Post-vintage grapevine management, particularly in dry years, is crucial to a favourable start to the following season. It’s in this light that Wine Australia is encouraging grapegrowers to brush up on post-harvest care as Vintage 2018 wraps up across the country.
Resources on Wine Australia’s website provide growers with information on the role of carbohydrates and nutrient reserves in the grapevine growth cycle and how irrigation and fertiliser can be used most efficiently to assist vine recovery in dryer vintages – such as Vintage 2018.
Dr Liz Waters, General Manager for Research, Development and Extension at Wine Australia, said that depending on where they are based, Australian grapegrowers have between a few weeks to a few months to prepare their vines for the next vintage.
‘Vine nutrition and the role of irrigation are important for growers to consider post-harvest, and in 2018 in particular there has been lower rainfall across Australia to assist vine recovery’, Liz said.
‘If vines are water-stressed during harvest, the canopy may not have the capacity to ripen fruit and restore carbohydrates at the same time. This means the vines are more reliant on post-harvest irrigation and nutrition.
‘One of the main benefits of improving post-harvest care in drier vintages is that leaves are better maintained, encouraging photosynthesis that maximises carbohydrate production, which is then stored in reserves with nutrients for the vine to draw from in the next season.’
Photosynthesis and mineral nutrition are closely linked, and adequate nutritional status is needed to maintain photosynthetic rates, while the carbohydrates produced by photosynthesis are in turn needed as a source of energy for mineral uptake.
Irrigation also assists in the movement of water through the soil profile, which helps fertilisers move into the root zone and makes nutrients more accessible through the moist soil, while assisting active leaf transpiration that is necessary to carry the major mineral nutrients through the grapevine.
Post-harvest irrigation is important because of its impact on the restoration of carbohydrate and mineral nutrient reserves. However, where reduced water allocations or low rainfall limit irrigation options after harvest, it may not always be possible to maintain soil moisture levels. In this case, research suggests that vines can tolerate one to two seasons of conditions where they enter vine dormancy with a dry soil profile.
Source: Wine Australia