Sustainable Farming Scheme: Carbon Sequestration Evidence Review Panel: summary report

Welsh Government set out its commitment to supporting a successful future for Welsh farming and to tackle the climate and nature emergency in a written statement on Farming in Wales issued on 27 February 2024. The statement sets out some potential next steps on the basis of the views expressed on the Sustainable Farming Scheme (SFS) consultation proposals by the farming industry. These included an evidence-based review of any further and alternative proposals to achieve carbon sequestration within the SFS.

The Deputy First Minister and Cabinet Secretary for Climate Change and Rural Affairs has committed to listen to and work with farmers and all stakeholders, to develop a scheme that will help deliver the ambition for Wales to be a world leader in sustainable farming. As part of this process the Deputy First Minister created a Roundtable to review key programme outputs produced by working-groups and sub-groups. This report summarises the output of the evidence review undertaken by the Carbon Sequestration Evidence Review Panel sub-group (the Panel). 

The Panel is made up of eight members of the Roundtable, formed to discharge the above review action with secretariat support provided by Welsh Government. 

The Panel members are:

• Victoria Bond – Country, Land & Business Association (CLA) Cymru
• Elaine Heckley – Confederation of Forest Industries UK (Confor)
• Aled Jones – National Farmers’ Union Cymru (NFU Cymru)
• Hywel Morgan – Nature Friendly Farming Network (NFFN)
• Ian Rickman – Undeb Amaethwyr Cymru (UAC) / Farmers’ Union of Wales (FUW)
• Cath Smith – Hybu Cig Cymru (HCC) /Meat Promotion Wales 
• Andrew Tuddenham – Soil Association (and representing the wider Wales Environment Link)
• Darren Williams – Independent farmer

The aim of the review is set out in the Terms of Reference for the Panel, which sets the scope to consider alternative or additional SFS [1] Universal Actions (UAs) to sequester carbon in response to the Welsh Government’s statutory and policy obligations.

To deliver this commitment, the Panel’s objectives were to discuss the options available for on farm carbon sequestration, the evidence that supports these options, and the scale of opportunity in Wales. A rapid review of the evidence was conducted in order to:

• compare and contrast alternative options with the existing SFS Universal Actions to assess which have the potential to sequester more carbon (create new woodland and agro-forestry, hedgerow management, woodland maintenance and habitat maintenance)
• offer opinion for further or alternative proposals within the SFS to sequester carbon, including a critical appraisal of included evidence, the scale of opportunity in Wales and potential co-benefits for Sustainable Land Management (SLM) objectives
• provide a summary of the Panel’s position on the evidence associated with further and alternative proposals to achieve carbon sequestration within the SFS

[1] Universal Actions (UAs) are actions that all farmers participating in the SFS will need to deliver to receive the Universal Baseline Payment, unless exemptions apply. 

To undertake this task, the Panel took a mixed approach to gathering the evidence. After initial scoping of relevant subject areas and experts, the Panel opened a call for evidence. In response to this call, the Panel received both written evidence submissions and verbal evidence sessions alongside a considerable body of scientific papers recommended by the Roundtable and experts alike.   

In addition, the Panel heard presentations from Welsh Government officials on the details of statutory and policy obligations, along with presentations on the modelling of the SFS undertaken through the Environment, Rural Affairs Monitoring and Modelling Programme (ERAMMP).   

The Panel identified a number of limitations of their review, including the short timescale in which to carry out their work and the lack of availability of experts over the summer period. In addition, it should be noted the Panel is made up of industry experts, not academic experts, and therefore the review focused on the weight of evidence and practicalities of proposals made, rather than a critique of the science.

Any evidence review is only ever a snapshot in time. The science of carbon sequestration on land is emerging all the time and evidence should be regularly reviewed to ensure that the SFS stays up to date with the latest techniques.

The review looked at actions proposed in the SFS consultation document and identified within the Terms of Reference as having the potential to sequester carbon. These were:

• UA13: Create new woodland and agroforestry 
• UA11: Hedgerow Management
• UA12: Woodland Maintenance
• UA7: Habitat maintenance 
• Scheme Rule 2 (SR2) requires at least 10% of suitable land to be under tree cover as woodland or individual trees by 2030

In addition to reviewing the SFS UA’s proposed by Welsh Government, the Panel reviewed the evidence from experts on a range of alternative or additional measures to sequester carbon including:

• soil organic carbon 
• liming and pH
• multispecies leys
• rotational grazing
• foliar feeding
• deep cultivation
• slurry and farmyard manure (FYM) treatment (including Bokashi)
• enhanced rock weathering
• peatlands
• biochar 
• biomass crops 

The Panel compiled the evidence they heard and read on each of the topics above. They assessed each proposal against a set of criteria, including appropriateness for Wales, scalability, appropriateness for all farm types and strength of evidence. This approach enabled an overall assessment for each of the proposals. 

In this report, the Panel offers its opinion on the evidence received before setting out the recommendations for the SFS that arise from this analysis. The report also includes a number of reflections and recommendations on the wider policy context in which the SFS is being developed.

Panel recommendations

The views presented in this report represent the majority view of the Panel. 

Although the Panel review focused on carbon sequestration actions on farm, taking a pragmatic approach they did not wish to exclude wider discussions in respect to emissions avoidance, reduction and sequestration. As a result, a number of recommendations emerged that are relevant to the wider policy context.

SFS and the principle of universality

The Panel heard from a range of experts and it is clear that there is no one ‘silver bullet’ or ‘one size fits all’ solution for carbon sequestration on Welsh farms. This is a highly complex field dealing with biological systems; the effectiveness of actions is often dependent on a range of factors; and, in many instances, the science is emerging. There are also interdependencies, overlaps and unintended consequences between actions for carbon sequestration and other processes, for example, biodiversity. 

Recommendation

1. In this context, the Panel recognises and supports the Welsh Government’s overarching framework for the SFS based around three layers including a Universal Action layer for which participating farmers will receive a Universal Baseline Payment for the delivery of a set of Universal Actions. The Panel emphasises that, in the context of achieving carbon sequestration on Welsh farms, the SFS Universal Action layer must be designed to take account of this inherent variability so as not to act as a barrier to scheme participation. 

Emissions reductions

It is widely accepted that net zero agriculture will require a range of actions to reduce production related emissions, increase on-farm carbon sequestration and increase renewable energy generation. 

Evidence and expert presentations routinely referred to the interdependencies between actions to sequester carbon and their varying impact on the three farm-level emissions (methane (CH4), nitrous oxide (N2O) & carbon dioxide (CO2)), in addition to wider country or global emissions. The Panel accepts that the root cause of the focus on carbon sequestration is due to the high level of global greenhouse gas (GHG) emissions, however, given the interdependencies it has been challenging and is arguably inadvisable, for the Panel to consider actions using carbon sequestration as the only metric. 

One Wales-based study on beef and sheep farms referred to the ability to reduce emissions on average by 28% applying only 5-7 abatement measures. Naturally, if emissions are reduced, the need for additional carbon sequestration is reduced, at both farm-level and wider country-level. Therefore, whilst not in the direct remit of the group, it was important to consider how these actions would influence agriculture’s GHG position (see baselining and GHG inventories) and the wider carbon leakage threat of offshoring food production. 

Recommendation

2. Alongside carbon sequestration, the Panel believes that opportunities for emissions reductions through production efficiencies should be a key element of the SFS, complementing wider government policy and targets for GHG reductions. Improving resource use efficiencies on farms will be key to this.

Farmer decision-making

The strength of feeling that surrounds the 10% tree cover scheme rule, in particular, is well documented. This has been presented within the analysis of responses to successive SFS consultations, including the analysis of consultation responses undertaken by [2] Miller Research. In this context, the Panel welcomed the insight provided within the evidence submissions that focused on the behavioural questions of what carbon sequestration measures farmers are most willing and able to adopt. The evidence shows that supporting behavioural change on any issue requires consideration of a range of factors. In respect of the introduction of on-farm environmental measures, this includes the fit into production priorities and existing practice. There are also wider practical barriers including capital and lost opportunity costs where land use change is involved (through tree planting, for example) that the policy response needs to recognise and address. 

The Panel acknowledges the current exercise of mapping existing tree cover on farms using the latest data. This, it is believed, will significantly aid farmer engagement in the existing carbon assets on their farms and should be undertaken and shared with individual farms as soon as possible. 

Recommendations 

3. Overall, it is clear from the evidence that an understanding of the behavioural insights into farmer decision-making and practice is of central importance in land use policy development and is going to be critical in the next phase of SFS design.
4. The Panel identifies that enhanced communication with the sector over further carbon sequestration actions will be critical, including the co-benefits.

Statutory and policy obligations

The Panel recognises the legislative context and climate change commitments made by Welsh Government. 

The specific climate change targets in relation to carbon sequestration and their read across to the SFS are considered in the full report. However, the Panel has examined the Climate Change Committee’s (CCC) advice and Welsh Government’s Carbon Budget Plan and wish to draw attention to the flexibility embedded within these policy statements. The CCC describes the balanced pathway as ‘not a prescriptive path that must be followed exactly’. Welsh Government, through Carbon Budget 2, refers to generating a set of ambitions and actions which better reflect the geography, culture and economy of Wales. 

Recommendations 

5. On this basis, whilst the Panel recognises the unique role of farming as both a carbon source and sink in addressing climate change, the inherent flexibility provided by the CCC and Carbon Budget 2 is clear and the SFS should be developed in this context. 
6. As part of this review, the Panel has considered a vast amount of evidence and recommend that the review findings should be shared with the CCC to inform the development of future advice to Welsh Ministers.

Just transition

The CCC advice also includes recommendations around a just transition and a fair distribution of costs. The CCC is clear that climate action on Welsh land needs to be balanced with other essential functions and competing demands, including maintaining food production, climate change adaptation and biodiversity. The risks of investment that could potentially lead to undesirable large-scale changes in land ownership are also recognised. Welsh Government’s Carbon Budget 2 also points to the need to embed fairness across all aspects of the carbon budget plan. 

Recommendation 

7. The need for a just transition cannot be overstated. The Panel concurs with the CCC that meeting net zero will have most success where people are involved in developing proposed solutions and the work of the Panel must be seen as an important first step in this process. An ongoing commitment to partnership working with farming is going to be needed. 
8. To ensure a just transition, the Panel also supports an approach to scheme development that recognises that no farming system or size should be disadvantaged. 

Universal baselining 

The Panel recognises that every farm is unique and is starting the journey from a different place, with different opportunities to contribute to net zero. For individual farmers determining the starting point or baseline is, in itself, a difficult process given the complexity and lack of standardisation of the carbon audit tools available on the market. This limits confidence in the results and hinders the on-farm action needed to make progress. The SFS has a key role supporting farmers to better understand their own farm carbon balance, as well as the impact of changes in farming practice and uptake of techniques to both increase opportunities for carbon sequestration and reduce greenhouse gas (GHG) emissions. 

Recommendations 

9. At farm level, the Panel recognises that understanding the baseline is a public good and is key to driving on-farm action. Critical to the integrity of the data is the need for both emissions and sequestration data to operate at tier 3 (actual on-farm data) rather than using calculations that use national or international averages. The Panel, therefore, strongly recommends that baselining should be rewarded as a Universal Action within the Sustainable Farming Scheme and acknowledged in the payment rates. Baselining needs to be simple for the farmer to undertake using data already collected.

GHG inventories

The Panel learned that Welsh statutory commitments and carbon budgets are based on GHG inventories that are reported to the United Nations Framework Convention on Climate Change. It is important to recognise that farming activity is captured across a range of internationally recognised inventories. Despite the contribution of Welsh farms as carbon sinks and, in many cases, as generators of renewable energy, these contributions are accounted for separately to the inventory for agriculture. 

Recommendation

10. The Panel notes the challenges of reflecting farming’s contribution in international GHG Inventories. At Wales-level, on-farm actions across the agriculture, Land Use, Land Use Change & Forestry (LULUCF) and Energy Inventories should be measured, understood and clearly communicated to reflect Welsh farming’s contribution in the round.

GHG measurement

Being able to measure greenhouse gases is an important part of net zero journey and the Panel understands the different effects that different GHGs have on climate change linked to their Global Warming Potential (GWP). The shortcomings of GWP100 (the accepted metric for describing the warming impact of GHG) are particularly pertinent in the Welsh context where livestock farming predominates. 

Recommendation

11. In line with the Intergovernmental Panel for Climate Change (IPCC) position on this matter, the Panel recommends that calculations for international reporting consider both the GWP and the GWP* methodology which more accurately reflects the impact of methane as a short-lived gas. 

Delivering the SLM objectives

The Panel notes the Agriculture (Wales) Act 2023 provides the framework to support farmers to mitigate and adapt to climate change as one of the four SLM objectives. The Panel notes that Welsh Ministers must consider all four SLM objectives during the exercise of their duties, echoing the Well-Being of Future Generations Act which requires public bodies to consider economic, environmental, social and cultural well-being. 

Evidence shows that total emissions from agriculture declined by 10% between the base year (1990) and 2019, driven largely by a general decline in livestock numbers and nitrogen fertiliser use. The Panel learned that since 2019 livestock numbers have reduced further – a trend mirrored across the UK. This has potential consequences for the sector which plays a key role in the economy of Wales providing significant employment in both rural and urban areas. 

The Panel also received evidence which highlighted the issues of [3] carbon leakage and is clear that whilst an overall reduction in livestock numbers in Wales may be reflected in inventory reporting as positive progress towards net zero, this is not the case where production has been offshored, particularly to where emissions per unit of production are higher. 

Recommendations 

12. In line with the Agriculture (Wales) Act, the role of the SFS in contributing to the delivery of all four objectives, including sustainable food production, should be considered. Modelling of all Universal Actions is needed to understand their GHG mitigation, carbon storage and sequestration potential. The modelling should also consider economic, social, cultural and wider environmental impacts and carbon leakage effects, recognising that carbon is one metric of sustainability. 
13. The Panel also identified the need for modelling to be supported by a dynamic governance structure that drives a more comprehensive modelling and monitoring programme of the effects of the scheme, with the specific addition of social, cultural and economic analysis (including post farm gate effects) alongside environmental change reflecting the commitments of the Agriculture (Wales) Act. 

[2] Sustainable Farming Scheme: consultation analysis report

[3] Definition of carbon leakage:  Where reducing greenhouse gas emissions in one location increases emissions in another location.

In line with the Terms of Reference, the Panel sought to compare and contrast this Scheme Rule with alternative / additional actions to sequester carbon and noted that achievement of this target offsets 4.7% of modelled baseline agricultural emissions by the year 2100.  This compared to the contribution of soils and peats which could offset 5-10% of emissions and ‘perfect’ farm management which the Welsh Government reported could deliver reductions of 1.8 Mt – or 36% - of agriculture’s 5 Mt contribution. 

The Panel concludes that there are comparable actions to tree cover targets that deliver at least equivalent levels of carbon sequestration. The challenge lies in how these comparable actions can be designed as Universal Actions within the Universal layer of the scheme.

The Panel also examined the universal applicability (i.e. appropriateness on all Welsh farms) of a tree cover scheme rule. The Panel acknowledges that universal applicability is a challenge for all carbon sequestration actions. It was identified that the effectiveness of tree planting as a carbon sequestration action is dependent upon a range of site specific and management factors. The Panel heard that mandatory tree cover targets could lead to unintended outcomes and that the carbon leakage associated with afforestation of agricultural land should also be considered. 

The Panel also noted that creating new woodlands results in a one-off (finite) increase in carbon stocks and not permanent, ongoing carbon sequestration per se. The permanence of carbon capture is also associated with the product derived from the woodlands, and this needs to be considered as part of the management of woodland creation. The carbon sequestration is reversible, as with most of the options considered by the Panel.   

Tree planting on Welsh farms

The Panel acknowledges the evidence of the positive benefits (carbon sequestration and wider benefits) that trees within agricultural systems can provide in line with a right tree, right place approach. 

From a carbon sequestration perspective, evidence shows that agroforestry / silvopasture systems encompassing hedgerows, shelterbelts, riparian woodlands and single or groups of trees in pasture and crops and on less productive areas of the farm are effective in both preserving carbon stocks and locking up carbon successfully alongside the production of food. 

Recommendation

14. On the basis of the evidence that the effectiveness of tree planting as a sequestration action is dependent upon a range of site specific and management factors and including a degree of social science, the Panel do not support a mandatory tree cover Scheme Rule within the SFS as it is likely to deter participation and the delivery of wider SLM objectives.  
15. The Panel recommends that within the SFS and in broader policy, the Welsh Government address the barriers to tree planting on Welsh farms that are currently contributing to an underachievement of tree planting targets. This includes the costs (both capital and longer term (lost) opportunity costs that are seen to arise from land use change) and poorly developed local markets, recognising that funding will be needed beyond CAP replacement funds.
16. Farms that have already undertaken work and have trees on their farms should be recognised in line with the Panel recommendation  that the SFS should reward existing actions that sequester carbon. 
17. Given the effectiveness of tree planting is dependent on a range of factors and the high costs (including upfront capital and lost opportunity costs associated with land use change), the Panel supports moving UA13: Create new woodland and agroforestry to the SFS Optional Action layer. 
18. The Panel recommends that the SFS provides opportunities and rewards to farmers to facilitate uptake of agroforestry / silvopastoral / silvoarable approaches on farm where appropriate.

Other options for further review  

• to review the restocking conditions attached to creation of woodlands, so that planting of silvopasture would allow for thinning and removal of trees planted to revert back to pastureland eventually if required
• application of biochar to trees at planting to further increase carbon sequestration levels
• note the opportunities that exist through targeted planting for co-benefits, such as flood mitigation, water/nutrient run-offs, and livestock shelter
• recommend that Welsh Government considers terminology around trees (using silvopastoral and silvoarable rather than agro-forestry)

The Panel noted that the carbon sequestration associated with the precise requirements of this Universal Action had not been modelled by the ERAMMP programme. 

It is also important to note that the specific requirements of this Universal Action proposed by Welsh Government (i.e described as good condition) have not been considered by the Panel. Detailed feedback can be found in the respective consultation responses of each organisation on this proposal. 

The Panel noted that ERAMMP modelling and wider evidence did, however, clearly show that hedgerows have a carbon sequestration function on Welsh farms. The Panel acknowledges the multiple benefits that hedgerows provide and there is consensus that hedgerows in all their diversity are an important and valued feature common to most Welsh farms which should be proactively supported through the SFS.

Recommendation

19. The Panel recommends a stronger emphasis on the carbon sequestration of ‘hedges and edges’ within the SFS Universal layer, recognising the multiple benefits they provide. The overall scheme should prioritise a range of management options and ongoing maintenance techniques to enhance carbon sequestration.   
20. The Panel also recommend that the scheme should focus on hedgerow creation within the Optional Action layer.

Other options for further review 

• the Panel recommends that the potential of coppicing hedgerows to produce on farm biochar be further explored, which could create a fully sustainable hedgerow management system
• one management technique the Panel heard evidence on worthy of consideration is incremental cutting, to gradually increase the size of hedges to thicken the hedge and increase above ground carbon storage

The Panel did not review ERAMMP modelling of UA12 Woodland Maintenance, therefore it was not possible to enable direct comparison., However, the Panel received evidence that shows that management can make a contribution to the rate of carbon sequestration in existing woodlands. On this basis, the Panel is supportive that proposals for woodland management to be included alongside other actions that sequester carbon within the Scheme. The Panel also recognises the opportunity to bring small scale farm woodland into active management. 

Recommendations

21. The Panel would recommend support and training for farmers for woodland management, support to create access tracks for the management of woodlands, as well as market development for small scale timber, woodland product development, and biomass, in the Optional and Collaborative Action layers of the scheme.
22. Farms that have already undertaken work and have trees on their farms should be recognised. 

The Panel learned that semi-natural habitats in good condition are generally in a stable carbon flux. The Panel received limited evidence on the ability to increase carbon sequestration within habitats, as research is generally focused on the biodiversity benefits of habitat management. Therefore, it is more appropriate to focus on protecting the existing soil carbon store within habitats.

The Panel noted that the range of habitats supported under UA7: Habitat Management went beyond semi-natural habitats and included habitats such as traditional orchards, wood pasture and in-field trees. These features have a carbon sequestration benefit.

The Panel also received evidence that shows that habitat ‘creation’ or restoration which either increases woody biomass cover (hedgerows, dwarf shrub cover etc) or increases soil carbon sequestration (floodplain meadows, low input species rich pastures, buffer strips in arable fields), particularly on more intensively managed land, has more potential to increase above and below ground carbon. However, this can have production implications as reflected in the industry’s concerns to the 10% habitat proposal. 

Recommendation 

23. The Panel concluded that habitat creation or restoration could therefore be considered an additional carbon sequestration action and should be supported through the Optional Action layer, with a particular focus on grassland habitat restoration and creation.

Evidence shows there are a range of comparable carbon sequestration actions suitable for Welsh farms with ranging levels of permanence, timescales of effectiveness, scalability, costs, benefits and trade-offs. Every farm is different and will have different opportunities to work towards net zero. In this context, whilst acknowledging the principle of universality, the Panel recommends a suite of carbon sequestration Optional Actions are prioritised within the SFS, outlined below. The actions listed are those which the Panel received evidence on and considered. The list should not be seen as exhaustive and the Panel noted that science and technology was emerging all the time. 

The Panel noted that many of the evidence submissions focused on soil carbon, and the potential to either increase soil organic carbon or lose it via management practices. A range of practices were discussed including enhancing mychorrhizal fungi, grazing management, minimum tillage, multi-species leys and deep rooting plants, nitrogen fixing legumes, fertiliser applications – organic and inorganic, liming and cover crops. The importance of protecting existing stocks was emphasised, however there was a mixture of opinions and research on the carbon ‘saturation’ or equilibrium point of soils and to what extent soil organic carbon could be increased in soils with existing high levels.

However, the evidence was clear on the numerous co-benefits to high levels of soil organic carbon: namely soil health, biodiversity, water infiltration, biomass production and nutrient retention. In relation to carbon storage, soil can be considered a more permanent and stable store than above ground vegetation. Whilst the ERAMMP showed no current significant changes in soil carbon tested to 15cm depth over the last 50 years in Wales, the Panel received evidence of trials which demonstrated the ability to increase the soil organic carbon equilibrium. The increase potential is dependent on soil characteristics and past management practices. 

Recommendations

24. The Panel recommends that the SFS should play a role in incentivising the management practices which both protect existing stores and increase sequestration levels in soils. Furthermore, given farmers’ interest in soil carbon, the scalability of these management practices and their numerous co-benefits, these soil carbon actions have the potential to be very impactful across Wales. This also applies to the proposed Universal Actions around baselining, Continuing Professional Development (CPD) and soil health planning proposed within the SFS. 
25. The Panel recommends that further Wales-based trials and research should be undertaken to address the ‘saturation’ concern and consider actions to improve the permanence of soil organic carbon levels.
26. The Panel recommends that Welsh Government makes improvements to its soils monitoring programme to ensure it meets United Nations Framework Convention on Climate Change (UNFCCC) compliant standards to assess soil carbon to a minimum of 30cm, recognising that good practice involves sampling to 1m or the bedrock.

Given this interest, and as per the evidence presented by leading academics in this field, the additional actions to sequester carbon considered by the Panel below are largely focused on soil carbon. The Panel was clear that as implementing many of these actions do not require a permanent land use change, nor a significant reduction in food production, they are arguably easier and more appropriate to implement on-farms than other carbon sequestration actions. 

Diverse & deep rooting leys

The Panel received evidence on how plant diversity and root depth can increase soil organic matter and soil organic carbon, in addition to storing carbon at deeper depth and therefore with improved permanence. There are two ways of achieving this; via reseeding ‘multispecies leys’ into arable rotations and species-poor improved pastures, or through management practices which enhance diversity and rooting depth in permanent pastures. Numerous co-benefits include improved soil health, biodiversity through species and structural diversity, and production and animal performance. There are concerns about the carbon (and fungal) implications of cultivating land to reseed multispecies leys, therefore, as with all of these actions, they are farm and context dependent. 

Recommendation

27. The Panel recommends support for:
    • new multispecies leys 
    • over-seeding legumes and herbs into existing agriculturally modified swards
    • management and grazing practices which increase species diversity and rooting depth in permanent pastures 

These should be implemented within the SFS Optional Action layer.

Other options for further review  

• the perceived benefits in regard to livestock production efficiencies are undeniable, although these could be investigated further
• the plethora of co-benefits must be considered in full i.e. increased soil organic carbon, improved water infiltration and retention, reduced flood risk and drought resistance, improved water quality (in certain areas), increased biodiversity, reduced need for manufactured fertilisers, etc

Rotational grazing

The Panel received evidence from numerous studies and field trials showing how ‘graze and rest’ management (rotational, cell, mob) was shown to increase soil organic carbon in pastures, in comparison to set-stocked management. Whilst much of Wales is under permanent pasture with existing high levels of soil organic carbon, these studies showed how the ‘saturation point’ or equilibrium can be shifted under certain management conditions, not dissimilar to adding compost to soils - essentially focusing on returning more organic matter than is degraded during a grazing cycle to create a net carbon gain. The co-benefits of rotational grazing are well evidenced, including improved soil health, grass production, animal welfare and biodiversity benefits. Furthermore, it has a role to play in reducing wider GHG emissions via reduced fertiliser use and purchased feed. Implementing 'graze and rest’ systems can require additional fencing materials and corresponding infrastructure, however the appropriateness and scalability of this action for carbon sequestration is high in Wales due to Wales’ world leading grassland management and livestock skills. Implementing a rotation on open mountain, common land and certain habitat land or topography are more challenging, and thus the SFS scheme design would need to reflect this. 

Recommendation

28. Due to the existing evidence and the scalability for Welsh agriculture as a pasture-based livestock sector to adopt rotational grazing methods which increase soil organic carbon, this action should be supported within the SFS Optional Action layer across part of the grazing area. Corresponding advice, financial incentives and capital infrastructure will also be required to support the implementation of this action.

Peatlands

The Panel received evidence on how peatlands are managed can result in either net emissions, emissions avoidance or net sequestration. The storage capacity and permanence of carbon in peatlands represents the most effective carbon stores in the biosphere, out-performing standing forest and mineral soils. Initial restoration of damaged peatlands can be expensive to implement (rewetting, re-profiling and clearing vegetation) and therefore requires capital support to the farmer/landowner. However, the machinery and techniques needed are well established in Wales. There is also a balance where methane emissions are increased during peat formation due to anaerobic conditions. Co-benefits of peatlands in good condition include high levels of biodiversity and flood alleviation via increased water storage capacity. Furthermore, food production via sensitive livestock grazing can also continue on restored peatlands, albeit with reduced dry matter production, thus reducing carbon leakage. 

Recommendations

29. Peatlands are evidently key to Wales, representing one of the biggest abatement potentials, therefore those with peatlands within the SFS should receive support for restoration and/or maintenance and management via the Optional Action or Collaborative Action layers where appropriate. 
30. Further work on identifying and enhancing shallow peat and blanket bogs in Wales should be undertaken, particularly to ensure inappropriate tree planting as part of the SFS does not occur on these soils which could inadvertently release carbon, noting that tree planting is not permitted on peat deeper than 50cm.  
31. Further research could also be undertaken on applying biochar and iron sulphate to peat which could suppress CH4 and N2O emissions and increase carbon sequestration rates.

Other options for further review  

• the Panel noted that restoring lowland peat has different challenges and will need a different approach

Biomass crops 

Biomass crops are part of the CCC’s land use recommendation for achieving Net Zero in Wales. The benefits are wider than on-farm carbon sequestration and include opportunities for Bioenergy with carbon capture and storage (BECCS), displacement of fossil fuels via bio-energy production, and displacement of energy intensive materials. Certain crops can work on lower land classifications, thus increasing its scalability in Wales (notwithstanding EIA regulations, protecting habitat land and establishment costs). There appears to be a lack of consensus around increases to soil organic carbon under biomass crops. However deeper rooting and perennial crops can offer flood-alleviation benefits, and no need for fertiliser or additional inputs, alongside income diversification for farms. 

Co-benefits include flood mitigation and reduced fertiliser needs however potential trade-offs with food production and biodiversity were identified.

Recommendations

32. Growing and harvesting biomass crops is not appropriate or financially viable on all farms, and therefore not appropriate as a Universal SFS Action. However, due to its ability to sequester carbon into vegetation (and soil to a lesser extent), it should be included alongside tree planting to offer flexibility in the range of carbon sequestration options available to farmers enabling them to grow miscanthus, willow or other short rotation coppices as opposed to permanent tree cover.
33. Barriers to its scalability within Welsh supply chains should be explored to achieve wider GHG mitigation benefits and support to landowners.

Other options for further review 

• when considering carbon sequestration potential in isolation, more carbon will be sequestered in biorenewable products than biomass crops used for fuels and energy. However, biomass crops should be considered for their potential to help decarbonise energy production, while also providing an additional income stream for farmers, and a tool for farmers to mitigate flood risk

Whilst producing a well oxygenated nutrient rich slurry or a well composted FYM does not represent a direct carbon sequestration action, co-benefits of these treatments include soil organic matter increases, artificial fertiliser use reduction, ammonia emission reduction and improved soil microbial health, thus having an indirect and positive effect on agricultural GHG mitigation and carbon sequestration in soils. The Panel believe knowledge transfer in these techniques and products will be essential to their uptake. These applications could be appropriate for all farms dealing with slurry or FYM, dependent on government support for the cost of the treatment and further trials and evidence. 

Recommendations

34. On the strength of the evidence presented to the Panel Slurry treatment and microbial FYM treatment is not being recommended for inclusion as a direct carbon sequestration action within the Universal Action layer of the scheme. However, the Panel noted its benefits for soil health and its positive impacts for soil carbon alongside emission reduction benefits.

Liming and soil pH

Maintaining optimum pH in agricultural soils has been best practice for decades. In regard to carbon, for grassland systems on mineral soils a soil pH of 6 or more will, generally, facilitate higher levels of soil organic carbon, although research is not clear to what extent. This is due to the increased biological activity from liming which enables plant carbon to be better incorporated into the soil organo-mineral pools, thus increasing soil carbon. Co-benefits include increasing the availability of nutrients and crop growth, thus reducing the need for inorganic nitrogen fertiliser, alongside improved water infiltration. However, there is an emissions factor involved in the quarrying and transportation of lime, nor is it appropriate for soils with very high organic matter/peatland. The Panel noted that identifying pH is also incorporated into the proposed Universal Action on soil health planning (UA3)

Recommendations

35. On the strength of the evidence heard by the Panel, liming and soil pH is not being recommended for inclusion as a carbon sequestration action within the Universal Action layer of the scheme. However, the Panel noted its benefits for soil health and its likely positive impacts for soil carbon. 
36. There should be more emphasis on soil health and correcting soil pH in nutrient management plans, where appropriate.

Foliar feeding

Foliar feeding is a more efficient method to applying nutrients to plants than granular or liquid fertilisers, aimed at addressing some of the  potential impacts of artificial fertilisers to soil health, whilst improving the plant’s ability to take up nutrients. It is considered an emissions reduction method (via significantly reduced artificial fertiliser use, and subsequent reduction of nitrate leaching or ammonia emissions) but as it is connected to soil organic matter, it is likely to have a subsequent positive impact on soil carbon. The capital costs of specialist machinery or the ability to adapt existing machinery is a barrier, therefore, the Panel is supportive of capital support within the SFS. 

Recommendations

37. On the strength of the evidence heard by the Panel foliar feeding is not being recommended for inclusion as a carbon sequestration action within the universal layer of the scheme, at this time. However, the Panel noted its benefits for soil health and its positive impacts for soil carbon.

Other options for further review

• in conducting its review, the call for evidence was focussed on carbon sequestration and did not include carbon emissions reduction, and therefore the volume of evidence specifically on this area was not gathered.  The Panel identified this action has potential for emissions reductions

Deep cultivation/sub-soil carbon storage 

The Panel heard that the vast majority of soil carbon research focuses on topsoil, whereas subsoils may have a greater ability to store carbon with greater permanence and stability. The reduced microbial activity in subsoils also reduces the ability for carbon to be re-released. This could be done in fields via a one-off deep cultivation, potentially accompanied by a simultaneous deep burial of biochar or basalt. 

This practice may not be achievable or appropriate to shallow soils.  Wider benefits could include increased plant yield in soils where ameliorating subsoil constraints can occur at the same time (e.g. mixing with lime; uplift of subsoil CaCO3; improved aeration, compaction alleviation), or where existing surface soil problems (e.g. herbicide-resistant weed seeds) become buried at sufficient depth to remove this constraint to crop production.

Recommendations

38. At this stage the Panel have strong reservations regarding deep cultivation, and it should not be considered an SFS Universal Action. However, due to its potential to increase stable carbon storage in ‘saturated’ topsoil under permanent pasture, further research should be brought forward for it be considered as a future action. The science points to the use of deeper rooting plant species to encourage carbon at deeper soil depths as more appropriate. 

Other options for further review

• to be considered in conjunction with the deep burial of biochar, basalt / rock dust and lime

Enhanced rock weathering

Enhanced rock weathering (ERW) has been extensively modelled as a long-term carbon sequestration and storage action with great potential, however testing at field-scale is still in early development, particularly in an upland Welsh context. The co-benefits to soil health are promising, which could offer Welsh agriculture the ability to reduce artificial fertiliser rates alongside increased carbon sequestration, using existing on-farm machinery for spreading the material (generally basalt). Research is ongoing however to determine if there are any nutrient leaching issues. 

In terms of its appropriateness in Wales, ERW is most efficient at sequestering carbon in humid climates, therefore our wet weather may be beneficial. However, it would appear that transportation costs and high application rates are a barrier to scalability in Wales, in part dependent on the proximity of quarries with basalt stockpiles available to farms. Research also indicates a higher sequestration potential on arable land as opposed to pasture/grassland.

Recommendations

39. Due to the early stage of field-scale research and practical application barriers, the Panel do not believe ERW is appropriate in the Universal Action layer of the SFS but could be positioned within the Optional or Collaborative Action layer in the future once further field-trials are analysed, and monitoring, reporting and verification improved. 

Other options for further review

• Welsh Government should also consider the wider policy and regulatory implications around ERW, for instance due to the commercial carbon market interest in ERW which is outpacing research

Biochar

The Panel heard about biochar’s ability to lock up carbon from biomass for thousands of years in soil in a stable form. Furthermore, it ranks highly with farmers as a potential carbon sequestration measure, possibly due to the additional benefits it can bring to soils such as increasing pH, improving water holding capacity and nutrient exchange between plant and soil. However, UK-based and long-term research data is limited, particularly in relation to grassland systems. Further barriers include cost and rates / tonnage of application, regulation / permitting and the availability of suitable feedstocks in Wales within a close radius of production. 

Recommendations

40. Due to the evidence and scalability barriers outlined above, the Panel do not believe that biochar is appropriate as an SFS Universal Action. However, its variety of co-benefits and farmers’ willingness to trial biochar should warrant further Welsh and grassland-specific research including potential co-benefits and disbenefits, a review of the regulatory and supply chain barriers to improve scalability, and farm-based pilots which also consider financial and practical implications.

Other options for further review

• priority to be revisited as more scientific work becomes available and replicated. 
  Consider any necessary regulatory framework/standards for application within Wales. Potential for trialling/piloting

The Panel supports Welsh Government’s overarching framework for the SFS based around three layers including a Universal Action layer, however, the Panel’s review of the evidence has shown that there is no one ‘silver bullet’ or ‘one size fits all’ solution for carbon sequestration on Welsh farms. 

Every farm is different and will have different opportunities to sequester carbon and reduce emissions through production efficiencies and for this reason the Panel recommends that baselining should be rewarded as a Universal Action within the Sustainable Farming Scheme. 

The Panel is clear that the evidence does not support a tree cover Scheme Rule for every farm participating within the Sustainable Farming Scheme. In fact, this is likely to deter participation and the delivery of wider SLM objectives. 

The Panel determined that the existing carbon sequestration actions at the Universal Action layer of the scheme do sequester carbon, although to varying degrees and their potential can be enhanced in line with the Panel recommendations referred to above. 

Panel recommendation for the SFS Universal Action Layer

• New UA: Baselining
• UA11: Hedgerow management 
• UA12: Woodland Maintenance
• UA7: Habitat Maintenance

The Panel recognises the contribution that a number of other Universal Actions will play in driving data-led decision-making for climate action, including carbon sequestration, including:

• UA1: Benchmarking
• UA2: CPD
• UA3: Soil Health Planning

Following the review of the evidence, the Panel have identified a range of alternative / additional actions that can be undertaken on farms to sequester carbon. However, from the evidence supplied, direct comparison and scalability from a Welsh perspective is difficult. As with the existing carbon sequestration UAs, their effectiveness is related to a range of site specific and management factors. 

The evidence presented by leading academics points to the potential of soils as carbon sinks with the potential for management changes to sequester additional carbon. The Panel noted that implementing many of these actions do not require a permanent land use change, nor a significant reduction in food production. They are, therefore, likely to be easier and more appropriate to implement on Welsh farms than other carbon sequestration actions. 

The Panel identified a suite of actions that sequester carbon which can be undertaken within the SFS and prioritised within the Optional Action layer. In no particular order, these are: 

• create new woodland and agroforestry
• managing existing woodland 
• hedgerow creation
• habitat restoration and creation
• diverse and deep rooting leys
• rotational grazing
• peatlands
• biomass crops

Noting the interdependencies, the Panel believes that opportunities for emissions reductions in production should be a key element of the SFS, alongside carbon sequestration. Wider actions immediately implementable with associated soil health and soil carbon benefits include:

• slurry and FYM treatment 
• liming and soil pH
• foliar feeding

Actions identified by the Panel as having potential for carbon sequestration but requiring more research and on farm trials prior to being included within the SFS Optional Action layer included:

• enhanced rock weathering
• biochar
• deep cultivation / sub-soil carbon storage

The Panel wish to express their deepest appreciation to all of the expert witnesses, who took time to prepare verbal or written evidence for the Panel during the course of their review. 

The Panel are also extremely grateful to Welsh Government officials and staff who supported the secretariat function of this review exercise and those who contributed to expert sessions on the ERAMMP modelling. 

The Panel wish to also acknowledge the important role and contribution of their shadow technical staff throughout the course of this review. 

The Panel also wish to express their sincere thanks to PhD student Emily Holmes, for their support to finalise the report structure, formatting and content.