Application of satellite-derived vegetation indices for frost damage detection in grapevines

The increasingly frequent heat waves during grape ripening pose challenges for premium wine grape production. This makes the development of irrigation and canopy management techniques of great importance to maximize yield and grape quality. A field experiment was carried out during 2021 and 2022 using Manto negro wine grapes to study the effect of two irrigation strategies and different light exposure levels on grape quality.

Red grapes contain significant amounts of phenolic compounds, known to contribute to wine quality and to provide important health benefits. Berry skin phenolics can be elicited by plant hormones. The aim of this work was to increase the content of anthocyanins and trans-resveratrol in five red varieties cultured in Argentina: Malbec (M), Bonarda (B), Syrah (S), Cabernet Sauvignon (CS), and Pinot Noir (PN), in two different growing regions: Santa Rosa (SR) and Valle de Uco (VU), by applying a post-veraison hormonal treatment with abscisic acid (ABA) and methyl jasmonate (MeJA).

Barolo DOCG is an economically important wine producing region in Northwest Italy. It is a small region of approximately 70 km2 gross area. The topography is very complex with steep sloped hills ranging in elevation from below 200 m to 550 m. Barolo DOCG wine is made exclusively from the Nebbiolo grape. Bioclimatic indexes are often used in viticulture to gain a better understanding of broader climate trends which can be compared temporally and geographically. These indexes are also used for identifying potential phenological timing, growing region suitability, and potential risks associated with expected climatic changes. Understanding how topography influences bioclimatic indexes can help with understanding of mesoscale climate behaviour leading to improved decision making and risk management strategies. The average monthly maximum and minimum temperatures, the Cool Night Index, the Huglin Index, and the monthly diurnal range (from July to October) were calculated using data from 45 weather stations within a 40 km radius of the Barolo DOCG growing area between the years 1996 and 2019. Linear and multiple regression models were developed using independent variables (elevation, aspect, slope) extracted from a digital elevation model to identify significant relationships. Bioclimatic indexes were then kriged with external drift using independent variables that showed significant relationships with the bioclimatic index using a 100 m resolution grid. The maximum monthly temperatures and the Huglin Index showed consistent significant negative relationships with elevation in all years. The minimum monthly temperatures showed no relationship with elevation but in some months a small but significant relationship was observed with aspect. Due to the lack of a relationship between minimum monthly temperatures and elevation compared to the significant relationship between maximum monthly temperatures and elevation, monthly diurnal range had a negative relationship with elevation.

A multidisciplinary approach aiming at studying the grape-growing areas also referred as “Terroir” was initiated a few years ago in Switzerland.

Plus de la moitié du vignoble suisse (14’000 ha) est situé sur des coteaux en forte pente (> 30%). Dans certains vignobles, la pente naturelle du terrain a été réduite par la construction de terrasses soutenues par des murs.