Review Review of scenario analyses to reduce agricultural nitrogen and phosphorus loading to the aquatic environment Fatemeh Hashemi ⁎, Jørgen E. Olesen, Tommy Dalgaard, Christen D. Børgesen Department of Agroecology, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark HIGHLIGHTS • The most widely applied measures in scenarios are changes in land use and agricultural land management. • None of the reviewed papers considered spatial differentiated measures due to variation in groundwater reduction of nitrogen. • Scenario evaluation was carried out with a limited set of models. • All scenario studies have limitations as well as technical and conceptual uncertainties. • Scenario building should better consider spatial information and the use of participatory approaches. abstract article info Article history: Received 28 June 2016 Received in revised form 19 August 2016 Accepted 19 August 2016 Available online xxxx Editor: D. Barcelo Nutrient loadings of nitrogen (N) and phosphorus (P) to aquatic environments are of increasing concern globally for managing ecosystems, drinking water supply and food production. There are often multiple sources of these nutrients in the landscape, and the different hydrological flow patterns within stream or river catchments have considerable influence on nutrient transport, transformation and retention processes that all eventually affect loadings to vulnerable aquatic environments. Therefore, in order to address options to reduce nutrient loadings, quantitative assessment of their effects in real catchments need to be undertaken. This involves setting up scenar- ios of the possible nutrient load reduction measures and quantifying their impacts via modelling. Over the recent two decades there has been a great increase in the use of scenario-based analyses of strategies to combat exces- sive nutrient loadings. Here we review 130 published papers extracted from Web of Science for 1995 to 2014 that have applied models to analyse scenarios of agricultural impacts on nutrients loadings at catchment scale. The review shows that scenario studies have been performed over a broad range of climatic conditions, with a large focus on measures targeting land cover/use and land management for reducing the source load of N and P in the landscape. Some of the studies considered how to manage the flows of nutrients, or how changes in the landscape may be used to influence both flows and transformation processes. Few studies have considered spatially targeting measures in the landscape, and such studies are more recent. Spatially differentiated options include land cover/use modification and application of different land management options based on catchments characteristics, cropping conditions and climatic conditions. Most of the studies used existing catchment models such as SWAT and INCA, and the choice of the models may also have influenced the setup of the scenarios. The use of stakeholders for designing scenarios and for communication of results does not seem to be a widespread prac- tice, and it would be recommendable for future scenario studies to have a more in-depth involvement of stake- holders for the elaboration and interpretation of scenarios, in particular to enhance their relevance for farm and catchment management and to foster better policies and incentives. © 2016 Elsevier B.V. All rights reserved. Keywords: Diffuse water pollution Model based scenario analysis Nitrogen reduction Phosphorus reduction Spatial differentiation Scenario planning Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609 2. Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610 Science of the Total Environment 573 (2016) 608–626 ⁎ Corresponding author. E-mail address: fatemeh.hashemi@agro.au.dk (F. Hashemi). http://dx.doi.org/10.1016/j.scitotenv.2016.08.141 0048-9697/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv