Climate change is putting a strain on forage production in Switzerland and large parts of Europe, in particular due to increasing climatic extremes, such as periods of drought alternating with heavy rainfall. In this study, five different drought-resistant summer leys were tested on three farms in the Swiss Jura: (1) Sudan grass (Sorghum sudanense); (2) hybrid sorghum (Sorghum bicolor × Sorghum sudanense) – Persian clover (Trifolium resupinatum) – Egyptian clover (Trifolium alexandrinum); (3) foxtail millet (Setaria italica); (4) pearl millet (Pennisetum glaucum); (5) black oat (Avena strigosa) – Crimson clover (Trifolium incarnatum); and compared with a commonly used ley (6) oat (Avena sativa) – pea (Pisum sativum) – common vetch (Vicia sativa). The trial was carried out during the summers of 2021 (characterized by heavy rainfall in July) and 2022 (characterized by drought in July and extreme temperatures in July and August). The yields and the costs of the six leys were assessed. The yield was significantly different among leys (P<0.001), while there were no significant differences between years. Overall, the leys providing the highest biomass production were (2) and (3), with 2.8±0.2 and 2.9±2.1 Mg DM ha-1. Our results show that there is a range of summer leys that can be sown to produce forage as an alternative to (6), at comparable or often lower costs. Their nutritional quality will be analysed to assess possible adaptation strategies to climate change.
