Vineyard Deficit Irrigation Strategies
(book excerpts)While “fully irrigated” may seem like a desirable goal for vineyards, modern strategies focus on managed irrigation, often involving deficit irrigation to control growth and improve grape quality rather than providing maximum water. Strategic management techniques, such as deficit irrigation, are commonly used in growing wine grapes to reduce water consumption, control vegetative growth, and improve fruit and wine quality. In general, moderate water deficit affects a range of fruit quality attributes, including berry size, seed maturity, acidity, pH, tannins, flavonols, and color. Two irrigation techniques that have been shown to be helpful for this are regulated deficit irrigation (RDI) and partial root-zone drying (PRD). These two methods of irrigation do, however, differ fundamentally in two key respects. With regulated deficit irrigation, water application is manipulated over time, whereas with partial root zone drying, irrigation is manipulated over space. With regulated deficit irrigation, a water deficit is applied in a vineyard over a critical period (i.e., after fruit set and up to véraison or harvest). By contrast, partial root zone drying relies on alternating dry and moist roots, achieved through an irrigation system that produces the desired pattern of soil wetting. Partial root zone drying can be targeted to a specific grapevine growth phase, but is typically maintained throughout the entire growing season.
Click on the following topics for more information on vineyard deficit irrigation strategies.
Topics Within This Chapter:
- Regulated Deficit Irrigation
- Timing of Water Deficits
- Fruit Set to Veraison
- Veraison to Harvest
- Fruit Set to Harvest
- Post Harvest Irrigation Deficits
- Important Considerations Using RDI Strategy
- Cover Crops
- Soil Attributes
- Rainfall
- Rootstocks
- Varietal Responses
- Low Vigor Vineyards
- Mid-day Leaf Water Potential (MDLWP)
- Partial Rootzone Drying
