Environmental impact assessment of agricultural production systems using the life cycle assessment methodology: I. Theoretical concept of a LCA method tailored to crop production

A new life cycle assessment (LCA) method is presented, which is specifically tailored to plant nutrition in arable crop production. Generally, LCA is a methodology to assess all environmental impacts associated with a product or a process by accounting and evaluating its resource consumption and emissions. In LCA studies the entire production system should be considered, i.e. for crop production systems the analysis includes not only the on-field activities, but also all impacts related to the production of raw materials (minerals, fossil fuels) and farm inputs like fertilizers, plant protection substances, machinery or seeds. The LCA method developed in this study evaluates the impact of emissions and resource consumption associated with crop production on the following environmental effects: depletion of abiotic resources, land use, climate change, toxicity, acidification, and eutrophication. In order to enable conclusions on the overall environmental impact of alternative crop nutrition systems, an aggregation procedure to calculate indicators for resource depletion (RDI) and environmental impacts (EcoX) has been developed. The higher the EcoX value, the higher is the overall environmental burden associated with the product under investigation. An environmental analysis of arable crop production systems based on this LCA method is especially appropriate in order to: (1) detect environmental hot spots in the system; (2) trace back environmental impacts of arable farming products to their sources and on that basis to suggest options for improvement; and (3) contribute to the debate on the environmental preference of alternative cropping systems in an informed way.