Long-Term Effects of Vineyard Floor Vegetation Management on Grapevine Physiology, Yield and Wine Color Attributes 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 four 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 grass weeds 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-color attributes were monitored. The tall fescue treatments progressively reduced vegetative growth and were associated with more negative stem water potential. Yield declined over the three growing seasons because cluster numbers decreased, with the largest cumulative decline in the tall fescue between-row treatment, followed by the full-cover tall fescue treatment. 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 color attributes but the response depended on cover-type and duration of use. The selective promotion of naturally occurring winter grasses through targeted herbicide application produced intermediate responses in vine water status, vegetative growth, and yield, suggesting that limiting active ground cover to the wettest part of the season may reduce prolonged summer competition with grapevines.