Proceedings of Terroir 1996

In recent years, there has been a growing interest in characterizing the ecological environment of vineyard production, and the growing need to delimit and characterize with precision the different homogeneous viticultural units. This has allowed the development of new studies which have as their objective the Vineyard Zoning. The delimitation and characterization of wine-growing areas poses specific problems in Spain, not only linked to the specific characteristics of the territory, but also to the size, distribution and index of viticultural occupation in the designations of origin.

“The vine and the wine are great mysteries. Only the vine makes us intelligible what is the true flavor of the earth”. Colette. The notion of terroir has always been the basis of the notion of AOC from which it is inseparable. It is moreover the definition of the production zone which was at the start of the attempts to set up the designation of origin, at the beginning of the century, after the phylloxera crisis.

L’utilisation de levures sélectionnées est généralement considérée comme le moyen d’éviter les problèmes fermentaires. Néanmoins de nombreux viticulteurs pensent que ces levures sont à l’origine d’une standardisation des vins et militent pour le respect d’une flore indigène (Bourguignon, 1992).

The reflections presented here are a synthesis of a set of research on the construction of a scientific logic concerning the relations between the terroir, the vine, the wine, and on the study of a product, the wine, considered as the resulting from many interactions between factors of various orders. This work has benefited greatly from discussions of an epistemological as well as a technical nature with all the researchers at URVV (Angers) and with our colleagues at the Institut National des Appellations d'Origine, over several years.

Le vigneron européen est de plus en plus à la recherche de la valorisation de son terroir par la personnalisation de la typicité de ses produits. Dans ce contexte, il est apparu depuis longtemps que la part des facteurs technologiques ou humains est d’une importance capitale face aux conditions de l’envirormement naturel. Le terroir se construit plus qu’il ne se subit.

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.

Pinot noir is an interesting vat variety for the high quality products it provides in the most suitable areas. In France, the most important Pinot Noir growing areas are Burgundy, Champagne, Alsace and the Loire. In Italy, Pinot Noir is grown almost exclusively in the northern regions of Trentino-Alto Adige, Lombardy and Friuli-Venezia Giulia.

Vine water status has a significant influence on vineyard yield and berry composition (Williams and Matthews, 1990; Williams et al., 1994). It has been hypothesized that the response of plants to soil water deficits may be due to some sort of “root signal” (Davies and Zhang, 1991). This signal probably arises due to the roots sensing a reduction in soil water content or an increase in the mecanical impedance as the soil dries out.

The qualitative and quantitative distribution of the phenolic compounds in red wines depends on cultivars features, on grapes maturation state, on grapes processing technology including must obtention, as well as on maceration-fermentation method (Margheri, 1981). The last two factors are responsible for the different phenolic composition of the wines produced from the same cultivar.

The Pomerol vineyard, located 35 km east of Bordeaux, covers around 800 ha on the left bank of the Isle. There is a system of fluvial terraces with more or less coarse gravel and pebble spreading, resting on a Tertiary substratum ranging from the Middle to Upper Eocene to the Lower Oligocene (Dubreuilh, 1993). This interweaving of terraces of varying thickness results in a brutal superposition of differentiated materials which give rise to various types of soil. Several site studies in this sector of the Libounais show significant morphological and analytical differences from one point to another (Guilloux et al ., 1978; Duteau, 1982; Van Leeuwen et al.., 1989). The distribution of the soils of the Pomerol vineyard was studied and resulted in a cartography at 1/25000th (Merouge, 1995).

It is not easy at first sight to give an exhaustive definition of the notion of terroir as it can be simplified or complicated at will. Thus the vagueness that surrounds this concept leaves the door open to various interpretations of the terroir. These tend towards a questionable level of objectivity because the fields they explore are not sufficient to explain the notion on their own, constituting only part of a whole.

The notion of terroir covers multiple components, from geology, pedology, geomorphology and climatology (Doledec, 1995), to aspects that are less well identified but which also intervene in the “typicality” of wines. This justifies the “zoning” approach (Moncomble and Panigaï, 1990) to define homogeneous areas, under the same agro-viticultural management and also identified at the product level (Morlat and Asselin, 1992).

The research carried out by the URVV of the INRA center in Angers aims to develop a methodology for the integrated characterization of the natural factors of viticultural terroirs, representative of the operating conditions of the vine and the sensory differences of the wines. In this context, the concept of Basic Terroir Unit (UTB) has been developed. The UTB represents a viticultural surface of variable geographical extension, defined as the association in a given place of a geological, pedological and landscape component, Morlat (1989), Riou et al. (1995).

The Appellation d'Origine Contrôlée of Bandol covers an area of ​​1365 ha, 83% of which are planted with vines, the annual production being around 40,000 hl. Among the wines produced, there are mainly reds which assert themselves over time, but also rosés characterized by their pale colour, generally orange; the whites represent a small part of the production. The main grape variety of this AOC is Mouvèdre, of Spanish origin, which is also found in Provence and Languedoc.

Ce travail a pour objet l’analyse des résultats agronomiques obtenus sur trois unités expérimentales du Centre d’Etudes Vitivinicoles du Douro (CEVDouro), localisées dans des écosystèmes différenciés de la Région du Douro/Vin de Porto, à différentes altitudes (130, 330 et 520 mètres) et à des expositions diversifiées (SE, N et W).