Nitrogen Footprint accounting and food sustainability: Insights from the Italian wine industry

Anthropogenic perturbation of the nitrogen cycle poses significant environmental and social challenges, highlighting the need for effective nitrogen management in sustainable food systems. The Nitrogen Footprint (N-Footprint) offers an innovative metric to quantify reactive nitrogen (Nr) emissions and trace their environmental pathways. This study refines a previous N-Footprint accounting framework to include both direct and indirect Nr emissions throughout the life cycle, providing a comprehensive perspective on Nr dynamics. The methodology is applied to a case study of Italian wine production, covering vineyard cultivation, winemaking, and bottling processes. Results indicate total emissions of 7.67 g Nr per 0.75 L wine bottle, with the vineyard phase accounting for 64.4 % of the overall impact, largely due to intensive fertilizer use. Water is identified as the most affected environmental compartment (55.7 % of emissions), primarily as a result of nitrate leaching. Additionally, the study quantifies the Virtual Nitrogen Factor (VNF) to evaluate nitrogen use efficiency. Italian wine production demonstrates relatively high efficiency (2.28 g Nr per gram of nitrogen intake) compared to other fruit-based products. However, the lack of a standardized N-Footprint methodology hinders cross-sectoral comparability. This research calls for the development of nitrogen-specific Life Cycle Assessment (LCA) standards to promote sustainable agricultural practices. • A refined N-Footprint method is presented, incorporating direct and indirect emissions. • An assessment of reactive nitrogen associated with the production of grapes and wine is performed. • A comprehensive inventory of N-containing molecules is compiled and converted into Nr quantities. • The measured N-Footprint is quantified: 5.35 g Nr per kg of grapes, 8.52 g Nr per liter of wine. • A compared N-footprint analysis for (agro)food products is offered.