terclim by ICS banner
IVES 9 IVES Conference Series 9 High-resolution aerial thermography for water stress estimation in grapevines

High-resolution aerial thermography for water stress estimation in grapevines

Abstract

Aerial thermography has emerged as a promising tool for water stress detection in grapevines, but there are still challenges associated with this technology, particularly concerning the methodology employed to extract reliable canopy temperature values. This consideration is relevant especially in vertically trained vineyards, due to the presence of multiple surfaces which are captured by drone thermal cameras with high-resolution. To test the technology and the data analysis required, a field study was conducted during the 2022-2023 season in a model vineyard with multiple scions-rootstock combinations trained on a vertical shoot-positioning (VSP) system. Additionally, three irrigation regimes were implemented to introduce variability in water stress levels. A commercial Unmanned aerial vehicle (UAV) equipped with an integrated RGB, and thermal camera was used to capture high-resolution aerial images over the vineyard. Eight different pixel extraction methods, considering classical and novel approaches, were tested against manual pixel extraction to determine which method performed the best. From the methods tested, the two Gaussian mixture models (GMM2) showed the best performance in terms of accuracy and precision. The average canopy temperature obtained by this method was contrasted with stem water potential measurements, showing significant differences between well-watered and dryland treatments. Aerial thermography complemented by the GMM2 method shows great potential as a tool for water stress estimation in grapevines, however, several factors play a role in method performance. These include the degree of stress in the vineyard, amount of cover crops, and canopy density amongst others. Suggestions regarding the critical aspects that need to be evaluated further to optimize the methodology and reduce the uncertainties associated to the application of this technology will be discussed in context of the results obtained.

Download the abstract

DOI:

Publication date: June 14, 2024

Issue: Open GPB 2024

Type: Article

Authors

Carlos Poblete-Echeverria1*, Thomas Chalmers1, Melane A. Vivier1

1 South African Grape and Wine Research Institute (SAGWRI), Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa

Contact the author*

Keywords

Precision viticulture, Water management, Digital analysis, Pixel extraction methods, Thermal imagery

Tags

IVES Conference Series | Open GPB | Open GPB 2024

Citation

Related articles…

Viticulture, landscapes and the marketing of our wine

The global wine market is polarising over brands versus origin. Provenance is emerging as a marketing megatrend in many fast moving consumer goods. Origin has always been important in wine but does that mean consumers understand, or care about terroir?

Read More

Assessing the feasibility of direct injection for pesticide residue analysis in grape juice by liquid chromatography/triple quadrupole mass spectrometry

In Brazil, the regulation of pesticide residues is guided by the National Health Surveillance Agency (ANVISA) and the Ministry of Agriculture and Livestock (MAPA), emphasizing the importance of monitoring pesticide levels in agricultural products to protect consumer health.

Read More

A nutraceutical based on mediterranean diet with omega-3 fatty acid and resveratrol from grapewine counteracts ocular degenerative diseases

More recently, studies have shown that polyphenols could also prevent or improve vision in patients with ocular diseases and especially Age-related macular degeneration (AMD) which is an eye disease characterized by damage to the central part of the retina, the macula, and that affects millions of people worldwide. Despite therapeutic advances thanks to the use of anti-vascular

Read More

Perception, liking and emotional response of tropical fruit aromas in Chardonnay wines

Tropical fruit aromas in wines are thought to be important to wine consumers, although there is little research to confirm this statement. With so many wine styles available, it has become important to understand the qualities that are desirable to consumers and how to achieve those qualities. Thiols and esters are compounds that have been found to cause tropical fruit aromas in chardonnay (ref). Fermentation temperature gradients and skin contact were found to increase these compounds using micro scale fermentations. This work aimed to scale up these fermentations/operations to determine if the desired tropical fruit aromas could still be achieved and if there is a perceivable difference in tropical fruit aromas, liking, and emotional response in the wines at the consumer level.

Read More

Effects of bottle closure type on sensory characteristics of Chasselas wines

Several winemaking operations, such as filtration, pumping, and racking, are known to potentially facilitate the incorporation of atmospheric O2 into the wine. Control of grape must oxidation is one key aspect in the management of white wine aroma expression, color stability and shelf-life extension. On the one hand, controlled must oxidation may help to remove highly reactive phenolic compounds, which otherwise could contribute to premature oxidation. And on the other hand, in certain cases of extreme protection of the must from O2 (e.g. pressing under inert atmosphere), it can help to preserve varietal aromas and natural must antioxidants.

Read More