With temperatures hitting the mid-40s across NSW in January, there was no better time for the Riverina region to expand its focus on helping grapegrowers cope with heat stress.
Late last year, a series of workshops run as part of Wine Australia’s Regional Program explored management options available to mitigate extreme heatwave conditions.
Now a new project run jointly by Wine Australia, the NSW Department of Primary Industries (DPI) and the Riverina Wine Grapes Marketing Board is exploring the potential of new technology to assess vine stress and make informed irrigation decisions.
Sap flow meters and dendrometers have been installed at two vineyards, in partnership with Edaphic Scientific, to monitor vine stress in Shiraz, Cabernet Sauvignon, Merlot and Chardonnay varieties at temperatures of 40 degrees and above.
‘Generally sap flow is highest during the day when plants are actively transpiring and minimal at night when little or no transpiration occurs’, said NSW DPI viticultural development officer, Adrian Englefield.
‘We are measuring sap flow trends and comparing them during the growing season. Any reductions in sap flow during extreme weather events, compared with baseline measurements, can indicate vine stress.'
- Adrian Englefield
‘Dendrometers measure tiny changes in trunk diameter; a healthy vine has a smooth dendrometer cycle where trunks expand during the day and shrink at night when transpiration has ceased.’
During the 18–23 January heatwave, a reduction in sap flow and daily maximum trunk shrinkage indicated vine stress occurred at one site.
Live data from the project and information about vineyard management is available online here.
NSW DPI viticultural development officer Adrian Englefield
Given the importance – and cost – of irrigation in Riverina, NSW DPI is also about to run a series of energy audits in the region.
‘Over the next couple of months, we’ll be looking at energy use in a number of vineyards and wineries of different sizes that are using a variety of power sources with varying energy use patterns’, Adrian said. Sector specialists will use this information to develop case studies and identify ways people can reduce their power bills.
‘We want to look at options and alternatives, such as solar or hybrid systems, and present these in the context of actual energy use.'
‘This is quite a big issue. Some growers are struggling with the rising cost of electricity and are looking for alternatives and where to get relevant information, including rebates or subsidies.’
This May, another regional initiative will deliver a series of workshops using fleabane case studies to explore weed resistance in vineyards.
‘We will show growers that this is a real issue, with significant implications’, Adrian said. ‘Chemical resistance management strategies and other weed control options offer growers the ability to avert herbicide resistance.’