Vineyards can still thrive in times of water shortages

A new study published in the journal Frontiers in Plant Science has found that vineyards can use half of the irrigation water normally used by grape crops without compromising crop yields or quality (measured in terms of flavor, color, and sugar content).

The research, led by Professor Kaan Kurtural of the UC Davis, sheds light on how the effects of drought on California’s vineyards can be mitigated in a time of severe water shortages caused by climate change. 

“It is a significant finding,” said Professor Kurtural. “We don’t necessarily have to increase the amount of water supplied to grape vines.” 

Professor Kurtural and his colleagues studied the correlation between irrigation levels and cabernet sauvignon grape quality at a research vineyard in Napa Valley during two growing seasons, a rainy season in 2019 and a very arid season in 2020. 

The research team focused on crop evapotranspiration, which is the amount of evaporated water from the vineyard system based on canopy size. They used irrigation to replace 25, 50, and 100 percent of what has been lost by crops through evapotranspiration. 

The scientists discovered that replacing only 50 percent of the water through irrigation was the most beneficial in maintaining the grapes’ yield and flavor. In addition, this level of irrigation did not compromise the amount of symbiotic arbuscular mycorrhizal fungi, which are crucial for helping grapevines overcome stresses such as water deficits. 

Moreover, the lower irrigation level proved to be more environmentally friendly, since the water used to dilute nitrogen application was significantly reduced.

“In the end, drought is not coming for wine,” concluded Professor Kurtural. “There doesn’t need to be a tremendous amount of water for grapes. If you over irrigate in times like these, you’re just going to ruin quality for little gain.”

According to Professor Kurtural, although the research was focused on cabernet sauvignon, the findings can easily be extended to account for most types of red grapes.

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By Andrei Ionescu, Earth.com Staff Writer