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According to a study published on the research website oeno-one , vines can survive periods of heat and drought without damage using one-twentieth the amount of water of conventional irrigation. In the study organised by the University Nacional de Cuyo in Mendoza, Argentina, the vines were treated with a pulsating spray on the foliage. This only required 0.53 litres per vine per day, whereas with conventional irrigation methods the requirement is estimated at 10.6 litres per vine per day. The pulsed micro-spray water treatment was applied at the height of the tractor cab exclusively during heat waves. Heatwaves were defined as days with minimum temperatures of 21 degrees Celsius and maximum temperatures of 35 degrees Celsius.
Vines of the Malbec, Bonarda and Syrah varieties were treated. During the growing period, which was characterised by two heat waves, the researchers measured leaf and berry temperature, water potential, stomatal conductance, fluorescence, berry weight, soluble solids content and pH value, among other things. At harvest, the anthocyanin profile, total polyphenol index, fruit production, number of bunches and their average weight were also recorded.
The pulse-irrigated vines showed significantly better values than those of the non-irrigated comparison group. The weight of the grapes was significantly higher and the concentration of anthocyanins was the same in both groups. The polyphenol content and pH values were also unaffected. The potential risk of fungal diseases was not increased.
According to the researchers, the results indicate that the vines treated in this way were exposed to less physiological stress and achieved higher grape production. The short spraying of the leaves could help vines to adapt to extreme temperature fluctuations and extreme temperatures themselves. Winegrowers in warm and dry regions could thus significantly mitigate the effects of hot spells with low water consumption.
(al / Source: oeno-one)