Terroir 2004 banner
IVES 9 IVES Conference Series 9 The use of remote sensing for intra-block vineyard management

The use of remote sensing for intra-block vineyard management

Abstract

[English version below]

L’unité de gestion technique d’un vignoble est aujourd’hui la parcelle. Néanmoins, au sein d’une même parcelle, la variabilité de l’expression végétative et de la constitution des raisins à maturité, peut être grande, en particulier à cause d’une hétérogénéité du sol. Dans une parcelle expérimentale, la surface foliaire a été deux fois plus élevée sur les placettes de forte vigueur par rapport à celles de faible vigueur. Le taux de sucres des baies a varié de 205 à 235 g/ L. Cette variabilité devrait être prise en compte dans une gestion optimale du vignoble. Des images ont été obtenues par la télédétection à haute résolution, dont les pixels représentent 100 à 200 cm2 de surface au sol. Des pixels contenant seulement de l’information du feuillage ont alors pu être isolés de l’image. A partir des données spectrales contenues dans ces photos, un indice de végétation appelé « NDVI » (Normalized Difference Vegetation Index) peut être construit pour caractériser la vigueur de la vigne. Des zones de vigueur variable ont été identifiées au sein d’une parcelle. La similitude entre les cartes du NDVI et des variables d’expression de la vigueur, démontre la faisabilité de cartographier la vigueur à l’aide du NDVI obtenu par télédétection haute résolution, et ainsi permettre d’expliquer les variations de certains paramètres qualitatifs de la vendange qui en découlent.

In vineyard management, the technical work unit is now the block. However, considerable variability can exist inside a block with regard to vegetative growth and fruit composition at ripeness, because of soil heterogeneity. In this research, vine characteristics were measured on 96 plots of a block of 0,3 ha. Leaf area was two times greater on the plots with the highest vigour compared to the leaf area on the plots with the lowest vigour. Berry sugar content varied from 205 to 235 g/L. Optimised vineyard management should take in account this variability. Variations in soil (depth, texture) can be surveyed by soil sampling and mapped. They can also be assessed more rapidly and more precisely by geophysics, a technique based on variations in soil resistance to electric current. Vine behaviour can be measured by means of physiological indicators: N-tester for vine nitrogen status, leaf water potential and carbon isotope discrimination (δ13C) for vine water status. To represent spatial variability of physiological parameters, repeated measurements are necessary on a great number of plots inside a block, making this approach very time and money consuming. Remote sensing can be considered as an interesting alternative way to map intra-block heterogeneity. In satellite pictures, one pixel represents more than one square meter on the soil. Because a vine row rarely exceeds 60 cm in width, these pixels contain both information from the vine canopy and from the soil, making them difficult to interpret. In high resolution remote sensing, pictures are taken at an altitude of approximately 300 meters. Pixels represent 100 to 200 square centimeters on the soil. Pixels containing only information from the canopy can thus be extracted from the picture. On these photographs, vine vigour can be characterised by transforming spectral data from the canopy into a vegetation index, for instance “NDVI” (Normalized Difference Vegetation Index). This approach was used in this study. Zones of variable vine vigour were identified inside a block. The high correlation between NDVI and vigour parameters demonstrates the possibility to map the vigour with the NDVI by means of high resolution remote sensing, and consequently to explain the variations of linked quality factors.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

E. Marguerit (1), J.-P. Goutouly (2), C. Azais (1), S. Merino (1), J.-P. Roby (1), C. Van Leeuwen (1)

(1) ENITA de Bordeaux-UMR Œnologie Ampélologie, 1 Crs du Général de Gaulle, BP 201, 33 175 Gradignan-cedex, France
(2) INRA-UMR Œnologie Ampélologie, ECAV, 71, av. Edouard-Bourlaux, BP 81, 33 883 Villenave d’Ornon Cedex

Contact the author

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

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.

Climate change impacts: a multi-stress issue

With the aim of producing premium wines, it is admitted that moderate environmental stresses may contribute to the accumulation of compounds of interest in grapes. However the ongoing climate change, with the appearance of more limiting conditions of production is a major concern for the wine industry economic. Will it be possible to maintain the vineyards in place, to preserve the current grape varieties and how should we anticipate the adaptation measures to ensure the sustainability of vineyards? In this context, the question of the responses and adaptation of grapevine to abiotic stresses becomes a major scientific issue to tackle. An abiotic stress can be defined as the effect of a specific factor of the physico-chemical environment of the plants (temperature, availability of water and minerals, light, etc.) which reduces growth, and for a crop such as the vine, the yield, the composition of the fruits and the sustainability of the plants. Water stress is in many minds, but a systemic vision is essential for at least two reasons. The first reason is that in natural environments, a single factor is rarely limiting, and plants have to deal with a combination of constraints, as for example heat and drought, both in time and at a given time. The second reason is that plants, including grapevine, have central mechanisms of stress responses, as redox regulatory pathways, that play an important role in adaptation and survival. Here we will review the most recent studies dealing with this issue to provide a better understanding of the grapevine responses to a combination of environmental constraints and of the underlying regulatory pathways, which may be very helpful to design more adapted solutions to cope with climate change.

Heatwaves and grapevine yield in the Douro region, crop model simulations

Heatwaves or extreme heat events can be particularly harmful to agriculture. Grapevines grown in the Douro winemaking region are particularly exposed to this threat, due to the specificities of the already warm and dry climatic conditions. Furthermore, climate change simulations point to an increase in the frequency of occurrence of these extreme heat events, therefore posing a major challenge to winegrowers in the Mediterranean type climates. The current study focuses on the application of the STICS crop model to assess the potential impacts of heatwaves in grapevine yields over the Douro valley winemaking region. For this purpose, STICS was applied to grapevines using high-resolution weather, soil and terrain datasets over the Douro. To assess the impact of heatwaves, the weather dataset (1989-2005) was artificially modified, generating periods with anomalously high temperatures (+5 ºC), at certain onset dates and with specific durations (from 5 to 9 days). The model was run with this modified weather dataset and results were compared to the original unmodified runs. The results show that heatwaves can have a very strong impact on grapevine yields, strongly depending on the onset dates and duration of the heatwaves. The highest negative impacts may result in a decrease in the yield by up to -35% in some regions. Despite some uncertainties inherent to the current modelling assessment, the present study highlights the negative impacts of heatwaves on viticultural yields in the Douro region, which is critical information for stakeholders within the winemaking sector for planning suitable adaptation measures.

How can historical cultivars mitigate the effects of climate change?

IFV, INRAe and the national network “Partenaires de la Sélection Vigne” representing 37 organizations from the different wine regions, have been working increasingly closely over the last 2 decades towards the preservation of the French varietal patrimony. There are approximately 600 patrimonial varieties according to INRAe and SupAgro Montpellier experts, including ancient cultivars (400) and intravarietal crossbreeds obtained since the 19th century. In the context of a drastic reduction in such varieties from the mid 1980’s in favor of mainstream varieties, it was essential to carry out an inventory of old vines and vineyards. INRAe Vassal collection plays a key role here as it holds the largest diversity available, along with a rich bibliography and herbariums, offering us the opportunity to document and double check the identity of a cultivar, consolidating the expertise of ampelographers. The work is carried out in several stages, from verifying the existence of a variety in a small region, through to rehabilitation. During this session, the authors present the process that leads to the official registration of a variety. After this, IFV selection center takes over to initiate the process of selection and propagation. A specific focus within regions such as the Alps, Champagne and the South-West will provide details of the full procedure. Bia, Bouysselet, Chardonnay rose, Mecle and the aptly named Tardif, are some of the cultivars that have followed this procedure. Furthermore, a recent regulation established by INAO on “varieties of interest for adaptation purposes” might boost uptake by growers. Since 2006, 36 historical cultivars have been registered. Most of these have been neglected in the past due to late maturity, lack of sugar and high titratable acidity at harvest time. Such characteristics are today considered as positive qualities, not only in mitigation of the effects of climate change, but also as an opportunity for restoring diversity…

Measurement of redox potential as a new analytical winegrowing tool

Excell laboratory has initiated the development of an analytical method based on electrochemistry to evaluate the ability of wines to undergo or resist to oxidative phenomena. Electrochemistry is a powerful tool to probe reactions involving electron transfers and offers possibility of real-time measurements. In that context, the laboratory has implemented electrochemical analysis to assess oxidation state of different wine matrices but also in order to evaluate oxidative or reduced character of leaf and soil. Initially, our laboratory focused on dosage of compounds involved in responses of plant stresses and we were also interested in microbiological activity of soils. These analyses were compared with the measurement of redox potential (Eh) and pH which are two fundamental variables involved in the modulation of plant metabolism. Indeed, the variation of redox states of the plant reflects its biological activity but also its capacity to absorb nutriments. The Eh-pH conditions mainly determine metabolic processes involved in soil and leaf and our goal is to determine if this combined analytical approach will be sufficiently precise to detect biological evolutions (plant health, parasitic attack…).