Beschreibung

The rate of warming in South Tyrol significantly exceeds the global average, a trend which, depending on anthropogenic greenhouse gas emission pathways, is projected to continue during the 21st century. Even though past and projected future trends in precipitation are largely absent in the area, the warming is expected to exacerbate aridity due to increases in evapotranspiration and changes in the timing and amount of runoff from snow and glacier melt supplying water for irrigation. As a consequence, agriculture in South Tyrol is expected to face an increasing frequency in heatwaves and drought periods with consequences for viticulture, which already has experienced significant temperature-driven advances in phenology and harvesting dates. In recent years, the local wine industry has reached a level of excellence recognised in national and internationals markets. In order to a avoid reductions in the quantity and especially in the quality of vine production and associated economic losses, an early detection of abiotic (temperature and drought) stress for grapevine is of vital importance for mitigating negative consequences of climate extremes on viticulture. Capitalising on the complementary expertise available at the University of Innsbruck (Department of Ecology), the Free University Bolzano (Faculty of Science and Technology) and the Research Center Laimburg (Research Area Viticulture), the proposed project will explore the use of chlorophyll fluorescence at leaf, canopy and landscape scale in a combination of field and laboratory experiments as an early warning signal of abiotic stress and will investigate the effects of heatwaves and drought on the quality of grapevine berries. 

The major hypothesis underlying this project is that temperature extremes and drought, in particular in combination, will affect (i) the carbon balance of grapevine through stomatal and non-stomatal limitations of photosynthesis and (ii) that this in turn will lead to yield reductions and the berry and wine quality, as a consequence of the degradation of organic acids, the oxidation of aromatic volatile compounds and of sunburn damages. To this end, the multi-disciplinary project team will blend measurements using the well-established active chlorophyll fluorescence technique with novel proximal and remote sensing of passive (solar-induced) chlorophyll fluorescence and concurrent measurements of the carbon dioxide and water vapour exchange at leaf and ecosystem scale. The consequences of the climate stress on the grape and wine quality will be established by the evaluation of physiological disorders of the grapes, the assessment of the ripening progress and the measurement of stress indicators in the musts and in the wines. For this purpose, microvinifications of grapes treated with different stress levels will be executed and the wine quality will be assessed by experts.

Partner

Lead Partner Universität Innsbruck, Institut für Ökologie, Partner Versuchszentrum Laimburg, Partner Freie Universität Bozen, Fakultät für Ingenieurwesen