This project will complement and interact with other studies within the NT26 programme. The review projects NT2601 and NT2602, and the field-based research conducted under NT2603, have identified the most likely prospects for alternatives to ammonium nitrate (AN), but have also highlighted critical potential problems concerning their use that must be overcome. Urea-based fertilisers offer the best prospect, including urea in both solid (urea prills or granules) and liquid (UAN, urea ammonium nitrate solution) forms. However, a number of outstanding problems need to be assessed, and solutions found where possible. These issues will be further explored in this project, and the work can be summarised under the following headings.
1. Emissions of ammonia to the atmosphere
2. Emissions of nitrous oxide to the atmosphere
3. The effectiveness of urease inhibitors
4. Losses of N to surface watercourses
5. Agricultural productivity and phyotoxicities
6. Economic impacts on farmers and UK agriculture