Irrigation: Management and influence of water stress on the quality of wines.
There is a general idea that irrigation in vineyards favors vegetative development and increases production. This is true, but depending on the use we give to our irrigation system we can control all this and obtain the result we want according to our production objective.
With irrigation we have a direct consequence, which is that the skin / pulp ratio decreases , and with it the coloring substances, observing a loss of color and a delay in the ripening of the grapes.
Some authors recommend reducing the water intake to the vineyards to produce a slight hydric stress that favors the concentration of sugars and polyphenols.
The water deficit influences the quality of the wine , by reducing the vegetative growth and favoring the lighting of the bunches, increasing the production of polyphenols, and improving the skin / pulp ratio.
Research carried out with the Cabernet Sauvignon variety in California indicates that reductions in water supply close to 70% produce a wine with better color and pH compared to vines that did not suffer water stress.
What we do know for sure is that applying water stress to vines leads to a decrease in production.
The decrease in water intake significantly reduces the vegetative growth, the weight and diameter of the berries , which translates into a decrease in viticulture yield.
We also know that the coloring intensity , concentration of polyphenols and anthocyanins increase significantly in treatments carried out with water stress.
The good winegrower, with good irrigation management, can “control” the quality of the grapes to obtain wines that are better adapted to current quality demands.
Irrigation strategy from veraison
During the grape ripening period, the watering must be carried out, but taking into account a series of criteria.
Each production strategy must have an associated irrigation strategy.
Irrigation from veraison must be carried out with the following criteria:
Maintain the activity of the plant , but without overdeveloping.
Water enough so that there is no vegetative stoppage and the activity of the plant continues but without generating new growth.
Maintain the weight of the berries. You have to water below the physical growth needs of the plant, but without generating excessive stress that causes physiological stops and poor maturation.
Maintain the photosynthetic activity so that the grape can mature under conditions but without new growth.
Ripening delays can be done by using excessive watering so that the plant has a high growth of the shoots and delays maturation.