A field day was held at the Coonawarra Rootstock Trial site on 5 April 2022 to view soils pits and learn about each rootstock’s ability to access soil water and deliver desired yield and quality outcomes.

Rootstock expert Nick Dry from Foundation Viticulture and soil and viticulture expert David Hansen from Hansen Consulting Group spoke to an engaged group of about 25 growers, winemakers, researchers and service providers who discussed soil and rootstock impacts on vine performance.

The trial compares the performance of own-rooted Cabernet Sauvignon (CW44 clone) vines against that of eight rootstocks of varying vigour: Ramsey, Börner, 140 Ruggeri, 1103 Paulsen, 110 Richter, Merbein 5512, Merbein 5489 and Merbein 6262 planted at Wynns Coonawarra Estate’s Alexander Vineyard.

The field day highlighted the importance of rootstock choice in harmony with scion variety, soil structure, desired yield and quality specifications, and current and future climate.

“This workshop provided an excellent opportunity to see what’s going on below the soil surface with these rootstocks. We’re seeing clear and consistent trends in both vigour and yield for the highest yielding rootstocks of 140 Ruggeri and 1103 Paulsen and the lowest yielding rootstocks of M6262, Börner and Own Roots. Observing the side-by-side root systems helped us understand why we’re seeing these trends,” said Vinehealth Australia Technical Manager Suzanne McLoughlin, who organised the field day.

“The field day demonstrated that as an industry, we largely haven’t placed enough emphasis on managing our soils as a resource. We still have a lot to learn about managing soil structure for desired vine performance. This was a fascinating deep dive into spatial soil variability, rootstock root systems, and implications of our management actions on vine root growth – particularly around ripping and soil compaction.

“We also were able to reflect on what sort of soils are perhaps best suited to the various vigour rootstocks and how our management of these rootstocks might then change as climate warms and dries, and how vine spacing and irrigation for example can be altered to moderate vigour in these different situations.

“I think everyone left planning to dig soil pits in their own vineyards, recognising the importance of understanding their own soils to better manage current vine plantings, but also as a key tool to use to match soil type with rootstock and scion choice in new plantings.”

Field day participants were given two sets of shoe covers to wear before entering the vineyard and were also asked to wear clean clothes, to reduce the risk of introducing unwanted pests on shoes and clothing.

After the visit to the vineyard, they also had the opportunity taste wines made from each of the rootstocks. In 2019 about 50kg of all but the M6262 rootstock was hand harvested in duplicate and then made into small lot wines by the AWRI Commercial Services. Winemakers Pete Bissell and Sue Hodder described the wine tasting results and preference scores.

The Coonawarra Rootstock Trial is a long-term partnership between Vinehealth Australia, Coonawarra Vignerons and Wynns Coonawarra Estate.

The field day was supported by the Limestone Coast Landscape Board’s Grassroots Grants program and funded by regional landscape and water levies. 

For more information about the Coonawarra Rootstock Trial click here.