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.

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…

Impact on leaf morphology of Vitis vinifera L. cvs Riesling and Cabernet Sauvignon under Free Air Carbon dioxide Enrichment (FACE)

Atmospheric carbon dioxide (CO2) concentration has continuously increased since pre-industrial times from 280 ppm in 1750, and is predicted to exceed 700 ppm by the end of 21st century. For most of C3 plant species elevated CO2 (eCO2) improve photosynthetic apparatus results in an increased plant biomass production. To investigate the effects of eCO2 on morphological leaf characteristics the two Vitis vinifera L. cultivars, Riesling and Cabernet Sauvignon, grown in the Geisenheim VineyardFACE (Free Air Carbon dioxide Enrichment) system were used. The FACE site is located at Geisenheim University (49° 59′ N, 7° 57′ E, 94 m above sea level), Germany and was implemented in 2014 comparing future atmospheric CO2-concentrations (eCO2, predicted for the mid-21st century) with current ambient CO2-conditions (aCO2). Experiments were conducted under rain-fed conditions for two consecutive years (2015 and 2016). Six leaves per repetition of the CO2 treatment were sampled in the field and immediately fixed in a FAA solution (ethanol, H2O, formaldehyde and glacial acetic acid). After 24 h leaf samples were transferred and stored in an ethanol solution. Subsequently, leaf tissue was dehydrated using ethanol series and embedded in paraffin. By using a rotary microtomesections of 5 µm were prepared and fixed on microscopic slides. Subsequent the samples were stained using consecutive staining and washing solutions. Afterwards pictures of the leaf cross-sections were taken using a light microscope and consecutive measurements were conducted with an open source image software. Differences found in leaf cross-sections of the two CO2 treatments were detected for the palisade parenchyma. Leaf thickness, upper and lower epidermis and spongy parenchyma remained less affected under eCO2 conditions. The observed results within grapevine leaf tissues can provide first insights to seasonal adaptation strategies of grapevines under future elevated CO2 concentrations.

De novo Vitis champinii whole genome assembly allows rootstock-specific identification of potential candidate genes for drought and salt tolerance

Vitis champinii cultivars Ramsey and Dog-ridge are main choices for rootstocks to adapt viticulture in semi-arid and arid regions thanks to their distinctive tolerance to drought and salinity. However, genetic studies on non-vinifera rootstocks have heavily relied on the grapevine (Vitis vinifera) reference genome, which difficulted the assessment of the genetic variation between rootstock species and grapevines. In the present study, this limitation is addressed by introducing a novo phased genome assembly and annotation of Vitis champinii. This new Vitis champinii genome was employed as reference for mapping RNA-seq reads from the same species under drought and salt stresses, and for comparison the same reads were also mapped to the Vitis vinifera PN40024.V4 reference genome. A significant increase in alignment rate was gained when mapping Vitis champinii RNA-seq reads to its own genome, compared to the Vitis vinifera PN40024.V4 reference genome, thus revealing the expression levels of genes specific to Vitis champinii. Moreover, differences in coding sequences were observed in ortholog genes between Vitis champinii and Vitis vinifera, which therefore challenges previous differential expression analyses performed between contrasting Vitis genotypes on the same gene from the Vitis vinifera genome. Genes with possible implications in drought and salt tolerance have been identified across the genome of Vitis champinii, and the same genomic data can potentially guide the discovery of candidate genes specific from Vitis champinii for other traits of interest, therefore becoming a valuable resource for rootstock breeding designs, specially towards increased drought and salinity due to climate change.

Climate ethnography and wine environmental futures

Globalisation and climate change have radically transformed world wine production upsetting the established order of wine ecologies. Ecological risks and the future of traditional agricultural systems are widely debated in anthropology, but very little is understood of the particular challenges posed by climate change to viticulture which is seen by many as the canary in the coalmine of global agriculture. Moreover, wine as a globalised embedded commodity provides a particularly telling example for the study of climate change having already attracted early scientific attention. Studies of climate change in viticulture have focused primarily on the production of systematic models of adaptation and vulnerability, while the human and cultural factors, which are key to adaptation and sustainable futures, are largely missing. Climate experts have been unanimous in recognising the urgent need for a better understanding of the complex dynamics that shape how climate change is experienced and responded to by human systems. Yet this call has not yet been addressed. Climate ethnography, coined by the anthropologist Susan Crate (2011), aims to bridge this growing disjuncture between climate science and everyday life through the exploration of the social meaning of climate change. It seeks to investigate the confrontation of its social salience in different locations and under different environmental guises (Goodman 2018: 340). By understanding how wine producers make sense of the world (and the environment) and act in it, it proposes to focus on the co-production of interdisciplinary knowledge by identifying and foreshadowing problems (Goodman 2018: 342; Goodman & Marshall 2018). It seeks to offer an original, transformative and contrasted perspective to climate change scenarios by investigating human agency -individual or collective- in all its social, political and cultural diversity. An anthropological approach founded on detailed ethnographies of wine production is ideally placed to address economic, social and cultural disruptions caused by the emergence of these new environmental challenges. Indeed, the community of experts in environmental change have recently called for research that will encompass the human dimension and for more broad-based, integrated through interdisciplinarity, useful knowledge (Castree & al 2014). My paper seeks to engage with climate ethnography and discuss what it brings to the study of wine environmental futures while exploring the limitations of the anthropological environmental approach.

Copper contamination in vineyard soils of Bordeaux: spatial risk assessment for the replanting of vines and crops

Copper (Cu) is widely and historically used in viticulture as a fungicide against mildew. Cu has a strong affinity for soil organic matter and accumulates in topsoil horizons. Thus, Cu may negatively affect soil organisms and plants, consequently reducing soil fertility and productivity. The Bordeaux vineyards have the largest vineyard surfaces (26%) within French controlled appellation and a great proportion of French wine production (around 5 million hl per year). Considering the local context of vineyard surfaces decreasing (vine uprooting) and possible new crop plantation, the issue of Cu potential toxicity rises. Therefore, the aims of this work are firstly to evaluate the Cu contamination in vineyard soils of Bordeaux, secondly to produce a risk assessment map for new vine or crop plantation. We used soil analyses from several local studies to build a database with 4496 soil horizon samples. The database was enhanced by means of pedotransfer functions in order to estimate the bioaccessible (EDTA-extractable) Cu in soils of samples without measurements. From this database, 1797 georeferenced samples with CuEDTA concentrations in the topsoil (0-50 cm depth) were used for kriging interpolation in order to produce the spatial distribution map of CuEDTA in vineyard soils. Then, the spatial distribution of Cu was crossed with vine uprooting surfaces and municipality boundaries. CuEDTAconcentrations ranged from 0.52 to 459 mg/kg and showed clear anomalies. Our results from spatial analysis showed that almost 50% of vineyard soil surfaces have CuEDTA concentrations higher than 30 mg/kg (moderate risk for new plantation) and 20% with concentrations higher than 50 mg/kg (high risk for new plantation). A decision-support map based on municipalities was realised to provide a simple tool to stakeholders concerned by land use management.

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.