Impact of training system, soil management and soil water holding capacity on vine water status in a changing climate over 60 years in the Cognac production area

Abstract

This study investigates the impact of vine training systems on water deficits in the Cognac region (France), through the application of a vine water balance model, taking into account different soil water holding capacities (SWHC) and soil management strategies, including grass cover. Using climate data from the SAFRAN gridded database, over 2 million simulations were performed for the period 1962 to 2021 to quantify the response of grapevine water status under varying training systems and environmental conditions. Indices based on simulated relative stomatal conductance were developed to characterise the intensity of grapevine water deficit during the critical flowering-to-maturity period. Results show a significant trend of increasing water deficit between 1962 and 2021, particularly in the north-western part of the region, affecting 23 % of the Cognac production area. Sensitivity analysis of the water balance model indicates that SWHC is the predominant factor influencing grapevine water status, explaining nearly 80 % of the variance in water deficit days. The simulations further suggest that adjustments in canopy width and grass cover have a significant effect on the duration and severity of water deficit. The methodology developed in this research allows quantifying the relative importance of major drivers of vine water deficits: SWHC, training system parameters and vineyard floor management, under different climatic conditions. It can be used as a basis for providing easy-to-implement vineyard management strategies to mitigate the effects of climate change in viticulture. It was applied to the Cognac region, but the workflow developed is applicable to any grape-growing region in the world.

Keywords

• grapevine
• water status
• modelling
• sensitivity analysis
• FTSW
• climate change