Abstract/Summary

Executive summary Nature of the problem • Reactive nitrogen (Nr) occurs in different forms, arises from a wide range of activities and sources, and leads to environmental impacts over different spatial and temporal scales. • Integrated approaches to N management are anticipated to provide more eff ective (larger decreases in unwanted emissions) and /or more efficient (less side effects, less costs) policy measures than policy measures based on single sources and pollutant species. • There are many notions of integrated approaches, but as yet little consensus about the best integrated approaches. There is also little quantitative empirical evidence of the performance of these approaches in practice. • The pitfall of integrated approaches is that they may be more complex to agree, leading to a delayed implementation. Approaches • Based on recent literature and a discussion among experts, the present chapter provides a conceptual framework for developing integratedapproaches to N management. • Whilst discussing the framework, various examples of existing partially integrated N management approaches have been considered. • A package of key actions in different sectors is envisaged that, together, should contribute to further developing integrated approaches to N management in the future Key findings/state of knowledge • The conceptual framework developed here distinguishes five dimensions of integration: (i) vertical dimension, i.e., cause–effect relationships of N species; (ii) horizontal dimension, i.e., integration of all N species via for example N budgets; (iii) integrating N management with the management of other elements, such as SO2, P, CO2, and CH4, (iv) integrating stakeholders views, and (v) regional integration, i.e., integration over spatial scales. • The toolbox for developing integrated approaches to N management has various types of tools, including systems analyses, communication,integrated assessment modeling, N budgeting, stakeholder dialogue and chain management. • Integrated approaches may be most applicable to agriculture, because of the role of N in food, feed and fiber production and the relative large diffuse N losses from multiple sources in multiple forms. Major uncertainties/challenges • There is as yet little empirical evidence of the perceived increased effectiveness and efficiency of integrated N management approaches relative to single Nr species and single Nr source management approaches. Potentially, integrated N management approaches may also achieve a broader set of societal targets simultaneously, but there is as yet little empirical evidence for this promise. • The ‘optimum’ level of integration likely depends on many factors, and it remains a challenge to define such optima for various situations and cases.