Assessment of management options to reduce nitrogen load from agricultural source in the Grado‐Marano Lagoon (N‐E Italy) applying spatial decision support system techniques

Purpose – The purpose of this paper is to present an application of spatial decision support system tools (SDSS) for assessing management option to reduce the nitrogen load from agricultural sources. The SDSS has been developed within a case study for the drainage basin of the Grado and Marano Lagoon (N‐E Italy). Design/methodology/approach – The problem is at least partially solvable replacing some actual cash crops with alternative crops requiring lower nitrogen input but which are economically profitable. The decision support was designed with two components: a non‐spatial one (DSS) to support the choice among alternative crops (within different scenarios), and a spatial one (SDSS) to analyse and evaluate the spatial distribution of the cash crops finding suitable areas for the alternative crops. Findings – The use of alternative crops for reducing nitrogen loads to the Grado and Marano lagoon waters seems feasible and appropriate. A mosaic of poplar, grassland and cash crop areas in these areas of the pollution risk is the best alternative both in terms of total nitrogen reduction and in terms of farmers' income. Research limitations/implications – The paper proposes a SDSS to implement alternative crops in an area where the cash crops constitute a very strong consolidated agricultural system. The feasibility of the alternatives is dependent on the willingness of farmers to participate in the research and then to exploit its results. The availability of data only at municipal level limited the research, thus imposing a spatial resolution constraint. Originality/value – It is so far the first attempt, in Friuli Venezia Giulia region, to develop a spatial decision support system to mitigate the pollution of a lagoon from agricultural sources by trying to find suitable alternatives to well consolidated agricultural practices. It also constitutes a model that can be applied in similar contexts by coupling ecological and economic considerations.