Monitoring soil health in a changing climate is a priority for the Scottish Government.
In 2020, CXC published a baseline report that pulled together existing research on the vulnerability of Scottish soils to climate change. The report found that, while Scotland has a significant knowledge base on soils, there was no single indicator that could be applied to all soils, climatic conditions or land uses.
This scoping study takes the 13 potential indicators the baseline report identified and considers their strategic relevance to monitoring soil health in the context of existing land use Scotland.
Key points
- Potential primary soil health indicators were identified for several land use categories.
- However, it is not possible to identify a single, definitive indicator for each individual land use category and suitable indicators were not identified for several categories such as Urban or Amenity soils.
- Seven indicators were considered extremely important for more than 50% of the categories assessed:
o soil organic matter content
o topsoil depth
o erosion features
o bulk density
o bacteria and archaeal diversity (DNA methods)
o fungal and nematode diversity (DNA methods) - Visual assessment of soils, moisture content and dissolved organic matter were considered extremely important for the fewest categories, though moisture content was considered the primary indicator for transport infrastructure.
The issue of dependency between indicators generates a layer of complexity that requires further exploration.
Monitoring soil health in a changing climate is a priority for the Scottish Government.
In 2020, CXC published a baseline report that pulled together existing research on the vulnerability of Scottish soils to climate change. The report found that, while Scotland has a significant knowledge base on soils, there was no single indicator that could be applied to all soils, climatic conditions or land uses.
This scoping study takes the 13 potential indicators the baseline report identified and considers their strategic relevance to monitoring soil health in the context of existing land use Scotland.
Key points
- Potential primary soil health indicators were identified for several land use categories.
- However, it is not possible to identify a single, definitive indicator for each individual land use category and suitable indicators were not identified for several categories such as Urban or Amenity soils.
- Seven indicators were considered extremely important for more than 50% of the categories assessed:
o soil organic matter content
o topsoil depth
o erosion features
o bulk density
o bacteria and archaeal diversity (DNA methods)
o fungal and nematode diversity (DNA methods) - Visual assessment of soils, moisture content and dissolved organic matter were considered extremely important for the fewest categories, though moisture content was considered the primary indicator for transport infrastructure.
The issue of dependency between indicators generates a layer of complexity that requires further exploration.
This report was commissioned to analyse the indicators available to monitor Scotland’s soil health. Soil health is essential: the benefits range from food production to filtering water, reducing flood risk and regulating climate.
The second Scottish Climate Change Adaptation Programme (SCCAP) identifies soil health as a priority research area, following concerns over a perceived lack of data or gaps in understanding Scotland’s soils. This study summarises previous work on Scottish soils, explores existing datasets, and identifies metrics to support the monitoring of soil health and the vulnerability of Scottish soils to climate change.
Key findings
- Scotland has a significant, world-leading soil knowledge base and a broad data resource portfolio. However, the existing evidence base does not contain tools identified as appropriate for monitoring change in Scottish soils.
- Thirteen indicators with potential to measure soil vulnerability to climate change in all soil types were identified.
- A total of 41 existing datasets that contain baseline and/or resurvey data for Scottish soils have been identified. Resampling of some of these long-term national datasets has potential to support further development of the 13 identified indicators (Table A10).
- A critical knowledge gap exists regarding the dependencies of the 13 identified indicators (i.e. factors they are reliant on), their interactions and hence whether a reduced core set of indicators could be identified at a future stage. This is compounded with critical gaps in our understanding of the interactions between soil properties. This knowledge gap has a major impact on soil biological diversity and therefore functioning of the soil system.
- No single indicator measures the full range of relevant properties encompassing all soils or climatic conditions.