Nitrogen Use Efficiency Indicator – key for farm performance and environmental sustainability

Developing and testing indicators for agricultural resource use, productivity and environmental impact, such as the Nitrogen Use Efficiency (NUE) indicator, are key for characterizing farm performance in Europe, because of the role of nitrogen in food production and environmental sustainability.

This is one of the main conclusions of the 9th meeting of the EU Nitrogen Expert Panel which took place on 6 and 7 May 2019 in Budapest and gathered scientists from all over Europe with the aim of improving the management of nitrogen in the environment.

During the meeting, EUNEP members welcomed the fact that the NUE indicator – as developed by the Panel members in 2015 – has now been taken up by both scientists and industry stakeholders. As an example, Dr. Laura Cardenas and co-authors in a recent paper on “Nitrogen Use Efficiency and nitrous oxide emissions from five UK fertilized grasslands” (Sci. Total Env., 661, 696-710) used the NUE concept for interpretation of their data. In addition, the momentum for joined-up nitrogen actions is growing at international level. For instance, the Resolution on Sustainable Nitrogen Management, recently adopted at the 11-15 March 2019 meeting of the UN Environment Assembly (UNEA) in Nairobi, calls for coherent evidence-based, global policy coordination to address negative impacts of reactive nitrogen stemming from multiple sources. This is also the mission of the EUNEP. In this context, the International Fertilizer Association (IFA) in a released statement referred to optimal nutrient use efficiency (NUE), which should be in the range of 50-90%, according to the EU Nitrogen Expert Panel, whereas currently the average global NUE is around 45-50%.

In terms of next steps, the EU Nitrogen Panel members are currently preparing a paper in which different data sets from several European countries are compared for the purpose of testing the NUE indicator in real farm level case studies. In parallel, the NUE Guidance document prepared by the Panel in 2016 will be reviewed and finalized with the aim of publishing it around summer 2019 on the dedicated website for further use by farm advisors, extension services and farmers. This guidance could also lay the grounds for similar work to be undertaken in the context of the International Nitrogen Management Systems, and thus create synergies between the European and the international scientific communities. The EUNEP is finally working on a new report, which will set a framework to derive Best Management Practices for achieving NUE targets in crop production.