Vineyard irrigation is a major issue for vine growers and its timing and quantity must be carefully planned in order to minimize environmental impacts. Climate adversities, particularly drought, impact yield and berry quality.
Irrigation is one of the solutions to ensure an economically profitable yield, regular production (in volume and quality) and a sustainable vineyard.
What are the challenges of precision irrigation management?
Throughout the vegetative growth of the vine, water stress triggers different responses:
- Leaf surface: Severe water stress causes defoliation and limits shoot growth. Competition for water between the roots and the shoots sets in.
- Berry volume and weight: After veraison, water deficit leads to a reduction in berry size and a drop in yield.
- Sugar: Sugar loading is faster and more important in grapevines following an optimal water regime.
- Polyphenols / anthocyanins: The synthesis of anthocyanins is stimulated by water stress before veraison. Polyphenol concentrations are higher with significant water stress.
- Acidity: Musts from vineyards exposed to moderate water stress have a lower pH than those from vines exposed to severe water stress
The winegrower must be aware of these physiological effects in order manage water stress throughout the season, optimize grapevine responses and thus fullfill production objectives that he/she has set for his vineyards.Nonetheless, other factors play a role: for example, 65-70% of the current season’s yield is built up in the previous year N-1, when flower bud initiation takes place.A precise vineyard management is thus a function of a number of parameters that allow the calculation of the optimal water regime.
Triggering the first irrigation: a crucial decision
Selected grape varieties have an increasingly earlier phenology, and earlier growth resumption is also triggered by milder winters. The soil available water storage is not full at the beginning of the season. Triggering the first irrigation in advance allows the soil to be recharged before the vine empties the available water storage for its vegetative growth. In the vineyard, vegetative growth and grape production are the first responses to be affected by water stress. The number of clusters per tree and the number of berries per cluster are determined well before any significant water stress. It is therefore necessary to advance irrigations before observing signs of water stress in the vineyard.
Yoann Schaefer of Domaine Aubian (11) says: “Starting the irrigation earlier gives me a head start and comfort for the rest of the season. Vintel makes it possible to ensure that the water storage is filled before the onset of the first water stresses”
The triggering of irrigations obviously depends on the type of soil and its water storage capacity. Shallow soils require a small and frequent water inputs during the season. On the other hand deeper soils should receive larger inputs less frequently.On dry soils, it is recommended to start irrigations quite early in the season. These early inputs prevent water deficit to hamper mineralization of organic matter and the development of new shoots.
How does Vintel help wine growers to plan the first irrigation ?
For the past five years Vintel has supported wine growers in France and abroad in the water management of their vineyards. This solution makes it possible to monitor the water status of a plot in real time using an agronomic model and daily weather data.
Leaf potential is simulated (black curve) by the model so that it can be monitored throughout the season by users.
To start the first irrigation at the start of the season:
1: Check that phenological stages and past irrigations (in winter) have been entered in the application.
2: Choose a date when Vintel recommends a relevant amount to add at once.
3: Make sure that the planned irrigation does not exceed the maximum recommended intake
4: Enter the irrigation. Observe the curve and the new recommendations. Plan the next irrigation
“Often we notice in the field that first irrigations are triggered too late, when shoots stop growing. Vintel makes it possible to plan the first irrigation at the best time.Moreover, irrigation infrastructures at vineyard estates do not always allow the entire estate to be irrigated at the same time. Vintel allows more flexibility in its irrigation operations because the tool helps to identify the plots that need to be irrigated first“, says Loïc Debiolles, Business Developer, Wine Market at ITK.
Agronomist and scientific editor