Background/objectives:
Sorghum bicolor (L.) Moench is still a minor crop in Switzerland, with approximately 400 ha currently under cultivation. Agronomic recommendations for temperate environments are therefore still limited. As a drought-adapted C4 species with high biomass potential, sorghum may contribute to climate-resilient cropping systems and serve as an alternative to maize, particularly in regions where forage production is challenging.
Methods:
A three-year field trial (2022-2024) was conducted in Zurich (Switzerland). Four sorghum varieties (CSSH-45, ES Athena, ES Biomass, KWS Zerberus), one maize variety (P8834) and a maize-sorghum mixture were evaluated at three row spacings (37.5, 50, and 75 cm) and three seeding densities. Agronomic performance was assessed using multiple traits, including lodging, dry matter (DM) yield, net energy for lactation (NEL) and digestibility of organic matter (DOM).
Results:
Variety was the main factor influencing both DM yield and forage quality. ES Biomass and KWS Zerberus achieved higher DM yields, whereas CSSH-45 and ES Athena showed superior NEL and DOM values. Overall, sorghum reached energy yields comparable to maize, although distinct varietal differences were observed in the balance between biomass production and forage quality. Increasing seeding density significantly increased DM yield but partially increased lodging. Row spacing significantly affected DM yield, with the highest yields observed at 50 cm, whereas no consistent effect on forage quality parameters was detected.
Conclusion:
These findings highlight the importance of varietal selection and planting configuration for optimizing sorghum production under temperate Swiss conditions. While higher plant populations increased DM yield, they were also associated with greater lodging risk, whereas forage quality was mainly determined by varietal differences.