Grassland-based ruminant production systems are integral to sustainable food production in Europe, converting plant materials indigestible to humans into nutritious food, while providing a range of environmental and cultural benefits. Climate change poses significant challenges for such systems, their productivity and the wider benefits they supply. In this context, grassland models have an important role in predicting and understanding the impacts of climate change on grassland systems, and assessing the efficacy of potential adaptation and mitigation strategies. In order to identify the key challenges for European grassland modelling under climate change, modellers and researchers from across Europe were consulted via workshop and questionnaire. Participants identified fifteen challenges and considered the current state of modelling and priorities for future research in relation to each. A review of literature was undertaken to corroborate and enrich the information provided during the horizon scanning activities. Challenges were in four categories relating to: 1) the direct and indirect effects of climate change on the sward 2) climate change effects on grassland systems outputs 3) mediation of climate change impacts by site, system and management and 4) cross-cutting methodological issues. While research priorities differed between challenges, an underlying theme was the need for accessible, shared inventories of models, approaches and data, as a resource for stakeholders and to stimulate new research. Developing grassland models to effectively support efforts to tackle climate change impacts, while increasing productivity and enhancing ecosystem services, will require engagement with stakeholders and policy-makers, as well as modellers and experimental researchers across many disciplines. The challenges and priorities identified are intended to be a resource 1) for grassland modellers and experimental researchers, to stimulate the development of new research directions and collaborative opportunities, and 2) for policy-makers involved in shaping the research agenda for European grassland modelling under climate change.
Leaf production dynamics of timothy (Phleum pratense L. cv. Tarmo) and meadow fescue (Festuca pratensis Huds. cv. Kalevi) were studied in Finland under field conditions in mixed swards containing timothy, meadow fescue and red clover (Trifolium pratense L. cv. Björn) harvested by cutting. Fifteen randomly selected tillers of both species were marked and leaf number, leaf appearance rate (LAR), leaf elongation rate (LER), leaf senescence rate (LSR) and leaf live span (LLS) were followed through weekly observations. Concurrently another set of fifteen tillers of each species was dissected on each occasion to determine the number of unemerged leaves and development stage of the apex. The first observation period was between 26 April and 22 June and the second between 22 July and 22 September.
The species differed clearly for most of the measured parameters but most differences were dependent on the season. In spring, timothy started growth earlier, had higher LAR (+57%), produced more leaves (+83%) with higher LERgross (+58%), higher LSR (+61%), higher LERnet (+54%) and produced larger tillers (+193% in leaf area) than meadow fescue. In autumn, timothy still had a higher LAR (+80%), produced more leaves (+60%) with higher LERgross (+36%), but had also a higher LSR (+77%) and thus similar LERnet (0%) to meadow fescue. Timothy tillers were only slightly larger than meadow fescue tillers (+20% in leaf area). The consequences of these findings on competition in mixed swards and implications for grazing theories are discussed.
The main objective of the study was to compare nutrient balances of phosphorus (P), potassium (K), magnesium (Mg) and calcium (Ca) on fertilized grass pasture (high input) and unfertilized grass-clover pasture (low input) both grazed by dairy cattle. The second aim was to quantify P loss in surface runoff from the fertilized grass pasture. The study was conducted on a lysimeter field that included two surface runoff collector ditches. The whole area was rotationally stocked five times per year and the amount of milk was recorded. Nutrient balances were negative on both grass and grass-clover pastures except the P balance for grass pasture, which was 18 kg ha-1 positive. The amount of total P in the surface runoff from fertilized grass pasture was 1.2–0.9 kg ha-1 y-1. It seems that in short-term ley farming, grass-clover swards can retain nutrients in the soil better than pure grass swards.
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