Implementing a fodder tree hedgerow system in permanent grasslands as supplementary forage resources
AgroForageTree, 2024-2028, SNSF project n°215044 (PhD Julie Botzas-Coluni)
Agroforestry for forage production could be a promising solution to provide additional tree-based forage, especially during summer, when risks of drought-induced decrease in forage production are the highest. Leaves of specific fodder tree species, such as Fraxinus spp., Morus spp. and Salix spp. can have excellent digestibility and nutritional value for livestock. Moreover, many fodder tree species achieve their maximum leaf production over summer and they can maintain high leaf forage quality until late summer/early autumn, i.e. when forage yield, quality and digestibility of herbaceous species generally decrease, above all during drought periods. The AgroForageTree project aims at evaluating the potential of fodder tree hedgerows to provide supplementary tree-based forage (in addition to grass-based forage) in late summer-beginning of autumn and is organized following four main objectives, i) monitoring the survival, annual growth and photosynthetic activity of five selected fodder tree species in different permanent grassland sites across an altitudinal and climatic gradient, ii) determining leaf production and leaf chemistry and digestibility of the five fodder tree species and their variation along the vegetation season, iii) investigating the impacts of fodder tree hedgerows on ecosystem biodiversity and services after the establishment of the agroforestry system, and iv) assessing the palatability and selection for the five fodder tree species by different livestock categories, as well as methane emissions, nutrient absorption and digestibility resulting from the tree-grass diet.
Determining drought-resistant mixtures for temporary mountain grasslands
DryMount, 2023-2026, Funding from Agroscope and Swiss Cantons (PhD Emilie Roinel)
Permanent grasslands play a pivotal role in Switzerland because of the forage yield and quality they produce, mainly resulting from the productivity of a few dominant species with functional traits associated with acquisitive resource strategy. By contrast, numerous low abundant species, which have traits associated with conservative resource strategy, tend to grow slower and produce less biomass than these dominant species. However, they may be more resistant to drought and compensate for the decline of more competitive dominant species during drought events. This four-year project aims to assess the resistance of different permanent mountain grassland mixtures to summer drought events, simulating future climate change scenarios on Swiss mountain areas. Nine new mixtures were created to evaluate the best compromise between productivity and drought resistance. The mixtures are based on the dominance of the main, more productive species and the proportion of species considered drought-resistant. They are dominated either by cocksfoot or meadow foxtail, or by these two species together, supplemented by other species common to standard mixtures. Drought-resistant species (red fescue, ribwort plantain, common bent and birdsfoot trefoil) are added to this basic mix. Two mixtures commonly sown in mountain areas serve as controls. A total of 11 mixtures are sown on the 5 sites of the project in May-June 2023, along a rainfall gradient (850 to 1600 mm). Drought events will be tested by means of rainout shelters compared to ambient conditions at one site. The results of this study will guide the choice of drought-tolerant mixtures for sustainable delivery of mountain grassland services and increase general understanding of the response of temporary grassland communities to future drought.
Targeted grazing of robust livestock for the restoration of green alder-encroached pastures
ROBUSTALPS, 2019-2023, SNSF project n°184925 (PhD Mia Svensk)
Throughout the last decades, the reduction of agro-pastoral activities in Swiss mountain areas has determined profound landscape modifications, with extensive reforestation processes over former pastures, particularly by green alder (Alnus viridis), which is the most expanding shrub species across all Central Europe. The project aims to investigate specific ecological dynamics, such as botanical composition evolution and N translocation fluxes, in A. viridis-encroached pastures under the challenge of targeted grazing. We propose to strategically place attractive points (AP), i.e. molasses-based salt blocks, within encroached areas to increase their exploitation by robust livestock species (here Highland cattle). With AP placement, we expect to increase the time spent by livestock herds within A. viridis-encroached areas, their consumption of green alder foliage, N content in their excreta, and consequently N translocation towards livestock resting areas. Moreover, thanks to the actions exerted by animals around AP locations, such as increased A. viridis defoliation, mechanical damages to green alder branches by trampling, as well as seed transportation, significant variations in vegetation communities are also expected, with beneficial effects on the restoration of typical pasture botanical composition. Therefore, this research could help filling knowledge gaps on the (i) forage potential of A. viridis foliage for robust animals, (ii) short-term vegetation dynamics after intense livestock pressure in green alder-dominated areas, (iii) and N redistribution fluxes within encroached pastures. As a consequence, it could provide useful insights to design innovative and sustainable grazing management systems for the restoration of A. viridis-encroached pastures.
Swiss grasslands supply multiple benefits and services as a function of their management, the plant species of which they are composed, and pedo-climatic conditions. Thanks to the development of cross-disciplinary decision-support tools, the farmer or any other decision-maker should be able to grasp these services in their multiplicity and optimise them for contrasting conditions and production systems. Managing grasslands also means managing species communities. To make the best use of these communities, we must also know about grass growth and quality, and master grassland conservation. The ‘IntoGrass’ project aims to develop tools to facilitate grassland management, grass utilization and grass quality assessment, focusing particular attention on the effect of pedo-climatic factors. Launched in 2017, this transdisciplinary project involves four Agroscope teams, and is based on a network of 32 grasslands distributed across Switzerland, which will help us better understand the impact of climatic conditions (temperature, precipitation) on grass growth and quality.
Interactive effects of altitude and management on resistance and resilience of permanent grasslands to drought: combining agronomic, functional and ecophysiological approaches
GRASSALT, 2016-2019, SNSF project n°156282 (PhD Amarante Vitra)