A comparison of environmental impacts of three contrasting cropping systems for barley production under Mediterranean conditions

Agriculture is a key contributor to environmental degradation and to global change. Consequently, the design of sustainable agricultural systems and the assessment of their relevance is a major priority for European agriculture. Different cropping systems, with variable objectives and constraints, can be used in cereal production in Spain. This study focused in comparing three winter barley cropping systems, ranging from intensive no-till to organic approaches. To assess the environmental impacts of each system, a Life Cycle Assessment was conducted. The findings indicate that the impacts varied depending on the chosen functional unit. When land area was considered the functional unit, the lowest impacts were obtained in the organic system, while the no-till system showed the highest. This difference was primarily attributed to variations in N fertilization. Nitrogen use had a significant impact across various categories, primarily due to the energy demands for its production and transportation, as well as the emissions of NH₃ and N₂O. However, when evaluating agricultural goods production as the functional unit, the organic system exhibited the highest impacts in terms of energy demand, freshwater ecotoxicity and freshwater eutrophication. These differences are explained by the loss of production in the fallow year and the low yields of the legume crop. The middle-way option provided the lowest impacts when economic net revenues were considered. The main reason for this was its higher total revenues associated to high crop production and EU subsidies.