Photo: Ewen Bell / Wine Australia

Canopy management is a question of time and place

RD&E News
Photo: Ewen Bell / Wine Australia
11 May 2018
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The VitiCanopy app is in the unique position of being both a product of and a contributor to some important new research.

A team from the University of Adelaide and University of Melbourne, led by Drs Roberta De Bei and Cassandra Collins, developed and released the app in 2015 in the early stages of a four-year project funded by Wine Australia.

The free app provides a fast, reliable, portable and non-destructive way for grapegrowers to measure canopy architecture at any time in the season. It also allowed the researchers to capture the canopy architecture of the different management techniques that they wanted to analyse and compare as part of the project.

Interestingly, when VitiCanopy was unable to show a significant change in canopy architecture after the application of a practice, the practice inevitably did not affect vine performance or fruit and wine quality, suggesting that the practice was not applied at a high enough level.

‘For example, with shoot thinning, which is a very common practice in many vineyards, if you don’t remove a significant proportion of the shoots (at least 40–50 per cent) then often you don’t have any significant impact on the canopy and final fruit and wine composition’, Dr Collins said.

viticanopy app

 

One of the main aims of the project was to determine canopy parameters that indicate optimal vine performance and wine quality, and evaluate how effectively these can be manipulated using management techniques.

In collaboration with Treasury Wine Estates, the team evaluated a range of canopy management treatments over three seasons on Shiraz and Semillon vines across five South Australian regions, with a focus on how these change vine vigour and yield. Vine performance was assessed using measures of yield and yield components, canopy architecture, and berry and wine quality.

They found that how we choose to manipulate our canopies also has a significant impact on performance.

The canopy can be manipulated directly by physically removing leaves, bunches or shoots. However, indirect approaches (such as a cover crop or leaving more nodes at pruning) that induce some form of competition can regulate canopy growth and reduce vigour at a fraction of the cost of direct methods.

‘In some of the experimental trials the greatest impact on fruit and wine composition was found when indirect methods were applied, suggesting that we think carefully about how we manipulate our canopies’

- Dr De Bei 

The performance and analysis of different canopy management practices can be found in the final project report here.

A significant overall finding was that canopy architecture measures, such as leaf area index and porosity, correlated better than yield with grape and wine quality. It was also observed that the early season canopy architecture measures are better indicators of quality than the veraison measures.

In addition, a greater growth rate early in the season correlated positively with grape and wine chemistry measures. Conversely, a greater late-season growth rate, from veraison to harvest, was detrimental to quality.

A follow-up project to build on this work has already begun, including further development of VitiCanopy to allow it to be used with a greater range of canopies and to develop a platform to easily visualise the results.

A second app, Vitisense, has been developed to make berry sensory assessments more accessible and able to be carried out in-field. It is now being prepared for release.

The findings from a partner project that also investigated vine balance were presented in our March issue of RD&E News and the project’s final report is also available online.


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