Road-testing of indicators for assessing site specific soil quality: Phase II

 

Objective

To test proposed ‘prompt values’ for the soil quality indicators (SQIs) pH, organic carbon, extractable P, total N and bulk density against field experimental data to determine whether they are sufficiently protective of environmental interaction and habitat support soil functions.

Summary

Numerical limit values are used to assess soil quality in a number of regulatory and advisory regimes. However, there are few instances where these values have been validated to determine whether they have performed in accordance with stated policy and management aims. ‘Prompt values’ for the environmental interaction and habitat support soil functions were derived for a number of soil quality indicators by the UK Soil Indicators Consortium (Merrington et al., 2006).

In Phase I of this project, heavy metal soil ‘prompt values’ were tested against field experimental soil quality data (e.g. biomass size, respiration rate), to assess their performance in protecting soils in comparison with existing regulatory and guideline limit values.

This process now needs to be repeated for the other soil quality indicators identified (i.e. pH, organic carbon, extractable phosphorus (P), total nitrogen (N), bulk density). A part of this study will be to enhance the scientific evidence base underpinning the existing ‘prompt values’ and, if appropriate, to suggest revisions to the values in the light of the objective to protect the environmental interaction and habitat support functions of soils.

Approach

• Undertake a literature search to identify field experimental data that could potentially be used to test the SQIs and to enhance the scientific robustness of the proposed ‘prompt values’ (e.g. data from Defra projects – SOIL-QC [SP0530], BD1415 etc.)
• Where possible, collate the field experimental soils data into a single database.
• Agree suitable environmental and habitat measurements which are indicative of changes in soil function (e.g. drainage water P concentration, species richness etc.)
• Develop a suitable methodology for testing SQI ‘prompt values’ for environmental interaction and habitat support against field experimental data.
• Assess the performance of the proposed SQI ‘prompt values’ in relation to protecting the soil functions of environmental interaction and habitat support.

Funder

Environment Agency

Contacts

Brian Chambers and Fiona Nicholson
ADAS Gleadthorpe
Meden Vale
Mansfield
Notts NG20 9PF
Tel: 01623 844331
E-mail: fiona.nicholson@adas.co.uk

Rob Parkinson
School of Biological Sciences
University of Plymouth
Tel: 01752 238324
E-mail: r.parkinson@plymouth.ac.uk

References

Merrington, G (2006).  The Development and Use of Soil Quality Indicators for Assessing the Role of Soil in Environmental Interactions.  Environment Agency Science Report SC030265, 241pp.