The workshop addressed the increasingly important issue of global food security and the role that nitrogen (N) has to play in ensuring that sufficient food is produced to meet the demands of an increasing global population. The past 50 years have seen dramatic changes in food production. In the coming 50 years it is likely that global populations will plateau at around 9–10 billion people, with food demand outstripping this growth. At the same time there is increasing demand to improve the sustainability of agricultural production through the reduction of reactive N losses to the environment. Research on improving N utilization and reducing losses to the environment has been on-going since the early 1980s, when the first Nitrogen Workshop was convened. However, there still appears to be a gap between current scientific knowledge and best farming practice, indicating a deficit in terms of communication and knowledge transfer.

The 17th Nitrogen Workshop aimed to address issues pertaining to food security and reducing reactive N losses to the environment. The 265 delegates were mainly from Europe, the Americas, Oceania and Asia, and came from a range of backgrounds including researchers, farmers/farm advisors, policy makers and industry. This wide range in both professional backgrounds and geographic spread represented a unique opportunity to gauge expert opinion through a quantitative survey that was carried out during the main auditorium and workshop sessions, covering four thematic areas. The survey produced a unique insight into the expert opinions of researchers and non-researchers across the world. Some specifics can be found at the end of these concluding remarks, and the full results of auditorium and workshop questions are available in online Supplementary materials 1 and 2, respectively (available at: http://journals.cambridge.org/AGS).

Nitrogen cycling in agricultural systems has been the subject of extensive research over the past 40 years: the driver for this research has changed from agronomic to environmental issues and more recently to sustainable food security. The low N use efficiency within livestock systems was highlighted by delegates but they were pessimistic about how far N use efficiency could be improved, based on scientific limitations. Mitigation of N losses to the environment was possible using the measures currently known and applied globally, but often at a cost to the producer.

Where there is a demand for a product, the market forces will adjust accordingly. Overwhelmingly delegates identified that demand-side measures, such as changing human protein consumption patterns, were the key to reducing demand for low-efficiency protein products but they felt that was unlikely to occur in a scenario where global population growth is linked to increased affluence in developing countries. Delegates agreed that education was one of the key methods for changing protein consumption patterns and that policies should be implemented to reduce demand for N-intensive food products. Linking food choice and N footprint to the impact of protein consumption choice on human health is likely to be an effective approach to modifying consumption patterns.

There is a substantial body of knowledge in relation to N cycling in agricultural systems. Often there is a barrier between knowledge and the impact that knowledge has on the end user or the stakeholder. Delegates identified that trust between the stakeholders and the researchers was the most important factor for effective knowledge transfer and implementation of change. The pressure on researchers to publish scientific papers came through as a key driver and a potential barrier for implementing change at farmer level. The majority of researchers felt that more focussed research was required, whereas the majority of non-researchers indicated the opposite. This clearly highlighted the difference in drivers between the two groups.

The challenge for agriculture to continue to meet the increasing demand for sustainably produced food to meet the growing demands for animal-protein-based foodstuffs affects both agricultural, environmental and social scientists. Agricultural systems can be further optimized to increase efficiencies and reduce damaging losses of N to the environment, but there is a limit to how much further this can be achieved due to the large increase in production costs. Tempering the demand for food products with higher environmental footprints is key to reducing losses to the environment and underpinning a viable agricultural industry. Research should focus on the impact of knowledge generation on practice adoption while producing new science for publication.