Although climate change is often mainly associated with droughts, heatwaves and wildfires, it also has very negative effects on agriculture related to the alteration of the natural development cycles of plant species. The increase in winter temperatures promotes earlier flowering, which increases crop vulnerability to spring frosts.
In the case of chestnut trees, the risk of spring frosts extends from early March to mid-May. During this period, the phenological stages most sensitive to cold correspond to stages B (BBCH 07), C (BBCH 09) and D (BBCH 11), with sensitivity thresholds of −8 °C, −3 °C and −2 °C, respectively. Frost events can cause damage to apical buds and fruit buds, leading to potentially very high losses.
This risk is exacerbated by the advancement of the main developmental stages of chestnut trees in the context of climate change, especially in well-exposed plots with south-western orientation, where budburst, flowering and ripening have advanced by several days, and even weeks, in recent years.
To measure the influence of soil moisture and ground cover management on the intensity of spring frost events in a chestnut orchard, assessing how these factors condition the thermal behaviour of the crop–soil–atmosphere system.
The trial is carried out in an experimental plot managed by Invenio, located in Douville (Dordogne, France). The plot, planted in 2014, covers an area of approximately 1.83 hectares and presents a marked topographic gradient, with altitude differences between the upper and lower parts of the orchard, allowing the analysis of the effect of relief on frost intensity.
The plant material consists of Bellefer and Bournette chestnut varieties, alternated by rows, with the presence of pollinating varieties, grafted onto Marsol rootstock.
The plot is divided into two experimental modalities:
MAg1 (wet modality): soil maintained close to field capacity through irrigation, combined with intensive ground cover management through frequent mowing during the frost risk period.
MAg2 (dry modality): non-irrigated soil with full ground cover maintained, without mowing during spring, with the aim of promoting soil drying.
This design allows comparison of the effect of soil water content and ground cover management on the intensity of spring frost events.
The main activities of the trial include:
preparation and adaptation of the experimental plot for the implementation of the two modalities,
installation of differentiated irrigation systems and soil moisture sensors,
high-precision real-time climatic monitoring,
monitoring of spring frost events,
assessment of crop yield during the 2024, 2025 and 2026 seasons,
acquisition of high-resolution thermal images through drone flights during real frost events.
The orchard is equipped with complete meteorological stations and specific sensors to monitor air temperature at different heights, relative humidity, soil moisture and leaf wetness. In addition, Tinytag stations installed on representative trees are used to measure air and soil temperature.
Climatic monitoring has been carried out continuously since October 2024, providing detailed time series for the analysis of orchard thermal behaviour during frost events.
Drone flights equipped with radiothermal cameras are carried out to map the spatial distribution of temperatures during frost events. Flights are scheduled one hour before sunrise, at sunrise and under daytime conditions, in order to capture the thermal evolution of the orchard and compare the effect of the two management modalities.
