Terroir 2004 banner
IVES 9 IVES Conference Series 9 Characterization of vine performance using remote sensing tools

Characterization of vine performance using remote sensing tools

Abstract

Today, a variety of remote sensing tools are used to characterise plant performance. However, the vine is rarely studied, as a major crop specificity is canopy discontinuity. Registered images of the vineyard are anisotropic, therefore difficult to analyse.
All current plant performance evaluation technologies pick up and record the energy of emitted or reflected electromagnetic radiation, and analyse information for later interpretation. Most importantly, they allow the expression of information in terms of spacial location. Application of these technologies in the vineyard differ considerably according to the tools used.
The different radiations recorded provide a wide range of information. The spectral behaviour of plant reflectance in the visible field (380 to 700 nm) is linked only to pigment composition. In this field, plants produce a low reflectance (around 15%) with a peak of 550 nm, mainly due to chlorophyll a and b pigments.
These pigments do not interfere with spectral response in the near-infrared field (750 to 1300 nm). The internal structure of leaf cells induces variations of the reflectance value. Estimating the health of the vine plant can be carried out utilising the near-infrared reflectance value. It is therefore possible to define different leaf indicators such as the Normalized Difference Vegetation Index (NDVI). Thermal infrared radiation values indicate the energetic and hydrous status of the plant. Measures of thermal infrared radiation can be taken on the ground, close to the plant, by means of a thermal infrared gun or by airborne shooting. From these, it is then possible to construct a water stress index. These data can then be exploited to analyse vineyard intraparcel heterogeneity. Data require the use of high resolution remote sensing tools (pixel representing a ground distance inferior to 20 cm).
Hyper-spectral bands, already used in cereal fields could reveal a spectral signature of diseases such as esca or eutypa before leaf symptoms are visible.
Whatever the captor, information quality depends on picture resolution. Today, the main difficulty in working on the vine comes from the anisotropic aspect of photographs. Above all, the researcher must be able to automatically distinguish vine rows. This is possible for vines growing on flat ground without grass but difficult for sloping vineyards with inter-row grass. The main risk lies in uniformly interpreting pixel values from different sources such as ground, grass or vine.
Different vehicles such as aeroplanes, satellites, helicopters and, of course, the vine grower’s tractor can be used, although not all captors can adapt to these different vehicles. In term of development, each captor/vehicle combination must be considered. Later, analysed and geo-referenced pictures will have to be integrated in the tractor onboard computer equipped with GPS. This is the way forward to allow tomorrow’s vine growers to apply real precision viticulture.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

J.P. Roby, E. Marguerit, O. Schemel, C. Germain, G. Grenier, C. Van Leeuwen

ENITA de Bordeaux, 1 cours du Général de Gaulle BP 201, 33175 Gradignan Cedex

Contact the author

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

VineyardFACE: Investigation of a moderate (+20%) increase of ambient CO2 level on berry ripening dynamics and fruit composition

Climate change and rising atmospheric carbon dioxide concentration is a concern for agriculture, including viticulture. Studies on elevated carbon dioxide have already been on grapevines, mainly taking place in greenhouses using potted plants or using field grown vines under higher CO2 enrichment, i.e. >650 ppm. The VineyardFACE, located at Hochschule Geisenheim University, is an open field Free Air CO2 Enrichment (FACE) experimental set-up designed to study the effects of elevated carbon dioxide using field grown vines (Vitis vinifera L. cvs. Riesling and Cabernet Sauvignon). As the carbon dioxide fumigation started in 2014, the long term effects of elevated carbon dioxide treatment can be investigated on berry ripening parameters and fruit metabolic composition.
The present study aims to investigate the effect on fruit composition under a moderate increase (+20%; eCO2) of carbon dioxide concentration, as predicted for 2050 on both Riesling and Cabernet Sauvignon. Berry composition was determined for primary (sugars, organic acids, amino acids) and secondary metabolites (anthocyanins). Special focus was given on monitoring of berry diameter and ripening rates throughout three growing seasons. Compared to previous results of the early adaptative phase of the vines [1], our results show little effect of eCO2 treatment on primary metabolites composition in berries. However, total anthocyanins concentration in berry skin was lower for eCO2 treatment in 2020, although the ratio between anthocyanins derivatives did not differ.
[1] Wohlfahrt Y., Tittmann S., Schmidt D., Rauhut D., Honermeier B., Stoll M. (2020) The effect of elevated CO2 on berry development and bunch structure of Vitis vinifera L. cvs. Riesling and Cabernet Sauvignon. Applied Science Basel 10: 2486

A better understanding of the climate effect on anthocyanin accumulation in grapes using a machine learning approach

The current climate changes are directly threatening the balance of the vineyard at harvest time. The maturation period of the grapes is shifted to the middle of the summer, at a time when radiation and air temperature are at their maximum. In this context, the implementation of corrective practices becomes problematic. Unfortunately, our knowledge of the climate effect on the quality of different grape varieties remains very incomplete to guide these choices. During the Innovine project, original experiments were carried out on Syrah to study the combined effects of normal or high air temperature and varying degrees of exposure of the berries to the sun. Berries subjected to these different conditions were sampled and analyzed throughout the maturation period. Several quality characteristics were determined, including anthocyanin content. The objective of the experiments was to investigate which climatic determinants were most important for anthocyanin accumulation in the berries. Temperature and irradiance data, observed over time with a very thin discretization step, are called functional data in statistics. We developed the procedure SpiceFP (Sparse and Structured Procedure to Identify Combined Effects of Functional Predictors) to explain the variations of a scalar response variable (a grape berry quality variable for example) by two or three functional predictors (as temperature and irradiance) in a context of joint influence of these predictors. Particular attention was paid to the interpretability of the results. Analysis of the data using SpiceFP identified a negative impact of morning combinations of low irradiance (lower than about 100 μmol m−2 s−1 or 45 μmol m−2 s−1 depending on the advanced-delayed state of the berries) and high temperature (higher than 25oC). A slight difference associated with overnight temperature occurred between these effects identified in the morning.

How does aromatic composition of red wines, resulting from varieties adapted to climate change, modulate fruity aroma?

One of the major issues for the wine sector is the impact of climate change linked to the increasing temperatures which affects physicochemical parameters of the grape varieties planted in Bordeaux vineyard and consequently, the quality of wine. In some varietals, the attenuation of their fresh fruity character is accompanied by the accentuation of dried-fruit notes [1]. As a new adaptive strategy on climate change, some winegrowers have initiated changes in the Bordeaux blend of vine varieties [2]. This study intends to explore the fruitiness in wines produced from grape varieties adapted to the future climate of Bordeaux. 10 commercial single–varietal wines from 2018 vintage made from the main grape varieties in the Bordeaux region (Cabernet franc, Cabernet-Sauvignon and Merlot) as well as from indigenous grape varieties from the Mediterranean basin, such as Cyprus (Yiannoudin), France (Syrah), Greece (Agiorgitiko and Xinomavro), Portugal (Touriga Nacional) and Spain (Garnacha and Tempranillo), were selected among 19 samples using sensory descriptive analyses. Both sensory and instrumental analyses were coupled, to investigate their fruity aroma expression. For sensory analysis, samples were prepared from wine, using a semi preparative HPLC method which preserves wine aroma and isolates fruity characteristics in 25 specific fractions [3,4]. Fractions of interest with intense fruity aromas were sensorially selected for each wine by a trained panel and mixed with ethanol and microfiltered water to obtain fruity aromatic reconstitutions (FAR) [5]. A free sorting task was applied to categorize FAR according to their similarities or dissimilarities, and different clusters were highlighted. Instrumental analysis of the different FAR and wines demonstrated variations in their molecular composition. Results obtained from sensory and gas chromatography analysis enrich the knowledge of the fruity expression of red wines from “new” grape varieties opening up new perspectives in wine technology, including blending, thus providing new tools for producers.

Bioclimatic shifts and land use options for Viticulture in Portugal

Land use, plays a relevant role in the climatic system. It endows means for agriculture practices thus contributing to the food supply. Since climate and land are closely intertwined through multiple interface processes, climate change may lead to significant impacts in land use. In this study, 1-km observational gridded datasets are used to assess changes in the Köppen–Geiger and Worldwide Bioclimatic (WBCS)

Short-term relationships between climate and grapevine trunk diseases in southern French vineyards

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...