Proceedings of International Terroir Congress 1996

Massif and the first sedimentary formations of the western aureole of the Paris Basin. If it is found all over the world (California, Israel, South Africa), it is in this region that it best asserts its identity. It is one of the most interesting grape varieties due to the variety and complexity of the wines it can produce. It can give very dry or very sweet, still or sparkling wines, fresh when young and sublime when ageing, expressing the characteristics of each vintage as much as those of the terroir. The Chenin is a faithful witness of its geographical, geological, pedological and climatic environment; he is the foil of the land. It has strong aptitudes for the production of sweet wines conditioned by overripe grapes often botrytised in the AOC Coteaux du Layon.Massif and the first sedimentary formations of the western aureole of the Paris Basin. If it is found all over the world (California, Israel, South Africa), it is in this region that it best asserts its identity. It is one of the most interesting grape varieties due to the variety and complexity of the wines it can produce. It can give very dry or very sweet, still or sparkling wines, fresh when young and sublime when ageing, expressing the characteristics of each vintage as much as those of the terroir. The Chenin is a faithful witness of its geographical, geological, pedological and climatic environment; he is the foil of the land. It has strong aptitudes for the production of sweet wines conditioned by overripe grapes often botrytised in the AOC Coteaux du Layon.

The climatic component is one of the elements of the zoning of viticultural potential, alongside the geological and pedological components (Morlat, 1989; Lebon et al , 1993). Many climatic indices have thus been defined to estimate the potential for wine production at the scale of a region or a country (Carbonneau et al ., 1992). The main climatic variables used are temperature and radiation. We note in particular the indices of Branas, Huglin and Ribereau-Gayon (Huglin, 1986). However, few studies have been undertaken on the spatial variability of microclimatic conditions at the scale of a vineyard, a valley, or even a municipality.

La topographie du vignoble de Côte Rôtie, la prédominance de la non culture ainsi que la structure très légère des sols amènent les vignerons à s’interroger sur l’entretien du sol, la conduite de la fertilisation de leurs parcelles ainsi que sur le développement racinaire de la vigne.

The studies developed by INRA and UV, in Angers, concern wine-growing areas and their optimized management, both from an agro-viticultural and oenological point of view. Previous work (Morlat, 1989) made it possible to give a scientific dimension to the concept of viticultural terroir and demonstrated the considerable influence of this production factor on the quality and typicity of wines (Asselin et al, 1992 ) . A methodology for the integrated characterization of terroirs, based on the "Basic Terroir Natural Unit" (considered as the smallest spatial unit of territory usable in practice, and in which the response of the vine is homogeneous), has been development (Riou et al , 1995).

La Région Piemonte a commencé en 1994 un projet de caractérisation des productions vitivinicoles des terroirs du Barolo (Piemonte, Italie) par une équipe pluridisciplinaire avec la participation de 6 Instituts de recherche qui travaillent dans la Région et la collaboration de 2 Associations des producteurs viticoles et des organismes de valorisation du vin Barolo.

The "Terroirs d'Anjou" project led by the Agronomy sector of the Vine and Wine Research Unit of the INRA center in Angers aims to characterize the viticultural terroirs in a study area which includes 29 municipalities in the Maine et Loire and cuts across the Anjou, Coteaux du layon and Coteaux de l'Aubance appellation areas.

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).

Cette recherche a eu pour but l’étude des effets d’un renforcement radiatif et thermique sur les zones inférieures de la canopée de la vigne (solarisation par des films ou des paillages réfléchissants installés sur le sol, sous les ceps), notamment l’étude de leurs conséquences sur la composition biochimique des moûts à la vendange et sur la qualité des vins.

La diffusion récente et “explosive” du Chardonnay dans pratiquement toutes les zones de culture viticole du monde a fait penser, à tort, que cette variété s’adapte facilement à toutes les conditions pédo-climatiques ou presque. Cette thèse a été confirmée par la grande faculté d’adaptation dont a fait preuve le vignoble et par la popularité dont jouit le vin auprès des consommateur du monde entier.

A study of the influence of environmental factors on the ripening of grapes under the conditions of Alsace is carried out. Emphasis is placed on the analysis of the mesoclimate and pedoclimate. The experiment is conducted on a network of plots of gewurztraminer grafted on SO4. The production conditions are standardized throughout the device.

The need to classify the vineyards of an area according to the quality of its wines is not recent, but it is only in the last ten years that studies on the suitability of different areas for the cultivation of vineyard take on an integrated and interdisciplinary character (Boselli, 1991). The definition of the suitability of the environment is thus obtained by making the climatic, pedological, topographical and cultural information interact with the vegetative, productive and qualitative expression of the grape varieties.

Ecological resources represent vegetation factors, or even production factors, in quantitative expression. These, used by plants, transformed and organized according to their genetic program, become the material components of biomass. Subsequently, the ecological resources can be used as synthetic indicators of the ecological supply, necessary for the analysis of favorability for the understanding of ecosystems.

For a long time environment was known as one of the most important factors to characterize the quality of wines but at the same time it appears very difficult to distinguish inside the “terroir” the role of the single factor. These remarks partially explain why methods for viticultural evaluation are often quite different (Amerine et al., 1944; Antoniazzi et al., 1986; Asselin et al., 1987; Astruc et al., 1980; Bonfils, 1977; Boselli, 1991; Colugnati, 1990; Costantinescu, 1967; Costantini et al., 1987; Dutt et al., 1981; Falcetti et al., 1992; Fregoni et al., 1992; Hidalgo, 1980; Intrieri et al., 1988; Laville, 1990; Morlat et al., 1991; Scienza et al., 1990; Shubert et al., 1987; Turri et al., 1991).

With the Federation of Wine Syndicates of Anjou and the Wine Syndicate of Angevin for direct sale to the Property, the Higher School of Agriculture of Angers was led to carry out, in 1995, a survey of winegrowers in Maine and Loire, with a view to grouping the supply of some of the wines intended for direct sale (Huet, 1995).

The quality of grapevines measured by yield and must density in the northern part of Europe -conditions can be characterized as a type of “cool climate” – vary strongly from year to year and from one production site to another, i.e. différences in must densities can range from 30 to 50 °Oe. An explanation may be changes of weather conditions during critical developmental stages of the grapevines (2, 3, 5). These can be categorized as “macro climatic” influences.