Canopy management as a short-term adaptation strategy to counteract heatwaves' impacts on grapevine

Viticulture faces significant challenges due to climate change, impacting grapevine growth, grape quality, and wine production. Environmental factors such as rising temperatures, altered precipitation patterns, and extreme weather events are undergoing substantial changes. These issues, once confined to warmer regions of Southern Europe, now affect cooler areas like Northern Italy, where there is an increasing frequency of storms, heavy rainfall, and heatwaves, which can lead to ripening arrest and quantitative and qualitative losses (i.e. sunburn). This issue affects both red and white grape varieties, with white grapes particularly vulnerable due to reduced acidity levels, crucial for aromatic and sparkling wine production. To address the impact of high day and nighttime temperatures in the summer (from July until harvest), we tested different short-term adaptation solutions, including the use of shading nets and the spraying of particle films such as kaolin and zeolite, the first reducing overall incoming solar radiation and the latter increasing solar radiation reflectance, thereby reducing the temperature of the vine canopy and the grapes. The experiment was carried out in an organic vineyard of Vitis vinifera cv. Glera intended for Prosecco wine production. From pre-véraison to harvest, continuous monitoring of berry temperature and canopy microclimate was carried out, and physiological and morphological measurements were taken. Overall, the results revealed significant differences among the treatments in terms of plant yield, berry size, and the chemical composition of the grape must, suggesting these approaches may hold relevance for other viticultural regions facing heat-related challenges. Additionally, photosynthetic activity varied between treatments, further highlighting the potential usage of these applications in mitigating the impacts of high temperatures on grapevine physiology and wine production.