Scientists will be testing whether dairy farms can replace synthetic nitrogen fertiliser with biological alternatives to reduce harmful emissions as part of Defra's Farming Innovation Programme.
The University of Nottingham is a research partner in Bio-Phage UK, a Defra-funded Low Emissions Farming project led by Terrafarmer and delivered through Innovate UK. The research is testing whether dairy farms can replace approximately 50% of synthetic nitrogen fertiliser with biological alternatives, while maintaining or improving forage performance and reducing nitrous oxide emissions.
The project is one of 15 innovation projects across England sharing £21.5 million in funding to help farms cut emissions, strengthen resilience and boost productivity.
Agriculture remains a major contributor to UK greenhouse gas emissions and is a major source of nitrous oxide (N2O), a potent greenhouse gas approximately 300 times more powerful at driving climate warming than carbon dioxide over 100 years. Dairy systems are intensive users of synthetic nitrogen fertilisers, making them a key source of N2O emissions.
With increasing pressure to meet national climate targets, alongside rising fertiliser input costs and greater climatic variability, there is an urgent need to identify practical, science-led approaches that can reduce emissions at source without undermining productivity or resilience in farm systems.
Improving nitrogen use efficiency, by making better use of biologically mediated processes in soils, offers a pathway to more sustainable farming. However, adoption depends on clear, independent evidence that alternative approaches can maintain yields, support soil function, and perform reliably under commercial farm conditions.
Researchers at the University of Nottingham will focus on in-field greenhouse gas monitoring, optimisation of biofertiliser strategies, and life-cycle assessment (LCA) of emissions across dominant dairy crop types, including ryegrass, herbal leys, and whole-crop systems. Field trials are being conducted on three commercial dairy farms in England, supported by controlled glasshouse experiments at the University of Nottingham. Alongside biological inputs, the team will also be testing BIOCAT, a phage-based soil treatment that specifically targets bacteria responsibly for N2O production, providing a further potential pathway for emissions mitigation.
Dr Nick Girkin, Associate Professor in Environmental Science and Director, Centre for Sustainable Agricultural Systems is leading the Nottingham component of the project, he said: "By combining direct measurements of greenhouse gas emissions, soil chemistry, microbial community responses, and whole-system life-cycle assessment alongside impacts on yield, the project leverages the University of Nottingham's Centre for Sustainable Agricultural Systems' expertise and its ability to work at scale with multiple partners to generate robust evidence on a vital sustainability challenge for UK and global agriculture."
If successful, Bio-Phage UK could demonstrate a credible route to lower-emissions dairy forage production, delivering reduced reliance on synthetic nitrogen, improved nitrogen efficiency, and more resilient soil systems. Crucially, the findings will help farmers and policymakers distinguish between biological solutions that offer genuine, system-wide benefits and those that do not, supporting evidence-based decision-making for the transition to more sustainable UK agriculture.
