GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 Monitoring vineyard canopy structure by aerial and ground-based RGB and multispectral imagery analysis

Monitoring vineyard canopy structure by aerial and ground-based RGB and multispectral imagery analysis

Abstract

Context and purpose of the study – Unmanned Aerial Vehicles (UAVs) are increasingly used to monitor canopy structure and vineyard performance. Compared with traditional remote sensing platforms (e.g. aircraft and satellite), UAVs offer a higher operational flexibility and can acquire ultra-high resolution images in formats such as true color red, green and blue (RGB) and multispectral. Using photogrammetry, 3D vineyard models and normalized difference vegetation index (NDVI) maps can be created from UAV images and used to study the structure and health of grapevine canopies. However, there is a lack of comparison between UAV-based images and ground-based measurements, such as leaf area index (LAI) and canopy porosity. Moreover, most vineyard 3D model studies provide limited details on how they can be used to guide vineyard management. This study evaluated the accuracy of UAV-based canopy measurements, including canopy volume and NDVI and compared them with ground-based canopy measures, such as LAI and canopy porosity.

Material and methods – Throughout the 2017-18 growing season, UAV flights were performed to collect RGB and multispectral images in the research vineyard at the Waite Campus, University of Adelaide, South Australia. Using these images, canopy volume and NDVI were calculated. Ground-based measurements for LAI and canopy porosity were also carried out for comparison.

Results – LAI measured from budburst to harvest showed a peak at around veraison, before starting to decline. Similar trends were also observed in canopy volume and NDVI. Using linear regression, canopy volume of Shiraz and Semillon blocks showed a strong positive correlation with LAI (R2 = 0.75 and 0.68, respectively). NDVI was also positively correlated with LAI (R2 = 0.75 and 0.45 for Shiraz and Semillon, respectively). Canopy volume extracted from UAV-based RGB imagery could be used to monitor canopy development during the growing season. However, canopy volume has limited capacity to inform on important canopy architecture properties such as leaf density, total leaf area and porosity, known to affect yield and fruit quality. The accuracy of NDVI was also found to be strongly affected by the presence of vegetation on the vineyard floor at early development stages.

DOI:

Publication date: September 28, 2023

Issue: GiESCO 2019

Type: Poster

Authors

Jingyun OUYANG1, Roberta DE BEI1, Bertram OSTENDORF2, Cassandra COLLINS1*

1 The University of Adelaide, School of Agriculture, Food and Wine, Waite Research Institute, PMB 1 Glen Osmond, 5064, South Australia. Australia
2 The University of Adelaide, School of Biological Sciences, Adelaide, 5000, South Australia. Australia

Contact the author

Keywords

remote sensing, unmanned aerial vehicle, leaf area index, canopy architecture, canopy volume, NDVI

Tags

GiESCO | GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Effect of polysaccharide extracts from grape pomace on the oxidative evolution of hydroxycinnamic acids

Phenolic acids are especially sensitive to oxidation, so they can greatly impact wine sensory characteristics and stability [1]. Furthermore, extracts derived from grape pomace have been previously postulated as possible oenological adjuvants for wine protection [2].

Modeling island and coastal vineyards potential in the context of climate change

Climate change impacts regional and local climates, which in turn affects the world’s wine regions. In the short term, these modifications rises issues about maintaining quality and style of wine, and in a longer term about the suitability of grape varieties and the sustainability of traditional wine regions. Thus, adaptation to climate change represents a major challenge for viticulture. In this context, island and coastal vineyards could become coveted areas due to their specific climatic conditions. In regions subject to warming, the proximity of the sea can moderate extremes temperatures, which could be an advantage for wine. However, coastal and island areas are particular prized spaces and subject to multiple pressures that make the establishment or extension of viticulture complex.
In this perspective, it seems relevant to assess the potentialities of coastal and island areas for viticulture. This contribution will present a spatial optimization model that tends to characterize most suitable agroclimatic patterns in historical or emerging vineyards according to different scenarios. Thanks to an in-depth bibliography a global inventory of coastal and insular vineyards on a worldwide scale has been realized. Relevant criteria have been identified to describe the specificities of these vineyards. They are used as input data in the optimization process, which will optimize some objectives and spatial aspects. According to a predefined scenario, the objectives are set in three main categories associated with climatic characteristics, vineyards characteristics and management strategies. At the end of this optimization process, a series of maps presents the different spatial configurations that maximize the scenario objectives.

Optimization of in vitro establishment of grapevine varieties for fast micropropagation 

Micropropagation is an important alternative to conventional methods of plant propagation. The objective of this study was to optimize a protocol for in vitro micropropagation of selected grapevine hybrids (H19 and H20) that are included in our breeding program. For the sprouting initiation experiment, nodal cuttings with only one axillary bud from two hybrids were separated, disinfected, and cultivated in 50% Murashige Skoog nutrient medium (½ MS) and Woody Plant Medium (WPM), adding 4.4 µM benzyladenine (BA) in both mediums.

NEW INSIGHTS INTO THE FATE OF MARKERS INVOLVED IN FRESH MUSHROOM OFF-FLAVOURS DURING ALCOHOLIC FERMENTATION

The fresh mushroom off-flavour (FMOff) has been appearing in wines since the 2000s. Some C8 compounds such as 1-octen-3-one, 1-octen-3-ol, 1-hydroxyoctan-3-one, 3-octanol and others are involved in this specific off-flavour [1-3]. At the same time, glycosidic precursors of some FMOff compounds have been identified in musts contaminated by Crustomyces subabruptus [4], highlighting the role of aroma precursors in this specific taint. However, the fate of these volatile molecules and glycosidic fractions during fermentation is not well known.

South Africa’s top 10 Sauvignon blanc wines. How do the chemical and sensory profiles compare?

FNB Top 10 Sauvignon Blanc competition, presented by the Sauvignon Blanc Interest Group of South Africa and sponsored by First National Bank, is the country’s foremost platform for producers of this cultivar to showcase and benchmark their wines. Wines entered in the competition originated from all over the winegrowing regions of the country and the winning wines showed good representation of quality South African Sauvignon blanc wines. The ten selected wines were subjected to various chemical analyses including volatile thiol and methoxypyrazine determination, while the sensory profile of each wine was determined using projective mapping.