The EU Soil Monitoring and Resilience Directive — Soil Monitoring Law

Kenneth Loades, Nikki Baggaley (The James Hutton Institute), and Jackie Potts (BioSS)

The 5th July 2023 saw the EU proposing the Soil Monitoring Law aiming to ‘address key soil threats in the EU, such as erosion, floods and landslides, loss of soil organic matter, salinisation, contamination, compaction, sealing, as well as loss of soil biodiversity’. This has been a long time coming, starting in November 2021 where the commission adopted the EU Soil Strategy for 2030 with the aim of achieving healthy soils by 2050, highlighting the need for Scotland to develop its own soil monitoring network. Some of the work in developing this is being done within the Healthy Soils for a Green Recover project with links to other areas in the wider strategic research programme.

Eroded peatland Shetland

With the need for effective soil monitoring becoming more and more critical what data do we have already that could help establish the baseline?

Recently we have begun identifying existing datasets offering the potential for assessing change. One significant component of the Soil Monitoring Law is the inclusion of data related to subsoils with many datasets excluding subsoil due to a focus on top soils (for example the Land Use and Coverage Area Frame Survey (LUCAS). Two key Scottish national data sets, that include both topsoil and subsoil, are the National Soils Inventory for Scotland (NSIS) and BioSOIL, with a further 47 offering some, but not all, parameters and soil horizons and therefore varying degrees of applicability for baselining a soil monitoring framework.

NSIS was initially sampled from 1978-1988 (NSIS I) with 25% resampled from 2007-2009 (NSIS II) with the latter sampling including some additional measures. The benefit of NSIS over some of the other 47 data sets is the inclusion of multiple land use types with sampling using established protocols, BioSOIL surveying however was only conducted in woodland. This change in land use types is reflected in the sample numbers, 721 and 183 sites within the NSIS I and II, and 69 for BioSOIL. The Soil Monitoring Law has recommended a resampling time of 5 years with a sampling resolution ensuring that data ‘should provide a level of uncertainty of soil health measurement of maximum 5% at national level’.

So, what is being defined as a ‘healthy soil’?

This is where some of the challenges begin, key to assessing the health of a soil relies on understanding what measures/indicators should be taken and the thresholds beyond which a soil may be deemed unhealthy. Some measures have had thresholds defined within the law (such as subsoil bulk density required to be less than 1.8 g/cm3 in lighter, sandy soil, and less than 1.47 g/cm3 in clay soils, thresholds for soil types in between have also been defined), others, such as water holding capacity, have been left for member states to define. It is in these areas that we can potentially utilise existing datasets to set thresholds, once we have these set we can understand where we need more information and data for future monitoring towards achieving healthy soils by 2050.

As this work within the Healthy Soils for a Green Recovery, and wider strategic programme, develops we will keep you updated.

We would welcome your thoughts and questions on this topic also so please don’t hesitate to get in touch through emailing healthysoils@sefari.scot or contacting either Nikki Baggaley (nikki.baggaley@hutton.ac.uk) or Kenneth Loades (kenneth.loades@hutton.ac.uk) directly.

Disclaimer: The views expressed in this blog post are the views of the author(s), and not an official position of the institute or funder.