is undertaken as part of the activities of Global Environmental Change and Food Systems (GECAFS) and with staff at the University of Dundee.
- 2005 Director of SCRI.
- 1994 -2005 Leader of a research group at the University of Reading investigating root/soil interactions and the introduction of integrated nutrient management into systems of crop production. The main areas of research were in characterising the physical and chemical environment of the rhizosphere, investigating the appropriate use of fertilisers and manures in Nepal, modelling water and nutrient uptake in agroforestry systems in Kenya, and characterising the movement of the weevil Sitona lepidus to roots of white clover.
- 1990 - 1993 Leader of a research group (six scientists plus five technicians; from 1993 responsible for a program of 12 scientists and 12 technicians) to improve the water use and yields of dryland crops. The main purpose of the research was to investigate means of improving crop yields on duplex soils in Western Australia. Components of the soil water balance (using neutron probes, tensiometers, piezometers and time domain reflectometry) were monitored at several sites and soil constraints to root growth (particularly the physical and chemical properties of hardsetting sands) measured. Other research in the group investigated genotypic differences in rates and duration of grain growth of wheat and studied the allocation of carbon and nitrogen within the plant. The physiological ability of roots to take up nitrogen was investigated using 15N techniques.
- 1980 - 1990 Water movement through the unsaturated zone of the chalk was investigated in a collaborative study with ICI at West Ilsley from 1981 until 1983.
- Genotypic differences in root growth of barley and chickpea were investigated in collaborative research with ICARDA, Syria. The consequences of the differences were investigated in field experiments in Syria which measured the amount and timing of water use in relation to grain yield.
- Water balances of dryland crops (mungbean and soyabean) were investigated in a collaborative project with IRRI, The Philippines. Glasshouse work at Reading examined the effects of temperature and soil water potential on germination and emergence and field work in the Philippines investigated the effects of tillage on emergence and growth following paddy rice.
- Research into the partitioning of carbon within cereal crops and water use and growth of barley and wheat crops (in Perth, Western Australia).
- 1976 - 1980 Root growth and water use of mono- and inter-cropped millet and groundnut and the effects of temperature on root growth of millet were studied as part of a programme under the direction of Professor J L Monteith. The research involved field studies at ICRISAT, India and controlled experiments in glasshouses at Sutton Bonington.
- Dupuy, L., Gregory, P.J. and Bengough, A.G. 2010. Root growth models: towards a new generation of continuous approaches. Journal of Experimental Botany 61, 2131-2143. (doi:10.1093/jxb/erp389)
- Clayton, S.J., Clegg, C.D., Bristow, A.W., Gregory, P.J., Headon D.M. and Murray, P.J. 2010. Movement of newly assimilated 13C in the grass Lolium perenne and its incorporation into rhizosphere microbial DNA. Rapid Communications in Mass Spectrometry 24, 535-540. (doi:10.1002/rcm.4392)
- Johnson, S.N., Barton, A.T., Clark, K.E., Gregory, P.J., McMenemy, L.S. and Hancock, R.D. 2010. Elevated atmospheric CO2 impairs the performance of root-feeding vine weevils by modifying root growth and secondary metabolites. Global Change Biology. (doi:10.1111/j.1365-2486.2010.02264.x)
- Smith, P., Gregory, P.J., van Vuuren, D., Obersteiner, M., Havlik, P., Rounsevell, M., Woods, J., Stehfest, E. and Bellarby, J. 2010. Competition for land. Philosophical Transactions of the Royal Society B, 365, 2941-2957. (doi:10.1098/rstb.2010.0127)
- Murray, P.J., Gregory, P.J., Granger, S.J., Headon, D.M. and Johnson, S.N. 2010. Dispersal of soil-dwelling clover root weevil (Sitona lepidus Gyllenhal, Coleoptera: Curculionidae) larvae in mixed plant communities. Applied Soil Ecology. (doi:10.1016/j.apsoil.2010.09.008)
- Hargreaves, C.E., Gregory, P.J. and A.G. Bengough. 2009. Measuring root traits in barley (Hordeum vulgare ssp. vulgare and ssp. spontaneum) seedlings using gel chambers, soil sacs and X-ray microtomography. Plant and Soil 316, 285-297. (doi:10.1007/s11104-008-9780-4)
- Gregory, P.J., Johnson, S.N., Newton, A.C. and Ingram, J.S.I. 2009. Integrating pests and pathogens into the climate change/food security debate. Journal of Experimental Botany 60, 2827-2838. (doi:10.1093/jxb/erp080)
- Wojciechowski, T., Gooding, M.J., Ramsay, L. and Gregory, P.J. 2009. The effects of dwarfing alleles on seedling root growth of wheat. Journal of Experimental Botany 60, 2565-2573. (doi:10.1093/jxb/erp107)
- Swanson, M.M., Fraser, G., Daniell, T.J., Torrance, L., Gregory, P.J. and Taliansky, M. 2009. Viruses in soils: morphological diversity and abundance in the rhizosphere. Annals of Applied Biology 155, 51-60. (doi:10.1111/j.1744-7348.2009.00319.x)
- Gregory, P.J., Bengough, A.G., Grinev, D., Schmidt, S., Thomas, W.T.B., Wojciechowski, T. and Young I.M. 2009. Root phenomics of crops – opportunities and challenges. Functional Plant Biology 36, 922-929. (doi:10.1071/FP09150)
- George, T.S., Richardson, A.E., Li, S.S., Gregory, P.J. and Daniell, T.J. 2009. Extracellular release of a heterologous phytase from roots of transgenic plants: does manipulation of rhizosphere biochemistry impact microbial community structure? FEMS Microbiology Ecology 70, 433-445. (doi:10.1111/j.1574-6941.2009.00762.x)
- Johnson, S.N., Gregory, P.J., McNicol, J.W., Oodally, Y., Zhang, X. and Murray, P.J. 2009. Effects of soil conditions and drought on egg hatching and larval survival of the clover root weevil (Sitona lepidus). Applied Soil Ecology 44, 75-79. (doi:10.1016/j.apsoil.2009.10.002)
- Gregory, P.J. and Ingram, J.S.I. 2008. Climate change and the current "food crisis". CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 3, No. 099.
- Clayton, S.J., Read, D.B., Murray, P.J. and Gregory, P.J. 2008. Exudation of alcohol and aldehyde sugars from roots of defoliated Lolium perenne L. grown under sterile conditions. Journal of Chemical Ecology 34, 1411-1421.
- George, T.S., Gregory, P.J., Hocking, P. and Richardson, A.E. 2008. Variation in root-associated phosphatase activities in wheat contributes to the utilisation of organic P substrates in-vitro, but does not explain differences in the P-nutrition of plants when grown in soils. Environmental and Experimental Botany 64, 239-249.
- Mahmood-ul-Hassan, M, Akhtar, M.S. and Gregory, P.J. 2008. Solute movement through intact columns of cryoturbated Upper Chalk. Hydrological Processes 22, 2086-2093.
- Ingram, .S.I., Gregory, P.J. and Izac, A.-M. 2008. The role of agronomic research in climate change and food security policy. Agriculture, Ecosystems and Environment 126, 4-12.