This webinar is supported by the Wine Grape Council of South Australia, through funding from the Australian Government’s Future Drought Fund and the Government of South Australia.
Grapegrowers and winemakers periodically encounter conditions when it is more economic not to produce a crop, or to ‘rest’ their vineyards, than to harvest fruit. These conditions may be due to reduced water allocations for irrigation and/or increases in growing costs or oversupply.
Methods for fruit removal to facilitate vineyard resting were trialled at two sites - Shiraz in the Riverland, SA and Chardonnay in the Riverina, NSW. Treatments included second pruning and the application of calcium nitrate and/or ethephon. Ethephon was found to be the most effective treatment - reducing yield to approximately 2 t/ha (or 7% of the control) for the Shiraz. Three levels of irrigation were applied to better understand the interactions between crop load and potential water savings. When irrigation was reduced, vines with the crop manually removed recorded the highest stomatal conductance and lowest midday stem water potential.
Ethephon is likely to be a cost-effective option to reduce vineyard yield to close to zero, also lowering irrigation requirements. This provides an alternative management option for growers looking to minimise input costs in years when harvesting fruit is not economic. The return yield will be investigated in the 2024 vintage.
16 авг 2023
