Overview

Project Highlights:

  • Experimental systems with earthworms and ants
  • Developing sustainable practice for agriculture
  • Methods for enhancing ecosystem services and natural capital

The role of soil in delivering key ecosystem services is becoming increasingly apparent (Wall et al., 2012.) In particular, the ability of soil to sequester and store carbon is being recognised as a key aspect influencing future carbon budgets. Recent research (Kravchenko et al., 2019) has demonstrated the importance of good soil structure in determining the ability of soil to store carbon. Soil structure has been damaged by tillage and overstocking in many regions and sustainable techniques are required to address the issue.

This project will use both field observation and controlled system experiments to identify the effects of alternate management techniques. A fundamental aspect will be to consider methods of assessing structure (e.g. infiltration rate, hydraulic conductivity, pore size distribution) and investigate the use of easier-to-assess surrogates such as bulk density and carbon content as proxies.

The outputs will be journal articles and guidance to the Trust in terms of how staff can assess soil structural integrity with confidence and adapt their management accordingly.

A soil pit showing a profile with a well-structured humic loam overlying a poorly structured B-horizon

Methodology

The project will involve three strands of investigation. The first will be field based on National Trust properties looking at the variation in soil structure as a function of land management. Selected pastures on similar soil type, but with different management histories, will be investigated to assess whether stocking patterns have a demonstrable impact on soil structure.

The second strand will be a controlled experiment using an array of replicated mesocosms. Initially identical profiles of homogenised soil (Araya et al., 2010) will be subjected to treatments involving earthworms and/or meadow ants to create a factorial randomised controlled study of the effects of soil animals on structural development.

The third strand will be lab-based. It will consider the use of easier-to-measure proxies of soil structure, such as bulk-density and organic matter content. Soil cores from a range of soil types and management histories will be analysed directly using tension tables and pressure plates to determine the soil-moisture-release curve and pore-size distribution. Potential proxy measurements of the same cores will be assessed for their effectiveness in predicting actual structural properties.

Training and Skills

Full training will be given in the use of techniques in the Soil Physics lab. Botanical identification skills will also be taught to allow characterisation of the vegetation in the field s from which soils are sampled. The Open University will offer support in the use of “R” for data analysis.   The student will be located within a team of conservation ecologists, who will provide support with respect to accessing the literature and developing presentation skills. They will also attend regular internal forums to discuss initiatives in conservation science.

Timeline

Year 1: Literature review of how targets are set for ecological restoration schemes and what factors are most critical for success against the criteria set. On the basis of the review and in consultation with partners, to select treatments to trial as part of a new restoration scheme. Botanical training and practising vegetation, soil and topographic survey.

Year 2: Implementation of trials at main site, botanical surveys for baseline.   Visits to secondary sites with botanical survey as required. Draft paper on selection of success criteria for restoration schemes. Presentation at National meeting, such as British Ecological Society.

Year 3: Repeat surveys at main and subsidiary sites. Data analysis. Thesis planning. Presentation at international conference, such as European Geological Union, Vienna.

Funding is available for 3.5 years and it is expected that the thesis can be completed within that period.

Partners and collaboration (including CASE)

The National Trust will act as a CASE partner with Dr Stewart Clarke and Rob Macklin contributing to the project’s steering group. The trust will facilitate field site selection and access. It will also offer the successful candidate some work-experience opportunities.

The Floodplain Meadows Partnership (www.floodplainmeadows.org) will make its database of soil structural properties available and will provide logistical support in terms of fieldwork and data analysis.

Further Details

This project has been selected as a CENTA Flagship project. This is based on the projects fulfilment of specific characteristics e.g., NERC CASE support, collaboration with our CENTA high-level end-users, diversity of the supervisory team, career development of the supervisory team, collaboration with one of our Research Centre Partners (BGS, CEH, NCEO, NCAS), or a potential applicant co-development of the project.

 

Please contact Prof. David Gowing (d.j.gowing@open.ac.uk) for additional information.

Applications should include: