Abstract
Irrigation experiments were conducted on French-American hybrid Baco noir in a vineyard in Virgil, Ontario, Canada, in 2005–2007. Effects on vine physiology, shoot growth, and yield components of three regulated deficit irrigation (RDI) levels [100%, 50%, 25% crop evapotranspiration (ETc)] combined in a factorial experiment with three timings of irrigation initiation [fruit set (FS), lag phase (LP), veraison (VRN)] were studied vs. a non-irrigated control. The control and late deficits were frequently below wilting point in all seasons, and soil water content exhibited substantial variation between treatments up to the 50 cm depth. Transpiration (E) rates were highest in July and August and dropped by late August. Over the growing season, the control had the lowest E rate while the 100% ETc initiated at FS was highest. In 2005 and 2007, shoot growth rate had almost the same trend; 25% ETc was slightly greater than the control. The 100% ETc imposed at FS had the highest growth rate. Leaf water potential (ψ) was higher (less negative) in 100% and 50% ETc compared to the control throughout the growing seasons. Leaf ψ displayed a downward trend at the end of August in all treatments and experimental years. The control had the lowest (most negative) leaf ψ value in 2007. The control and 100% ETc initiated at FS did not show differences in all yield components. Trends in yield were not constant across treatments, although RDI treatments showed an increase in some yield components compared to the control. The RDI technique could be a profitable management tool in Ontario vineyards, with positive effects on vine physiology and yield.
- evapotranspiration
- French-American hybrids
- leaf water potential
- regulated deficit irrigation
- soil water content
- transpiration
- ©2017 by the American Society for Enology and Viticulture
Sign in for ASEV members
ASEV Members, please sign in at ASEV to access the journal online.
Sign in for Institutional and Non-member Subscribers
Log in using your username and password
Pay Per Article - You may access this article (from the computer you are currently using) for 2 day for US$10.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.