Recent initiatives to increase European protein production while reducing fertiliser and pesticide use have reinforced the importance of cropping systems that remain productive with lower inputs. This study evaluated the effects of cropping system and fertiliser level on silage yield and quality, land use efficiency, and incidences of pests and beneficials. Field experiments were conducted in 2024 and 2025 with maize pure stands, bean pure stands and maize–bean mixed cropping at 100% and 75% of the Swiss recommended nitrogen fertiliser rate. In 2024, the mixed crop and a lower fertiliser rate reduced silage yield, whereas no differences between cropping systems and fertiliser application rates were observed in 2025. The mixed crop had an increased protein content in 2024. The land use efficienc was increased by mixed cropping, indicated by a land equivalent ratio that exceeded 1. Regarding natural enemies, lacewing oviposition was higher on maize plants than bean plants. Mixed cropping resulted in more pollinator visits compared to maize pure stands. By combining agronomic and agroecological parameters, this study evaluates the potential of maize–bean mixed cropping as a strategy to reduce environmental impacts while maintaining productivity.