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.
Increasing woodland planting is a land use change that will help Scotland achieve its statutory commitment to achieve net-zero greenhouse gas emissions by 2045. Scotland’s Climate Change Plan includes commitments to incrementally increase the annual woodland creation target from 10,000 to 15,000 hectares per year by 2024/25.
This short study updates a Woodland Expansion Advisory Group (WEAG) 2012 report that provided detailed analysis of the land area that might be suitable for new woodlands. It summarises the results of an initial re-analysis of the opportunities and constraints for woodland expansion, using a GIS spatial analysis. It finds that the estimated land area suitable in principle for woodland creation has risen by 270,000 hectares, 10%, to 2.96 million hectares. This is due to changes in peat soil classification and extent (-263,352 ha) and the inclusion of potential planting on higher quality agricultural land (+533,352 ha).
Soils are one of the world’s biggest stores of carbon. The level of carbon storage depends on several factors, including the type of organic matter, climatic conditions and land management practices, both past and present. This report explores how the level of storage over time could be measured, and how this could help improve land management practices through a payment system.
Key points
- Agricultural soils (across pasture and arable) account for more than 10% of Scotland’s estimated soil carbon. Changes in land management practices affect the balance between soil carbon accumulation and loss, with conversion from grassland to cropland as the largest single change that releases soil carbon on Scottish agricultural land.
- Evidence suggests there is large potential for increasing carbon storage in agricultural soils through changes in management practices. Any increase in carbon in the soil is likely to have a positive impact on soil quality, whilst the climate change mitigation benefit may be modest but positive in the longer term.
- Mechanisms for support through payments exist, but they are largely focused on wider benefits such as preventing soil erosion and there are none that currently specifically enable soil carbon sequestration.
It is important to know where peatland has been drained in the past when prioritising areas for restoration.
No comprehensive data exists, so ClimateXChange carried out a scoping study on whether the presence of drainage could be modelled using remote sensing data presented in the report ‘Detection of peatland drainage with remote sensing’.
The results were promising, and a second phase of work, ‘Comparison of remote sensing approaches for detection of peatland drainage in Scotland’, has refined how this might be taken forward in future.