Biological indicators of soil quality

The protection of our soil resources has become a significant political, as well as environmental, objective as highlighted by the Soil Action Plan (Defra) and the EU Thematic on Soil Protection. The 19th report of the Royal Commission on Environmental Pollution on Sustainable Use of Soil highlighted the fact that, although soil biology had been much neglected and there are significant knowledge gaps in this research area, there are sound scientific reasons for including soil biological measures in future soil monitoring. A major review of potential national indicators of soil quality for UK Government Departments and Agencies clearly identified the need for the identification and development of interpretable biological indicators to underwrite assessment and monitoring of soil health.

See also: Soil Animals.

The activities of, and interactions between, soil biota are an implicit requirement for the provision of soil functions, both ecological and socio-economic. Soil biota decompose organic matter, drive or mediate soil processes that supply nutrients, regulate water supply and trace gas emissions, modify soil structure etc., besides being an important genetic resource and a significant, but largely undervalued, component of terrestrial biodiversity. It logically follows that the biological components of soils should have considerable potential as indicators of soil quality – although the mechanistic details of the relationships between soil biota and associated functions remain elusive.

Research to date has identified a wide range of potential biological indicators (bio-indicators) of soil quality. We lead a UK consortium with National Soils Research Institute and the Macaulay Institute (funded by Defra as part of the UK Soil Indicators Consortium) which has been assessing the relative performance of these bio-indicators. The key requirement is to resolve outstanding scientific and technical issues that will enable effective bio-indicators to be defined for imminent application in soil monitoring frameworks.