Sustainable soil management is a particular challenge as Scotland adapts to a changing climate, and has been highlighted by the Adaptation Sub-Committee, in its UK Climate Change Risk Assessment 2017. Soil compaction and erosion have been identified as being important, particularly in exacerbating flooding impacts and decreasing soil carbon storage.

This report collates the current state of confident knowledge for Scotland – what we know, what we don’t know and what is under active debate.

Key findings

  • Much of what we know about erosion rates on agricultural land in Scotland comes from a few, individual studies of erosion events, but there is a growing body of evidence that can be used to examine the role of land use (both current and historic), soil type and slope on erosion susceptibility. Other factors such as antecedent moisture content, ground cover and presence of tramlines also play a role, making it difficult to be certain when, or if, erosion will occur.
  • Soil erosion models with sediment yield as an output seem to exaggerate the amount of soil loss and are difficult to validate, although they do offer a way to examine the relative changes in erosion rate under different land uses and changing climates.
  • There is a link between soil compaction and erosion; soils that become compacted have a restricted capacity to store rainfall and generate overland flow more quickly than soils that are not compacted. This overland flow can then cause erosion.
  • The greatest driver of soil compaction is machinery weight, which has been increasing over the past few decades, although using wide tyres, dual wheels and low pressure tyres can reduce the impact.
  • We have a better understanding of field level effects with evidence gathered in Aberdeenshire following storm Frank (December 2015) suggesting erosion seemed more prevalent in areas that were more intensively managed.

Agro-forestry is the integrated use of trees on a farm or small holding for a wide range of benefits.  The Scottish Government has set statutory targets for the reduction of GHG emissions in Scotland through the Climate Change (Scotland) Act 2009. Agroforestry in Scotland is one option that could help achieve these targets, while also supporting sustainable adaptation to a changing climate.

This report identifies the wide range of potential benefits of increasing the use of agroforestry practice in Scotland and will support further discussion towards implementation.

The boundary between productive land and hill land in Scotland has moved over time, in response to climate and also to market demand. Scotland’s climate is changing, and this will mean changes for those areas of Scotland that sit on the margins of productive agriculture.

In this context sustainable soil management is a specific challenge as Scotland adapts to a changing climate.

This report examines the four dominant ways that farmers will adapt to climate change, and their impact on different services.

Key findings:
  • It is likely that land use change will result in the intensification of land management. The result would be a reduction in most aspects of natural capital including soil carbon, water quality and biodiversity. An increase in arable cropping from current levels and a switch to winter cereals could increase soil erosion and flood risk.
  • An exception would be the potential increase in forestry and woodland, though the benefits of planting depend greatly on what is planted and where it sits within the landscape or catchment.
  • It is particularly difficult to assess the likely changes in livestock numbers. This makes it difficult to assess the greenhouse gas emissions from their rearing, as it is not possible to predict the balance of their removal to allow arable cropping, the increase in extensive livestock management which would affect emissions intensity, and the intensification of management on currently more marginal ground.
  • One approach to assessing the risk of autonomous adaptation would be to model the impacts of a set of scenarios of change so that comparison could be made with changes expected from other drivers; if potential impacts are large in comparison then greater attention would need to be given to strategies to avoid or mitigate impacts.

This project looked at improving the measurement of the GHG emissions intensity of the main agricultural commodities at a national level. 

The Scottish Agricultural Emissions Model (SAEM) calculates the amount of commodity produced per herd/flock or per hectare of crop and the GHG emissions arising from this production. The emissions intensity of the commodity can then be calculated.

SAEM complements the UK GHG Inventory by providing estimates of the emissions intensities of the main agricultural commodities in Scotland. SAEM uses the IPCC’s widely accepted and transparent Tier 2 approach to calculating GHG emissions, which has a clear scientific rationale as is consistent with the UK GHG Inventory approach.

Using SAEM does require a moderate knowledge of MS Excel and some familiarity with agricultural processes and the emissions arising from them. SAEM is therefore not intended for use by the layperson or occasional user but provides experienced users with significant scope for investigating the drivers of agricultural emissions.

We derive a wide range of benefits from how we use the land; it underpins our economic prosperity, supports the provision of essential supplies of food and clean water. Its sustainable management is essential to how we reduce our greenhouse gas emissions, and adapt to a changing climate. 

‘Payment for Ecosystem Services’ schemes have been developed in a broad range of areas that seek to support good environmental management. Common to all the schemes is that they take a voluntary approach to offering financial incentives to land-managers for actions that maintain or enhance services that are not routinely bought and sold or provided through regulation.

The characteristics of different ‘Payment for Ecosystem Services’ schemes vary considerably. For the purposes of meeting climate change needs, ‘Payment for Ecosystem Services’ has substantial potential but with several key issues:

  • The degree to which participation by actors, particularly providers can be facilitated.
  • The type of scheme (inputs or outcomes based), the structural arrangement for the relationships between actors and how well it fits with the objectives.
  • How well the scheme balances the need for supply of other ecosystem services (and biodiversity).

 

Soil is a fundamental resource for Scotland, underpinning our society, economy and environment and we were asked to explore the mechanisms currently in place for its management.

This project aimed to understand the extent of the different legislative and policy mechanisms for the conservation and management of soil in Scotland, and how they relate to key national institutions.

Key findings:

  • Policy relating to soil is wide-ranging and on multiple scales, and close reading of the original texts indicate key relationships between different instruments. However, we confirmed the existing understanding of no single policy designed specifically for the protection of soil.
  • Policy instruments can be categorised into three broad areas:
    • Regulatory – environmental protection and regulation
    • Framing – principles and standards
    • Enabling – shaping and encouraging direction of travel.
  • Soil protection and management is a feature of a range of policy areas, including environmental protection (such as habitat, biodiversity, landscape, heritage protection, etc.), water, climate change, pollution, waste, land use & planning and land ownership; it may not however be directly mentioned in the primary legislation, but in supporting ‘instruments’ for delivery.
  • It is clear that understanding of soil policy is held within the knowledge and experience of the responsible institutions, and the Scottish Government, although this is not well-documented.
  • Gaps arise in policies specifically focused on land – for example, the Land Rights and Responsibilities Statement, or planning policy and legislation in Scotland (e.g. Planning (Scotland) Bill); soil protection is an implicit rather than explicit outcome.

Read the Scottish Soil Framework

Peatlands cover nearly a quarter of Scotland and contain over half of the total Scottish soil carbon. However, more than 90% of the lowland raised bogs (and over half of the blanket bog) have been altered to such an extent that they are now degraded, causing substantial Greenhouse Gas (GHG) emissions.

This report looks at the costs and benefits of peatland restoration activities in Scotland to get a sense of the cost effectiveness of different techniques, primarily targeting work carried out since 2010.

Scottish Government has set ambitious peatland restoration and rewetting targets in the Climate Change Plan. This project provides information about which techniques work in certain circumstances to achieve the initial goal of sustainable rewetting of peatlands.

The Scottish Government’s ambition is to increase woodland cover in Scotland to 25% by the second half of the century. The Scottish Climate Change Plan (2017) has an ambition to increase from the current 18% to around 21% of woodland cover by 2032. This will make an important contribution to reducing Scotland’s net greenhouse gas (GHG) emissions.

However, it is important to understand the consequences of forestry activity, given that approximately two-thirds of Scotland is covered by high carbon-content organic soils of varying depths, including nearly a quarter with deep peat soils

This report examines new evidence published since the Forest Research report ‘Understanding the GHG implications of forestry on peat soils in Scotland’ (Morison et al., 2010). The review broadly confirms the findings of the 2010 report. It remains probable that moderate and high productivity forests planted on shallower peat soils with limited disturbance provide a substantial net carbon uptake over the forest cycle.

Scotland’s extensive peatlands are central to both climate change adaptation and mitigation through being a carbon sink, securing biodiversity and habitats, and reducing flood risk – to name a few benefits. CXC’s contribution in this area needed to add to the work done by the strategic research programme, which mainly is data collection and model development, and cost-benefit analysis at both national scale and at the RSPB Forsinard Flows reserve.

CXC’s contribution has been on the need to better understand the potential for peatland restoration and how it might contribute to greenhouse gas emissions reduction in Scotland, for example through the following work:

  • developing a peatland restoration decision support tool (WISE Peatland Choices)
  • call-down requests on the emissions abatement potential of peatland restoration, which led to further policy briefs

This work has been in close cooperation with agencies like Scottish Natural Heritage (SNH). SNH have in parallel commissioned research on the scope for blanket bog peatland restoration in Scotland for carbon and biodiversity benefits, and published a range of resources for peatland restoration.

Together, the research was used by the climate change policy team within Scottish Government as oral evidence presented to the Report on Policies and Procedures (the mechanism for implementing the Climate Change (Scotland) Act), and a Rural Affairs, Climate Change and Environment (RACCE) Committee meeting on the benefits of peatland restoration. Interviews with members of the policy community in Scottish Government suggest that the evidence presented to these committees was instrumental in the allocation of £1.7m, subsequently rising to £15m for peatland restoration between 2012-16 as a Green Stimulus initiative, now called Peatland Action. This same body of evidence also laid the foundation for a proposal in the second Report on Policies and Priorities in 2013 that 21,000 ha of peatlands per year should be restored in the period to 2027. Hutton researchers helped draft the national Peatland Plan, which was put out to consultation in 2014.

This led to several further CXC projects:

  • assessing the use and further potential for the Peatland Carbon Calculator
  • gathering lessons learnt from the Peatland ACTION programme (established in 2014)
  • identifying peatland research priorities
  • assessing evidence for the Muirburn Code

As is typically the case with impact identification, it is difficult to disentangle the influence of one strand of research evidence (in this case the CXC’s) and the influence of other entities (in this case NGOs and agencies such as the IUCN’s UK Peatland Programme, RSPB, SNH and the Forestry Commission) in shaping a policy decision – in this case, increasing the level of investment from £1.7m to £15m. Social Network Analysis data (Reed et al., in prep.) suggests that NGOs and agencies played an important role in translating research evidence from CXC research and elsewhere on the GHG benefits of peatland restoration to Scottish Government at this time.

The process of distilling whisky creates by-products
that can be a feed source for sheep and cattle.

This report looks at the entire lifecycle impacts of using some forms of these by-products in renewable energy, traditional animal feed or concentrated dark grains animal feed.

The initial report was published in November 2017, and shared with key stakeholders. We were asked what happened when only draff was produced (i.e., no pot-ale), which prompted a further analysis.

We found a negligible difference between the renewable energy and animal feed scenarios. However, when draff was used to produce renewable energy to replace heavy fuel oil, this had a significant benefit over its use as an animal feed.

Key findings

  • All three scenarios were found to have a net beneficial climate change impact, offsetting GHG emissions by avoiding the production of energy, animal feeds and/or fertilisers by other means.
  • The renewable energy scenario offset the largest amount of GHG emissions overall.
  • While the two animal feed scenarios perform better in certain life-cycle phases, such as capital burdens and material use, the generation of renewable energy avoids a significant amount of carbon through the offsetting of grid electricity and heat.
  • The sensitivity of these results to some underlying assumptions was tested during the study:
    • it was found that switching the offset cattle feedstock from rape meal to soya bean meal slightly increases the GWP benefits for the two animal feed scenarios;
    • including woodchip co-firing significantly increases the GWP benefits for the renewable energy scenario;
    • assuming that any heat produced would offset heavy fuel oil (rather than natural gas) improved the GWP results for all three scenarios to varying amounts.
  • However, the overall positioning of the three scenarios was unaffected by the sensitivities modelled; the renewable energy scenario remained the most favourable.

Blog by Ricardo https://ee.ricardo.com/lca-for-policy