Inventory analysis The activities performed in the production system under

2.3. Inventory analysis
The activities performed in AG 494 production system under study were identified by means of interviews, surveys and by literature.
More specifically, for Subsystem 1 (tomato cultivation) information regarding fertilizer and pesticide applications was collected considering the integrated production guidelines of Emilia Romagna and Lombardy (Regione Emilia Romagna, 2014). As regards the field operations, the agricultural processes reported in the database Ecoinvent (Nemecek and Kägi) have been modified considering the characteristics (mass, power, life span, specific fuel consumptions, etc.) of the machines (tractors and implements) used in the tomato fields. In more details, the diesel fuel consumption was estimated by using the model SE3A (Fiala and Bacenetti, 2012) that considers the power requirements of machines, their work capacity and soil characteristics as well.
Emissions due to the nitrogen fertilizer applications (nitrate, ammonia, and nitrous oxide) were computed according to the IPCC (IPCC, 2006) and Brentrup et al. (2000).