Research to reveal best irrigation practice in dry winters

Research to reveal best irrigation practice in dry winters

NEW RESEARCH IN the Barossa Valley is seeking to determine whether drip irrigation can provide enough water for vine development in regions that endure winter droughts.
SARDI and CSIRO scientists are driving the research, which aims to inform growers on how best to maintain grape quality and yield in low-rainfall winter seasons.
Principal scientist of SARDI's Water Resources, Viticulture and Irrigated Crops Science Program Dr Michael McCarthy said the research would help secure the future of Australia's wine regions in a changing climate.
'All the climate projections point towards lower winter and spring rainfall, and greater variability in rainfall. This research will help us understand whether drip irrigation can supplement the lack of rainfall, or whether we need to consider other forms of irrigation such as micro-sprinklers,' he said.
The research, which forms part of a GWRDC-funded project, will take place over three years at the Nuriootpa Agricultural Research Centre.
The research started last month with the erection of 16 rainout shelters covered in plastic film at the Barossa-based trial Shiraz vineyard (on own roots). The shelters, which are similar to animal shelters used by the livestock industry, will remain in place during the growing season, until budburst.
During this time, CSIRO Plant Industry scientist Dr Everard Edwards will investigate the effects of drip versus micro-sprinkler irrigation application on root growth and turnover. These assessments will be undertaken throughout the growing season, and will provide industry with a better understanding of how changing water availability at different points of the season can affect the roots.
'The shelters will exclude all winter rainfall from the vineyard floor, allowing for the simulation of a normal amount of winter and spring rainfall applied with drip irrigation to partially wet the root system, or micro-sprinklers to completely wet the rootzone,' McCarthy said.
The shelters do not, in effect, act as a glasshouse as they are not heated and have no ends or sides. The clear plastic film will be removed at budburst to allow the vines to experience normal growing season conditions.
McCarthy said there was enough evidence from growers in coastal regions to suggest drip irrigation doesn't work as a substitute for winter rainfall.
'Growers have tried to make up for lack of winter and spring rainfall by putting their drip irrigation on before budburst, but it takes a considerable amount of water to have any effect,' he said.
McCarthy and Edwards will also investigate how growers can manage salt that builds up in the soil profile when leaching rainfall is lacking.
The project will also look at vine storage reserves and vine physiological changes, rootzone water content and climate indices.
McCarthy said the research would help determine best vineyard practice for economic sustainability.
'If vines go into the growing season with a dry root system, they won't develop the right amount of canopy and the vines won't produce high quality fruit,' he said.
'So, one it will impact on quality and secondly, it will impact on yield. It's all about economic sustainability.'

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