Work Package Agricultural systems and land management
Introduction
Agriculture is one of the largest sources of greenhouse gas emissions in Scotland and globally as well, and it is becoming more and more important as other sectors of the economy decarbonise at a faster pace. At the same time agriculture also offers opportunities to sequester carbon dioxide from the atmosphere.
A considerable amount of scientific and practical knowledge on low carbon farming practices has been accumulated over the past few decades. A number of practices have been identified to be “win-win” options, providing greenhouse gas mitigation and cost savings at the same time. However, a combination of financial, technical, policy and behavioural barriers hinders the wider uptake of these practices; this poses challenges for the development of efficient agri-environmental policies.
Aim of Research
The aim of this research is to address some key farm-level and policy-level issues to help develop policies in Scotland and more widely in the UK and in Europe, as part of a wider national and international research programme. The research includes a combination of environmental economic modelling, survey work and development of monitoring and evaluation tools and approaches. Specifically, focus is placed on providing improved understanding and estimates of agricultural greenhouse gas mitigation at national and farm level and developing tools for policy makers, farmers and researchers.
Progress
Co-adoption of breeding management and other GHG reduction practices of dairy farmers has been studied. The results show that the breeding management practices are not jointly adopted, but there are complementarities in adopting the breeding index and animal feeding and sward management practices. Policy support for adopting “packages” of practices and technologies might be an efficient way to speed up GHG mitigation adoption.
A modelling exercise was undertaken to assess baseline GHG emissions using real farm data across all sectors of the farming industry. The study included farms from Scotland England and Wales, reporting area-based emissions and emissions per unit of product. This work also looked at the extent to which the application of multiple mitigation measures applied on farms could reduce emissions. This demonstrated that such mitigation measures could reduce GHG emissions by 23% and ammonia emissions by 15% across the UK assuming wide-scale adoption (100% across the UK). While this is encouraging, it also indicates much more innovation, adoption and the realisation of carbon capture is necessary (including carbon sequestration) A report on this work is available on the CIEL website and is being further developed as a peer reviewed publication.
The role that biochar in reducing greenhouse gas emissions and nutrient leaching, and its interaction with nitrification inhibitors has been investigated in order to inform policy makers if biochar application is a viable and risk-free option for helping Scotland reduce its agricultural GHG emissions. Results show that there was no significant effect of the biochar tested on agricultural GHG emissions and the nutrient retention was short-lived. More research is required in relation to ‘tried and tested’ benefits of biochar use and associated risks in different Scottish agricultural systems.
Previously, we calibrated several outputs of the model STICS, a process based simulator of plant growth and soil biogeochemistry, to experimental barley plant and soil nitrate-ammonium data using a technique called history matching. History matching yielded a plausible parameter space and this was used to construct two different types of emulators (meta-models) of STICS. The predictive out-of-sample performance of the two emulators, multiple regression (MLR) models and Gaussian process regression (GPR) models, was evaluated and showed that while both were accurate, produced on average unbiased predictions, the GPR models were much more precise. The emulators were also used to evaluate climate change effects on plant growth and soil biogeochemistry.
Highlights:
RD 2.3.5 scientists have contributed to policy formulation on agricultural greenhouse gases via multiple channels, including being a member of the Nutrient Management Expert Group of Defra, giving specialised advice to the Department of Agriculture, Environment and Rural Affairs in Northern Ireland and contributing to the work of the Scottish Government’s farmer led groups on greenhouse gas mitigation.
A selection of podcast, webinars and videos on soil health were created and published for the farming audience. Training on greenhouse gas sampling and measuring soil carbon stocks was provided to farmers, researchers, and students.
Progress: A scientific article on soil carbon storage potential in grasslands was published. Work suggested that methods used to predict maximum mineral-associated carbon in soils reflect the soil in situ to provide more accurate assessments of carbon sequestration potential. . Another article on soil methane emissions highlighted that there are significant differences in methane uptake and emissions between contrasting agricultural sites.
The STICS crop model was used to predict the growth of spring barley under various UKCP18 projections for climate change. By the end of the century, yields are projected to decline under by approximately 10%.
Work on environmental practice uptake in low-intervention regulatory environment showed that certainty around policy and also around the effectiveness of practices is essential, particularly for farmers who delay action until compelled to act due to succession or regulation. This finding supports the idea that delaying policy formulation on greenhouse gas mitigation hampers the wider uptake of mitigation practices.
Highlights: The UK’s experience of developing a Tier 2 reporting system for N2O emissions and was shared internationally at an inventory reporting workshop in Denmark, while the Scottish perspective of soil carbon management was shared with the industry at an NFU workshop.
Large audiences attended the online industry meetings organised by Arable Scotland and AHDB (Agronomy Winter Roadshow), in July and February, respectively. RD 2.3.5 scientists contributed to the ask the expert and Q&A sessions on soil health and presented VESS (visual evaluation of soil structure) and other practical guidance materials. On these topics information sheets, infographics and farmer guidance sheet were also made available for stakeholders.
Scientists from RD 2.3.5 published the Scottish Farmer article ‘Successful soil and nutrient management: Healthy soils and environment’ online in September.
Irish policy stakeholders heard about the Scottish GHG mitigation research at a workshop organised by the Department of Agriculture and the Irish EPA in June and Defra and other policy stakeholders heard about it at the AES-Defra conference.
The SRUC team continued to provide evidence to Scottish and UK policy on GHG mitigation on multiple occasions, including for the 6th UK carbon budget.
The voluntary uptake of environmentally friendly measures is influenced by the certainty around the policy and information on the effectiveness of the practices.
Work has continued on providing evidence on the effectiveness of mitigation measures and this information is being used to inform the development of AgreCalc. This has been developed in order to understand and quantify the uncertainties associated with carbon footprinting (Sykes et al. 2019). The model has also been used to improve our understanding of changes required on farms to meet the governments targets of net zero emissions (Rees et al. 2020).
A review of methane emissions from Scottish grassland soils, using available experimental data and literature, was conducted. Findings indicated that methane emissions could be minimised through good timing of fertiliser and manure applications, maintaining field drainage (especially for poorly draining organic-rich grassland soils), reducing stocking rates to reduce excreta returns and avoidance of compaction/animal trampling and maintaining good soil structural quality through application of no-tillage practices if conditions are appropriate.
The relationships between visual evaluation of soil structure (VESS) and other soil quality functions were explored. Strong correlations were found between VESS and properties such as bulk density, earthworm numbers, aggregate stability and carbon stabilisation against decomposition. Findings confirmed that VESS can reveal differences between land use types and management options but supporting measurements (especially for soil chemical and biological functions) should be carried out alongside VESS. SRUC researchers also helped groups in Finland and Switzerland develop their own modified VESS field sheets and online tools (https://www.sruc.ac.uk/info/120625/visual_evaluation_of_soil_structure).
Previous GHG field experiments funded by AHDB Dairy (and RESAS) have shown that the use of a nitrification inhibitor reduces nitrous oxide emissions from compacted grassland with different soil types and climatic conditions. Findings were recently submitted for publication.
Nitrous oxide emissions have been incorporated into the farm level economic model (ScotFarm) by converting the emissions to a carbon cost. The crop growth model (STICS) has been calibrated for spring barley production. Parameter combinations for this subset were found that yielded predictions of barley and soil nitrogen that were similar to field measurements. A workshop on emulation held in April 2019 brought together three international experts on emulation and provided guidance and direction on the handling of exogenous forcing factors, e.g., daily weather data, and pointed us to an R package for Gaussian process-based emulation, RobustGaSP, which is now the platform we are using for emulation of STICS.
Highlights:
Data on the future mitigation potential of GHG emissions potential from agriculture was provided to the economy-wide TIMES model (run by the Scottish Government). Evidence has also been provided on the capacity for the UK GHG inventory to reflect the mitigation activities in Scotland.
Presentations on GHG emissions has been given to NFU Scotland in July 2019, and to an International Research Conference in New Zealand in February 2020.
In conjunction with the Soil association, a Mob grazing group field lab event was held at Tarbolton and Mossgiel farm on 20th May 2019. A presentation was given on ‘Measuring soil health and soil carbon storage’, based on samples submitted by the farmers, and VESS was practically demonstrated in the field.
VESS was used as part of a Royal Society Evidence Synthesis on soil structure to help inform the Government’s upcoming Agriculture Bill (https://royalsociety.org/-/media/policy/projects/soil-structures/soil-structure-evidence-synthesis-report.pdf).
The effectiveness of a climate change focused agri-environmental participatory programmes in Scotland has been evaluated surveying both participating and non-participating farmers and interviewing 20 programme participants. The work focused on environmental performance indicators and human-social aspects, i.e. social learning, resilience, and management skills. The mixed qualitative and quantitative approach provided a more holistic understanding of the change achieved by the programme, showing that sometimes the quantitative results are not corroborated by in-depth interviews.
The method to estimate greenhouse gas mitigation in Scotland for cost-effectiveness analysis has been further developed in order to be in line with recent changes in the national greenhouse gas inventory methodology. For example, the method now takes into consideration synthetic nitrogen fertiliser types, emission actor differences between the four countries of the UK. The national greenhouse gas inventory methodology was scrutinised with respect of how Scottish circumstances and potential development in the uptake of mitigation measures are reflected currently in the inventory. The work highlighted four key areas where improved data collection would improve the greenhouse gas inventory estimates for Scotland.
Further work on the Extended Visual Evaluation of Soil Structure (VESS) system confirmed the value of visual soil assessment tools as proxies for assessing environmental quality status. A finalised set of simple score sheets for estimating the likelihood of agricultural soil greenhouse gas emissions, soil carbon status and nutrient leaching risk have been produced.
A crop growth model (STICS) has been calibrated and validated for a range of crops and a crop sequence (e.g. oats, undersown oats) considering the yields and the nitrogen flows in order to be used in a farm level economic model (ScotFarm). The statistical emulator methodology which is being developed to link the two models have been extended to encompass a wider range of agricultural model structures and model outputs, and to deal more coherently with climate variability and uncertainty. We have also incorporated calibration into the methodology.
Highlights:
- We provided evidence as requested by the Scottish Parliament on agricultural greenhouse gas mitigation: Evidence on the Climate Change (Emissions Reduction Targets) (Scotland) Bill to the Environment, Climate Change, and Land Reform Committee for the meeting on 13 November 2018
Recent international developments in the cost-effectiveness methodology, which compares technologies and changes regarding their environmental benefits and financial costs and is widely used by policy makers regarding greenhouse gas mitigation, has been summarised. This review helps stakeholders to understand results of such methodologies (e.g. marginal abatement cost curves) and also provides a guidance to countries where an agricultural mitigation cost-effectiveness analysis has not been done yet.
The uncertainties in the cost-effectiveness of agricultural greenhouse gas mitigation in Scotland have been analysed and quantified. The study found that the probability that the actual abatement will be less than half of the estimated abatement is between 1% and 32%. The main contributors to uncertainty are the level of future uptake of technologies and the mitigation effect of the technologies. While most mitigation options appear to be ‘win-win’ under some scenarios, many have a high probability of switching between being cost-ineffective and cost-effective. The study points out how more robust estimates could be obtained.
The Visual Evaluation of Soil Structure (VESS) system has been further tested and an ‘Extended VESS’ technique has been developed for assessing the risk of greenhouse gas emissions and potential for carbon sequestration in agricultural soils. The Extended VESS Environmental Quality scoring system considers the following properties: crop vigour, vegetation cover, exposed soil surface, soil porosity and evidence of waterlogging/mottling, incorporation/decomposition status of residues. For example an Extended VESS score 1-2 indicates low risk of high nitrous oxide emissions if soils are not saturated with water and have not recently received nitrogen fertiliser. Higher Extended VESS scores – compacted soils – suggest greater likelihood of nitrous oxide and methane emissions even at low moisture contents.
An initial version of a statistical emulator model which can link a crop growth and greenhouse gas emission model to a farm level economic model was designed, and the farm level economic model was further developed by adding soil nitrous oxide emission calculations to it. The crop growth model (SPACSYS) was used to estimate grass yield under three climate scenarios (2030s, 2050s and 2080s), these yield parameters were used in the farm level economic model (ScotFarm) alongside farm level data from 105 beef farms (drawn from the Scottish Farm Business Survey dataset) to examine the impact of climate change on Scottish beef farms.
Highlights:
- The role of on-farm carbon calculators in enhancing greenhouse gas mitigation was discussed at Scottish Government consultation workshop on new greenhouse gas emissions policies.
- The integrated crop and farm economics modelling platform was presented at the 3rd European Climate Change Adaptation Conference. The results highlighted potential farm management strategies that beef farms can adopt to maximise their farm profits under a changing climate.
- Invited speakers at the workshop ‘Economic Experiments for EU Agricultural Policy Evaluation: Methodological Challenges’ and a policy modelling workshop in Brussels to present finding on the greenhouse gas effects of precision farming technologies.
Work has been undertaken to study how climate change focused participatory programmes are evaluated. The work showed that while in developing countries evaluation is common, it is less so in developed countries, furthermore, evaluations tend to focus on easily measurable quantities, without allowing for deeper understanding from in-depth interviews conducted with participants.
A detailed comparison of the emission calculations and estimates of five farm-level greenhouse gas calculators on beef farms revealed that there are inconsistencies between the tools, and even where farm-level estimates appear to be similar between tools, the contribution of different sources (e.g. emissions from crop production and livestock rearing) are different, and such different tools would prioritise mitigation technologies differently. This highlights the need for a harmonised approach which is agreed by relevant stakeholders.
Experimental results showed that the Visual Evaluation of Soil Structure (VESS) method, which is a soil health check method for farmers, has the potential to be developed to assist in a visual assessment of greenhouse gas emission risk and carbon sequestration potential in soils. The results suggested that the approach can be suitable across soil types and agricultural land uses.
It has been explored how two scientific models, one estimating crop yield and greenhouse gas emissions (SPACSYS) and another estimating financial impacts of changes on farm (ScotFarm) can be harmonised so that more accurate predictions of climate change impacts and mitigation efforts can be provided by the farm model. The crop model has been used to estimate grass yield under climate change and these data were used in the farm level economic model.
Highlights:
- Evidence invited at a meeting of the Committee on Climate Change to assess the extent to which Scotland is currently meeting its ambitions for GHG mitigation in agriculture. Also invited as an expert witness to the Scottish Parliamentary Committee on Environment Climate Change and Land Reform. Furthermore, we provided consultation responses on the Draft Climate Change Plan RPP3 for both the Environment, Climate Change, and Land Reform Committee and the Rural Economy and Connectivity Committee.
- Four open days and several workshops for farmers, farm advisors and policy makers were held to demonstrate the importance of soil structural quality for agronomic business benefits and environmental benefits.
- An invited speaker at a multi-stakeholder workshop in Riga which was aiming to develop greenhouse gas mitigation cost-effectiveness analysis of the Lithuanian agricultural sector.
Future Activities
Future work will focus on i) further enhancing the cost-effectiveness methodology used to assess agricultural greenhouse gas mitigation and understanding the role of farmers’ perceptions ii) providing recommendations for reducing the carbon footprint of livestock systems using a carbon calculator, iii) analysing methane oxidation and production in grassland soil systems and iv) calibration and validation of the extended statistical emulator and modelling barley production in Scotland.
Selected Outputs
Hargreaves P.R., Baker K., Graceson A., Bonnett S., Ball B.C. and Cloy J.M. (2021) Use of a nitrification inhibitor reduces nitrous oxide (N2O) emissions from compacted grassland with different soil types and climatic conditions, Agriculture, Ecosystems and Environment, 310, 107307. https://doi.org/10.1016/j.agee.2021.107307
Paterson K.C., Cloy J.M., Rees R.M., Baggs E.M., Macdonald A.J., Fornara D., Martineau H. and Buckingham S. (2021) Estimating maximum mineral associated organic carbon in UK grasslands, Biogeosciences, 18, 605–620, https://doi.org/10.5194/bg-18-605-2021
Veenstra J.L., Cloy J.M. and Menon M. (2021) Physical and hydrological processes in soils under conservation tillage in Europe. In Conservation Agriculture: A Sustainable Approach for Soil Health and Food Security, (eds. Jayaraman S., Dalal R.C., Patra A.K., Chaudhari S.K.), Springer Singapore. https://www.springer.com/gp/book/9789811608261
Cowan N., Maire J., Krol D., Cloy J.M., Hargreaves P.R., Murphy R., Carswell A., Jones S., Hinton N., Anderson M., Famularia D., Bell M.J., Stack P., Levy P., Ute Skiba U., Drewer J. (2020) Agricultural soils: a sink or source of methane across the British Isles? European Journal of Soil Science, https://doi.org/10.1111/ejss.13075
Miller G.A., Rees R.M., Griffiths B.S. and Cloy J.M., 2020, Isolating the effect of soil properties on agricultural soil greenhouse gas emissions under controlled conditions, Soil Use & Management, 36, 285-298.
Rees, R. M., Eory, V., Bell, J., Topp, C. F. E., Sykes, A., MacLeod, M., Misselbrook, T., Cardenas, L., Chadwick, D. R., Sohi, S., Manning, A., and Smith, P. How far can greenhouse gas mitigation take us towards net zero emissions in agriculture? Chistensen, C. L., Home, D. J., and Singh, R. 2020. Palmerston North, New Zealand, Massey University. Farm Landscapes Research Centre Conference.
Sykes,A.J., Topp,C.F.E. & Rees,R.M. 2019. Understanding uncertainty in the carbon footprint of beef production. Journal of Cleaner Production, 234, 423-435.
Hargreaves, P. R.; K. L. Baker, A. Graceson, S. Bonnett, B. C. Ball, J. M. Cloy (2019) Soil compaction effects on grassland silage yields and soil structure under different levels of compaction over three years. European Journal of Agronomy, 109: 125916. https://doi.org/10.1016/j.eja.2019.125916
Miller, G. A.; R. M. Rees; B. S. Griffiths; B. C. Ball, J. M. Cloy (2019) The sensitivity of soil organic carbon pools to land management varies depending on former tillage practices. Soil and Tillage Research, 189: 236-242. https://doi.org/10.1016/j.still.2019.104299
Eory, V.; J. Maire, S. Anthony, C. F. E. Topp, R. Rees, H. Hamilton, E. Wall (2019) Non-CO2 abatement in the UK agricultural sector by 2050. Report to the Committee on Climate Change. SRUC, Edinburgh. https://www.theccc.org.uk/publication/non-co2-abatement-in-the-uk-agricultural-sector-by-2050-scotlands-rural-college-adas-and-edinburgh-university/
Eory, V.; C. F. E. Topp, R. Rees (2019) Mitigation measures in the 'smart inventory': Practical abatement potential in Scottish agriculture. ClimateXChange https://www.climatexchange.org.uk/research/projects/mitigation-measures-in-the-smart-inventory-practical-abatement-potential-in-scottish-agriculture/
Leinonen, I., V. Eory, M. MacLeod, A. J. Sykes, K. Glenk and R. Rees (2019) Comparative analysis of farm-based carbon audits. ClimateXChange https://www.climatexchange.org.uk/research/projects/comparative-analysis-of-farm-based-carbon-audits/
Firbank, L. G., S. Attwood, V. Eory, Y. Gadanakis, J.M. Lynch, R. Sonnino, and T. Takahashi (2018) Grand challenges in sustainable intensification and ecosystem services. Frontiers in Sustainable Food Systems 2, 7. https://doi.org/10.3389/fsufs.2018.00007
Eory, V., C.F.E. Topp, A. Butler and D. Moran (2018) Addressing uncertainty in efficient mitigation of agricultural greenhouse gas emissions. Journal of Agricultural Economics 69: 627-645 https://doi.org/10.1111/1477-9552.12269
Knook, J., V. Eory, M. Brander and D. Moran (2018) Evaluation of farmer participatory extension programmes. The Journal of Agricultural Education and Extension 1-29. doi: 10.1080/1389224X.2018.1466717 https://doi.org/10.1080/1389224X.2018.1466717
Eory, V., S. Pellerin, G. Carmona Garcia, H. Lehtonen, I. Licite, H. Mattila, T. Lund-Sørensen, J. Muldowney, D. Popluga, L. Strandmark, and R. Schulte (2018) Marginal abatement cost curves for agricultural climate policy: State-of-the art, lessons learnt and future potential. Journal of Cleaner Production 182:705-716. https://doi.org/10.1016/j.jclepro.2018.01.252
Balafoutis, A., B. Beck, S. Fountas, J. Vangeyte, T. van der Wal, I. Soto, M. Gomez-Barbero, A. Barnes and V. Eory (2017) Precision agriculture technologies positively contributing to GHG emissions mitigation, farm productivity and economics. Sustainability 9(8): 1339. https://doi.org/10.3390/su9081339
Sykes, A. J., C. F. E. Topp,; R. M. Wilson, G. Reid, R. M. Rees, (2017) A comparison of farm-level greenhouse gas calculators in their application on beef production systems. Journal of Cleaner Production, 164 (Supplement C), 398-409. https://doi.org/10.1016/j.jclepro.2017.06.197
Eory, V. and N. J. Hutchings (2017) A case study of agricultural nitrogen management policy in Denmark. ClimateXChange. http://www.climatexchange.org.uk/reducing-emissions/eu-climate-change-case-studies/
Eory, V., G. Allan, A. Bapasola, W. J. Bealey, I. L. Boyd, J. Campbell, L. Colen, K. Glenk, A. Kay, M. MacLeod, D. Moran, J. Moxley, R. M. Rees, C. Sherrington, C. F. E. Topp and C. Watson (2017) Evidence review of the potential wider impacts of climate change mitigation options: Agriculture, forestry, land use and waste sectors. A report prepared for Scottish Government. Scottish Government. http://www.gov.scot/Publications/2017/01/5347/downloads
Rees, RM Net zero implications for land use and agriculture. ZeroEmissions Agriculture Conference, Copenhagen, 2022
Cloy J.M. and Smith K.A. (2022) Greenhouse gas emissions. In: Reference module in earth systems and environmental sciences. Online reference database, Elsevier, Oxford. https://link.springer.com/referenceworkentry/10.1007/978-3-319-95726-5_65
Veenstra, J.L., Cloy, J.M., Menon, M. (2021). Physical and hydrological processes in soils under conservation tillage in Europe. In: Jayaraman, S., Dalal, R.C., Patra, A.K., Chaudhari, S.K. (eds) Conservation agriculture: A sustainable approach for soil health and food security. Springer, Singapore. https://doi.org/10.1007/978-981-16-0827-8_19
SRUC (2021) Valuing your soils: Practical guidance for Scottish farmers. CREW. https://www.farmingandwaterscotland.org/soil-nutrients/valuing-your-soils/
Research Deliverable Lead
Dr Vera Eory
Research Deliverable Staff
Adam Butler
Dr Joanna Cloy
Dr Klaus Glenk
Ken Newman
Professor Bob Rees
Dr Shailesh Shrestha
