Terroir 1996 banner
IVES 9 IVES Conference Series 9 Zonage et caractérisation des terroirs de l’AOC Côtes-du-Rhône: exemple du bassin de Nyons-Valreas

Zonage et caractérisation des terroirs de l’AOC Côtes-du-Rhône: exemple du bassin de Nyons-Valreas

Abstract

The southern Côtes-du-Rhône vineyard shows a significant variety of ecological facets over the Lower Rhone Valley. Intending to characterize such a variety of “terroir “called vineyard situations, a spatial approach based on identification of soil landscapes has been initiated. It was applied to a limited zone in part of the Valréas sedimentary basin, where local climate is likely homogeneous. Spatial distribution modelling of soil cover combine existing soil and geological data, using land survey, stereoscopic aerial photograph examination, satellite image processing. Map features are digitized within a Geographic Information System (GIS). 21 synthetic map units integrate 15 variables referring to soil, geomorphology, lithology, stratigraphy, vegetation, land form. The vine-growing terroirs, regarded as parts of agricultural lands consistent with both soil landscapes and harvestlwine response, are defined by clustering of the soil landscape units according to multivariate analysis. Terroir mapping is examined and validated in relation to wine response through Grenache harvest composition and its frequency over 1982-1996. Discriminant analysis is performed on the 1982-1996 must compositions of 14 sites related to 4 terroirs units. It shows that discrimination of the terroir units may be realized with the following variables: sugar content converted to expectable alcohol percentage (TAP, %), pH, titrable acidity (AT, g H2SO4/l.), weight of 200 berries (g/l), TAP/AT ratio.

DOI:

Publication date: March 2, 2022

Issue: Terroir 1998

Type: Article

Authors

EMMANUELLE VAUDOUR (1, 2), M.C. GIRARD (1), L.M. BREMOND (2), L. LURTON (3)

(1) UER Dynamique des Milieux et Organisations Spatiales
Institut National Agronomique Paris-Grignon – 78850 Thiverval-Grignon (France)
(2) Syndicat Général des Vignerons Réunis des Côtes-du-Rhône
6, rue des Trois Faucons – 84000 Avignon (France)
(3) Comité Interprofessionnel des Vins d’AOC Côtes-du-Rhône et de la Vallée du Rhône Service technique, 2260, route du Grès, 84100 Orange (France)

Keywords

soil landscapes, vine-growing terroirs, harvest composition frequency, GIS

Tags

IVES Conference Series | Terroir 1998

Citation

Related articles…

Optimisation de la fertilisation du Cot sur le Causse de l’Appellation d’Origine Contrôlée Cahors

The Appellation d’Origine Contrôlée area of ​​Cahors (Lot) covers an area of ​​21,700 ha, spread over 45 municipalities, of which only 4,300 are planted with vines. The main grape variety of this AOC is the Cot noir which represents 70% of the grape varieties, thus giving their typicality to the wines of this region; but despite this importance, to our knowledge, its physiology has remained relatively unstudied.

Microbial life in the grapevine: what can we expect from the leaf microbiome?

The above-ground parts of plants, which constitute the phyllosphere, have long been considered devoid of bacteria and fungi, at least in their internal tissues and microbial presence there was long considered a sign of disease. However, recent studies have shown that plants harbour complex bacterial communities, the so-called “microbiome”[1]. We are only beginning to unravel the origin of these bacterial plant inhabitants, their community structure and their roles, which in analogy to the gut microbiome, are likely to be of essential nature. Among their multifaceted metabolic possibilities, bacteria have been recently demonstrated to emit a wide range of volatile organic compounds (VOCs), which can greatly impact the growth and development of both the plant and its disease-causing agents.

An operational model for capturing grape ripening dynamics to support harvest decisions

Grape ripening is a critical phenophase during which many metabolites driving wine quality are accumulated in berries. Major changes in berry composition include a rapid increase in sugar and a decrease in malic acid content and concentration. Its duration is highly variable depending on grapevine variety, climatic parameters, soil type and management practices.

EFFECT OF DIFFERENT TEMPERATURE AND WATER-LOSS DEHYDRATION CONDITIONS ON THE PATTERN OF FREE AND GLYCOSYLATED VOLATILE METABOLITES OF ITALIAN RED GRAPES

Post-harvest grape berries dehydration/withering are worldwide applied to produce high-quality sweet and dry wines (e.i., Vin Santo, Tokaji, Amarone della Valpolicella). Temperature and water loss impact grape metabolism [1] and are key variables in modulating the production of grape compounds of oenological interest, such as Volatile Organic Compounds (VOCs), secondary metabolites responsible for the aroma of the final wine.
The aim of this research was to assess the impact of post-harvest dehydration on free and glycosylated VOCs of two Italian red wine grapes, namely Nebbiolo and Aleatico, dehydrated in tunnel under controlled condition (varied temperature and weight-loss, at constant humidity and air flow). From these grapes Sforzato di Valtellina Passito DOCG and Elba Aleatico Passito DOCG, respectively.

Using δ13C and hydroscapes as a tool for discriminating cultivar specific drought response

Measurement of carbon isotope discrimination in berry juice sugars at maturity (δ13C) provides an integrated assessment of water use efficiency (WUE) during the period of berry ripening, and when collected over multiple seasons can be used as an indication of drought stress response. Berry juice δ13C measurements were carried out on 48 different varieties planted in a common garden experiment in Bordeaux, France from 2014 through 2021 and were paired with midday and predawn leaf water potential measurements on the same vines in a subset of six varieties. The aim was to discriminate a large panel of varieties based on their stomatal behaviour and potentially identify hydraulic traits characterizing drought tolerance by comparing δ13C and hydroscapes (the visualisation of plant stomatal behaviour as a response to predawn water potential). Cluster analysis found that δ13C values are likely affected by the differing phenology of each variety, resulting in berry ripening of different varieties taking place under different stress conditions within the same year. We accounted for these phenological differences and found that cluster analysis based on specific δ13C metrics created a classification of varieties that corresponds well to our current empirical understanding of their relative drought tolerances. In addition, we analysed the water potential regulation of the subset of six varieties (using the hydroscape approach) and found that it was well correlated with some δ13C metrics. Surprisingly, a variety’s water potential regulation (specifically its minimum critical leaf water potential under water deficit) was strongly correlated to δ13C values under well-watered conditions, suggesting that base WUE may have a stronger impact on drought tolerance than WUE under water deficit. These results give strong insights on the innate WUE of a very large panel of varieties and suggest that studies of drought tolerance should include traits expressed under non-limiting conditions.