Undergraduate Augusto Sorrigotti uses a sensor to measure grapevine chlorophyll and vegetative index at Casa Verrone in Itobi, São Paulo state. Behind him is Luís Henrique Bassoi, a researcher at EMBRAPA Instrumentation and PI for the project (photo: Guilherme Lima/EMBRAPA Instrumentation)

Published on 08/14/2023

By André Julião in Itobi  |  Agência FAPESP – A layperson viewing rows of grapevines in a vineyard is unlikely to discern differences between them, but even in a small area the soil and vines have variable properties and produce grapes and wine with different characteristics. The variations are evident only when certain instruments are used to detect even the most subtle differences in soil and leaves. 

A project supported by FAPESP and led by scientists at the Brazilian Agricultural Research Corporation (EMBRAPA) is doing just that by mapping vineyards belonging to two wineries in São Paulo state: Casa Verrone in Itobi and Terras Altas in Ribeirão Preto.

Separate harvests are already producing experimental wines from different areas of the same vineyard. Grapes have more or less sugar, acid and phenolic compounds, depending on soil and plant conditions. The alcohol content of the wine made from them can also vary.

The project has paved the way for the creation of differentiated products embodying more added value and desirable characteristics without the need to extend vineyard acreage. Water and fertilizer management will also improve.

Furthermore, the project will drive the production of so-called winter wines, which have built market share in Brazil over the past decades. They are now produced in parts of the country without a long history of winemaking, such as Mato Grosso and Tocantins states in Central Brazil, Bahia state in the Northeast, and all states of the Southeast (São Paulo, Minas Gerais, Rio de Janeiro and Espírito Santo).

The Minas Gerais Agricultural Research Corporation (EPAMIG) has developed what is known as the double pruning technique for winter wines. By pruning in January, at the height of summer in the southern hemisphere, growers “fool” vines to interrupt their normal cycle and mature in winter. Instead of harvesting these grapes at the end of summer, between January and March, when there is more rain and crop diseases multiply, growers harvest in winter, between June and August, with warmish days, cool nights and very little rain. In conjunction with the altitude of the southeastern plateaus, this helps achieve optimal maturation for winter wine production purposes.

“We measure natural vineyard variability in several ways so that enologists and wineries can take advantage of specific characteristics of the wine produced in a particular area. We call this precision viticulture,” said Luís Henrique Bassoi, a researcher at EMBRAPA Instrumentation in São Carlos (São Paulo state) and principal investigator for the project.

In addition to the two wineries in São Paulo state, the project also involves EPAMIG’s Grape & Wine unit in Caldas, which developed the double pruning technique in the early 2000s, and São Paulo State University’s School of Agricultural Sciences (FCA-UNESP) in Botucatu, where Bassoi is a faculty member in the program of graduate studies in agricultural engineering.

“When traditional methods are used, too much rain may force growers to harvest earlier than usual, in summer, before the grapes ripen properly. Double pruning shifts the ripening period to fall and winter, when humidity is low and thermal amplitude is high in the Southeast,” said Renata Vieira da Mota, who heads EPAMIG’s viticulture research program and is on the project’s research team.

Cool nights help balance the acids and phenolic compounds responsible for the color and structure of wine, Mota explained. “This assures optimal quality for winter wines,” he said.

Blends

Márcio Verrona, the proprietor of Casa Verrone and the 35-hectare farm the family has run for 40 years, has had 15 hectares growing grapes for wine and juice since 2008. The project began in 2019 and has been supported by FAPESP since 2021. The prospects are excellent.

“We grow top-quality grapes in part of the area to produce a special wine, which could be labeled ‘precision agriculture’ or something of the kind, and could be blended with the wine from the other part to improve its quality. There are many possibilities,” Verrone said.

Ricardo Baldo, director of Terras Altas in Ribeirão Preto, already blends premium wine with wine from other areas of his vineyard and will soon create exclusive products from his very best grapes using the map of the property. “Precision viticulture also improves management of water and fertilizer,” he said. “We know which areas need more, less or the same amount of these resources, and can use them intelligently.”

Two portions of the same 1.1-hectare plot growing Syrah grapes for Casa Verrone were identified by cross-referencing data for humidity and soil apparent electrical conductivity, as well as measuring leaf transpiration (porometry), chlorophyll and vegetative index using sensors carried by the researchers, a drone or a satellite.

Based on the data, the area was divided into portions with high and low vegetative vigor, a plant growth parameter relating to biomass, besides other biochemical characteristics.

Isabella Magalhães, Casa Verrone’s enologist, invited Agência FAPESP to try the two experimental wines produced from grapes in the areas with high and low vegetative vigor in a process known as microwinemaking, conducted at EPAMIG’s Grape & Wine Technology Center in Caldas.

“Both are ruby red, but the color is more delicate in the wine from the area with high vegetative vigor and more intense in the wine from the area with low vegetative vigor. The former smells to me of fresh fruit and can be barrel-aged. The other one is best consumed young while it has all its vigor,” Magalhães said as she tasted the two products.

Other participants in the project include Larissa Farinassi and Anderson Pereira, PhD candidates at FCA-UNESP; and Victor Nogueira, Gabriel Ferreira, Victor Gambardella and Augusto Sorrigotti, trainees and undergraduates in agricultural engineering at the University Center of Central São Paulo (UNICEP) in São Carlos.

For Bassoi, the project is training people to work in the sector and innovating by extending precision agriculture, already present in coffee, soy and sugarcane, to the wine industry, where it is still incipient in Brazil. “We set out to introduce a new parameter for producers to market wine more effectively. Brazilians are reluctant to buy domestic wines. We have high-quality products,” he said.

 

Source: https://agencia.fapesp.br/42130