Influence of field beans (Vicia faba L.) on yield and environmental footprint of following spring barley (Hordeum vulgare L.) crops

Background and Aims
The urgent need to reduce greenhouse gas emissions has increased interest in legume-based cropping systems. Among the various crop-legume species available, the cool-season species Vicia faba L. (cv. minor; field beans) has attracted significant interest. Assessment of the environmental impact reduction of field beans in a crop-sequence (rotation) is understudied.

Methods
Data from a long term (2009–2023) field bean experimental platform (the Centre for Sustainable Cropping, CSC; James Hutton Institute, Scotland, UK) were analysed using attributional life cycle assessment (aLCA). This focused on elaborating the impacts of a spring field bean to spring barley (Hordeum vulgare L.) cropping sequence compared with a spring barley to spring barley cropping sequence.

Results
Field beans decreased the environmental impact of spring barley production in four of the five two-year crop-sequence periods, with mean impact reductions of approximately 25% across sequences. Spring barley grain yields tended to increase following field beans under drought conditions (2022). A combined index analysis indicated that humidity, maximum temperature, and previous field bean yields were the strongest determinants of spring barley production.

Conclusions
The integration of field beans to cereal-dominated rotations may be of interest to major industries who seek to improve value chain sustainability, whilst ensuring crop-sequence yields are climate-impact resilient.