Terroir 1996 banner
IVES 9 IVES Conference Series 9 Methodology and zoning of A.O.C. natural soils. Example of “Pic Saint-Loup”

Methodology and zoning of A.O.C. natural soils. Example of “Pic Saint-Loup”

Abstract

[English version below]

Les travaux menés, dans le cadre du programme départemental pour la connaissance et la valorisation des terroirs viticoles, sur l’aire A.O.C. Coteaux du Languedoc / Pic Saint-Loup ont permis d’appliquer à l’échelle d’une Appellation d’Origine Contrôlée (13 communes), une méthodologie d’étude axée sur les aspects sol/climat/topographie qui concourent à l’identification des terroirs naturels, facteurs de typicité des vins. Dans un premier temps, un «diagnostic» de l’ensemble des critères du milieu naturel a été réalisé. Après avoir défini le cadre géologique, une prospection agro-pédologique au 1/10.000ème a permis de cartographier les différentes unités de sol ainsi que leurs positions topographiques. Les conditions climatiques sont également précisées d’un point de vue statistique (stations météo au sein de l’aire et stations limitrophes).

Dans un second temps, il était intéressant d’associer plus étroitement ces caractéristiques agro­environnementales à la culture de la vigne et à l’élaboration d’un vin typique. On approche ainsi au plus près de la notion de «terroir». Dans ce cadre, une singularité bioclimatique du Pic Saint-Loup a été identifiée sur la base de 3 indices viticoles corrélés à des caractéristiques intrinsèques et spécifiques des vins du Pic Saint-Loup. Les différentes unités de terroir naturel ont été cartographiées (typologie du sol, avec une estimation de la disponibilité en eau, associée au bilan radiatif) et décrites sous les différents aspects qui font leurs identités.

The works led, within the local program for the knowledge and the valorization of the wine soils, on the area A.O.C. Coteaux du Languedoc / Pic Saint-Loup allowed to apply on the scale of a registrated appellation origin (13 municipalities), a methodology of study centered on aspects ground/climate/topography which contribute to the identification of natural soils, factors of typical wines. At first, a «diagnosis » of ail the criteria of the natural environment was realized. Having definite the geologic frame, an agro-pedological prospecting to the 1/10.000th allowed mapping the various unities of ground as well as their topographic positions. The climatic conditions are also clarified by a statistical point of view (meteorological stations within the area and bordering stations).

In a second time, it was interesting to associate more strictly these agro-environmental characteristics to the culture of the vineyard and to the elaboration of a typical wine. One approaches so in closer the notion of “soil”. In this frame, a bioclimatic peculiarity of the Pic Saint Loup was identified on the basis of 3 wine indicators correlated in intrinsic and specific characteristics of wines of Pic Saint Loup. The various units of natural soil were mapped (typology of ground, with an estimation of the availability in water, associated to the radiative assessment) and described under the various aspects which make their identities.

DOI:

Publication date: February 15, 2022

Issue: Terroir 2002

Type: Article

Authors

Jean-Paul STORAÏ (1), Jean-Luc TONDUT (2)

(1) Conseil général de l’Hérault – 1000 rue d’Alco – F. 34087 Montpellier cedex 4
(2) Association Climatologique de l’Hérault – 85 avenue d’Assas – F 34000 Montpellier

Keywords

méthodologie, terroir naturel, sol, climat, viticulture
methodology, natural soil, ground, climate, vine growing(2) Association Climatologique de l’Hérault – 85 avenue d’Assas – F 34000 Montpellier

Tags

IVES Conference Series | Terroir 2002

Citation

Related articles…

Climate and the evolving mix of grape varieties in Australia’s wine regions

The purpose of this study is to examine the changing mix of winegrape varieties in Australia so as to address the question: In the light of key climate indicators and predictions of further climate change, how appropriate are the grape varieties currently planted in Australia’s wine regions? To achieve this, regions are classified into zones according to each region’s climate variables, particularly average growing season temperature (GST), leaving aside within-region variations in climates. Five different climatic classifications are reported. Using projections of GSTs for the mid- and late 21st century, the extent to which each region is projected to move from its current zone classification to a warmer one is reported. Also shown is the changing proportion of each of 21 key varieties grown in a GST zone considered to be optimal for premium winegrape production. Together these indicators strengthen earlier suggestions that the mix of varieties may be currently less than ideal in many Australian wine regions, and would become even less so in coming decades if that mix was not altered in the anticipation of climate change. That is, grape varieties in many (especially the warmest) regions will have to keep changing, or wineries will have to seek fruit from higher latitudes or elevations if they wish to retain their current mix of varieties and wine styles.

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.

Impact of climate variability and change on grape yield in Italy

Viticulture is entangled with weather and climate. Therefore, areas currently suitable for grape production can be challenged by climate change. Winegrowers in Italy already experiences the effect of climate change, especially in the form of warmer growing season, more frequent drought periods, and increased frequency of weather extremes.
The aim of this study is to investigate the impact of climate variability and change on grape yield in Italy to provide winegrowers the information needed to make their business more sustainable and resilient to climate change. We computed a specific range of bioclimatic indices, selected by the International Organisation of Vine and Wine (OIV), and correlated them to grape yield data. We have worked in collaboration with some wine consortiums in northern and central Italy, which provided grape yield data for our analysis.
Using climate variables from the E-OBS dataset we investigate how the bioclimatic indices changed in the past, and the impact of this change on grape productivity in the study areas. The climate impact on productivity is also investigated by using high-resolution convection-permitting models (CPMs – 2.2 horizontal resolution), with the purpose of estimating productivity in future emission scenarios. The CPMs are likely the best available option for this kind of impact studies since they allow a better representation of small-scale processes and features, explicitly resolve deep convection, and show an improved representation of extremes. In our study, we also compare CPMs with regional climate models (RCMs – 12 km horizontal resolution) to assess the added value of high-resolution models for impact studies. Further development of our study will lead to assessing the future suitability for vine cultivation and could lead to the construction of a statistical model for future projection of grape yield.

Simulating climate change impact on viticultural systems in historical and emergent vineyards

Global climate change affects regional climates and hold implications for wine growing regions worldwide. Although winegrowers are constantly adapting to internal and external factors, it seems relevant to develop tools, which will allow them to better define actual and future agro-climatic potentials. Within this context, we develop a modelling approach, able to simulate the impact of environmental conditions and constraints on vine behaviour and to highlight potential adaptation strategies according to different climate change scenarios. Our modeling approach, named SEVE (Simulating Environmental impacts on Viticultural Ecosystems), provides a generic modeling framework for simulating grapevine growth and berry ripening under different conditions and constraints (slope, aspect, soil type, climate variability…) as well as production strategies and adaptation rules according to climate change scenarios. Each activity is represented by an autonomous agent able to react and adapt its reaction to the variability of environmental constraints. Using this model, we have recently analyzed the evolution of vineyards’ exposure to climatic risks (frost, pathogen risk, heat wave) and the adaptation strategies potentially implemented by the winegrowers. This approach, implemented for two climate change scenarios, has been initiated in France on traditional (Loire Valley) and emerging (Brittany) vineyards. The objective is to identify the time horizons of adaptations and new opportunities in these two regions. Carried out in collaboration with wine growers, this approach aims to better understand the variability of climate change impacts at local scale in the medium and long term.

The plantation frame as a measure of adaptation to climate change

The mechanization of vineyard work originally led to a reduction in planting densities due to the lack of machinery adapted to the vineyard. The current availability of specific machinery makes it possible to establish higher planting densities. In this work, three planting densities (1.40×0.80 m, 1.80×1 m and 2.20×1.20 m, corresponding to 8928, 5555 and 3787 plants/ha respectively) were studied with four varieties autochthonous of Galicia (northwestern Spain): Albariño and Treixadura (white), Sousón and Mencía (red). The vines were trained in a vertical shoot positioning system using a single Royat cordon, and pruned to spurs with two buds each. Agronomic data (yield, pruning wood weight, Ravaz index) and oenological data in must were collected. The higher planting density (1.40×0.80 m) had no significant effect on grape yield per vine in white varieties, although production per hectare was much higher due to the greater number of plants. In red varieties, this planting density resulted in a significantly lower production per vine, compensated by the greater number of plants. In addition, it significantly reduced the Brix degree in the must of the Albariño, Treixadura and Sousón varieties, and increased the total acidity in the latter two and Mencía. It also caused an increase in extractable and total anthocyanins and IPT in red grapes. The effects of high planting density on grapes are of great interest for the adaptation of varieties in the context of climate change. In the future, it could be advisable to modify the limits imposed by the appellations of origin on the planting density of these varieties in order to obtain more balanced wines.