Piloting grape ripening in a global warming scenario: feasible techniques are available

The grape volatile compounds determine the wine quality and typicity [1]. Thus, looking for agronomic tools to improve its composition it is of great interest in the sector [2]

Drought is one of the main challenges for viticulture in the context of climate change. Selecting drought-tolerant plant material can be an effective strategy for a sustainable viticulture.

Grape Phylloxera (Daktulosphaira vitifoliae Fitch) ordinarily has great difficulty establishing leaf galls on the European Grapevine (VitisviniferaL.). Yet populations of leaf-feeding Phylloxera are increasingly being observed throughout commercial vineyards world-wide. Effective plant protection strategies including quarantine actions are currently missing to fight, grape phylloxera populations in affected vineyards and combat linked negative effects on vines and yield. Contrary to the otherwise mandatory continuous infestation pressure from externally established populations (e.g. from populations developed on rootstock foliage or other interspecific hybrids, these leaf-feeding populations seem to establish themselves annually.

The impact of viticulture on soil can be determined by comparing the biophysical properties that represent soil health at a particular site and depth with those same properties in soil considered to represent the ‘pre-vineyard’ state (the headland). Information gathered by this method shows the changes in soil properties following the change to viticulture depend on individual vineyard management and environment.

Heatwaves or extreme heat events can be particularly harmful to agriculture. Grapevines grown in the Douro winemaking region are particularly exposed to this threat, due to the specificities of the already warm and dry climatic conditions. Furthermore, climate change simulations point to an increase in the frequency of occurrence of these extreme heat events, therefore posing a major challenge to winegrowers in the Mediterranean type climates. The current study focuses on the application of the STICS crop model to assess the potential impacts of heatwaves in grapevine yields over the Douro valley winemaking region. For this purpose, STICS was applied to grapevines using high-resolution weather, soil and terrain datasets over the Douro. To assess the impact of heatwaves, the weather dataset (1989-2005) was artificially modified, generating periods with anomalously high temperatures (+5 ºC), at certain onset dates and with specific durations (from 5 to 9 days). The model was run with this modified weather dataset and results were compared to the original unmodified runs. The results show that heatwaves can have a very strong impact on grapevine yields, strongly depending on the onset dates and duration of the heatwaves. The highest negative impacts may result in a decrease in the yield by up to -35% in some regions. Despite some uncertainties inherent to the current modelling assessment, the present study highlights the negative impacts of heatwaves on viticultural yields in the Douro region, which is critical information for stakeholders within the winemaking sector for planning suitable adaptation measures.