Multi-criteria assessment of integrating legumes into cropping systems across Europe

Abstract

Integration of legumes into European agricultural systems would diversify the highly specialized cropping systems that are dominated by cereals and increase resource efficiency of agricultural systems. By providing high quality protein for food and feed as well as regulating and supporting services, legumes contribute essential ecosystem services. In order to assess the overall effects of legumes in agricultural systems, it is necessary to consider how legumes are integrated in cropping systems and evaluate the impacts of this integration. As legumes influence the production of other crops in the rotation and as the interaction of legumes are multiplex, an assessment of the cropping system that considers multiple criteria is required. The objective of this work was to assess the impacts of changes in crop rotations through the integration of legumes using cropping systems implemented in practice. We used a multi-actor approach to incorporate the knowledge of a range of legume experienced actors representing value chains with soybean, pea, faba bean, lupin and forages for food and feed and evaluate thereby the role of legumes in crop rotations of diverse systems from Ireland in the West to Ukraine in the East. Within the research process we firstly identified region-specific crop rotations with cultivation techniques based on expert opinion in the 17 different study areas. One rotation representing the current farming without legumes and at least one alternative legume-based crop rotation was specified per region. Secondly, a valid set of indicators was developed, including environmental, economic and agronomic indicators. The indicators were calculated for each cropping system at the rotational level, considering pre-crop effects i.e. adapted N fertilizer application rates and yields. Finally, the cropping system assessment compared current farming practices to legume-based alternatives. Trade-offs and synergies between different indicators e.g. gross margins and N fertilizer use were identified. On average, crop rotations with legumes reduced nitrous oxide emissions by 21% and 26% and N fertilizer use by 26% and 45% in arable and forage systems, respectively. While protein output was increased by 13% and 5%, energy output was reduced by 10% and 9% in arable and forage systems. Gross margin effects of introducing legumes were variable and site specific. Consideration of the full economic value of the crops as feed, subsidies for legumes, and the application of carbon taxes increased the relative performance of the legume-supported systems. The presented cropping system assessment within a multi-actor approach enables an exploration of the opportunities and challenges for integrating legumes in European crop rotations considering the views of local actors and can thereby provide multi-criteria guidance on the validation of potential alternative strategies.