Impact of drought on the water status of vines in a Bordeaux vineyard

France is one of the largest producer of wine in the world. Thus, viticulture is a major activity area, particularly in south-west of France where vineyards occupy as much as 42% of the agricultural surface. Vineyards worldwide are being subjected to stress brought about by changes in average temperatures, precipitation, seasonal timing that drives phenology, as well as extreme weather events (van Leeuwen, 2004). Specifically, the Bordeaux vineyards are submitted to strong climate change impact, due to the increase in the duration of heat waves (i.e., increase in evaporative demand), and the decrease in summer precipitations (i.e., decrease in water availability in the soils; Soubeyroux et al., 2020). These stressors contribute to Grape yield and quality.

Our approach consists of identifying the factors that control water availability in vineyard soils in order to adapt cultivation practices.

For this purpose, we have instrumented a vineyard plot (~1 ha) in Medoc. This observatory allows the monitoring of water fluxes within the soil-vine-atmosphere continuum on two rows of vines located in areas with contrasting soil types: one is located in a sandy area, while the other is located in a clayey area. The observatory combines:

• Soil water status monitoring with
• Spectral Induced Polarization (SIP) measurement campaigns carried out along the two selected rows of vines and repeated at a bi-monthly rhythm,
• two permanent multi-level soil water content probes
• Vines water status monitoring using sap flow sensors, together with water potential measurement campaigns repeated on a monthly basis

• Ground water level continuous measurement sensors
• Meteorological parameters monitoring

Our observations show that during the drought of the summer 2022, the vines in the sandy row suffer of greater water stress than the vines in the clay row, and that the soil in the sandy row dries out more quickly and to a greater depth than the soil in the clay row. This highlights the impact of soil type on soil water availability. Our early results suggest that in the case of a prolonged drought period, the vines located on clay plots would thus suffer less from water stress than in the case of plots with more draining soil.

Références:

Soubeyroux, JM, Bernus, S, Corre, L, Gouget, V, Kerdoncuff, M, Somot, S, Tocquer, F, 2020. Le nouveau jeu de simulations climatiques régionalisées sur la France pour le service DRIAS, XXXIIIeme colloque de l’Assoc Internat de Climatologie, pp 637-642.

Van Leeuwen, Cornelis, Philippe Friant, Xavier Choné, Olivier Tregoat, Stephanos Koundouras, and Denis Dubourdieu. 2004. Influence of Climate, Soil, and Cultivar on Terroir. American Journal of Enology and Viticulture 55(3):207–17. doi: 10.5344/ajev.2004.55.3.207.