Research that revealed the link between rainfall in winter with canopy growth – and its implications on fruit and wine composition, has been recognised with an ASVO Best Oenology Paper Award 2022.
Conducted by Dr. Marcos Bonada and colleagues from the South Australian Research and Development Institute (SARDI) in collaboration with the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the research (funded by Wine Australia) stresses the importance that soil water availability in spring and winter has on defining wine style, and establishes a framework for the adoption of irrigation strategies that may maintain regional style in a context of a changing climate.
“Climate change will undoubtedly disrupt regional wine styles if we don’t adopt new practices or revise existing practices in the vineyard and in the winery,” said Marcos.
“In this work, we revealed the link between rainfall in winter with canopy growth and its implications on fruit and wine composition, and the implementation of informed irrigation practices that can preserve both vineyard productivity and wine styles.”
Focussing on Barossa Shiraz, irrigation strategies were assessed during three seasons in a vineyard where winter rainfall was excluded using rain shelters to mimic expected conditions under climate change. Irrigation was applied to top up the soil profile either during winter or at budburst and all treatments compared with vines receiving average winter rainfall.
The research found that a reduction in winter rain to approximately one third of the historical average had a major impact, reducing yield by up to 40 per cent. Yield was partially restored by irrigation but there were implications for vine balance and grape and wine composition. When soil moisture was restored at budburst by natural rainfall or by supplementary irrigation, as opposed to progressive wetting of the soil during winter, vines developed denser canopies and the concentration of phenolic substances was reduced in the fruit and wine.
“Refiling the soil profile at budburst following an extremely dry winter, as will be expected in Barossa in the future due to climate change, promoted canopy growth over yield, and impacted negatively on fruit and wine composition,” Marcos said.
Marcos said the award was very meaningful for him.
“Writing a paper is a process that takes years of work – first, designing the experiment and collecting the data and later, finding the opportunity to sit and write the results, sometimes resigning our own free time and putting family commitments aside.”
“This prize justifies those personal and family efforts, but it also confirms that the work we do has a real impact on the industry and contributes to preserving our iconic wines that enhance Australia's reputation worldwide.”
The paper is available from the ASVO here.