Terroir 1996 banner
IVES 9 IVES Conference Series 9 Identification of natural terroir units for viticulture: Stellenbosch, South Africa

Identification of natural terroir units for viticulture: Stellenbosch, South Africa

Abstract

[English version below]

Une unité de terroir naturel (UTN) peut être définie comme une unité de terre qui est caractérisée par une relative homogénéité topographique, climatique, géologique et pédologique. De telles unités sont de grande valeur pour mieux comprendre le système terroir/vigne/vin. Le but de cette étude est de caractériser la région viticole du Bottelaryberg. – Simonsberg-Helderberg en utilisant une information digitale existante et d’identifier des UTN en utilisant un Système d’information Géographique.

Cette région d’étude est située au sud-ouest de Stellenbosch et couvre approximativement 25 000 ha. Elle est située près de l’Océan Atlantique, bordée par des montagnes et découpée par une vallée produisant une variation spatiale notable de tous les paramètres climatiques. La géologie est complexe en raison de nombreux mouvements tectoniques et mélange de la roche-mère. Malgré un fort degré de variation du sol qui est difficile à représenter dans les associations pédologiques, un schéma de la distribution des sols a pu être noté en relation avec la position du paysage.

Les unités morphologiques de terrain, l’altitude et l’exposition ont été utilisées comme premières clés pour l’identification des UTN. De larges catégories de sols et attributs géologiques pour les sols résiduels ont été inclus à un niveau secondaire aboutissant à 203 unités. Ces unités doivent aussi être caractérisées en fonction de l’étendue à laquelle la proximité de la mer a une influence sur les caractères climatiques ainsi que du potentiel vitivinicole qui leur est associées.

A natural terroir unit (NTU) can be defined as a unit of land that is characterised by relatively homogenous topography, climate, geological substrate and soil. Such units are invaluable for better understanding of the terroir/vine/wine system. The aim of this study was to characterise the Bottelaryberg-Simonsberg-Helderberg wine growing area using existing digital information and to identify NTU using a Geographic Information System.

The study area was situated to the south west of Stellenbosch and covered an area of approximately 25 000 ha. It is bordered by mountains, situated close to the Atlantic Ocean and bisected by a river valley resulting in notable spatial variation of all climatic parameters. The geology is complex due to the high degree of tectonic movement and mixing of parent material. Despite a high degree of soil variation that is difficult to represent in soil associations, a pattern of soil distribution could be noticed in relation to landscape position.

Terrain morphological units, altitude and aspect were used as primary keys for the identification of NTU. Broad soil categories and geological attributes for residual soils were included at a secondary level resulting in 203 units. These units must be characterised with respect to the extent to which proximity to the sea has an influence on climatic characteristics as well as the associated viticultural and oenological potential.

Download the PDF

DOI:

Publication date: February 15, 2022

Issue: Terroir 2002

Type: Article

Authors

V.A. CAREY (1,2); E. ARCHER (2) and D. SAAYMAN (3)

(1) ARC lnfruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa
(2) Department of Viticulture and Oenology, Stellenbosch University, Private· Bag Xl, 7 602 Mati el and, South Africa
(3) Distell, P.O. Box 184, 7599 Stellenbosch, South Africa

Keywords

Unité de terroir naturel, Système d’information Géographique, topographie, géologie, sol
Natural terroir units, Geographic Information System, topography, geology, soil

Tags

IVES Conference Series | Terroir 2002

Citation

Related articles…

Climate projections over France wine-growing region and its potential impact on phenology

Climate change represents a major challenge for the French wine industry. Climatic conditions in French vineyards have already changed and will continue to evolve. One of the notable effects on grapevine is the advancing growing season. The aim of this study is to characterise the evolution of agroclimatic indicators (Huglin index, number of hot days, mean temperature, cumulative rainfall and number of rainy days during the growing season) at French wine-growing regions scale between 1980 and 2019 using gridded data (8 km resolution, SAFRAN) and for the middle of the 21th century (2046-2065) with 21 GCMs statistically debiased and downscaled at 8 km. A set of three phenological models were used to simulate the budburst (BRIN, Smoothed-Utah), flowering, veraison and theoretical maturity (GFV and GSR) stages for two grape varieties (Chardonnay and Cabernet-Sauvignon) over the whole period studied. All the French wine-growing regions show an increase in both temperatures during the growing season and Huglin index. This increase is accompanied by an advance in the simulated flowering (+3 to +9 days), veraison (+6 to +13 days) and theoretical maturity (+6 to +16 days) stages, which are more noticeable in the north-eastern part of France. The climate projections unanimously show, for all the GCMs considered, a clear increase in the Huglin index (+662 to 771 °C.days compared to the 1980-1999 period) and in the number of hot days (+5.6 to 22.6 days) in all the wine regions studied. Regarding rainfall, the expected evolution remains very uncertain due to the heterogeneity of the climates simulated by the 21 models. Only 4 regions out of 21 have a significant decrease in the number of rainy days during the growing season. The two budburst models show a strong divergence in the evolution of this stage with an average difference of 18 days between the two models on all grapevine regions. The theoretical maturity is the most impacted stage with a potential advance between 40 and 23 days according to wine-growing regions.
Read More

Nucleophilic fraction to estimate the antioxidant activity of inactivated yeast derivates

Oxidation in wine is mostly related to the Michael addition of nucleophiles on two quinones formed from the oxidation of ortho-diphenols. In wine this mechanism is responsible for the increase of the yellow hue and aroma loss. Glutathione exerts its antioxidant activity throughout its competitive addition onto quinones, but many other compounds can have the same behavior: sulfanyl
compounds, amino acids, etc. Addition of yeast derivates during the winemaking process can increase the level of those nucleophilic compounds and then confer to the wine a higher resistance

Read More

The Australian geographical indication process

The first white settlers arrived in Australia in 1788 and brought grape vine cuttings with them. As migration to Australia continued to grow during the XIX Century more and more vine cuttings, viticulturists and winemakers from Britain, France, Germany, ltaly, Switzerland and Yugoslavia founded their businesses.

Read More

Towards a better understanding of the root system diversity and plasticityin young grafted vines using 2D imaging and 3D modelling tools

Three-dimensional functional-structural root architecture models, which decompose the root system architecture (RSA) into elementary developmental processes such as root emission, axial growth, branching patterns and tropism have become useful tools for (i) reconstructing in silico the spatial and temporal dynamics of root systems in a soil volume, (ii) analyzing their genotypic diversity and plasticity to the environment, and (iii) overcoming the bottleneck associated with their visualization and measurement in situ. Here, we present an original work on RSA phenotyping and modelling in grapevine. First, we developed 2D image-based analysis pipelines to quantify morphological and architectural traits in young grafts. Second, we parametrized and validated the 3D root model Archisimple on two rootstock genotypes (RGM, 1103P) grafted with V. vinifera Cabernet-Sauvignon and grown in different controlled conditions (rhizotrons, pots, tubes).

Read More

EFFECT OF WHOLE BUNCH VINIFICATION ON THE ABUNDANCE OF A SWEETENING COMPOUND

In classic red wine-making process, grapes are usually destemmed between harvest and the filling of the vat. However, some winemakers choose to let all or a part of the stems in contact with the juice during vatting, this is called whole bunch vinification. For instance, this practice is traditionally used in some French wine regions, notably in Burgundy, Beaujolais and the Rhone Valley. The choice to keep this part of the grape is likely to affect the sensory properties of wine, as its gustatory perception1,2.

Read More