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.

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…

Physiological and growth reaction of Shiraz/101-14 Mgt to row orientation and soil water status

Advanced knowledge on grapevine row orientation is required to improve establishment, management and outcomes of vineyards on terroirs with different environmental conditions (climate, soil, topography) and in view of a future change to more extreme climatic conditions. The purpose of this study was to determine the combined effect of row orientation, plant water status and ripeness level on the physiological and viticultural reaction of Shiraz/101-14 Mgt.

Effects of mechanical leafing and deficit irrigation on Cabernet Sauvignon grown in warm climate of California

San Joaquin Valley accounts for 40% of wine grape acreage and produces 70% of wine grape in California. Fruit quality is one of most important factors which impact the economical sustainability of farming wine grapes in this region. Due to the recent drought and expected labor cost increase, the wine industry is thrilled to understand how to improve fruit quality while maintaining the yield with less water and labor input. The present study aims to study the interactive effects of mechanical leafing and deficit irrigation on yield and berry compositions of Cabernet Sauvignon grown in warm climate of California.

The effects of cane girdling on berry texture properties and the concentration of some aroma compounds in three table grape cultivars

The marketability of the table grapes is highly influenced by the consumer demand; therefore the market value of the table grapes is mainly characterized by its berry size, colour, taste and texture. Girdling could cause accumulation of several components in plants above the ringing of the phloem including clusters and resulting improved maturity. The aim of the experiments was to examine the effect of girdling on berry texture characteristics and aroma concentration.

Application of a fluorescence-based method to evaluate the ripening process and quality of Pinot Blanc grape

The chemical composition of grape berries at harvest is one of the most important factors that should be considered to produce high quality wines. Among the different chemical classes which characterize the grape juice, the polyphenolic compound, such as flavonoids, contribute to the final taste and color of wines. Recently, an innovative non-destructive method, based on chlorophyll fluorescence, was developed to estimate the phenolic maturity of red grape varieties through the evaluation of anthocyanins accumulated in the berry skin. To date, only few data are available about the application of this method on white grape varieties.

Different yield regulation strategies in semi-minimal-pruned hedge (SMPH) and impact on bunch architecture

Yields in the novel viticulture training system Semi-Minimal-Pruned Hedge (SMPH) are generally higher compared to the traditional Vertical Shoot Positioning (VSP). Excessive yields have a negative impact on the vine and wine quality, which can result in substantial losses in yield in subsequent vintages (alternate bearing) or penalties in fruit quality. Therefore yield regulation is essential. The bunch architecture in SMPH differs from VSP. Generally there is a higher amount but smaller bunches with lower single berry weights in SMPH compared to VSP.