This project will evaluate the efficacy of in-canopy misters in decreasing canopy temperatures via evaporative and convective cooling, by between 5-10°C below ambient.
The project will develop a model to determine the optimum mister configuration (nozzle size, mister spacing) and schedule (duration, water application rate), using the minimum amount of water. In addition, the effects of in-canopy misting during heatwaves on vine physiology and fruit composition will be investigated.
Predictions of future climatic conditions in premium Australian winegrape growing regions point to higher growing season temperatures and increased frequency and duration of heatwaves. High temperatures are detrimental to vine physiological performance, and can negatively affect yield and fruit composition.
Potential advantages of in-canopy misting over under-canopy sprinklers include higher cooling efficacy due to evaporative cooling of water off leaf surfaces, reduced effect of wind or interference of vineyard floor (cover crops), and reduced water and energy use due to use of a fine mist rather than (larger) water droplets.
The proposal builds on earlier research that showed that under-vine sprinklers were able to effectively cool grapevine canopies during heatwaves, with a neutral or positive effect on yield.
In-canopy misting will be trialled, as it uses the least amount of water per degree of cooling and therefore should result in cost savings to both vineyards and wineries.
In-canopy misters and under-canopy sprinklers will be activated and compared before, during and after heatwaves, with continuous measurements of canopy temperatures.
Soil and vine water status will be measured, together with vine physiology, grape and wine composition and grape yield.
This project aims to provide Australian grapegrowers with tools to enhance the physiological performance of their grapevine canopies and maintain or even improve the composition and quality of grapes during heatwaves.