Environmental life-cycle assessment of rapeseed produced in Central Europe: addressing alternative fertilization and management practices

This article presents a life-cycle assessment (LCA) of rapeseed produced in Central Europe (France, Germany and Poland), addressing different fertilization and management practices. Two alternative fertilization scenarios were compared (on the basis of the most common fertilizer types used in Europe, namely nitrogen, phosphate P2O5, and potash K2O fertilizers) and two different scenarios of soil management practices were assessed (taking into account climate and soil type prevalent in each region). Six environmental impact categories were investigated: abiotic depletion; global warming; acidification; eutrophication; ozone layer depletion; and photochemical oxidation. Results showed that the choice of fertilizer type had significant implications in the environmental impacts. Calcium ammonium nitrate (CAN) manufacturing had considerably higher greenhouse gas emissions than urea production, due to the use of nitric acid in the former. In terms of field emissions, ammonia and nitrate released following the application of nitrogen fertilizers dominated the acidification and eutrophication impacts. Nitrogen-phosphorus-potassium (NPK) compounds showed particularly high impacts in terms of photochemical oxidation, as a result of sulfur dioxide emissions from manufacturing. The remaining fertilizers (P2O5 and K2O) hardly contributed to the impacts. Soil carbon change associated with different agricultural management practices significantly contributed to the greenhouse gas (GHG) intensity of rapeseed production, but important soil carbon stock variations were calculated: between 938 (release) and 271 kg CO2eq/1000 kg dry seeds (sequestration) due to different standard soil organic carbon contents in the three rapeseed production systems and alternative tillage methods in the reference scenarios of land management.