Nitrogen exceedance and eutrophication: a regional model applied to Argentina

In recent years characterization models have incorporated site-dependent conditions for non-global impact categories in Life Cycle Analysis (LCA). However, regional impact characterization factors (CFs) have not been developed for all parts of the world. Ecosystems can be described according to nutrient supplies that limit growth and this can be considered the cornerstone of eutrophication research. The terrestrial eutrophication model is largely absent despite its importance for assessing agricultural commodity systems or land use activities. The objective of this study is develop regional indicators of terrestrial eutrophication, whose impact model compares the amount of deposited nitrogen (N) compounds that reach the soil with the limit or maximum value of N that natural ecosystems or crops can tolerate without suffering harmful effects due to the increase in nutrients. Methodologically, nitrogen oxide (NOx) and ammonia (NH3) emissions and their deposition were considered as N equivalents (kg N/ha). Atmospheric calculations were performed using the WRF-Chem model. Critical crop loads took into account the N present in the soil and fertilizer inputs. Excess N was defined as a category indicator and applied to Argentina as a case study. The results indicate that there is no potential contribution to excess N in the territory, based on the model and the data taken as a reference. Regionalized CFs reduce the overestimation of global models and offer more reliable results for LCA applications. This approach is appropriate for regions with limited data, generating solid results, and the possibility of extending the study to natural ecosystems is being considered.