Long-Term Effects of Vineyard Floor Vegetation Management on Grapevine Physiology, Yield and Wine Quality Under Mediterranean Conditions

Cover crops (CCs) are widely used to improve soil function, support water regulation, and moderate vine vigor. This study evaluated alternative vineyard floor management strategies designed to improve ecosystem services while minimizing excessive competition with grapevines under semiarid Mediterranean conditions. A long-term, three-season field experiment was conducted in Bekoa, Israel, using 4 treatments: standard-management control, selective herbicide promoting annual winter grasses, interrow tall fescue (Festuca arundinacea-TF), and full-TF ground cover. Unlike conventional perennial CCs, the selective herbicide treatment promoted naturally occurring winter grasses that completed their life cycle before the dry summer period, thereby limiting prolonged competition with grapevines. Vine water status, vegetative-growth, yield components, and wine-quality parameters were monitored. Grass-based treatments progressively reduced vegetative growth and induced moderate vine water stress, as reflected by lower leaf area index and more negative stem water-potential. Yield declined over the three growing seasons due to reductions in cluster number, with the strongest effects observed in perennial turfgrass. In contrast, the selective herbicide treatment consistently produced intermediate physiological and agronomic responses. In the third season, wines from the perennial turfgrass treatments exhibited greater color intensity, particularly under full-cover TF, while hue was not significantly affected. Overall, CC-based vineyard floor management affected vine performance and wine quality, but the response depended on cover-type and duration of use. The selective promotion of naturally occurring winter grasses through targeted herbicide application represents a practical vineyard floor management strategy that retains many of the benefits associated with vineyard floor vegetation while minimizing excessive summer water competition under Mediterranean conditions.