Rachael Osguthorpe

Rachael Osguthorpe



NERC DTP CASE studentship with Natural England


UK upland soils provide a wide range of ecosystem services such as hydrological functions, carbon storage and supporting important trophic interactions vital for biological conservation. These areas are largely used for livestock grazing, with a number of farms converting to organic management in response to consumer demands and the assumption that organic livestock management is more environmentally sustainable. However, it is not known whether this sheep farming method has any impact on key soil functions and therefore on ecosystem service provision, compared to conventional management. There is potential for soil physical and chemical properties to vary between organically and conventionally managed sheep farming systems, due to differences in factors such as grazing density, the use of fertilisers, and particularly the difference in use of veterinary medicines such as anthelmintics. This in turn can impact soil fauna communities, soil hydrological function and nutrient cycling. 

This project, joint funded by NERC and Natural England, aims to improve our understanding of the role of upland organic sheep grazing management in maintaining and enhancing the key soil functions of upland soils, with particular focus on in-bye pastures. The first half of the project focuses on differences in soil physical, hydrological and chemical properties between the two management systems, and the second half focuses on the differences in anthelmintic use and if this impacts earthworm populations.

Research questions

  1. How do soil physical and chemical properties differ under organic upland sheep farming compared to conventional upland sheep farming?
  2. Are anthelmintic residues found in the soil under organic livestock farming and does this differ from conventionally managed farms?
  3. Do earthworm populations differ under organic upland sheep farming compared to conventional upland sheep farming?
  4. Do anthelmintic residues from livestock farming impact the avoidance behaviour of earthworms?

Research chapters

  1. Field study – comparison of soil physical (bulk density, organic matter, soil strength, pore space, effective porosity) and chemical properties (pH, available N, exchangeable cations). 
  2. Field study – analysing soil samples for presence of anthelmintics (ivermectin, albendazole, levamisole and the metabolites of each compound) and conducting earthworm survey. 
  3. Avoidance behaviour of the earthworm Allolobophora chlorotica (green worm) under three different anthelmintics (ivermectin, albendazole, levamisole). 

Key findings to date:

  • Soil under conventional farms had slower infiltration rate (measured every 5 cm down to 20 cm depth) which gets slower with depth. Organically managed farms are slightly more permeable with the change with depth being much less significant. 
  • Soils under organic farms had higher bulk density and lower organic matter compared to conventional farms. However, as with hydrological properties, this is shown to change more significantly with depth under conventional management, suggesting soils under organic management are better mixed.
  • Overall earthworm populations under organically managed pastures are slightly higher. Significantly higher populations of A. chlorotica under organic farms.



  • 2013-2017 MEnvSci Environmental Science, University of Sheffield
  • 2016-2017 Research Assistant (placement), Department of Geography, University of Sheffield
  • 2016: University of Sheffield Alice Garnett Prize for best performance in 3rd year dissertation
  • 2017: University of Sheffield Alice Garnett Prize for best performance in masters thesis

Research groups and institutes

  • water@leeds
  • River Basin Processes and Management