Climate change-induced drought is an important driver of losses in forage yield and nutritive value in permanent grasslands, with water scarcity inducing up to 40% decrease in forage yield. Producing high-quality forage to feed livestock is becoming challenging and innovative solutions are thus needed to tackle this challenge, especially in the context of climate change. The Grazing Systems group of Agroscope is currently testing two novel solutions to maintain forage production in grassland areas strongly impacted by summer drought. In mountains, new forage mixtures varying in their dominant plant species and their abundance of drought-resistant species (0, 15 or 30%) have been created and seeded in the canton of Bern. These mixtures include a high abundance of legumes to promote atmospheric nitrogen fixation and reduce the need for nitrogen fertilization. A drought simulation (7 weeks in summer) has also been applied to evaluate the drought resistance of these mixtures in term of yield and nutritive value. In the lowland, a new agroforestry system consisting of fodder tree hedgerows is also evaluated to provide supplementary forage resources in summer. Indeed, trees are more resistant to drought due to their deeper root system that can access water in deeper soil layer. Six trees species that are resistant to drought and frost and known for the high nutritive value of their leaves for livestock have been planted in seven grassland sites in Western Switzerland. Leaves production and their nutritive value are assessed together with their palatability in livestock and their impact on methane emissions when included in the animal diet. Findings from both agricultural practices are promising to sustainably maintain forage production in Swiss grasslands under climate change.
