Use of White Non-Woven Polyester Sheets (TNTs) to Control Photoinhibition, Berry Dehydration, and Extreme Heat in the Vineyard

The protection of leaves from photoinhibition and berries from dehydration and sunburn has become an increasingly important objective in response to the rising frequency and intensity of heat waves worldwide. This research investigated the effect of a white nonwoven geotextile sheet (TNT) installed in the fruiting zone in the white cultivar ‘Verdicchio’ (Vitis vinifera L.) during critical summer periods with the aim of protecting leaves and berries from extreme heat. The study was conducted over two seasons (2020–2021) in a rainfed vineyard in central Italy using a randomized block design. Physiological and yield parameters were recorded. Vines protected with TNT did not show any changes in net photosynthesis, stomatal conductance, and water use efficiency, compared to unshielded vines. However, TNT reduced leaf temperature and increased berry total acidity and malic acid concentration while reducing sugar content, leading to wines with higher freshness and reduced alcohol levels. The use of TNTs shows significant potential as a practical tool for viticulturists to mitigate the effects of excessive heat, allowing for better management of berry ripening and ultimately improving final wine characteristics. Additionally, TNT is economically feasible, especially if applied only to the afternoon-exposed side of the canopy, and its cost can be amortized, especially in vineyards affected by frequent heat waves and/or dedicated to the production of premium wines.