Written Evidence submitted by Cranfield University (SH0088)

Cranfield University’s long-established research on the status and protection of national soil resources provides relevant and robust evidence to this inquiry. Cranfield is custodian of the National Soil Inventory (NSI) and the Land Information System (LandIS), recognised by the UK Government as the definitive source of national soils information. LandIS has provided the digital representation of soils and soils-related data collected for England and Wales for the past 60-70+ years. By combining spatial mapping of soils at a variety of scales with soil property and agro-climatological data, LandIS has been used to inform national policy formulation1 and implementation, and develop field-scale advisory tools (e.g. control of soil erosion and soil compaction2) based on the national soil data.

Our soils research is undertaken in close collaboration with government agencies and departments (Defra, EA, Natural England, JNCC and Welsh Government). Cranfield is recognised by Defra as providing the National Reference Centre for Soils. Our work provides robust scientific evidence to the Secretaries of State and to key Defra policy teams (e.g. Soils Policy Team; ELMS Test and Trials team; 25 Year Environment Plan Outcome Indicator Framework Team; Agri-Food Chain Directorate; and Net Biodiversity Gain Team), as they implement the 25 Year Environment Plan, and Agriculture and Environment Acts. We also work with industry (e.g. agricultural and horticultural producers, food processors, and retailers) and civil society (e.g. AHDB, NFU, WRAP, LEAF).

Our research on long-term changes in national soil resources has stimulated public and policy debate. Our evaluation of the total economic costs of soil degradation at £1.2 billion a year3 was cited in the National Audit Office’s briefing on environmental protection to the House of Commons Environmental Audit Committee4. We contributed evidence to the 2016 Environmental Audit Committee’s Soil Health Inquiry5, whose report specifically cites our research, including the losses of soil carbon since 1978 found in the National Soil Inventory6, the economic costs of soil degradation2 and assessments of contaminated land.

1Kibblewhite MG, Bellamy PH, Brewer TR, Graves AR, Dawson CA, Rickson RJ, Truckell I & Stuart J (2014) An exploration of spatial risk assessment for soil protection: Estimating risk and establishing priority areas for soil protection. Science of the Total Environment 473-474, 692-701.   https://doi.org/10.1016/j.scitotenv.2013.12.086

2Niziolomski, J. C., Simmons, R. W., Rickson, R. J. and Hann, M. J. (2020) ‘Efficacy of mulch and tillage options to reduce runoff and soil loss from asparagus interrows’, Catena, 191, p. 104557. https://doi.org/10.1016/j.catena.2020.104557(external)

3Graves AR, Morris J, Deeks LK, Rickson RJ, Kibblewhite MG, Harris JA, Farewell TS & Truckell I (2015) The total costs of soil degradation in England and Wales. Ecological Economics 119, 399–413.https://doi.org/10.1016/j.ecolecon.2015.07.026(external)

4https://www.nao.org.uk/wp-content/uploads/2014/06/Environmental-Protection-briefing.pdf

5https://publications.parliament.uk/pa/cm201617/cmselect/cmenvaud/180/180.pdf

6Bellamy PH, Loveland PJ, Bradley RI, Lark RM & Kirk GJD (2005) Carbon losses from all soils across England and Wales 1978–2003. Nature 437, 245–248. https://doi.org/10.1038/nature04038(external)

Cranfield University’s responses to the 6 questions are found below. 

1.      How can the government measure progress towards its goal of making all soils sustainably managed by 2030? What are the challenges in gathering data to measure soil health how can these barriers be overcome?

1.1.  Measuring progress towards sustainable soils

Sustainable management of soils requires a) soil degradation processes are controlled and b) soil health is maintained (or better still, improved). Sustainably managed soils deliver diverse ecosystem goods and services, directly linked to economic, environmental and social sustainability.

Cranfield University has undertaken several studies to measure both soil degradation and soil health. Past research on the causes, severity and extent of soil degradation processes has justified the need for a national soil protection policy. More recently, our focus has been on measuring and monitoring soil health, to inform a “scientifically and statistically rigorous, and reliable soil monitoring programme, based on routine data collection on soil condition”, as recommended in the 25 Year Environment Plan Outcome Indicator Framework (2018).

Our research has identified a ‘short’ list of key soil health properties (physical, chemical and biological) that can contribute to such a programme. They are linked to soil functioning and the delivery of several ecosystem services, including soil organic matter / soil carbon (SOM / SOC); infiltration/hydraulic conductivity; soil respiration; aggregate stability; microbial/fungal diversity; soil structure + aggregate distribution; earthworms; and microbial biomass carbon. These soil health properties will be needed to meet Defra’s (2023) Environmental Improvement Plan’s goal of publishing a “baseline map of soil health for England by 2028”.

We recognise that ‘soil health’ might be different for different ecosystem services. An on-going JNCC / Cranfield University project (C20-0171-1550) concludes that a ‘one-size fits all’ soil health indicator is unlikely to apply to all soils-based ecosystems services. The project outputs show soil health in relation to a particular ecosystem service, for any selected land parcel. The outputs can be displayed in an interactive dashboard showing a soil’s ability to contribute to selected ecosystem services, in relation to the total range of values possible across similar soils across all land uses, or when restricted to the current land use. The resultant indicator can be refined with directly recorded soil metrics and/or knowledge of local land management options. This enables users to get a more accurate view of the status of their selected land parcel and explore how implementing different soil management options would impact the soil health of their site, across the range of ecosystem services.

An alternative approach to measuring and monitoring soil health properties, is to collect data on the uptake of soil management practices associated with improving soil health (e.g. cover cropping, reduced tillage; Figure 1).

Figure 1. Uptake of no till (NT), minimum till (MT) and ploughing (PL) (Alskaf et al., 2020)

1.2.  Challenges in gathering this data

There are no agreed sampling or analytical protocols for soil health that are universal, unambiguous, repeatable and convenient. What is the spatial scale for soil health measurement and monitoring? Some soil properties vary widely over space (e.g. soil organic carbon across a field), requiring large numbers of samples (over the soil surface and with depth) to be representative. How often to sample and when? Some soil health properties take years to respond to management changes (e.g. soil carbon), whilst others change daily or seasonally (e.g. soil biology). This dynamic signal is an important aspect of soil health. Who is responsible for the soil sampling? Is training required? Do you need incentives? Would tenants be prepared to take samples as much as landowners?

It is likely different labs (even if accredited) may give different results (e.g. SOC), undermining the veracity of soil health benchmarking. The time and financial costs of sampling, measuring, analysing and monitoring several soil health properties may be prohibitive to the implementation of a soil health monitoring programme.

For monitoring management practices, Alskaf et al. (2020) recognise that farmer surveys can be biased, with low and unrepresentative response rates. Not all practices are effective everywhere and every year: sustainable soil management will be different for different soils, years and land uses. In arable agriculture, practices may focus on increasing soil carbon and reducing erosion. In urban environments, priority may be on remediating contaminated soil.

1.3.  Solutions to challenges

Finding solutions to these challenges are vital to meet the Environment Improvement Plan (EIP) goal of publishing a baseline map of soil health for England by 2028. Applying multiple approaches for data collection will help: national monitoring schemes, on-farm soil sampling, farmer-led soil assessments, remote sensing and field sensors. The selection of a ‘minimum data set’ of soil health properties will reduce time and financial costs. For example, soil carbon is regarded by many as the ‘best’ measure of soil health, as it is associated with multiple ecosystem services. Thus there is an urgent need to update the soil carbon database for England. There are methods of using existing soil databases to predict the level of soil organic content (Beka et al. 2022) and potential lessons to be learnt from the plan to measure soil carbon in all fields in Northern Ireland. However, to be meaningful, soil organic carbon must be expressed relative to bulk density and clay content (Prout et al. 2021). 

We recommend that data collected is centrally captured, so that it can be incorporated into a wider assessment of soil health, along with monitoring in the NCEA. This would provide the necessary granularity for a comprehensive assessment of soil health that reflects different soils and the sustainability of soil management practices.

2.      Do current regulations ensure that all landowners/land managers maintain and/or improve soil health? If not, how should they be improved?

Previous regulations focused on preventing harm to soils (rather than promoting soil health specifically). Even so, Cross Compliance rules include several practices that will maintain and improve soil health. It is encouraging that farmers must still follow these rules to claim certain rural payments. Some rules directly improve soil health: GAEC 6: Maintaining the level of organic matter in soil. Others only indirectly improve soil health via control of soil erosion: GAEC 4: Providing minimum soil cover; GAEC 5: Minimising soil erosion. Other rules are directed at protecting water bodies and have little effect on soil health per se: GAEC 1: Establishment of buffer strips along watercourses.

Also directed at water resource protection, the 2018 Farming Rules for Water regulations have some indirect impacts on soil health. “Take reasonable precautions to prevent significant soil erosion and runoff “ and protecting land “from poaching by livestock” are focused on control of degradation, rather than promoting soil health directly. The interim targets in EIP to “Reduce nitrogen, phosphorus and sediment pollution from agriculture to the water environment by 10% by 31 January 2028” have tenuous links to soil health.

Thus current regulations seem to focus on preventing soil degradation or protecting waterbodies, rather than promoting soil health per se. The obligations on farmers are patchy, subject to “buy-in” by early adopters. There is no impetus to support soil health improvement, which could be compulsory for all soils before other support mechanisms can be “unlocked” (e.g. access to other parts of ELMS and EIP depends on soil health measurement as an entry requirement).

Also, current regulations are mainly focused on agricultural land. Soil health may be at risk on other land uses. A project commissioned by Defra (SP1318B, Better understanding of the current soil protection landscape) estimated that about 9.5% of the total land use of the UK was both a) at risk of soil degradation processes and b) not covered by existing soil regulations such as Cross Compliance. Urban and construction sites may be covered by planning regulations, but again, these are focused more on waste regulations than on soil health per se. Even so, there has been some progress in these sectors (e.g. Society for the Environment’s Soils and Stones report; CIRIA’s Sustainable management of soil (RP1140)).

There needs to be research to verify that the regulations will deliver healthy soils for different soils, climates and farming systems. Verification of targets will require monitoring and reporting at sufficient resolution and timescales. Crucially this information should be fed back to farmers so they can implement actions appropriate for their farm with confidence.

3.      Will the standards under Environmental Land Management schemes have sufficient ambition and flexibility to restore soils across different types of agricultural land?

N.B. Drafted prior to the publication of the ELM update / new SFI Standards (03/02/2023), which no longer specifically mention ‘Soils’, but ‘Land’

Several ‘land management actions’ in the arable and horticultural, and grassland Soils Standards in ELMs will have direct effects on soil health, such as adding organic matter to all land at least once during the 3-year SFI Standards agreement. However, this action is required only ‘at least once’. A more ambitious action would be to do this every year. Coupled with adding organic matter, the ‘action’ of ‘testing soil organic matter’ will measure, monitor and potentially manage this key soil health property. However, the practical challenges of this are listed under section 1.2 above. Other land management actions (e.g. minimising bare ground; having cover crops on land over winter) will also improve soil health, such as increased SOM / SOC. However, ELM schemes should recognise that this practice is not suited to all soils (e.g. cover cropping on heavy soils in high rainfall areas).

The Standards will have indirect effects on soil health too. The requirement for a soil assessment and soil management plan will give land managers a greater awareness and interest in the state of their soils (and how they change), and in soils in general. However, this exercise needs a level of understanding and knowledge, that might need training, advice and guidance.

The Standards lack ambition as they only cover a 3 year period. Meaningful changes in soil health can take much longer than this. Conversely, a 3 year commitment may be too long for tenant farmers on short term agreements (possibly < 1 year). The figure of £20 per ha (with a maximum of £1000 per year) is unlikely to attract a wide pool of participants, resulting in large areas where little is known about trends in soil health. ELMs is still focused on agricultural land, but soil health is critical in other land uses too.

4.      What are the threats and opportunities for soil health as ELMs are introduced?

N.B. Drafted prior to the publication of the ELM update / new SFI Standards (03/02/2023), which no longer specifically mention Soils, which may be seen as a demotion of the importance of soils.

Soil health will be threatened if there is insufficient participation in the ELM scheme for the reasons given above. This would undermine adequate measurement and monitoring of soil health, despite this being required in the ELMs Soils Standards. There may be confusion as to financial incentives, environmental benefits and inspections required under ELMs, leading to poor uptake. Similar confusion may exist as to differentiating between available schemes (e.g. Countryside and Environmental Stewardship, Sustainable Farming Incentive and Landscape Recovery), and how they will interact.

The current Standards don’t address soil health explicitly enough. There is no management action that specifically proposes improving soil health: this is simply an anticipated outcome of some land management actions. There is little widespread evidence that the actions are (always, everywhere) cost-effective, losing confidence in the scheme. It should be recognised that ‘one size does not fit all’.

ELMs could offer further opportunities to improve soil health by introducing additional actions related specifically to soil health. There needs to be evidence and confidence that these are practical and cost-effective within the planning horizon of the land manager. Soils Standards could be extended both in time (>3 years) and to other land uses e.g. construction, urban and lowland peat (loss of soil carbon from cultivated peatlands is one of the greatest threats to soil security in the UK, according to the Environmental Audit Committee).

5.      What changes do we need to see in the wider food and agriculture sector to encourage better soil management and how can the Government support this transition?

The agricultural supply chain (“field to fork”) is very long, complex, dynamic and often opaque, covering primary production, processing, packaging and distribution. Final consumer products are often far removed from the farmer’s field. Even so, product providence should be more explicit, including the field / farm management practices used. Labelling with point of origin is increasingly available, giving the consumer information and confidence as to the source of the product and how it was grown. Inevitably, this introduces further costs, which are likely passed on to the retailer and consumer.

Certification / accreditation schemes recognise if products have been grown in a sustainable way, by avoiding degrading field practices and using those that restore, maintain and improve soil health. The LEAF Marque scheme is a leading global assurance system that celebrates sustainably farmed products. This accreditation requires the farmer to practise sustainable food production (including sustainable soil management) to demonstrate continuous improvement across the whole farm. Large retailers should explicitly support these accreditation schemes. This will help dispel perceptions that supermarket contracts with growers promote unsustainable soil management practices e.g. causing soil compaction by harvesting root crops during wet weather to meet consumer demands. Responsible and sustainable sourcing of food helps industry meet Corporate Social Responsibility goals.

6.      What does UK Government need to do to tackle other stressors on soil health such as soil contamination?

Our research on the cause, severity and extent of soil degradation processes (as stressors on soil health) was carried out in the 1990s and 2000s. Defra’s Construction Code of Practice for the Sustainable Use of Soils on Construction Sites also dates back to 2009. This evidence is out of date now, especially given the increasing impacts of climate change on soil degradation and loss of soil health (which we have also researched). Competing land uses (e.g. food, biofuels, urban development, rewilding, infrastructure) on finite land resources will increase pressures on soil health and soil degradation. Better knowledge of the causes, severity and extent of the stressors on soil health (e.g. soil degradation) will help target areas in need of soil protection policy and practice. This requires better soil measurement (and monitoring) across all land uses (including agriculture, urban, industrial and construction sectors) to help track local and national soil health.

February 2023

References

Alskaf, K., Sparkes, D.L., Mooney, S.J., Sjögersten, S. and Wilson, P., 2020. The uptake of different tillage practices in England. Soil Use and Management, 36(1), pp.27-44.

Beka, S., Burgess, P.J., Corstanje, R., Stoate, C. (2022) Spatial modelling approach and accounting method affects soil carbon estimates and derived farm-scale carbon payments. Science of the Total Environment 827, 154164 https://doi.org/10.1016/j.scitotenv.2022.154164

Prout, J.M., Shepherd, K.D., McGrath, S.P., Kirk, G.J. and Haefele, S.M., 2021. What is a good level of soil organic matter? An index based on organic carbon to clay ratio. European Journal of Soil Science, 72(6), pp.2493-2503.