Terroir 2016 banner
IVES 9 IVES Conference Series 9 Terroir effects from the reflectance spectra of the canopy of vineyards in four viticultural regions

Terroir effects from the reflectance spectra of the canopy of vineyards in four viticultural regions

Abstract

Knowledge of the reflectance spectrum of grape leaves is important to the identification of grape varieties in images of viticultural regions where several cultivars co-exist. As a non-destructive technique, spectroradiometry delivers reflectance spectra with high signal-to-noise ratios.

This work reports results from field measurements of the reflectance spectra of five grape varieties in the spectral range 450nm to 2500nm, performed in south Brazil. Four viticultural regions were visited, with different soils originated from basalt, granite, and sandstone. In vivo measurements of Cabernet Sauvignon, Merlot, Pinot Noir, Chardonnay and Italian Riesling were performed. All spectra were normalized to have unit area and were compared. The very high signal/noise ratio allowed the systematic detection of subtle spectral features of each variety, with intensities of the order of 10-4 to 10-5 with respect to the normalized reflectance range from 0 to 1. These spectral features were attributed to differentiation factors as the presence of pigments in leaves, which has an impact in leaf texture and so in infrared reflectance. Spectral differentiation due to terroir effects was also investigated.

The spectral database was subjected to statistical discriminant analysis to search for separation either of grape varieties and terroirs/regions. Grape varieties and terroirs were separated to accuracies of up to 100%. This methodology can be applied to zoning studies which look for typicity parameters; besides, a detailed knowledge of the spectral signatures of grape varieties can be relevant to the development of identification algorithms used to classify remote sensing images of viticultural regions where several cultivars are present, and to in-field inspections using radiometers.

Download the PDF

DOI:

Publication date: June 23, 2020

Issue: Terroir 2016

Type: Article

Authors

Jorge Ricardo DUCATI (1), Magno G. BOMBASSARO (1), Diniz C. ARRUDA (1), Virindiana C. BORTOLOTTO (2), Rosemary HOFF (3)

(1) Remote Sensing Center, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, CEP 91501-970 Porto Alegre, Brazil
(2) Instituto de Ciências Agrárias e Ambientais, Universidade Federal de Mato Grosso, Av. Alexandre Ferronato 1200, CEP 78557-267 Sinop, Brazil
(3) Centro Nacional de Pesquisas em Uva e Vinho, Empresa Brasileira de Pesquisa Agropecuária, Rua Livramento 515, CEP 95700-000 Bento Goncalves, Brazil

Contact the author

Keywords

Remote Sensing, Spectroradiometry, Soils, Reflectance, Classification

Tags

IVES Conference Series | Terroir 2016

Citation

Related articles…

Le cuivre sur raisins et moûts: dosage et intérêts de la mesure

Avec l’accroissement des surfaces viticoles conduites en Bio, la question de l’impact de la présence de résidus de cuivre (seul anti fongique autorisé dans l’UE dans ce cadre Règlementaire) sur le déroulement des fermentations et sur les qualités œnologiques et organoleptiques des vins s’est révélée de plus en plus cruciale.

Read More

Interactions of wine polyphenols with dead or living Saccharomyces cerevisiae Yeast Cells and Cell Walls: polyphenol location by microscopy

Tannin, anthocyanins and their reaction products play a major role in the quality of red wines. They contribute to their sensory characteristics, particularly colour and astringency. Grape tannins and anthocyanins are extracted during red wine fermentation. However, their concentration and composition change over time, due to their strong chemical reactivity1. It is also well known that yeasts influence the wine phenolic content, either through the release of metabolites involved in the formation of derived pigments1, or through polyphenol adsorption2,3.

Read More

Bioprotective non-Saccharomyces yeast as an alternative to sulfites for the winemaking process

Sulfur dioxide (SO2) is used in winemaking due of its antioxidant, antioxydasic and antiseptic properties. Excessive amount of SO2 can negatively impact wine sensory perception and be detrimental for health. Agri-food industries are more transparent towards consumers concerning addition of sulfites, and oenology is no exception in this clairvoyance. As a consequence, the increase of consumers preference for wine with low or absent of sulfites addition is notorious. In this context, the impact of low/zero sulfites winemaking process on the microbial community should be evaluated. Moreover, microbial agents corresponding to bioprotective cultures represent a growing interest as an alternative to sulfites preservation in the early stages of vinification. However, scientific studies conducted to demonstrate their real effect are almost rare.

Read More

Optimized grape seed protein extraction for wine fining

The extraction of proteins from grape seeds represents a promising strategy to revalorize wine industry by-products. As a natural endogenous fining agent, grape seed protein (GSE) offers an effective solution for wine clarification [1] without requiring label declaration.

Read More

Reduced fungicide sprayings: A biodiversity boost?

Pesticides are considered one of the main causes for arthropod decline in agriculture which in turn may affect ecosystem services such as natural pest control and soil fertility.

Read More