Written Evidence submitted by Fidra (SH0037)

On behalf of Fidra, I would like to submit evidence in relation to the measures that can be taken by UK Government to protect the health of soil in the UK. Particular focus is given to Fidra’s concerns around contaminated sewage sludge products being applied to agricultural land (https://www.fidra.org.uk/news/sewage_sludge_and_soil_health/).

Fidra is an environmental charity using the best available science to deliver solutions to environmental issues by working with the public, industry and governments. Our projects support sustainable societies and healthy ecosystems with a focus on reducing threats to the environment from pollution. Dr Cloy currently manages a Fidra project that aims to protect agricultural soils from contaminated inputs. Fidra seeks to remove the burden of chemical and plastic pollution on the environment and support resilient ecosystems and a clean safe circular economy.

Fidra’s key asks of UK Government, to ensure agricultural soils are sustainably managed and protected from contaminant stressors by 2030:

-          To protect the health of productive agricultural soils by preventing the application of sewage sludge to land until proven to be a safe clean resource, alongside aspirations of a circular sanitation economy with recognition of effective resource use, waste management and upstream and downstream impacts of chemical and plastic production levels.

-          Consider the impacts of persistent organic chemical contaminants (such as PFAS, bisphenol, pharmaceuticals and PAHs) and microplastics on agricultural soil biodiversity. These contaminants can persist for a long time but modern industries and society still depend on these substances.

-          Support the agricultural industry to avoid the practice of applying contaminated sewage sludge produced by wastewater treatment operators for soil nutrient provision and crop production.

-          Investigate the use of alternative organic fertiliser products (e.g. animal manures and slurries) that provide greater benefits to soil health such as increasing soil organic matter and structural stability and are not contaminated to the same extent as sewage sludge.

-          Explore the business viability of the alternative, relatively new technologies, such as extraction of nutrients from sludge and the processing of sludge for energy production are solutions that merit further investigation.

-          Push upstream solutions around the use of industrial chemicals.

Evidence: These recent studies including references within support statements above providing evidence that treated sewage sludge products that are applied to land contain potentially harmful chemical and microplastic contaminants.

de Souza Machado, A. A. et al. (2018) Microplastics as an emerging threat to terrestrial ecosystems, Global Change Biology, 24, 1405–1416. doi: 10.1111/gcb.14020.


Sun, J., Dai, X., Wang Q., van Loosdrecht, M., Ni, B. (2019) Microplastics in wastewater treatment plants: Detection, occurrence and removal. Water Research, 152, 375-393. Doi.org/10.1016/j.watres.2018.12.050.


2017 James Hutton Institute Scottish Government commissioned report


European Commision Impacts of the use of sludge on land Report


Guidance around best practice and encouraging better agricultural soil management to prevent diffuse pollution and improve soil structure (physical soil health):

-          A commitment to encourage and financially support land managers to maintain and enhance soil organic matter levels and to prevent soil compaction and erosion is needed.

-          One of the key causes of poor soil structure is compaction caused by trafficking along tramlines, therefore structural degradation and tramlines contribute to losses of nitrogen and phosphorus from agricultural soils.

-          To reduce soil compaction, farmers must reduce traffic when the soil is close to field capacity (i.e., water held in the soil after excess water has drained away), this can be achieved by considering the timing of operations.

-          Alleviation of topsoil and subsoil compaction is recommended, with ploughing for arable crops as well as amendment of the soil through increased organic matter, tied ridging with potatoes and surface spiking and sward lifting in grasslands.

-          Alleviation of subsoil compaction is more costly and difficult but it should be noted that some soils are naturally compact (assessments of soil types/profiles will help identify these soils).

-          Reduction of tramlines and aligning them across the slope, reduced or no tillage, spreading machinery loads as evenly as possible over a larger tyre diameter, use of correctly inflated very flexible tyres, delaying of tramline establishment and use of buffer strips all can reduce the effect of tramlines on pollutant and sediment transport.

-          Conservation tillage systems are beneficial to soil and water quality but choice of tillage system should be flexible depending on specific conditions such as soil surface and structural conditions before crop establishment, preceding crop and amount and decomposition status of plant residues.

-          The use of rotations, cover crops and controlled traffic farming offer opportunities to realise the full benefits of no-till.

-          Reducing the source of nutrient loss by employing nutrient management plans, growing suitable crops for the soil type, retention of stubble, contour farming and controlling the out-flow of field drains before they reach a water course need to be considered.

-          Use of Nitrate Vulnerable Zones, control of cultivation and animal movements close to water courses help control nitrate leaching.

Taken from Cloy et al. 2021, A state of knowledge overview of identified pathways of diffuse pollutants to the water environment. CREW report. https://www.crew.ac.uk/sites/www.crew.ac.uk/files/publication/CRW2018_18_Pathways%20report_FINAL.pdf


Other key asks of UK Government and guidance around agricultural soil health monitoring and measuring progress:

-          A commitment to encouraging and financially supporting farmers to use effective nutrient budgeting with the support of farm advisors. Rather than including in voluntary measures, make it compulsory and part of farm payment schemes.

-          Devise a UK-wide soils health monitoring plan, which reports on a 5-year cycle to monitor the health of UK soils (including simple cheap assessments of soil pH, organic matter, biological activity (e.g. earthworm counts) and soil structure (e.g. tools such as Visual Evaluation of Soil Structure).

-          Appoint Chief Soils Officers in Government to oversee targets and progress.


Fidra welcomes any opportunities to discuss issues concerning agricultural soil health and potential solutions with likeminded stakeholders.


February 2023