The risk of frost in the vineyards of the Bergeracois is a significant issue that can severely affect harvests. This risk is particularly high during spring frost events, between March and April, when the vine is in the budburst stage and young shoots are highly sensitive to cold.
Two main types of frost can be identified in vineyards: radiation frosts, which occur during clear and calm nights, and advective frosts, associated with the arrival of cold air masses, generally accompanied by wind, making them more difficult to control. To address this risk, winegrowers use different passive and active frost protection strategies, whose effectiveness depends on local and meteorological conditions.
To evaluate the impact of different active and passive frost mitigation techniques in vineyards, using new technologies such as thermal drones and lidar systems, in order to identify and recommend the most effective passive frost protection strategies under real field conditions.
The main activities of the pilot trial include:
literature review on frost events in vineyards,
preparation of agrometeorological equipment and installation of field devices,
instrumentation of the pilot plot with a complete weather station and soil and air temperature and humidity sensors,
analysis of recorded data for the characterisation of winter and spring frost events under different treatments,
acquisition of high-resolution thermal images through drone flights during real frost events,
planning of additional thermal flights depending on the evolution of meteorological conditions.
The pilot trial is located in a vineyard plot in the Bergerac wine-growing area, within the Monbazillac appellation, in the municipality of Pomport. In addition to the main plot, complementary monitoring is carried out on two other Monbazillac plots and one plot in the Pécharmant appellation, applying a simplified protocol with the aim of developing a lighter and more replicable monitoring methodology.
The main plot is equipped with a complete agrometeorological station measuring potential evapotranspiration (ETP) and ultraviolet (UV) radiation. This instrumentation is complemented by soil moisture and temperature sensors using tensiometry and capacitive probes, as well as temperature sensors installed on the vegetation and in the soil.
The collected data are integrated into specialised data management platforms, allowing continuous monitoring of climatic conditions and vineyard thermal behaviour during frost events.
At the beginning of March, an initial drone flight was carried out under frost conditions, together with a lidar study of the plots, with the aim of quantifying the impact of passive frost protection strategies. Depending on meteorological conditions, additional flights are planned during the first half of April, at night, at sunrise and in the mid-morning period.
The results of the trial will subsequently be shared with CA24 viticulture specialists and the winegrowers involved, within the framework of the project’s technical committees.
