LAICanopy app to help optimise vine balance

The old saying about ‘the value of the whole being greater than the sum of the parts’ comes to mind when talking with Cassandra Collins and Roberta De Bei about their current AGWA research project.

With a team of colleagues from the University of Adelaide, Treasury Wine Estates and DJs Growers they are working to identify which vineyard canopy measures most accurately indicate optimal vine performance – while at the same time developing a smartphone app that will make recording those measurements commercially practical.

Both endeavours are important and valuable in their own right, but if the two come together as planned it could be a game changer in terms of the sector’s ability to measure vine canopies and manipulate them to maximise grape quality.

Dr Collins is Chief Investigator and Dr De Bei a Postdoctoral Research Fellow for the four-year multi-faceted AGWA-funded project, which is being run at the University of Adelaide’s Waite Campus and at six experimental sites in two states.

As the first of several tools being developed, a smartphone app suitable for estimating leaf area index is due for release in the middle of the year.

‘It is the first part of the toolkit we want to develop’, Dr De Bei said. ‘It looks at the structure and vigour of the canopy and allows you to calculate some measures that are used to decide if a vine is in balance or not’.

Dr De Bei and other collaborators Dr Sigfredo Fuentes and Prof Stephen Tyerman were involved with the app’s early development, which received seed funding through two previous funding programs (Wine 2030 and Vineyard of the Future).

The key is algorithms originally developed in the forestry industry that analyse a photograph and provide an estimate of the leaf area index and canopy porosity. However, the code is too difficult and expensive for practical use.

‘The challenge has been getting code that’s been written for complex and expensive software programs and putting it into an iPhone or iPad that is easy to use and with us every day’, Dr De Bei said. The team hopes to be able to create an Android version of the app in the near future.

While this work has been going on, others have been looking at where such a tool can be used to best effect in assessing quality in terms of vine balance through canopy measurements.

The traditional way to measure vine balance is the Y/P ratio – the relationship between yield and pruning weight – but this is rarely done in commercial settings, because it is much too time consuming. An app would overcome that problem but the Y/P measure may, in fact, not be as important as previously assumed.

Dr Collins said many other vineyard trials have thrown up confusing results with vineyards renowned for consistently producing fruit for top-quality, high-value wines being technically out of balance according to the Y/P measure.

At the same time, an AGWA-funded project being carried out by Masters student James Hook in McLaren Vale is showing a strong relationship between harvest fruit grade and the ratio of leaf area index and yield.

‘In this project, James is assessing a number of vineyards that produce fruit of varying quality and there is a lovely correlation – I didn’t expect it to be so strong’, Dr Collins said. ‘There is also a correlation between these measures and fruit colour.

‘The more we look at all of our trials, the traditional Y/P measure for vine balance doesn’t hold up and this other measure may end up being more meaningful. We are about to analyse the second year’s data and if it holds as strongly as that first year, then I think we are going to feel even more that this is the way of the future’.

Another facet of Mr Hook’s research will be to attempt to manipulate a given vineyard’s quality (for example from C grade up to B grade) by taking these measures and changing the canopy. Can it be done and, if so, at what part of the season?

‘A number of the tools we are looking to develop are around trying to measure early enough in the growing season to make a management decision to get to where you are trying to be in terms of quality or yield’, Dr Collins said.

‘The other side of this project is knowing how to use these tools. We hope we can get to the point where we can say “hey these are all the different ways that we have been able to use them and what they mean and how you might be able to use them in your business”, rather than just saying “here’s a tool, you work it out”. I hope we’re on track to do this’.

Upward looking image of a grapevine canopy; LAICanopy home page with function tabs at the bottom; image uploaded to the App and automatically binarised; instant results by pop up containing leaf area index (LAI) and canopy porosity.
Upward looking image of a grapevine canopy; LAICanopy home page with function tabs at the bottom; image uploaded to the App and automatically binarised; instant results by pop up containing leaf area index (LAI) and canopy porosity.