Report for AHDB

Abstract The AHDB is developing a What Works Centre for agriculture and horticulture called the Evidence for Farming Initiative (EFI). AHDB has developed a programme to design and develop the evidence base for this new centre. The EFI brings together fragmented knowledge and evidence on the farming industry to provide a co-ordinated central point for the delivery of quality-assured advice. The evidence-base is being developed through sector-specific rapid evidence assessments (REAs). REAs are used to provide a systematic and transparent basis to identify, critically appraise and synthesise evidence that reduces the potential for bias. The initial focus of the EFI is in investigating Net Zero practices (i.e. those that reduce greenhouse gas (GHG) emissions or sequester atmospheric carbon). After recent REAs conducted in the dairy sector and the cereals and oilseeds sector, for this current project REAs were conducted for three further sectors: pork, potato and protected horticulture. Practices that had already been captured within the previous REAs were excluded to avoid overlap. Pork: During scoping, 17 practices were identified as having Net Zero potential, of which five were progressed to REA. Slurry cooling was found to have some indirect benefits of GHG reduction during storage, although the main target for research was its effectiveness at reducing ammonia emissions. For air scrubbing the overall GHG impact likely varies depending on the type of scrubbing system used, although all technologies were again effective at removing ammonia. Micro-anaerobic digestion shows promise to offset energy use through biogas generation, although there was a lack of case studies to be able to fully evaluate. Hydrogen electrolysis has potential future applications to reduce GHG emissions through offsetting fuel use, although there are several technical barriers to scalability. Precision feeding was found to effectively improve feed efficiency without impacting productivity, resulting in reduced GHG emissions. Overall, these practices have potential to reduce GHG emissions in the UK pig sector, although additional contextual evidence will be required to accelerate implementation. Potatoes: Due to overlap with previously conducted REAs in the cereals and oilseeds sector, this REA focused on potato-specific cultivations and energy efficiency of potato stores, the latter of which is responsible for a significant proportion of the emissions from potato production. The approach taken for the REAs failed to identify appropriate evidence syntheses within the academic publishing sphere. Instead, attention was turned to the grey literature. Sealing air leaks and optimising insulation presented a suitable evidence base for creation of narrative summaries. Depending on the condition of the potato store, adopting these practices could significantly reduce energy use. Protected horticulture: During scoping, 16 practices were identified as having Net Zero potential, of which five were progressed to REA. Biogas and biomass both have potential to offset fuel use in 6 the heated horticulture sector, although biogas has additional challenges around sourcing and price competitiveness with natural gas. North walls are a form of passive heat capture and storage which can reduce heating requirements by capturing and storing excess solar energy during the day and release it at night. Thermal screens were found to be highly effective at reducing energy use, although they are widely in use already so benefits going forward may be more around demonstrating best practice. Several aspects of glasshouse climate control have proven effective in reducing energy use, although these should be evaluated considering the whole production system. Overall, these practices have potential to reduce GHG emissions from energy use in the protected horticulture sector, although there are technical and economic challenges to implementation.