Rainout shelters as a tool to simulate climate change impacts on the vineyard ecosystem

Abstract

Drought can impact grapevine physiology, yield, berry composition and wine quality, as extensively demonstrated in controlled experiments (Flor et al., 2025; Hewitt et al., 2023). However, the effects on the whole vineyard ecosystem, combining vegetation, soil and its microbiome remain under explored in cooler viticultural regions.

To address this gap, we set up a drought simulation experiment in a vineyard in Yvorne, Switzerland, planted with cv. Chasselas L. on 3309C. Four rainout shelters were installed in April 2024 to exclude natural rainfall. Each shelter consists of a 200 μm ethylene-vinyl acetate plastic film, mounted on a 22.5 x 6.50 m steel frame, open laterally and at both ends to allow free air circulation and covering four vine rows. Along each side, a buffer row limits lateral water inflow. Temperature, humidity and light radiation are monitored continuously at 1 m height for each treatment.

Three water supply regimes are simulated under the shelters, via centralized irrigation: 1) control regime reproducing the 20-year average local rainfall; 2) moderate to severe water deficit based on RCP 8.5 projections for 2085; 3) severe water deficit, with water supply reduced to 50% of the 2085 projections. An external rainfed treatment is included for each replicate. Each shelter represents one replicate, with identical treatments. Vine physiology, berry composition, plant species composition, soil properties and soil microbial diversity are monitored over the 2024-2026 growing seasons.

In 2024, average air temperature under the shelters was +1.2 °C higher in July and +1.5 °C in August compared to the external treatment, with daily maxima up to +2°C during hot periods. Light intensity inside the shelters tracked ambient conditions, with a median transmission of 94%. During midsummer, transmission reached 120–150% around midday, likely due to enhanced light diffusion and internal reflections caused by the plastic film. Severe water deficit reduced vine fertility, berry weight, yield and most assimilable nitrogen compared to the control and altered soil cover by increasing mulch prevalence and drought-tolerant species cover, such as Plantago lanceolata.

This experiment provides an integrative, field-scale platform to disentangle coupled responses of grapevine, soil and associated vegetation. The combined modification of the light radiation, temperature and water availability, creates realistic multi-stress conditions that must be considered when interpreting vineyard and soil responses. These shelters represent a powerful tool for drought research, enabling more robust predictions of vineyard behaviour under future climate scenarios and supporting the development of targeted adaptation strategies.

References

Flor, S., Toro, G., Carriquí, M., Buesa, I., Sabater, A., Medrano, H., Escalona, J. M. (2025). Impact of severe water stress on drought resistance mechanisms and hydraulic vulnerability segmentation in grapevine: the role of rootstock. Journal of Experimental Botany, 76 (11), 3141–3157. https://doi.org/10.1093/jxb/eraf044

Hewitt, S., Hernández-Montes, E., Dhingra, A. et al. (2023). Impact of heat stress, water stress, and their combined effects on the metabolism and transcriptome of grape berries. Sci Rep 13, 9907. https://doi.org/10.1038/s41598-023-36160-x