Using remote sensing to understand Pinot noir vineyard variability in Ontario

Abstract

The study objective was to determine whether multispectral high spatial resolution airborne imagery could be used to segregate zones in Pinot noir vineyards to target highest quality fruit for premium winemaking. We hypothesized that remotely sensed data would be correlated with vine size and leaf water potential (ψ), and by extension with yield and berry composition. In 2008-2009, multispectral (blue, green, red, near-infrared) airborne images were acquired from four Ontario Pinot noir vineyards (four dates, 2008; three, 2009), with the final flight date near veraison. A process was developed to extract information from sentinel vine locations, and to calculate normalized difference vegetation index (NDVI). Data were extracted at 1 × 1, 3 × 3, and 5 × 5 pixel re-sampling rates to test for ideal image resolution. A method was developed to mask non-vine pixels to simplify qualitative assessment of images. The 3 × 3 pixel re-sampling provided most useful information. Masked images proved effective for viewing spatial trends in airborne images without full data extraction. Qualitative similarities existed between maps of vineyard and grape composition variables vs. maps of extracted data and masked images. Remote sensing may be useful to determine colour or phenolic potential of grapes, in addition to vine water status, yield, and vine size. This study was unique by employing remote sensing in cover-cropped vineyards and thereafter using protocols for excluding spectral reflectance contributed by inter-row vegetation.Key words: grapevine water relations, soil moisture, leaf water potential, vine vigour, anthocyanins.Résumé : L'étude devait établir si on peut se servir d'images aériennes multispectrales à haute résolution spatiale pour différencier des zones dans les vignobles de Pinot noir et identifier celles portant les fruits de la plus grande qualité en vue de la fabrication de vins plus fins. L'hypothèse de départ était que les données captées par télédétec-tion pourraient être corrélées à la taille de la vigne et au potentiel hydrique (ψ) des feuilles, donc, par extension, au rendement et à la composition du fruit. En 2008-2009, les auteurs ont acquis des images aériennes multispectrales (bleu, vert, rouge, proche infrarouge) de quatre vignobles de Pinot noir ontariens (quatre dates en 2008 et trois en 2009), le vol final coïncidant presque avec la véraison. Ils ont ensuite mis au point un procédé pour extraire les données de l'emplacement des vignes sentinelles et calculer l'indice de végétation par différence normalisée (IVDN). Les données ont été extraites aux taux de rééchantillonnage de 1 × 1, 3 × 3 et 5 × 5 pixels en vue d'établir la résolu-tion idéale. Une technique a été développée pour masquer les pixels qui ne correspondaient pas aux vignes afin de simplifier l'évaluation qualitative des images. Le taux de rééchantillonnage de 3 × 3 pixels fournit les données les plus utiles. En 2008, l'IVDN établi après rééchantillonnage de 3 × 3 pixels était corrélé (valeur R; p < 0,0001) avec le pH des...

Relationship between hyperspectral indices, agronomic parameters and phenolic composition of Vitis vinifera cv Tempranillo grapes

“…This positive effect of bunch shading on anthocyanins was demonstrated by Bonilla et al ., who found a positive correlation between NDVI and anthocyanins. However, similar to the present study, other studies have reported a negative correlation between this index and color and the anthocyanin composition of grapes . This suggests that vigor influence on anthocyanin accumulation essentially depends on environmental factors and especially on maximal temperatures.…”

“…However, similar to the present study, other studies have reported a negative correlation between this index and color and the anthocyanin composition of grapes. 47 This suggests that vigor influence on anthocyanin accumulation essentially depends on environmental factors and especially on maximal temperatures. Furthermore, Ledderhof et al 47 also found a negative correlation between NDVI and total phenols in grapes, which suggests that not only anthocyanins, but also other phenolic compounds of grapes could be related to this index.…”

“…47 This suggests that vigor influence on anthocyanin accumulation essentially depends on environmental factors and especially on maximal temperatures. Furthermore, Ledderhof et al 47 also found a negative correlation between NDVI and total phenols in grapes, which suggests that not only anthocyanins, but also other phenolic compounds of grapes could be related to this index. This is confirmed in the present study, as discussed below, because this index, amongst others, showed a significant negative correlation with the flavanol composition of grape skin.…”

Mapping Cabernet Franc vineyards by unmanned aerial vehicles (UAVs) for variability in vegetation indices, water status, and virus titer

“…However, use of aircraft-based RS is costly and in agricultural systems it can be imprecise [5]. Data must be converted to vegetation indices (VIs), e.g., normalized difference vegetative index (NDVI) through appropriate computer software [12][13][14][15]. Validation of data acquired by RS is necessary to determine whether ostensibly-unique zones are relevant from a standpoint of physiology, yield, and berry composition.…”

“…E3S Web of Conferences 50, 02010 (2018) https://doi.org/10.1051/e3sconf/20185002010 XII Congreso Internacional Terroir Aircraft-based RS has been proven useful for monitoring vegetative growth, and for making inferences about grape composition from multispectral measurements. In Ontario, NDVI data from RS was associated with numerous variables in Riesling [14,15] and Pinot noir [13] vineyards, including vine water status, yield components, and berry composition. RS was useful to determine Pinot noir anthocyanins and phenols, in addition to water status, yield and vine size [13].…”