Vine age, variety and planting density influencing the effects of water supply on yield and quality of wine grapes—A meta-analysis

Irrigation management influences wine grape yield and quality—key determinants of viticulture success.
Research in this field is critical for identifying and developing effective water management strategies under
diverse growing conditions. Through meta-analysis, this study systematically investigated the impacts of various
water conditions on wine grape yield, water productivity (WP), and fruit quality as affected by vine age, planting
density, and variety. The analysis was carried out based on 1228 datasets from 64 publications, including field
trials in both rainfed and irrigated vineyards. The results indicate that moderate water stress significantly
enhanced WP and fruit quality. In irrigated vineyards, a water input ranging from 400 to 500 mm optimized the
balance between WP and quality. Water stress before fruit setting minimally affected yield, whereas stress during
berry ripening improved grape quality. Vines aged 6–12 years presented superior WP and yield performance,
whereas those aged 1–5 years were more responsive to quality enhancement. The effects of planting density
varied regionally: in irrigated vineyards, a medium density of 3000–4000 plants/ha performed best, whereas in
rainfed vineyards, a low density of 1000–2000 plants/ha ensured a more stable yield and quality. The differences
among grape varieties indicated that red grapes were more sensitive to water deficit in terms of yield and WP,
whereas white grapes were more sensitive in terms of quality. The results indicate the importance in precisely vineyard water management to achieve the balance in water saving and the preservation of the wine quality. Optimized irrigation management to vineyards needs also to take into account the factors of vine age, density and variety.