IVES Conference Series

Temperature has a decisive influence on the growth and development of plants (Carbonneau et al., 1992). In particular, in the case of the vine, the temperature is an omnipresent variable in the climatic indices (Huglin, 1986). For reasons of convenience, these indices use the temperature of the air measured under shelter in a meteorological station, making the implicit hypothesis of a concordance between this temperature and that of the sites of perception of the thermal stimulus by the plant. However, development may be more dependent on soil temperature than air temperature (Kliewer, 1975). Morlat (1989) thus verified that the variability in the precocity of the vine, positively correlated with the quality of the harvest and of the wine in the Loire Valley, was mainly explained by differences in temperature of the root zones.

Natural factors such as the environment in which the vine is grown play an important role in the quality of the wine. If you want to produce a good wine, it is indeed essential to produce quality grapes. To do this, we must enhance and optimize the terroir effect which, for the moment, plays a role that is not very well known. It is therefore essential, for example, to have scientifically established and well quantifiable relationships in order to have the system of areas of controlled origin accepted. R. Morlat (1989) and G. Seguin (1970) have already carried out studies on the role of certain soil factors on grape quality. In particular, they showed the importance of soil temperature and water content.

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 Champagne vineyard extends over 35,300 ha under the Appellation d’Origine Contrôlée, of which 30,000 are in production. It mainly covers 3 departments: in order of importance, Marne (68% of the appellation area), Aube (22%) and Aisne (10%), and more anecdotally Haute Marne and Seine and Mame. It is a young vineyard (for more than half of the surface, the winegrowers have the experience of only one generation of vines), and fragmented (more than half of the exploitations extend over less than 1 ha; the average size of a cadastral parcel is 12 ares).

The influence of climatic conditions on the development of the vine and on the quality of the wines no longer needs to be demonstrated at the scale of the vineyard, by the regional climatic characteristics, determining on this scale the viticultural potentialities (Huglin, 1978; Branas, 1946; Riou et al ., 1994); but also on a local scale, at the level of the basic terroir unit (Morlat, 1989), by the landscape differentiation of the natural environment inducing climatic variability within the same vineyard, and partly explaining differences in functioning of the vine, in connection with the processes of maturation and the quality of the wine (Becker, 1977 and 1984; Morlat, 1989 and Lebon, 1993a). According to these authors, the climatic diversity in a wine region constitutes in addition to the edaphic component, an important component of characterization of the Basic Terroir Units (UTB).

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).

Le cru de Bonnezeaux est une des appellations prestigieuses des vins liquoreux et moelleux des Coteaux du Layon et sa réputation est ancienne. L’INAO a effectué sa délimitation en 1953. Le vignoble est situé au nord de la ville de Thouarcé et au sud du village de Bonnezeaux, le long du versant rive droite du Layon, exposé au sud-ouest. La superficie du vignoble est de 156 ha.

The grapes producing and wine making regions are différent in their use of agricultural, industrial or agroindustrial means. These means are quite often very original and/or specialised; and lately are also quite competitive. Such means are being defined with increased accuracy in the delimitation and definition of its characteristics (Paneque et al., 1996 a). Human action together with other Elements and Agents involved in the vine growing production (Reyner, 1989) over these means lead to agronomic systems with important characteristics. Finally, the transformation of the vine growing production, through different technologies (Fleet, 1992), results in the creation of products with a different acceptance and economical value in the market.

In the global economic context, an Appellation d’Origine Contrôlée must now more than ever control the typicity and originality of the wines it produces. It is in this spirit that the Côtes du Rhône have decided to acquire the means necessary for this control.

For several years, the development of computer resources, and in particular of Geographic Information Systems, have allowed the emergence of a new approach to the analysis and characterization of wine-growing areas (Morlat, 1989; Laville, 1990). These methods, which make it possible to identify homogeneous areas or units of terroir, are based on crossing, statistical analysis (in particular Principal Component Analysis: PCA) and the integration of parameters describing the natural environment in which develop the vine.

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.

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.

a) wine, a qualitative and user-friendly product, favors a visual support, even for a scientific study because it refers to the image of the terroir, in particular by its visible landscape. b) the vineyard landscape, which is fairly open by definition, favors this type of approach. c) the framework of the Terroir Test conducted by the URVV (INRA – Angers) comprises 15 micro-plots of 100 strains, and requires at this scale precise surveys of the environment, hence systematic shots, of the center of the plot, over 360°, at 50 mm intervals, at 1.70 m from the ground and horizontally.

In the Champagne vineyards, spring frosts are the cause of significant variations in the volume of the harvest which are very penalizing for the trade. This variability is reflected both in time (years without frost alternating with years with severe frosts) and in space. Certain sectors of the vineyard are in fact statistically more susceptible to frost than others, but each year no municipality can consider itself immune to this climatic accident. The objective of the study is precisely to analyze the spatial distribution of frost and to determine its main mechanisms, linked to the topography of the hillsides, their orientation but also to regional meteorological variables.

In this study macro and micro nutrients of plants (N = NH4 + NO3 , P, K, Ca, Na, Zn, Mn, Fe and Cu) were determined both in soil solution and bleeding sap and compared each other. Bleeding sap was collected from the nine varieties of grapevine Cvs. grafted on 5BB rootstock and grown in different soil conditions. For all varieties, plant nutrients content in bleeding sap as higher than in soil solution except for Ca and Na. While in soil solution Ca content was found at 10209 ppm, this value in bleeding sap was 49.20 ppm (Kozak Beyazy), 55.38 ppm (Trakya Ylkeren), 50.37 (Cardinal) and 74.27 ppm (Tekirdaô Çekirdeksizi) respectively. For the same varieties the Na values were as follows : 7.16 ppm (in soil solution) : 4.8, 3.23, 4.21,4.58 ppm (in bleeding sap) respectively. K content in bleeding sap was higher than in soil solution for a few varieties, and lower in some varieties. Traces of Fe and Cu were found in both media.

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.

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).

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.