The Crucial Role of Healthy Soils in Scotland's Economy: Costs and Mitigation Strategies

22nd July 2024

Healthy soils are the backbone of many sectors within the Scottish economy, playing a vital role in improving crop yields, storing water to mitigate drought and flooding, and regulating water flow to rivers and lochs. However, when these soils are degraded, the impacts, both direct and indirect, can lead to significant costs for individuals, society, and the broader economy.

Like soils worldwide, Scottish soils are susceptible to degradation. Current measurements indicate a significant portion of Scotland’s soils are already in a degraded state. Degradation due to soil sealing and compaction is linked to land use and soil type, with some soils being more vulnerable than others. The extent of degradation due to soil contamination remains unknown due to a lack of data. Although there are known sites with contaminated soils, the associated costs are yet to be determined.

Estimating the costs of soil degradation requires an understanding of the extent of degradation, its impacts, and the associated costs. This CREW project (Assessing the socio-economic impacts of soil degradation on Scotland’s water environment | CREW | Scotland's Centre of Expertise for Waters) found that the annual estimated costs of soil degradation in Scotland from soil sealing and compaction range from £25 million and £75 million due to reduced crop yield and increase fuel use. Furthermore, the study found that soil compaction can exacerbate erosion, increasing previous estimates of erosion costs. Soil degradation also creates increased costs due to greenhouse gas emissions. While the costs of contamination and loss of biodiversity are more difficult to estimate and further work is needed to calculate this additional cost, they also contribute to the overall economic burden.

Addressing soil degradation through informed strategies and robust monitoring is essential to mitigate its significant economic and environmental costs. Scotland’s policies to protect soils are not only environmentally prudent but economically beneficial, ensuring the sustainable use of this vital natural resource.

The Impacts of Soil Compaction and Sealing

Compacted soils have a reduced capacity to absorb water, reducing plant water availability and crop yields and increases water runoff to rivers. This runoff carries more pollutants to rivers and lochs and heightens the risk of flooding. Compacted soils also require more fuel for cultivation, increasing costs for farmers, greenhouse gas emissions, and reducing biodiversity. Soil sealing leads to more impermeable surfaces, escalating water flow into rivers and drainage systems, potentially causing significant flooding issues. Mapping efforts have revealed that the development of land for housing and transport networks continues to add impermeable surfaces (sealed soils) across Scotland.

The Role of Climate Change

All impacts of soil degradation are likely to be exacerbated by climate change. Spring droughts can lead to further yield reductions, while intense rainfall increases the risks of compaction, flooding, and pollutant runoff.

Mitigation Strategies

To minimize soil degradation, several strategies can be implemented. Timing agricultural operations to avoid farm traffic operations on wet soils, using controlled traffic approaches and lighter machinery helps reduce soil compaction. Applying targeted subsoiling with organic matter incorporation only when necessary is also an effective measure. Incorporating deep-rooting plants into crop rotations, reducing development on greenfield sites, and assessing the impacts of chemicals on soils, crops, and waters are further crucial steps. Additionally, coordinating soil health monitoring and interventions ensures that these strategies are effectively implemented and adjusted as needed.

CREW would like to thank the research team (James Hutton Institute, University of Aberdeen, and SRUC) and the Project Steering Group (SEPA, NatureScot, and Scottish Government) for their dedication and support to the project and in addressing this important issue.