App will allow wineries to better manage vines in response to climate change

The programme, with IRTA as the scientific lead, is part of the European VISCA project, which aims to increase growers’ resilience in the face of climate uncertainties.

One of the key factors is a technique used by IRTA called ‘crop forcing’, involving late pruning and regrowth. Originally devised to delay the grape maturity stage, it provides a second chance when disease affects the crop, while also achieving better quality grapes.

Of all the crops that suffer the effects of climate change, vines are among the hardest hit. Temperature increases and the rise in heavy rains and extreme drought affect both production levels and grape quality and, consequently, the quality of wine and cava production. In an attempt to boost the wine-growing sector’s resilience, the European VISCA project (2014-2020), in which the Institute of Agrifood Research and Technology (IRTA) is a participant, has developed an app to help wine producers manage climate uncertainties more efficiently, so as to minimise both costs and risks through better production management.

The project, which is about to be completed after four years of successful app testing, is being co-ordinated by Meteosim, a company specialising in meteorological and environmental services. Other partners include wine and sparkling wine producer and distributor Codorníu and the Barcelona Supercomputing Center – Centro Nacional de Supercomputació (BSC-CNS), as well as further partners from France, Italy, Portugal and the United Kingdom.

“The rise in temperatures means that, physiologically speaking, a grape matures very quickly, leading to a rise in sugar content. In terms of phenology, however, the fruit is still immature and lacks in both taste and aroma, which are the very parameters used for defining a good quality wine,” explains IRTA researcher Joan Girona, who leads the European project.

“At VISCA, we have developed an app that means growers can make better decisions,” says Girona. The programme works on computers and mobile devices, into which the grower regularly inputs information and through which they can then identify the vine’s real needs based on medium-term weather conditions. That way, growers can get ahead and make better decisions, for instance, regarding more efficient irrigation management, grape thinning, selective pruning in the summertime and organising the harvesting system so everything is ready on a specific day.

The programme’s capabilities include establishing how much irrigation and fertiliser is required under certain circumstances and estimating production based on when pruning takes place. It also alerts users to possible events that may cause complications.

“The app can send an alert if a major heatwave is expected within a few days,” explains Girona. “That means farmers can ensure proper irrigation beforehand to avoid heat damage to plants. Similarly, it can also warn of heavy rain in a week’s time. That way, the grower can bring the harvest forward by a week so the water does not ruin the grapes.” 

The programme starts out by using meteorological data from Meteosim for 10-day predictions, while also using seasonal predictions drawn up by BSC-CNS, which takes data from the European Copernicus platform and processes them to correct the models and adapt them to the scale adopted by users. Then, IRTA applies the data to different phenological models, which are optimised via artificial intelligence, to predict the stage at which the vine will find itself over the coming months.

“Using climate prediction models that can forecast how atmospheric behaviour on a larger scale will eventually end up forcing regional conditions, applied to phenological models, means growers can get ahead of the forthcoming conditions—be they heatwaves or drought—and decide on the best option for their crops months ahead of time,” says Raül Marcos, postdoctoral researcher with the Climate Services Group at BSC-CNS.

Forcing crop regrowth

One of the app’s key features is that it incorporates a technique that has been adjusted and refined by IRTA to control and mitigate the influence of pests and disease on vines due to the most extreme weather conditions, which has become an increasingly common occurrence in recent years. So-called ‘crop forcing’ drives the vine to regrow at a later stage than normal, which, as well as preventing crop disease, achieves better quality fruit.

The methodology consists of pruning the vine in June, thus ensuring the plant regrows at a later stage than normal. That way, the crop will not suffer the consequences of harsh weather in the spring, in a combination of rain and heat that promotes the incidence of pests and diseases such as mildew. This year, for instance, the fungus has led to 80% losses in Catalonia’s wine growing sector, especially in the Penedès and Terra Alta regions.

“The key lies in identifying the exact moment at which crop forcing can take place. Too early and the vine stock will not have the buds for regrowth. Too late and you will have leaves but no grapes,” says Girona. He also highlights that, as well as reducing disease, this pruning and late regrowth technique leads to higher quality grapes, with more fruit leading to better quality wine, thanks to their late maturity. So far, the technique has been successfully tested mainly with the Tempranillo and Chardonnay grape varieties.

The app developed as part of the VISCA project is expected to come to market, with IRTA currently in conversations with companies regarding its commercial development.