How choices in plant material and plantation practices (variety, rootstock, planting density and vine age) affect grapevine yield for main wine labels. Analysis of a big dataset from surveys to winegrowers in Languedoc-Roussillon.

Abstract

Abstract In vineyards, decisions regarding plant material and plantation practices are crucial for winegrowers when planning future vine plots. These choices often navigate within the bounds set by wine labels and are contingent upon a spectrum of management options. However, the comprehensive influence of these decisions on grapevine yield at a large scale remains a relatively unexplored domain. A deeper understanding of how plant material and planting strategies impact grapevine yield stands as a potential avenue for mitigating yield losses, especially exacerbated by the repercussions of climate change, thereby ensuring sustainable wine production. In this study, we employed random plot data from national surveys conducted among winegrowers in the Languedoc-Roussillon viticultural region (n = 3507). Our analysis focused on examining the relationship between grapevine yield and: i. plant material (varieties, rootstocks); ii. plantation practices (planting density, vine age); considering diverse vineyard management approaches (wine label, organic management, irrigation). Data analysis encompassed graphical observations, statistical tests, and modeling to evaluate the impact of these factors on grapevine yield. Our findings indicate that most cultivated varieties exhibited similar yield levels for the same type of wine label. Notably, SO4 rootstock displayed the best yield performance across multiple cultivated varieties. The combined influence of vine age and wine label explained up to 40% of the total yield variance. We observed a minor adverse effect of vine aging on grapevine yield, particularly in highly productive vineyards under the PGI wine label. However, the impact of vine age on yield in PDO wine plots was almost negligible. Organic management did also demonstrate an influence on yield. Unexpectedly, planting density did not significantly affect yield. These results underscore the significance of conducting real winegrowers' big data analysis at a regional level, particularly in connection with wine label and management choices.