Improved management of nitrogen fertiliser could reduce energy-related carbon dioxide equivalent impacts on English farms by between 8.8% and 13.0%, according to new modelling from Rothamsted Research.
The study, led by Rothamsted hydrologist Dr Yusheng Zhang, examines how existing best-practice approaches to nitrogen management could affect energy use across five representative farm types. The work was carried out through the Global Nitrogen Innovation Center for Clean Energy and Environment (NICCEE) and published in Food and Energy Security this month. Rothamsted Research published details of the research on 14 October 2026.
National modelling across five farm types
The analysis is a national-scale modelling exercise rather than a field trial. Researchers first constructed profiles of current energy use for cereal, dairy, mixed, general cropping and lowland grazing livestock farms in England. They then modelled the effect of adopting established best-practice measures for managing nitrogen.
That inclusion of lowland grazing livestock makes the findings relevant to farms where grassland and forage production form part of the system, although the study reports results across the farm types examined rather than isolating a separate sheep-farm result in the figures provided.
- The model covered five representative English farm types.
- It considered both direct energy used on farms and energy embedded in purchased inputs.
- The modelled reduction in total energy-related impacts ranged from 8.8% to 13.0%.
Fertiliser manufacture included in the assessment
Rothamsted’s assessment separates energy used directly on the farm, including fuel for machinery, from indirect energy consumed earlier in the supply chain. The latter includes the energy required to manufacture inputs such as nitrogen fertiliser before they reach the farm gate.
For the farms without livestock in the analysis, fertiliser-related embedded energy represented between 39% and 47% of total energy-related impacts. Under the improved nitrogen management scenario, the indirect energy associated with fertiliser fell by between 16% and 40%, depending on the farm type.
When those reductions were combined with direct on-farm energy savings, the resulting modelled change was an 8.8% to 13.0% reduction in total energy-related carbon dioxide equivalent impacts across the farm types studied. Carbon dioxide equivalent is used to express the warming effects of different greenhouse gases in a common unit.
A near-term climate measure
The research comes as UK agriculture is expected to contribute to the government’s wider net zero target while maintaining food production. The modelling presents nitrogen management as a practical route for reducing energy-related impacts without requiring a broad reduction in agricultural output.
Its findings do not represent measurements from a single farm or a field experiment. Instead, they show the results of applying existing best-practice nitrogen management assumptions to representative English farming systems. The work therefore provides a national comparison of the potential energy and carbon effect of changes to fertiliser management, including in the lowland grazing livestock category.
