Spring is predicted to be warmer and drier than average across most of the country, which means that growers will need to adapt some of their management strategies.
So, what should growers be doing – and when – to prepare?
Consultant viticulturalist Richard Hamilton, from Hamilton Viticulture, has more than three decades’ experience across most of Australia’s wine regions.
Here, he offers his top tips for growers in the coming weeks and months.
Fight the frost
Although spring temperatures are forecast to be warmer, particularly during the day, the risk of frost will increase. Why? Because moist soil has a greater capacity to store heat that is then radiated at night, providing a buffer against low temperatures. Conversely, dry soils don’t provide the same buffer, increasing the risk of frost damage.
Richard says key to fighting frost is remaining vigilant when it comes to managing vineyard floor vegetation.
‘Close attention to undervine weed control and mowing of inter-rows will be vital this season.’
– Richard Hamilton
‘This will minimise soil moisture loss to actively growing plants as well as optimising air movement through the vineyard and reducing the risk of pooling of cold air.’
Monitor soil moisture
Richard says many wine regions will again have limited water availability this season. As a result, growers will need to be strategic with their irrigation plans.
He said soil moisture probes provided a clear indication of soil moisture levels, particularly those that had sensors at 10cm intervals throughout the soil profile.
‘Attention to both deep reserves and upper surface moisture levels will inform the timing of irrigation applications’, Richard said. ‘If deep reserves are limited, then topping up should be undertaken early in the season before the upper soil levels dry out and require additional irrigation to wet them sufficiently to allow moisture to infiltrate into deeper reserves.’
Review your irrigation infrastructure
Under dry conditions, it is important to know how effectively and evenly irrigation applications are being delivered to the vineyard. While regular leak checking is essential to prevent water loss, Richard says more detailed checking is needed to ensure even distribution of water.
‘This includes drip rate monitoring at the highest and lowest sections to ensure even delivery across the vineyard.’
Consideration should also be given as to whether the irrigation infrastructure has the capacity to enable pulse watering of all sections of the vineyard at night to help mitigate heatwave conditions. If this is not possible then capital expenditure to upgrade pumps and valves could be considered.
‘Failing this possibility then preparing a plan for priority blocks for protection would be valuable’, he said.
You can read more here.
Keep alert for eutypa infection
Moisture stressed vines are more susceptible to active development and establishment of eutypa infections. With dry seasonal conditions and limiting soil moisture levels for premium red wine production, Australian vineyards tend to have high levels of infection.
Fortunately, a warm dry start to the season provides the best conditions for detecting eutypa symptoms.
‘Many managers are aware that eutypa is a looming issue in their vineyards but do not know where to begin to address the problem. An excellent start would be to evaluate the level of infection in the vineyard and then follow this up annually to determine the rate of decline in the vineyard. A simple tool for this assessment would be to use the Grape Assess app’, he said.
More information about Grape Assess is available here and the Grapevine Trunk Disease Best Practice Management Guide can be accessed here.
Review canopy management
As the climate becomes warmer and drier, it’s timely to review your canopy management plans.
‘Shoot positioning in cooler districts has moved from maximising light infiltration to consideration of protection of the northern and western sides of the canopy.’
Review inter-row management
There is a fine balance between minimising soil moisture competition by undervine and inter-row vegetation and the need to leave some vegetative cover to minimise heat reflectance into the canopies.
Richard says management programs should consider close mowing for frost risk in early spring, then maintaining a 10–15mm stubble for the remainder of the season.